What are the main factors that affect the price of stainless steel tubes? We analyze from the production process, inspection requirements, raw materials and other factors. 1. Production process. Due to the higher production cost of bright annealing, the price of bright annealed tubes will be higher than that of pickling annealed tubes. Because the heat treatment speed of the bright annealing furnace is slow, the number of stainless steel tubes passing through each time is smaller, and additional electricity and ammonia will be consumed. Since there are more production passes for small-diameter steel tubes, the price of small-diameter stainless steel tubes will be higher than that of large-diameter stainless steel pipes. In addition, polishing stainless steel tubing and U bend tube will also incur additional costs. 2. Inspection requirements According to ASME SA213 requirements, Each tube shall be subjected to the nondestructive electric test or the hydrostatic test. The…

2205 Duplex Stainless Steel Machining characteristics The machining of 2205 duplex stainless steel is similar to that of 316L, but there are still some differences. Cold forming operations must take into account the higher strength and higher work hardening properties of duplex stainless steels. Forming equipment may require higher load capacities, and in forming operations, 2205 stainless steel will exhibit higher resilience than standard austenitic stainless steels. The higher strength of 2205 duplex stainless steel makes it more difficult to machine than 316L. The welding of 2205 duplex stainless steel can use the welding method of 316L stainless steel. However, heat input and interpass temperature must be tightly controlled to maintain the desired austenite-ferrite phase ratio and avoid precipitation of detrimental intermetallic phases. A small amount of nitrogen in the welding gas helps avoid these problems. When performing welding procedure qualification for duplex stainless steels, the commonly used method is…

Material Form Type of Discontinuity Water-Washable Penetration Time* Aluminium Castings Porosity, Cold Shuts 5 to 15 min Aluminium Extrusions, Forgings Laps NR** Aluminium Welds Lack of Fusion, Porosity 30 Aluminium All Cracks, Fatigue Cracks 30, not recommended for fatigue crack Magnesium Castings Porosity, Cold Shuts 15 Magnesium Extrusions, Forgings Laps not recommended Magnesium Welds Lack of Fusion, Porosity 30 Magnesium All Cracks, Fatigue Cracks 30, not recommended for fatigue crack Steel Castings Porosity, Cold Shuts 30 Steel Extrusions, Forgings Laps not recommended Steel Welds Lack of Fusion, Porosity 60 Steel All Cracks, Fatigue Cracks 30, not recommended for fatigue crack Brass & Bronze Castings Porosity, Cold Shuts 10 Brass & Bronze Extrusions, Forgings Laps not recommended Brass & Bronze Brazed Parts Lack of Fusion, Porosity 15 Brass & Bronze All Cracks 30 Brass & Bronze       Plastics All Cracks 5 to 30 Glass All Cracks 5 to 30…

TP304H stainless steel has high thermal strength and good oxidation resistance, widely used in the high temperature section of boiler superheaters and reheaters over 600℃, and the maximum operating temperature can reach to 760℃. The use of TP304H stainless steel, to a certain extent, solves the over-temperature tube burst caused by the large temperature difference of the furnace smoke, and significantly improves the safety of the boiler operation. However, TP304H stainless steel is prone to structural transformation during long-term high temperature operation, resulting in material aging. Therefore, studying the structure transformation of TP304H austenitic stainless steel and its influencing factors when operating under high temperature conditions is of great significance for rationally arranging the running time of the material, monitoring the damage degree of the pipeline online, and improving the material itself. For this reason, through the high temperature aging simulation test, the influence of aging temperature and time on…

In the early stage of forging deformation of stainless steel flat welded flanges, because the porous preform is easy to deform, the deformation force is small, and the density increases rapidly. In the later stage of forging forming, due to the closure of most of the pores, the deformation resistance increases, and the deformation force required to eliminate the residual pores increases rapidly. The deformation resistance is closely related to the deformation temperature. A higher deformation temperature is conducive to compaction and reduces the deformation resistance. The higher deformation rate is also conducive to the compactness of stainless steel flat welded flanges. The forging process of stainless steel flat welded flanges has stricter equipment requirements than traditional die forging, and the displacement characteristics of the punch must match the deformation and compact characteristics of the preform. The contact time between the blank and the mold should be as short as…

304 stainless steel products often have various cracking phenomena during the deep drawing process. Among them, lateral or point cracks on the sidewall are common processing failure forms of 304 stainless steel products with relatively large deep drawing. Especially in recent years, the cost-reduction work of stainless steel products processing procedures has continued to advance. The number of drawing passes has been reduced from 5 times to 3 times commonly used at present, and the number of intermediate annealing has been changed to one annealing or no annealing after stamping. The formability of the material puts forward higher requirements. The lateral or point-like cracking defects on the sidewall of stainless steel products may be caused by material inclusions, delta ferrite and other material intergranular defects, or may be caused by factors such as the drawing process and drawing oil during the processing of stainless steel products. The lateral or point…

The main methods for continuous welding of ferritic stainless steel are: TIG welding, high frequency induction HFI welding, plasma arc welding PAW and excitation welding. High-quality welded pipes are more frequently used for high-frequency induction welding and excitation welding. Welding characteristics of stainless steel tubes for automobiles: Compared with traditional fusion welding, laser welding and high-frequency welding have the characteristics of fast welding speed, high energy density, and small heat input. Therefore, the heat affected zone is narrow, the degree of grain growth is small, the welding deformation is small, and the cold forming performance is good. It is easy to realize automatic welding and single-pass penetration of thick plates. The most important feature is that the I-shaped groove butt welding does not require filler materials. The use of laser welding and high-frequency welding of ferritic stainless steel pipes can meet the requirements of the cold working process for the…

