DIN 17751 2.4619 Hastelloy G3 Nickel Alloy

DIN 17744 17750 17751 17752 17753 2.4619 Hastelloy G-3 is a chemically stable and high-temperature resistant alloy, which is well weldable and has a good stability against grain border corrosion in welded condition. Alloy 2.4619 (alloy G-3) is used in flue gas scrubbers, and with phosphoric acid and sulphuric acid. Our product range in 2.4619 (alloy G-3) are tubes and pipes, fittings and flanges, accessories.

DIN 17744 17750 17751 17752 17753 2.4619 Hastelloy G-3 is a modified version of Hastelloy G in that the higher molybdenum and tungsten contents give this alloy improved corrosion resistance to the welded heat-affected zone. Applications are similar to those for Hastelloy G. Process equipment for flue gas scrubbers, sulfate compounds, mixed acids.

Machinability
Conventional machining techniques used for iron based alloys may be used. Machining characteristics are somewhat similar to those for the austenitic 300 Series stainless steel. This alloy does work-harden during machining and has higher strength and "gumminess" not typical of steels. Heavy duty machining equipment and tooling should be used to minimize chatter or work-hardening of the alloy ahead of the cutting. Water-base coolants of premium quality are preferred.

Rigid mounting of tooling and the workpiece are important to avoid "chatter" . Both carbide tool and high-speed tool may be used successfully. Carbide tooling permit twice, the feed rate of high-speed tooling for the same depth of cut or drilling.

Turning: For roughing cuts the tools should have -5 degree back rake for carbide and -10 degree back rake for high-speed steel. Normal and/or finish turning call for positive rake angles of about +10 degrees for both carbide and hig-speed cutters.



Cutting speeds and feeds are in the following ranges: For High-Speed Steel Tool For Carbide Tooling Depth Surface Feed Depth Surface Feed of cut speed in inches of cut speed in inches inches feet/min. per rev. inches feet/min.

Drilling: Steady feed rates must be used to avoid work hardening due to dwelling of the drill on the metal. Rigid set-ups are essential with as short a stub drill as feasible. Conventional high-speed steel drills work well. Feeds vary from 0.001 inch per rev. for holes of less than 1/16" diameter, 0.002 to 0.003 inch per rev. for 1/4" dia., 0.004 to 0.010 inch per rev. for holes of 7/8"diameter. Speeds of 10 to 25 surface feet/minute, are best for drilling.

Milling: To obtain good accuracy and a smooth finish it is essential to have rigid machines and fixtures and sharp cutting tools. High-speed steel cutters such as M-2 or M-10 work best with cutting speeds of 30 to 50 surface feet per minute and feed of 0.002-0.007 inch per cutting tooth.

Grinding: The alloy should be wet ground and aluminum oxide wheels or belts are preferred.

Welding
The commonly used welding methods work well with this alloy. Matching alloy filler metal should be used. If matching alloy is not available then the nearest alloy richer in the essential chemistry (Ni, Co, Cr, Mo) should be used. All weld beads should be slightly convex. It is not necessary to use preheating. Complete removal of slag is important after every weld pass and upon completion of welding. Usually this is accomplished by use of a wire brush (hand or powered). Surfaces to be welded must be clean and free from oil, paint or crayon marking. The cleaned area should extend at least 2" beyond either side of a welded joint.

Gas Tungsten Arc Welding (TIG): DC straight polarity (electrode negative) is recommended. Keep as short an arc length as possible and use care to keep the hot end of filler metal always within the protective atmosphere. Arc voltage should be in the range of 9 to 13 volts with current of 20-60 amps for thin material, 60-150 amps for material 1/8" thick or so, and 100-150 amps for material 1/4" thick.

Shielded Metal-Arc Welding (SMAW): Electrodes should be kept in dry storage and if moisture has been picked up the electrodes should be baked at 600 F for one hour to insure dryness. Use electrode positive polarity. Current settings vary from 60 amps for 3/32" dia. rods up to 180 amps for 3/16" dia. rods. It is best to weave the electrode slightly as this alloy weld metal does not tend to spread.

Metal-Arc Welding (MIG): Electrode positive polarity should be used and best results are obtained with the welding gun at 90 degrees to the joint. For Short-Circuiting-Transfer GMAW a typical voltage is 18-22 with a current of 75-150 amps and a wire feed of 8-10 inches per minute. Submerged-Arc Welding: Generally submerged-arc welding should be avoided. This weld process involves high heat input and may lead to cracking of the alloy workpiece.

Heat Treatment
The alloy may be annealed, but does not respond to age-hardening. It is normally furnished in the annealed condition. It is important to anneal after hot or cold working in order to restore optimum corrosion resistance.

Cold Working
Cold forming may be done using standard tooling although plain carbon tool steels are not recommended for forming as they tend to produce galling. Soft die materials (bronze, zinc alloys, etc.) minimize galling and produce good finishes, but die life is somewhat short. For long production runs the alloy tool steel ( D-2, D-3) and high-speed steels (T-1, M-2, M-10) give good results especially if hard chromium plated to reduce galling. Tooling should be such as to allow for liberal clearances and radii. Heavy duty lubricants should be used to minimize galling in all forming operations. Bending of sheet or plate through 180 degrees is generally limited to a bend radius of 1 T for material up to 1/8" thick and 2 T for material thicker than 1/8". In order to avoid "orange peel" surface effect the cold work reduction of area should be greater than 15% at any given operation. Intermediate annealing may be done, to restore ductility, during the sequence of cold forming operations.

Physical Properties: