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Heat treatment method of high-chromium martensitic stainless steel

A heat treatment method, high-chromium martensite technology, applied in the field of stainless steel heat treatment, can solve the problems of oil pollution, easy fire, and low safety factor in the production site of heat treatment furnaces, and achieve the goals of avoiding cracking of workpieces, eliminating quenching stress, and reducing quenching stress Effect

Active Publication Date: 2013-11-06
HENAN ZHONGYUAN SPECIAL STEEL EQUIP MFG CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

After the 4Cr16Mo stainless steel products are heat treated according to the conventional process, although the mechanical properties can be guaranteed, but because oil is used as the cooling medium during quenching, the oil fumes during production are relatively large, resulting in serious oil pollution in the heat treatment furnace, crane and production site, and due to the size of the workpiece Larger (the maximum diameter is about 450mm, the length is about 10m, and the weight of the forging is about 10t), the quenching temperature is high, and it is easy to catch fire when it is cooled in a horizontal oil tank, and the safety factor is low.

Method used

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  • Heat treatment method of high-chromium martensitic stainless steel

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] A heat treatment method for high chromium martensitic stainless steel, the method is as follows:

[0020] 1) Annealing

[0021] Put the forged stainless steel workpiece into the furnace at a surface temperature of 650°C, put it into a furnace at 700°C, and raise the temperature to 830°C at a heating rate of 100°C / h, and the holding time is 2.3 to 2.7 hours / 100mm Calculation, that is, calculate the holding time according to the length of the workpiece. After the holding is over, cool down with the furnace at a cooling rate of 30°C / h to 80-200°C and leave the furnace for air cooling;

[0022] 2) Preheat

[0023] After the annealing process, the stainless steel forgings are preheated twice at the furnace temperature of 300°C. The first preheating temperature is 560°C, and the holding time is 4h. The second preheating temperature is 820°C, and the holding time is 4h;

[0024] 3) Quenching

[0025] After twice preheating, the quenching temperature of the forging is 1060°C...

Embodiment 2

[0029] A heat treatment method for high chromium martensitic stainless steel, the method is as follows:

[0030] 1) Annealing

[0031] Put the forged stainless steel workpiece into the furnace at 700°C at a furnace temperature of 700°C, and raise the temperature to 830°C at a heating rate of 60°C / h. The holding time is calculated at 2.3 to 2.7 hours / 100mm. After the heat preservation is over, cool down with the furnace at a cooling rate of 10°C / h to 80°C and leave the furnace for air cooling;

[0032] 2) Preheat

[0033] The stainless steel forgings that have undergone the annealing process are preheated twice at a furnace temperature of 400°C. The first preheating temperature is 480°C, and the holding time is 1h. The second preheating temperature is 760°C, and the holding time is 1h;

[0034] 3) Quenching

[0035] After twice preheating, the forging is quenched at a quenching temperature of 950°C and the holding time is 0.8 to 1.3 hours / 100mm, so that the center of the wor...

Embodiment 3

[0039] A heat treatment method for high chromium martensitic stainless steel, the method is as follows:

[0040] 1) Annealing

[0041] Put the forged stainless steel workpiece into the furnace at 660°C at the furnace temperature of 660°C, and heat it up to 850°C at a heating rate of 80°C / h. The holding time is calculated at 2.3 to 2.7 hours / 100mm. After the heat preservation is over, cool down with the furnace to 140°C at a cooling rate of 20°C / h and leave the furnace for air cooling;

[0042] 2) Preheat

[0043] After the annealing process, the stainless steel forgings are preheated twice at a furnace temperature of 100°C. The first preheating temperature is 520°C, and the holding time is 2.5h. The second preheating temperature is 790°C, and the holding time is 2.5h;

[0044] 3) Quenching

[0045] After twice preheating, the forgings are quenched at a quenching temperature of 1000°C and the holding time is 0.8 to 1.3 hours / 100mm, so that the central part of the workpiece r...

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Abstract

The invention relates to a stainless-steel heat treatment technology, in particular to a heat treatment method of high-chromium martensitic stainless steel. The heat treatment method comprises the following steps of: 1) annealing; 2) preheating; 3) quenching; and 4) tempering. The heat treatment method has the following advantages that 4Cr16Mo stainless steel heat treatment process comprises the following procedures of: (1) complete annealing, controlling the furnace entering temperature after forging, the heating speed, the heating temperature, the insulating time and the furnace cooling speed; (2) quenching heating, controlling the preheating temperature, the heating speed, the heating temperature and the insulating time; (3) quenching cooling, adopting a gap-cooling mode of air-liquid-air-liquid-air-liquid, the quenching stress is furthest reduced while ensuring that a workpiece obtains enough quenching cooling severity and obtains a martensitic structure, and the cracking of the workpiece caused by excessive stress is avoided; and (4) tempering, strictly controlling the tempering furnace-entering time, tempering heating temperature and the insulating time, the structure transformation is complete, the quenching stress is eliminated, and fine and uniform tempering sorbite is obtained.

Description

technical field [0001] The invention relates to a heat treatment technology for stainless steel, in particular to a heat treatment method for high-chromium martensitic stainless steel. Background technique [0002] For the high-strength corrosion-resistant stainless steel used in the production of polyester fiber catalyst spindles in the petrochemical industry, it needs to install multiple blades on the shaft during work, and install them in polyester tanks as a rotating agitator. The working environment is very harsh, so it must have High corrosion resistance and good comprehensive mechanical properties. After heat treatment of 4Cr16Mo stainless steel products according to the conventional process, although the mechanical properties can be guaranteed, but because oil is used as the cooling medium during quenching, the oil fume is relatively large during production, resulting in serious oil pollution in the heat treatment furnace, crane and production site, and due to the si...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C21D1/18C22C38/44
Inventor 赵颖仲维王国宣王学玺马军平
Owner HENAN ZHONGYUAN SPECIAL STEEL EQUIP MFG CO LTD
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