In pipeline engineering, stainless steel flanges are mainly used for pipeline connections. Including: stainless steel plate flat welding flange, stainless steel neck flat welding flange, stainless steel neck butt welding flange, stainless steel socket welding flange, stainless steel threaded flange, stainless steel flange cover, stainless steel neck butt welding ring loose sleeve Flange, stainless steel flat welding ring loose flange, stainless steel ring groove face flange and flange cover, stainless steel large diameter flat flange, stainless steel large diameter high neck flange, stainless steel blind plate, stainless steel butt welding ring loose sleeve method Flange, stainless steel rotating flange, stainless steel anchor flange, stainless steel surfacing/overlay welding flange Pressure rating: 0.6Mpa ～32Mpa, 150Lbs ～2500Lbs, PN0.25-PN42.0Mpa Material: 20#, 304, 304L, 321, 316, 316L, 310S and other materials Common standards for flanges: ISO flanges KF fittings and flanges and CF fittings and CF flanges. China Standard: GB9113-2000～GB9124-2000 American Standard: ASTM A182 Flanges, forged, ASME…

All metals can react with oxygen in the atmosphere to form an oxide film on the surface, while the iron oxide formed on the ordinary carbon steel tube continues to oxidize, causing the corrosion to continue to expand and eventually forming holes. Paint or oxidation-resistant metal can be used for electroplating to protect the surface of carbon steel, but this protective layer is a thin film. If the protective layer is damaged, the steel below will begin to rust again. Stainless steel tube corrosion resistance is related to the chromium content, when the chromium content in the steel reaches 12%, in the atmosphere, a layer of passivated and dense chromium-rich oxide is formed on the surface of the stainless steel tube to protect the surface and prevent further Oxidation. This oxide layer is extremely thin, and the natural luster of the steel surface can be seen through it, giving the…

The high-temperature nitriding process refers to holding for a certain time under high temperature and nitrogen-containing atmosphere to obtain a thicker nitriding layer, so that the surface layer of ferritic stainless steel or austenitic ferritic duplex stainless steel is finally transformed into high nitrogen austenite The process of the structure of the stainless steel. Here we studies the influence of heating temperature, holding time, nitrogen pressure and other parameters on the high-temperature nitriding process by performing high-temperature nitriding on duplex stainless steel, hoping to provide a new technical approach for the in-depth study and further application of high-nitrogen stainless steel. Under the process conditions that the heating temperature is not less than 1200℃, the holding time is not less than 24h, and the nitrogen pressure is not less than 0.2MPa, a nitriding layer with a thickness of more than 2.0mm on one side can be obtained in stainless steel. For…

304 stainless steel: has good corrosion resistance, heat resistance, low temperature strength and mechanical properties, good hot workability such as stamping, bending, and no heat treatment hardening. Uses: tableware, cabinets, boilers, auto parts, medical appliances, building materials, food industry. 310 310S stainless steel: high temperature resistance, generally used in boilers and automobile exhaust pipes, and other properties are general. 303 stainless steel: By adding a small amount of sulfur and phosphorus, it is easier to cut than 304 stainless steel. Other properties are similar to those of 304 stainless steel seamless pipe. 302 stainless steel: 302 stainless steel rods are widely used in auto parts, aviation and aerospace hardware tools, and chemicals. The details are as follows: handicrafts, bearings, sliding flowers, medical instruments, electrical appliances, etc. Features: 302 stainless steel ball belongs to austenitic steel, which is close to 304, but the hardness of 302 is higher, HRC≤28, and it…

The main function of the flange is to facilitate the disassembly and inspection of the pipeline, to facilitate the replacement of a certain section of the pipeline, to connect the pipeline and maintain the sealing performance of the pipeline; to facilitate the closure of a certain pipeline. The main features of carbon steel flanges: It has compact structure, reliable sealing, simple structure and convenient maintenance. The sealing surface and the contact surface are often closed, not easy to be eroded by the medium, and easy to operate and maintain. It is suitable for general working media such as water, solvent, acid and natural gas. It is suitable for media with harsh working conditions, such as oxygen, hydrogen peroxide, methane and ethylene. It is widely used in various industries. The carbon steel flange is easy to operate and opens and closes quickly. It only needs to rotate 90° from fully open…

304 stainless steel products often appear various cracking phenomena during the stretching process. Among them, lateral or point cracks on the sidewalls are common processing failure modes of 304 stainless steel products with relatively large stretching. Especially in recent years, the cost-reduction work of stainless steel products processing procedures has continued to advance. The number of stretching passes has been reduced from 5 times to 3 times currently commonly used. The intermediate annealing is changed to one annealing or no annealing after stamping. The formability of the material puts forward higher requirements. The lateral or point cracking defects of the side wall of stainless steel products may be caused by material inclusions, delta ferrite and other material intergranular defects, or may be caused by factors such as the stretching process and stretching oil in the processing of stainless steel products. The lateral or pitting cracking of the side wall of…

