Nitriding heat treatment process of high temperature alloy material
A high-temperature alloy and nitriding technology, applied in the direction of metal material coating process, coating, solid diffusion coating, etc., can solve the problem of inability to form a wear-resistant nitriding layer, etc., to achieve easy and control, convenient implementation and operation, high quality stable effect
Active Publication Date: 2006-05-17
SHANGHAI ELECTRIC POWER GENERATION EQUIPMENT CO LTD
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Problems solved by technology
However, according to the conventional nitriding heat treatment process of nitriding materials or stainless steel, the parts made of GH901 superalloy materials are subjected to chemical heat treatment, and the wear-resistant nitriding layer cannot be formed on the surface at all.
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[0015] see figure 1 , the valve stem of the parts is made of GH901 superalloy material. Before nitriding treatment, the surface of the valve stem should be cleaned and degreased, and then the valve stem should be placed in a well-type resistance furnace with automatic temperature control and instrument recording devices. , hung on the bracket and arranged in a dispersed manner, and used enamel gas nitriding buns and placed ammonium chloride infiltration agent. The actual operation of the nitriding heat treatment process for GH901 superalloy materials is as follows:
[0016] (1) Heat the furnace temperature to 150°C ± 10°C, pass ammonia gas at the same time, and keep warm for 2 hours to remove the air in the furnace;
[0017] (2) Continue to heat the furnace temperature to 300°C±10°C and keep it warm for 2 hours;
[0018] (3) Heat the furnace temperature to 575°C±15°C at a rate of 50°C per hour, adjust the ammonia decomposition rate at 32-55%, keep it warm for 45 hours, and t...
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Abstract
The nitriding heat treatment process of high temperature alloy material includes the following steps: 1. heating the furnace with workpiece to be treated to 150 deg.c while introducing ammonia and maintaining for 2 hr to eliminate air from the furnace; 2. raising the temperature to 300 deg.c and maintaining for 2 hr; 3. raising the temperature in the rate not higher than 50 deg.c an hour to 575 deg.c, regulating ammonia decomposing rate in 30-65 %, maintaining for over 40 hr, and detecting outer sample to determine final maintenance terminating time; 4. raising the temperature to 650 deg.c, regulating ammonia decomposing rate to not lower than 90 % and maintaining for at least 4 hr; 5. turning off power supply, cooling the workpiece inside the furnace, introducing small amount of ammonia for positive pressure; and 6. discharging the workpiece after the temperature in the furnace is lowered to below 150 deg.c and cooling in the air. Thus treated workpiece has hardness over HV800 and high wear resistance.
Description
(1) Technical field [0001] The invention relates to a nitriding heat treatment process of a high-temperature alloy material, in particular to a nitriding heat treatment process of a GH901 high-temperature alloy material. (2) Background technology [0002] GH901 alloy is a Fe-Ni-Cr based superalloy with γ′ phase precipitation strengthening, the matrix is austenite structure, and Al, Ti, Mo are the main strengthening elements. The alloy has high strength, oxidation resistance, structural stability and good comprehensive performance below 650 °C. Because of the high content of alloying elements, especially Ti, Ni, and Mo elements, the diffusion coefficient of nitrogen in iron is reduced, and the action of alloying elements and air forms a dense protective oxide film on the surface of the part. This layer of oxide film The infiltration of nitrogen atoms is hindered, so the conventional nitriding heat treatment cannot form a wear-resistant nitriding layer on the surface. [0...
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IPC IPC(8): C23C8/24
Inventor 宫力丁丽锋
Owner SHANGHAI ELECTRIC POWER GENERATION EQUIPMENT CO LTD