The traditional heat treatment method of 2Crl3 generally recommends 1000 ° c-1050 ° C oil cooling or water cooling + 660 ° c-770 ° C oil cooling, water cooling or air cooling. The practice shows that if the AC3 point is too high, the grain size of the martensite structure will be coarse and the strength and initial property of the material will be reduced. When the temperature reaches 105ctc, the hardening and toughening will have little effect. The hardness is basically unchanged, and the toughness will decrease. Although the martensite is obtained by complete quenching to avoid the appearance of undissolved ferrite, thus improving the strength and hardness, However, once the heating temperature is too high, due to the continuous growth and extension of the grain, the coarse and uneven structure is caused, which has a bad impact on the strength and toughness requirements. The quenched martensite is “hard and brittle” and difficult to be machined. Therefore, tempering is continued to improve the plasticity, toughness and machinability. Generally speaking, tempering is conducted at 200 ° C-70 (TC). The microstructure and grain size of 2Crl3 stainless steel after quenching and tempering determine its performance. However, the heat treatment determines the structure type and grain size.
The strengthening and toughening treatment of 2Crl3 studied in the experiment was carried out by taking the heat treatment process as a means and the steam filter valve as an example to explore the performance change and mechanism under the heat treatment process parameters. The steam valve is a kind of valve body that controls the inlet and outlet of gas steam. The steam valve is precision cast with 2Crl3 stainless steel. Its valve body is mainly used for marine equipment, chemical equipment, power plant equipment, etc. with the development trend of high parameters, high performance and large-scale industrial equipment, it is required that the matched steam valve body also has higher performance.
As shown in the figure, the valve body equipment processed with 2Crl3 as the raw material is a failed valve part. Under the harsh and harsh working environment, the material itself has to accept a series of challenges such as high temperature and high pressure, alternating load and corrosive medium. It not only needs excellent manufacturing process, but also the performance index of the material itself is very important. Due to the stress concentration, grinding and erosion of the working environment, 2Crl3 material must have certain requirements for toughness, strength and hardness. According to the requirements of 2Crl3 stainless steel material given by China Shipbuilding Industry Fengfan Precision Casting Co., Ltd., the impact bremsstrahlung Akv value should be > 39.2j and the hardness should be about 220-255hbw, Tensile strength ＞ 490mpa, elongation ＞ 12%. Taking 2Crl3 material as the research object, through heat treatment test research and reasonable test scheme, the best process of strength and initial property matching is obtained. The formation mechanism of 2ch3 strengthening and toughening can be known through in-depth analysis of the structure of the material, which not only optimizes the heat treatment process of the material itself, but also improves the production efficiency, reduces resource waste and reduces the loss cost.