The difference between stainless steel seamless tubes and carbon steel seamless tube mainly refers to the difference in design rules between stainless steel and carbon steel, that mean, the design rules of these two types of steel are not commonly used. These differences are summarized as follows: The design rules for stainless steel cannot be used for carbon steel because there are three fundamental differences between stainless steel and carbon steel: 1. Stainless steel undergoes work hardening during cold working, for example, it has anisotropy when bent, that is, the transverse and longitudinal properties are different. The increased strength by cold working can be used, but if the bending area is small compared to the total area and this increase is ignored, the increased strength can increase the safety factor to a certain extent. 2. The shape of the stress/strain curve is different. The elastic limit of stainless steel is…

Basic requirements for roll pass design of sanitary stainless steel pipe: Complete the entire forming and deformation process with the least number of passes (that is, the shortest deformation zone length). 2. The edge extension generated during molding is as small as possible, so as not to produce bulging and wrinkles. 3. The edges are fully deformed, and there is no sharp mouth shape at the seam of the tube. 4. The stainless steel strip is stable in the shape of the pass. 5. Uniform deformation, small and uniform roll wear. 6. Low energy consumption. 7. It can ensure that the size and surface quality of the welded stainless steel pipe meet the standard requirements. 8. Roll processing is convenient, easy to manufacture, and pass design can be combined with processing. 9. The pass design has the characteristics of standardization and standardization, which can be suitable for products of the…

Stainless steel pipe fittings are a kind of pipe fittings, which are made of stainless steel. The internal threads of the stainless steel pipe fittings are mainly tapped by taps, which can improve the viscosity of the stainless steel pipe fittings. However, if it is not handled properly, during the tap tapping process, it is easy to cut and scratch the thread of the workpiece or the tap chipping. This will not only affect the processing efficiency, but also cause damage to the stainless steel pipe fittings and affect the use of the stainless steel pipe fittings Life and performance. (1) Choose a better tap material. Adding special alloy elements to ordinary high-speed tool steels can significantly improve the wear resistance and toughness of the tap. (2) Coating titanium nitride coating on the surface of the tap thread can significantly improve the wear resistance, heat resistance and lubricity of the…

When welding stainless steel tubes, it is mainly because of its strong dendrite direction, large linear expansion coefficient, large shrinkage stress during welding and cooling, hot cracking easily, and large deformation tendency. Measures to prevent hot cracking of stainless steel tubes in production include: welding austenitic stainless steel tubes with electrodes whose weld metal is austenite-ferrite duplex structure; using low-hydrogen electrodes to promote the refinement of weld metal crystals and reduce Harmful impurities in the small welds can improve the crack resistance of the welds; use the fastest welding speed possible, wait for the stainless steel tubes weld layer to cool before welding the next one to reduce the overheating of the weld; when the stainless steel tubes welding ends or is interrupted, the The arc should be slow to fill the crater to prevent crater cracks; use a smaller welding current. When the stainless steel tubes butt weld and…

Depending on the operating conditions, the requirements of high temperature stainless steel may be as follows: · High creep strength (and ductility)· Stability of internal microstructure· High oxidation resistance and HT corrosion· Good resistance to erosion-corrosion Mainly grade include: N04400, N06600, N06601, N06617, N06625, N06690, N08800, N08810, N08811, N08825, N08020, N08367,　N08028, N06985, N06022, N10276. All materials selection must be determined by the application and operating conditions in each individual case. Stainless steel offer a number of special high temperature stainless steel. Besides the common Austenitic High Temperature Alloys above (i.e., 1.4948, 1.4878,1.4828, 1.4833, and 1.4845), there are three proprietary Stainless steel alloys:  153 MA, 253 MA, and 353 MA. These three alloys are based on the same concept:  Improved oxidation resistance by an increased silicon content and addition of very small quantities of rare earth metals (micro-alloying  => MA). Enhanced creep strength due to increased contents of nitrogen (and carbon for 253 MA). In many cases, the properties of these steel have proved to be equivalent or even superior to those…

Martensitic Grade Comparison Chart: China GB ISO Unified Digital Code ASTM UNS Code EN Code Company Commercial Grade 06Cr13 S41008 410S S41008 1.4 – 12Cr13 S41010 410 S41000 1.4006 – 20Cr13 S42020 420 S42000 1.4021 API/13Cr L80 30Cr13 S42030 420J2 S42000 1.4028 – 14Cr17Ni2 S43110 431 S43100 – – 05Cr17Ni4Cu4Nb S51740 17-4PH S17400 1.4542 06Cr13Ni4Mo – S41500 1.4313 F6NM 0Cr16Ni5Mo1N – – – 1.4418 – 00Cr17Ni5Mo2Cu – 17Cr110/125 – – SM17CRS(NSSMC) Martensitic Stainless Steel Grades Alloy(UNS Designation) End Use Compositionnominal wt% Specifications Densitylb/in3 (g/cm³) TensileStrengthksi. (MPa) 0.2% YieldStrengthksi. (MPa) Elong-ation % Hardness AL 403S40300 Turbine blades, banding, strapping and hose clamps C 0.15 max, Mn 1.0 max, Si 0.5 max, Cr 11.5-13.0, Ni 0.6 max, P 0.04 max, S 0.03 max, Fe Balance ASTM A176 AMS QQ5763 0.280(7.75) 70 min(485 min) 30 min(205 min) 25 min 96 Rockwell B max 410S41000 Cutlery, dental and surgical instruments, nozzles, valve parts, hardened…

