Tubi in acciaio inox 409L Acciaio inox 409
ASTM A268 409 409L 1.4512 stainless steel is an alloy designed principally for the automotive exhaust industry, although it has been used successfully in other industrial applications. It combines good elevated temperaturaresistenza alla corrosione with medium strength, good formability and overall cost. 409L stainless steel is highly resistant to high temperatures, achievable engine and exhaust systems, and reduces the thickness of the exhaust system to reduce exhaust emissions. Low cost, good flexibility, high yield, easy replacement, and environmentally friendly new products.
409 Stainless Steel is a titanio stabilised ferritico stainless steel. Although regarded as a general-purpose chromium stainless steel the primary application for Grade 409 is automotive exhaust systems. Its applications are those where appearance is a secondary consideration to proprietà meccaniche e corrosione resistance and where some weldability is required.
Type 409 is a acciaio inossidabile ferritico that has a good combination of heat resistance and resistenza alla corrosione. Its titanium stabilized low nichel content provides for an economical metal to corrosion resistance and resistenza all'ossidazione .
More highly stabilised versions of 409 are useful where 409 has been proven marginal – these grades S40910, S40920 and S40930 are stabilised with titanio, niobium or both titanio and niobium. Used to automobile mufflers, catalytic converters, tailpipes, farm equipment, structural supports and hangers, transformer cases, diamond tread plate and shipping containers.
Magnetic Properties: 409 flat rolled stainless steel is magnetic and cannot be hardened by heat treatment. It can, however, be somewhat hardened by cold-working. Type 409 has great duttilità and is suitable for use in deep draw applications. It is also easily formable.
Chemical Composition of ASTM A268 409 S40900 Grade and EN 10088-2 1.4512 1.4516 Stainless Steel
| Grado | – | C | Mn | Si | P | S | Cr | Ni | Ti |
| A268 409 | min. max. | – 0.08 | – 1.00 | – 1.00 | – 0.045 | – 0.030 | 10.5 11.7 | – 0.50 | 6×C-0.75 |
| TP409L | min. max. | – 0.035 | – 1.00 | – 1.00 | – 0.045 | – 0.030 | 10.5 11.7 | – 0.50 | 6×C-0.75 |
| 1.4516 | min. max. | – 0.08 | – 1.50 | – 0.70 | – 0.040 | – 0.015 | 10.5 12.5 | 0.50-1.50 | 0.05-0.35 |
| 1.4512 | min. max. | – 0.030 | – 1.00 | – 1.00 | – 0.040 | – 0.015 | 10.5 12.5 | – 0.50 | 6×(C+N)-0.65 |
Mechanical properties of ASTM A268 409 Grade and EN 10088-2 1.4512 stainless steel
| Grado | Resistenza alla trazione | Resistenza allo snervamento 0.2% Proof | Allungamento | Durezza | Durezza |
| Grado | ksi(MPa) min | ksi (MPa) min | (% in 50 mm) min | Rockwell B (HR B) max | Brinell (HB) max |
| 409 | 55 (380) | 25 (170) | 20 | 95 | 207 |
| 1.4512 | 380-560 | 210 | 25 |
Typical physical properties for annealed grade 409 stainless steels are given in table 3.
Tabella 3. Physical properties of 409 grade stainless steel in the ricotto condition
| Grado | Densità (kg/m³) | Modulo elastico (GPa) | Coefficiente medio di Thermal Expansion (mm/m/°C) | Coefficiente medio di Thermal Expansion (mm/m/°C) | Coefficiente medio di Thermal Expansion (mm/m/°C) | Conduttività termica (W/m.K) | Conduttività termica (W/m.K) | Specific Heat 0-100°C (J/kg.K) | Resistività elettrica (nW.m) |
| 0-100°C | 0-315°C | 0-538°C | a 100°C | a 500°C | |||||
| 409 | 7600 | 208 | 11.0 | 11.7 | 12.4 | 25.8 | 27.5 | 460 | 600 |
Grade Specification Comparison
Approximate grade comparisons for 409 stainless steel are given in table 4.
Tabella 4. Grade specifications for 409 grade stainless steel
| Grado | UNS | BS | BS | IT | IT | Svedese | Giapponese |
| – | No. | IT | Nome | SS | JIS | ||
| 409 | S40900 | 409S19 | – | 1.4512 | X6CrTi12 | – | SUH 409 |
Questi confronti sono solo approssimativi. L'elenco è da intendersi come un confronto tra materiali funzionalmente simili. non come tabella degli equivalenti contrattuali. Se sono necessari equivalenti esatti, è necessario consultare le specifiche originali.
Possible Alternative Grades
Possible alternative grades to grade 409 stainless steel are given in table 5.
Tabella 5. Possible alternative grades to 409 grade stainless steel
| Grado | Why it might be chosen instead of 409 |
| 3CR12 | Similar corrosion resistance, easier welding and more readily available than 409, particularly in heavy sections. (409 may have better drawability than 3CR12.) |
| 304 | Better corrosion resistance and heat resistance but at higher cost. |
| 321 | Higher heat resistance than 409 or 304. |
| Aluminised steel | Lower resistance to exhaust gases, but at lower cost than stainless steel grade 409. |
Resistenza alla corrosione
Grade 409 resists atmospheric and exhaust gas corrosione. A light surface rust will form in most atmospheres; this rust retards further corrosion but makes the surface undesirable for decorative applications. The corrosion resistance is about the same as that of 3CR12 and the 12% chromium martensitic grades such as 410, and inferior to the 17% chromium grade 430.
Resistenza al calore
Generally 409 is classified as resistant to scaling in intermittent service up to 850°C and up to 650°C in continuous service, but these temperatures are dependent upon the exact service environment.
Trattamento termico
Ricottura – calore to 790-900°C and air cool. This grade cannot be hardened by thermal treatment.
Saldatura
Readily welded but a pre-heat of 150-260°C is recommended. Grade 409 or Grade 430 electrode or filler rods can be used, but AS 1554.6 pre-qualifies welding of 409 with Grade 309 rods or electrodes. These austenitic fillers result in a more ductile weld.
Post-weld annealing at 760-815°C improves weld ductility.
Post-weld annealing is not required when welding thin sections. Automotive exhaust tubing is typically welded without filler metal (autogenously).
All welding must be carried out with minimum heat input to reduce grain growth effects.
Applicazioni
Le applicazioni tipiche includono:
• Automotive exhaust systems
• Catalytic converters
• Mufflers
Riferimenti correlati:
1. Acciaio inossidabile superferritico
2. Acciaio inossidabile ferritico Ferrite
3. Tabella di confronto dei gradi di acciaio inox ferritico
4. Rispetto agli acciai inossidabili ferritici, gli acciai inossidabili duplex vulnerabili
5. Acciaio inox 409L resistente al calore