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Aluminum		0.2 - 0.5
Boron		0.015 max
Carbon		0.05 - 0.15
Chromium		20 - 24
Cobalt		5 max
Iron		3 max
Lanthium		0.005 - 0.05
Manganese		0.3 - 1
Molybdenum		1 - 3
Nickel		Balance
Phosphorus		0.03 max
Silicon		0.25 - 0.75
Sulphur		0.015 max
Tungsten		13 - 15

Principal Design Features		This alloy of nickel-chromium and tungsten is another in the family of high temperature oxidation resistant, high strength alloys. It may be utilized effectively at temperatures up to 2100 F.

Applications		Gas turbine hot section components such as combustion cans, thermocouple protection tubes, heat exchangers and industrial furnace fixtures and muffles.

Machinability		Conventional machining techniques used for iron based alloys may be used. 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. Most any commercial coolant may be used in the machining operations. Water-base coolants are preferred for high speed operations such as turning, grinding, or milling. Heavy lubricants work best for drilling, tapping, broaching or boring. Turning: Carbide tools are recommended for turning with a continuous cut. High-speed steel tooling should be used for interrupted cuts and for smooth finishing to close tolerance. Tools should have a positive rake angle. Cutting speeds and feeds are in the following ranges: For High-Speed Steel Tools 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. per rev. 0.250" 25-35 0.030 0.250" 150-200 0.020 0.050" 50-60 0.010 0.050" 325-375 0.008 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. Heavy-duty, high-speed steel drills with a heavy web are recommended. Feeds vary from 0.0007 inch per rev. for holes of less than 1/16" diameter, 0.003 inch per rev. for 1/4" dia., to 0.010 inch per rev. for holes of 7/8"diameter. 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 30-40 feet per minute and feed of 0.004"-0.006" per cutting tooth. Grinding: The alloy should be wet ground and aluminum oxide wheels or belts are preferred.

Forming		This alloy has good ductility and may be readily formed by all conventional methods. Because the alloy is stronger than regular steel it requires more powerful equipment to accomplish forming. Heavy-duty lubricants should be used during cold forming. It is essential to thoroughly clean the part of all traces of lubricant after forming as embrittlement of the alloy may occur at high temperatures if lubricant is left on.

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 responds to annealing after cold working. It is not hardenable by heat treatment.

Forging		Forging may be done at 2150 F to 1700 F.

Hot Working		See "Forging".

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 steels ( 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".

Annealing		Annealing is done at 2225 F followed by rapid cooling or water quenching.

Hardening		Hardens by cold working only.

Other Mechanical Props		Strength for annealed material.

Physical Data : [top]

Density (lb / cu. in.)	0.324
Specific Gravity	8.97
Specific Heat (Btu/lb/Deg F - [32-212 Deg F])	0.099
Electrical Resistivity (microhm-cm (at 68 Deg F))	753
Melting Point (Deg F)	2450
Mean Coeff Thermal Expansion	7
Modulus of Elasticity Tension	30.6

Form		Plate
Condition		Solution Annealed
Temper		70
Tensile Strength		125.4
Yield Strength		57.4
Elongation		50
Form		Plate
Condition		Solution Annealed
Temper		1000
Tensile Strength		102.5
Yield Strength		40.3
Elongation		53
Form		Plate
Condition		Solution Annealed
Temper		1200
Tensile Strength		97.7
Yield Strength		39.5
Elongation		55
Form		Plate
Condition		Solution Annealed
Temper		1400
Tensile Strength		87.7
Yield Strength		42.5
Elongation		52
Form		Plate
Condition		Solution Annealed
Temper		1800
Tensile Strength		35.2
Yield Strength		21.1
Elongation		83
Form		Plate
Condition		Solution Annealed
Temper		2000
Tensile Strength		19.5
Yield Strength		10.8
Elongation		83