The steel shall conform to the chemical requirements prescribed in Table 1. Designation C Mn P S Si Ni Cr Mo N Cu Others S31200 0.030 2.00 0.045 0.030 1.00 5.5–6.5 24.0–26.0 1.20–2.00 0.14–0.20 . . . . . . S31260 0.030 1.00 0.030 0.030 0.75 5.5–7.5 24.0–26.0 2.5–3.5 0.10–0.30 0.20–0.80 W 0.10–0.50 S31500 0.030 1.20–2.00 0.030 0.030 1.40–2.00 4.3–5.2 18.0–19.0 2.50–3.00 0.05–0.1 . . . . . . S31803 0.030 2.00 0.030 0.020 1.00 4.5–6.5 21.0–23.0 2.5–3.5 0.08–0.20 . . . . . . S32001 0.030 4.00–6.00 0.040 0.030 1.00 1.0–3.0 19.5–21.5 0.60 0.05–0.17 1.00 . . . S32003 0.030 2.00 0.030 0.020 1.00 3.0-4.0 19.5-22.5 1.50-2.00 0.14-0.20 . . . . . . S32101 0.040 4.0-6.0 0.040 0.030 1.00 1.35-1.70 21.0-22.0 0.10-0.80 0.20-0.25 0.10-0.80 . . . S32202 0.030 2.00 0.040 0.010 1.00 1.00–2.80 21.5–24.0 0.45 0.18–0.26 . . . . . . S32205 0.030 2.00 0.030 0.020…

Austenitic Stainless Steel Types China GB ISO Unified Digital Code ASTM / ASME Grade UNS Code EN Code Company Commercial Grade 06Cr19Ni10 S30408 304 S30400 1.4301 – 07Cr19Ni10 S30409 304H S30409 1.4948 – 022Cr19Ni10 S30403 304L S30403 1.4307 – 022Cr19Ni10N S30453 304LN S30453 1.4311 – – – Super304 S30432 – Super304H(NSSMC) 06Cr18Ni11Ti S32168 321 S32100 1.4541 – 07Cr18Ni11Ti S32169 321H S32109 1.494 – 06Cr17Ni12Mo2 S31608 316 S31600 1.4401 – 022Cr17Ni12Mo2 S31603 316L S31603 1.4404 – 022Cr17Ni12Mo2N S31653 316LN S31653 1.4406 – 06Cr17Ni12Mo3Ti S31668 316Ti S31635 1.4571 – 00Cr17Ni14Mo2 316LMoD/316LUG S31603 1.4435 – 022Cr19Ni13Mo3 S31703 317L S31703 1.4438 – 022Cr19Ni16Mo5N S31723 317LMN S31725 1.4439 – 06Cr25Ni20 S31008 310S S31008 1.4845 – 00Cr19Ni11 – 304L S30403 1.4307 3RE12(Sandvik) – – 310L S31002 1.4335 2RE10(Sandvik) 20Cr25Ni20 S31020 310H S31009 1.4821 16Cr25Ni20Si2 S38340 314 – 1.4841 022Cr25Ni22Mo2N S31053 310MoLN S31050 1.4466 2RE69(Sandvik) – – 310HCbN S31042 – HR3C(NSSMC) 07Cr18Ni11Nb S34749 347H S34709 1.4942 –…

Stainless steel pipe fittings are a kind of pipe fittings, which are made of stainless steel. The internal threads of the stainless steel pipe fittings are mainly tapped by taps, which can improve the viscosity of the stainless steel pipe fittings. However, if it is not handled properly, during the tap tapping process, it will be prone to cutting and scratching the thread of the workpiece or the tap chipping. This will not only affect the processing efficiency, but also cause damage to the stainless steel pipe fittings and affect the use of the stainless steel pipe fittings. Life and performance. (1) Choose a better tap material. Adding special alloy elements to ordinary high-speed tool steel can significantly improve the wear resistance and toughness of the tap. (2) Coating titanium nitride coating on the surface of the tap thread can significantly improve the wear resistance, heat resistance and lubricity of…

304H stainless steel has high thermal strength and oxidation resistance. It is widely used in the high temperature section of boiler superheaters and reheaters over 600℃, and the maximum service temperature can reach 760℃. The use of TP304H stainless steel, to a certain extent, solves the over-temperature tube burst caused by the large temperature difference of the furnace smoke and significantly improves the safety of the boiler operation. However, TP304H stainless steel is prone to structural transformation during long-term high temperature operation, resulting in material aging. Therefore, studying the microstructure transformation of TP304H austenitic stainless steel and its influencing factors when operating under high temperature conditions is of great significance for rationally arranging the running time of the material, monitoring the damage degree of the pipeline on-line, and improving the material itself. For this reason, through high-temperature aging simulation tests, the effects of aging temperature and time on the structure…

