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Páginas: 5 (1182 palabras) Publicado: 13 de octubre de 2012
Rene 95
Principal Design Features | | This is one of the nickel base high temperature, high strength alloys that is age-hardenable by heat treatment. It is one of the strongest alloys up to temperatures of 1400 F in this alloy category. |
Applications | | Gas turbine hot section components. |
Machinability | | Conventional machining techniques used for iron based alloys may be used. Thisalloy 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, ormilling. 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 ToolingDepth 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 workbest 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 nearestalloy 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. 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: 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. Shielded Metal-Arc Welding: 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. Current settings vary from 60 amps for thin material (0.062" thick) up to 140 amps for materialof 1/2" and thicker. It is best to weave the electrode slightly as this alloy weld metal does not tend to spread. Cleaning of slag is done with a wire brush (hand or powered). Complete removal of all slag is very important before successive weld passes and also after final welding. Gas Metal-Arc Welding: Reverse-polarity DC should be used and best results are obtained with the welding gun at 90...
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