Heat treatment technology of martensite stainless steel workpiece

Abstract

The invention discloses a heat treatment technology of a martensite stainless steel workpiece. The technology comprises the steps of annealing, quenching, a primary tempering technology and a secondary tempering technology. By adopting the above mode, the heat treatment technology allows a forged piece to satisfy a heat treatment hardness requirement, guarantees the heat treatment performance, realizes a high quenching hardness, and also realizes alloy uniformization, crystal grain refinement and forging stress elimination.

Description

technical field [0001] The invention relates to the field of metal material processing, in particular to a heat treatment process for martensitic stainless steel. Background technique [0002] For a long time, the current status of heat treatment of traditional domestic martensitic stainless steel 410ss forgings (75K) is as follows: do not pay attention to the role of preparatory heat treatment, annealing is often annealed at a lower temperature of 760-780 ° C; some do not even anneal, direct quenching + tempering; heat treatment process Large randomness, wide range of quenching temperature: 950-1040°C cooling medium used is N32 mechanical quenching oil, water, air cooling, etc.; two temperings are air-cooled. These treatment methods will cause the following problems: 1. No annealing or non-standard annealing, lack of the first phase change recrystallization process, easy to coarse grains or uneven grains, alloy elements cannot be fully dissolved, often resulting in quenchin...

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Problems solved by technology

These treatment methods will cause the following problems: 1. No annealing or non-standard annealing, lack of the first phase change recrystallization process, easy to coarse grains or uneven grains, alloy elements cannot be fully dissolved, often resulting in quenching, After tempering, the hardness is uneven, and the quenching stress is large, which also affects the low-temperature impact performance; 2. The randomness of the quenching temperature is not conducive to the potential of the material, and the obtained mechanical properties are different; 3. N32 mechanical quenching oil heat treatment is outstanding The problem is that the cooling speed is slow, the quenching hardness of the workpiece is low, and the oil fume overflows during heat treatment at the same time, the operating environment is poor, and it is easy to catch fire; water is used as a quenching medium to quench and has a tendency to crack. The disadvantages of air cooling for larger 410 forgings are: low surface hardness, quenching The penetration layer is shallow and the low-temperature impact performance is poor; 4. Since it has been recognized that the metal material 410ss has temper brittleness, the low air-cooled low-temperature impact value after the second tempering has been confirmed by heat treatment experiments