Stainless steel decorative pipe is a kind of heat-resistant and corrosion-resistant steel with good compression resistance. In our daily life, almost all places where metal materials are used, there are stainless steel decorative tubes, such as stainless steel handrails, stainless steel guardrails, stainless steel anti-theft doors and windows, etc., which are made of stainless steel decorative tubes. There are also display racks used in some shopping malls, as well as stainless steel table legs, stainless steel chairs, etc. Although some products are not mainly stainless steel decorative tubes, there are also many stainless steel decorative tube parts. In addition, as for stainless steel pipes used in industry, stainless steel decorative pipes do not meet the requirements and are not very common. Industrial pipes are basically made of stainless steel seamless pipes, and stainless steel decorative pipes are welded pipes. Therefore, industrial pipes basically do not use stainless steel decorative pipes.…

Stainless Steel Stainless steel is not easy to rust steel. It should be noted here that it is not easy to rust, nor is it impossible to rust. However, objectively speaking, stainless steel is not easy to rust or corrode. There is a protective film on the surface of stainless steel, that is, chromium-rich oxide film. Due to the existence of this kind of film, stainless steel has the property of not being prone to rust and corrosion. Studies have shown that with the increase of chromium content in steel, the corrosion resistance of steel in weak media such as the atmosphere, water and oxidizing media such as nitric acid increases. When the chromium content reaches a certain percentage, the corrosion resistance of steel changes drastically, that is, from easy to rust to hard to rust, from no corrosion resistance to corrosion resistance. Stainless iron Stainless iron is made from…

Stainless steel are iron-based alloys usually containing at least 11.5% chromium. Other elements, Nickel being the most Important, may be added in combination with chromium to obtain special properties. Stainless steel are highly resistant to corrosive attack and to oxidation at high temperature. in general, corrosion resistance and oxidation resistance increase progressively, though not proportionately, with the increase in chromium content. Stainless steel pipe and tubing are used for a variety of reasons: to resist corrosion and oxidation, to resist high temperature, for cleanliness and low maintenance costs, and to maintain the purity of materials which come In contact with stainless. The inherent characteristics of stainless steel tubing permits the design of thin wall piping systems without fear of early failure due to corrosion. The use of fusion welding to join such piping eliminates the need for threading. Type 304 stainless steel is the most widely used analysis for general corrosion resistant tubing and pipe applications, it is used in…

Duplex stainless steel has become an important engineering material, which is widely used in petrochemical, offshore and coastal facilities, oilfield equipment, paper-making, ship-building and environmental protection. 2507 duplex stainless steel is developed on the basis of the second-generation duplex stainless steel 2205. At present, there are SAF2507, UR52N+, Zeron100, S32750, 00Cr25Ni7Mo4N, etc. The 2507 structure is composed of austenite and ferrite, and both The dual characteristics of stainless steel and ferritic stainless steel have a lower thermal expansion coefficient and higher thermal conductivity than austenitic stainless steel. Its pitting corrosion coefficient (PREN) is greater than 40, and it has high resistance to pitting and gaps. Corrosion, chloride stress corrosion cracking resistance, high strength, high fatigue strength, low temperature and high toughness at the same time, is a widely used duplex stainless steel. In recent years, with the continuous expansion of the application fields of duplex stainless steel pipes, the demand…

Due to the essential difference between stainless steel and carbon steel, stainless steel has good ductility. If used improperly, the screw and nut cannot be unscrewed after being matched, commonly known as “locked” or “seized”. The improvement of “lock-up” or “bite” is mainly improved in the following areas: 1. Choose the correct product: Before use, confirm whether the mechanical properties of the product meet the requirements of use, such as the tensile strength of the bolt and the safety load of the nut. The length of the bolt is tightened and the nut is exposed by 1-2 tooth saws. 2. Correctly reduce the friction coefficient: The thread must be kept clean, it is recommended to add lubricant oil before use. 3. Correct use method: 　　1) The nut must be screwed perpendicular to the axis of the screw, and do not tilt; 　　2) During the tightening process, the force must be…

Stainless Steel Feed Material Preference for Yongxing Special Materials Technology or similar quality manufacturer (to be nominated if not Yongxing) Feed material certificates to be issued to the buyer for approval prior to commencing production PREN Pitting Corrosion Equivalent Adequate corrosion resistance shall be achieved by ensuring the pitting resistance equivalent (PRE) exceeds 36 for all tubes. The pitting resistance equivalent shall be calculated as follows and reported for each heat.PRE = %Cr + (3.3 x %Mo) + (16 x %N) Dimensional Tolerances Outside Diameter – 38.1mm +/- 0.25mm Wall Thickness – 1.65 +/-0.17mm Length – 7315mm -nil +5mm Surface Condition All tubes shall be free of mill scale or any other oxide form that may reduce corrosion resistance in service. Chemical Composition The stainless steel shall STRICTLY conform to the chemical requirements of UNS S32205 Critical Pitting Temperature Corrosion Test A sample from each lot shall be tested in…

Duplex tubes shall be furnished in the solution annealed and water quenched condition. ·Material shall be pickled after the final anneal and water quench to provide surfaces free of discoloration. Heat treatment of all U-bends shall be required. o Tubes shall be heated by induction or electric resistance and held within the temperature range 1870–2010ºF (1020–1100ºC) for UNS S32205 and 1880–2060ºF (1025–1125ºC) for UNS S32750 as permitted by ASTM A789/A789M, Table 2, followed by a rapid cool below 600ºF (315.6ºC) using forced air, inert gas, or water. §  Total time above 600ºF (315.6ºC) shall be less than 5 minutes. §  The full tube bend and a minimum of 305mm of each leg beyond the tangent point of the bend shall be heated to the required bending temperature. §  The controlling temperature shall be measured using a thermocouple or calibrated optical pyrometer. §  The inside diameter (ID) and outside diameter (OD)…

Gas tungsten arc welding (GTAW or TIG) This is the most widely used process due to its versatility and high quality as well as the aesthetic appearance of the finished weld. The ability to weld at low current, and hence low heat input, plus the ability to add filler wire when required, make it ideal for thin materials and root runs in one sided welding of thicker plate and pipe. The process is easily mechanised and the ability to weld with or without the addition of filler wire (autogenous welding) make it the process for orbital welding of pipe. Pure argon is the most popular shielding gas, but argon rich mixtures with the addition of hydrogen, helium or nitrogen are also employed for specific purposes. Inert backing gas protection of the weld under-bead is employed with single-sided welding to prevent oxidation and the loss of corrosion resistance. Plasma arc welding (PAW) A derivative of the…

The petro-chemical industry, including the fertilizer industry, has a great requirements for stainless steel pipes and tubes. The industry mainly uses stainless steel seamless tubes and pipes. The material grade include: 304, 321, 316, 316L, 347, 317L, etc., and the outer diameter is around ￠6-￠610mm. The wall thickness is about 0.5mm-50mm (generally the medium and low pressure conveying pipes with specifications above Φ159mm are selected), and the specific application areas are: furnace tubes, material conveying tubes, heat exchanger tubes, etc. E.g: Heat-resistant stainless steel pipes are mainly used for heat exchange and fluid transportation. The domestic market has an annual capacity of about 230,000 tons, and high-end demand still needs to be imported. Duplex stainless steel pipes are mainly used in the heat exchanger and fluid pipe markets of chemicals and fertilizers. Because of their high strength, stress resistance, corrosion resistance and economy, their annual consumption is about 8,000-10,000 tons.…

The hydraulic bulging process of stainless steel tee requires a large tonnage of equipment. At present, it is mainly used in the manufacture of stainless steel tee with standard wall thickness less than DN400 in China. The hydraulic bulging process of stainless steel tee can be formed at one time, and the production efficiency is high. Hydraulic bulging is a forming process in which branch pipes are expanded by axial compensation of metal materials. The hydraulic bulging process of the stainless steel tee uses a special hydraulic press to inject liquid into the tube blank with the same diameter as the stainless steel tee, and the tube blank is squeezed by the two horizontal side cylinders of the hydraulic press. After the volume becomes smaller, the liquid in the tube billet will increase in pressure as the tube billet volume becomes smaller. When the pressure required for the expansion of…

Super martensitic stainless steel is a new type of martensitic stainless steel that strictly controls the carbon content below 0.03% on the basis of traditional martensitic stainless steel and increases the nickel content. Compared with the traditional low-carbon martensitic stainless steel, super martensitic stainless steel not only has good ductility toughness and higher strength and hardness, but also has higher fracture toughness, underwater fatigue strength and abrasion resistance. After the martensitic stainless steel is normalized, lath martensite can be obtained, and after tempering at a certain temperature, further tempered martensite can significantly affect and improve the overall properties of the material. Predecessors studied super martensitic stainless steel normalizing at 1050°C and tempering between 500°C and 700°C, focusing only on its microstructure and mechanical properties, and did not study its abrasion resistance. In the study, the super martensitic stainless steel 1.4314 (S41500) was normalized and tempered once and selected part of…

As an important component of stainless steel, nickel has a huge impact on the performance and cost of stainless steel, and the market price of stainless steel is also following it. Taking 304 stainless steel as an example, its nickel content is usually around 8%. Corresponding to the cost of stainless steel, the cost of nickel accounts for about 55%. Therefore, even if the stainless steel uses nickel as the weather vane, its fluctuation range It should be positively correlated rather than fluctuating in the same proportion. In the process of nickel and stainless steel price fluctuations, the situation that achieves the same proportional fluctuation is mostly the case of price declines. In this process, stainless steel is obviously affected by the weak market. Although this is attributed to the dual effect of market and demand, The same proportion of volatility is beyond reasonable. From the perspective of overall supply…

There is an oxide scale on the surface of the stainless steel tube. This oxide scale is thin and dense, and it is not easy to fall off. Normally, the stainless steel cast billet will produce 0.2～0.3mm oxide scale in the heating furnace. The cast billet defects in this range can be As the scale is removed, if the defects are not within this range, the surface defects on the cast slab will inevitably be brought into the final product if it is not treated. Stainless steel casting billets generally cannot be cleaned by flame cleaning the surface defects of the casting billets. Flame cleaning will cause changes in the composition and crystal phase composition of the cleaned area of ​​the cast billets, which will affect the corrosion resistance of stainless steel pipe products. Therefore, mechanical cleaning is a common and effective method for surface treatment of stainless steel. The…

Stainless steel tube condenser is superior to copper tube condenser as follows: Good erosion resistance. It can resist the impact of steam and water droplets at high speed. As early as the mid-1850s, the United States began to arrange stainless steel pipes around the tube bundle. Good resistance to ammonia corrosion. Ammonia media can cause stress corrosion cracks in copper pipes, and can also lead to condensate corrosion, which is called ammonia corrosion. The use of stainless steel pipes does not require other anti-corrosion measures. Excellent resistance to water side impact corrosion and phobic corrosion. The pipe end may not need ferrous sulfate protection. After adopting the stainless steel tube condenser, the unit can adopt the copper-free tube subsystem, and the PH value can be increased to reduce the corrosion rate. The condenser with stainless steel tube can achieve no leakage of the condenser like the titanium tube condenser, which…

Unsuitable factors for stainless steel tube condenser: It is more sensitive to chloride, so when stainless steel pipe is used, there is a limit to chloride. Stainless steel tubes and copper tube sheets will produce galvanic corrosion and zinc corrosion, so cathodic protection should be used. During shutdown, there will be calcium acid deposits, stainless steel TP304 and TP316 will produce pitting corrosion, so before the unit is out of service for a long time, clean water should be used to flush the water chamber and pipes, and open the water chamber cover, and air dry for two days to avoid water droplets After evaporation, the FeCl-1 concentration is too high and pitting corrosion occurs. In addition, some power manufacturing companies recommend using stainless steel bellows instead of copper pipes. The heat transfer effect can increase by 25% to 30%. However, the resistance loss of pipes of the same diameter…

The application of stainless steel to condenser tubes has been around since the 1960s. At present, more than 60% of condenser in the United States use stainless steel tubes. The used length is 243.84 million meters, and more than 96% of the pipes installed on the condenser are still in use. Among European countries, companies such as Germany and France began to use stainless steel tubes as condenser tubes in the 1970s. Feasibility analysis of stainless steel tube: Technical analysis The wall thickness affects only 2% of the total thermal resistance, and the material has a relatively large effect. According to the HEI standard, the material heat transfer coefficient of navy brass is 1.01 (tube φ25×1), while the material heat transfer coefficient of stainless steel is 0.89 (tube φ25×0. 6) Therefore, it can be seen that the heat transfer coefficient of stainless steel pipes of the same specification is about…

Electrochemical polishing is the same as Electropolishing. Before electropolishing, stainless steel tube must be thoroughly degreasing and scrubbed with decontamination powder to prevent the oil from polluting the polishing bath. It is necessary to frequently measure the relative density of the electropolishing solution during use. If the relative density is less than the specified value of the formula, it indicates that the electropolishing solution contains too much water. The evaporation method can be used to heat the solution to above 80°C to remove the excess water. The insufficient volume can be supplemented with phosphoric acid and sulfuric acid according to the formula ratio. Before the stainless steel pipe enters the electrochemical polishing tank, it is best to drain or blow dry the water attached to the pipe. If the relative density is too high and exceeds the specified value of the formula, it means that the moisture is too low.…

Tensile strength test is to make a sample of stainless steel pipe, pull the sample to break on a tensile testing machine, and then measure one or several mechanical properties, usually only the tensile strength, yield strength, elongation after fracture and section are measured Shrinkage. Tensile strength test is the most basic test method for mechanical properties of metal materials. Almost all metal materials require tensile test as long as they have requirements for mechanical properties. Especially for those materials whose shape is not convenient for hardness test, tensile strength test becomes the only means of testing mechanical properties. The hardness test is to slowly press a hard indenter into the surface of the sample with a durometer under specified conditions, and then test the depth or size of the indentation to determine the hardness of the material. Hardness test is the simplest, fastest and easiest method in material mechanical…

For the heat treatment technology of the surface of stainless steel pipes, non-oxidation continuous heat treatment furnaces with protective gas are generally used abroad for intermediate heat treatment and final heat treatment of finished products. As a bright surface without oxidation can be obtained, the traditional pickling process is eliminated. The adoption of this heat treatment process not only improves the surface of stainless steel pipes, but also overcomes the environmental pollution caused by pickling. According to the manufacturer of stainless steel pipes, according to the current world development trend, bright annealing continuous heat treatment furnaces are basically divided into the following two types: (1) Roller-type bright annealing heat treatment furnace. This bright annealing furnace type is suitable for heat treatment of large-size and large-volume special-shaped stainless steel pipes, with an hourly output of above 1.0 Tons. The protective gases that can be used are high-purity hydrogen, decomposed ammonia and…

What is the performance of stainless steel welded pipe at low temperature? The resistance, linear expansion coefficient, thermal conductivity, mass melting and magnetism of stainless steel welded pipe will change greatly at low temperature. Electrical resistance and linear expansion coefficient decrease at low temperatures; thermal conductivity and mass heat capacity decrease sharply at low temperatures; Young’s modulus (longitudinal elastic modulus) increases at the same time as the temperature drops. Because austenitic stainless steel pipes have a low temperature (Subzreo temperature) Ms point (martensite transformation start temperature or martensite formation temperature), martensite can be formed when kept below the Ms point. The formation of martensite at low temperature makes 304 (18Cr-8Ni), the representative steel of austenitic stainless steel, non-magnetic at room temperature, but becomes magnetic at low temperature. In a low temperature environment, the deformation energy is small. In a low temperature environment, the phenomenon that elongation and reduction of area…

When brown rust spots appeared on the surface of stainless steel, people were surprised: “Stainless steel does not rust, and rust is not stainless steel. It may be a problem with the steel.” In fact, this is a one-sided wrong view of the lack of understanding of stainless steel. Stainless steel can also rust under certain conditions. Stainless steel has the ability to resist atmospheric oxidation, that is non-rust, and it also has the ability to resist corrosion in media containing acid, alkali, and salt, that is corrosion resistance. But the size of its anti-corrosion ability is changed with the chemical composition of the steel itself, mutual status, use conditions and environmental media types. Such as 304 material, in a dry and clean atmosphere, has absolutely excellent corrosion resistance, but it is moved to the beach area, in the sea fog containing a lot of salt, it will quickly rust.…

Stainless steel flanges will not produce corrosion, pitting, rust, and are not easily worn. Stainless steel is one of the highest-strength metal materials for construction. Because stainless steel has good corrosion resistance, it can make structural components permanently maintain the integrity of engineering design. There are more and more types of stainless steel flanges in the production process, and the installation methods are different for different types of flanges. Next, I will introduce the correct installation sequence of stainless steel flanges. 1. The contaminated stainless steel pipe or stainless steel pipe fittings should be cleaned up before the stainless steel flange connection; 2. The pipes to which the stainless steel flange is connected are respectively fitted with a flange with a grooved ring; 3. Perform 90° flanging process on the two pipe ports. After flanging, the port surface should be polished vertically and flat without burrs, unevenness, or deformation. The…

When the chromium-nickel austenitic stainless steel is heated to the temperature range of 450-800℃, corrosion along the grain boundary often occurs, which is called intergranular corrosion. Generally speaking, intergranular corrosion is actually caused by the precipitation of carbon in the form of Cr23C6 from the saturated austenitic metallographic structure, which makes the austenite structure at the grain boundary depleted in chromium. Therefore, avoiding chromium depletion at grain boundaries is an effective way to prevent intergranular corrosion. The elements in stainless steel are sorted according to their affinity for carbon, and the order is titanium, niobium, molybdenum, chromium and manganese. It can be seen that the affinity of titanium and carbon is greater than that of chromium. When titanium is added to steel, carbon will preferentially combine with titanium to form titanium carbide, which can effectively prevent the formation of chromium carbide and the precipitation of chromium depletion at grain boundaries.…

Antibacterial stainless steel is a “national invention patent” technology developed by the Institute of Metals, Chinese Academy of Sciences for ten years, and has won 5 national invention patents. In 2014, Zhongkepujin succeeded in industrialized trial production and put it into the market. At the same time, the application in the fields of home appliances, bathroom, tableware and other fields has been well received by the market and users. In 2016, the crude steel output of ordinary stainless steel was 26 million tons. With rising consumption demand, the market size of antibacterial stainless steel has exceeded trillions. The field and status of entrepreneurial projects The entrepreneurial project belongs to the field of new materials. Due to the widespread use of stainless steel, according to statistics, the amount of stainless steel used in kitchen utensils reached more than 3.5 million tons in 2016. Because antibacterial stainless steel is a new material…

How to Choose Stainless Steel Seamless Pipe or Welded Pipe? Based on the characteristics and differences of stainless steel seamless pipes and stainless steel welded pipes, reasonable choices should be made during application to achieve economic, beautiful and reliable effects: 1. When used as decorative pipes, product pipes, and prop pipes, they generally require good surface effects, and stainless steel welded pipes are usually used; 2. For generally lower pressure fluid transportation, such as low pressure systems such as water, oil, gas, air, and heating water or steam, stainless steel welded pipes are usually used 3. For pipelines used in industrial engineering and large-scale equipment to transport fluids, as well as pipelines that require high temperature, high pressure, and high strength on power plants and nuclear power plant boilers, stainless steel seamless pipes should be used; 4. Stainless steel welded pipes are generally used for liquid transportation below 0.8MPa, and…

Stainless steel has good comprehensive performance and good appearance and surface characteristics, and is widely used in various industries. Similarly, stainless steel pipe is no exception. Stainless steel pipe is a kind of steel with a hollow section, generally divided into stainless steel seamless pipe and welded pipe. Their processing methods and performance also have certain differences, the differences are as follows: 1. The difference in production process Stainless steel welded pipes are made of steel plates or steel strips that are crimped and formed by a unit and a die. Generally, there is a weld on the inner wall of the pipe; while Stainless Steel Seamless Pipes are perforated using round tube blanks as raw materials, and are cold rolled, cold drawn or It is made by the production process of hot extrusion, and there is no welding point on the tube. 2. The difference in the appearance of…

What is The Difference Between Stainless Steel Industrial Pipe and Stainless Steel Decorative Pipe? Surface Condition Mostly, the surface of Stainless Steel Industrial Pipe is Mill Surface (Rough) or Britht Annealed Finished. Stainless Steel Decorative Pipe is bright surface. Application Stainless Steel Industrial Pipe for Decoration projects, Furniture, etc. Stainless Steel Industrial Pipes are mainly used for steel structures and on construction sites, Petro-chemical, Fertilizer, Aerospace, oil and gas, and so on. neither of which is food grade Wall Thickness Then Stainless Steel Decorative Pipes are generally below 2mm in thickness, stainless steel industrial pipes are mostly bigger than 2mm. Material Grade Stainless Steel Decorative Pipes mostly in grade 201, 202, 301, 302, 303, 304, 410, 420, 430. Stainless Steel Industrial Pipes mostly in 304, 304L, 316, 316L, 321, 309S, 310S. Stainless Steel Industrial Pipes are characterized by high temperature resistance, Corrosion Resistance, and their advantages are high nitrogen content…