固溶处理对高氮不锈钢微观组织及力学性能的影响

高氮不锈钢具有优异的综合性能。通过增加铬、锰含量在氮分压为80 000 Pa下成功冶炼出氮质量分数为0.54%的Cr-Mn-Mo系高氮不锈钢；试样钢热轧后分别经800、900、1000、1100、1200 ℃保温1、2、3、4、5 h固溶处理后正交分析，研究在不同温度和保温时间下的组织、屈服强度、抗拉强度、断后延伸率、断面收缩率和强塑积，旨在找到试验钢最佳的热处理温度和时间。结果表明，未经固溶处理和经800、900 ℃固溶处理后的试样中有Cr₂N析出，1200 ℃固溶处理后试样中析出铁素体，1000、1100 ℃固溶处理的材料为纯奥氏体组织，且在1000 ℃下保温4 h的试样塑性最好并有较高的强度，其断面收缩率和断后延伸率分别可以达到67.5%和69.5%。未经热处理的试样强度最高，并且断面收缩率和断后延伸率仍然保持在42%和49.9%。在1000 ℃下保温1 h的试样综合力学性能最好，强塑积可达到58.59 GPa%。

Effect of Solution Treatment on Microstructures and Mechanical Properties of High Nitrogen Stainless Steel

High nitrogen stainless steel has excellent mechanical and chemical properties. Cr-Mn-Mo high nitrogen stainless steel with a nitrogen content of 0.54wt% was smelted by increasing the content of Cr and Mn at the nitrogen partial pressure of 80 000 Pa. The sample steels after hot rolling were held at 800, 900, 1000, 1100 and 1200 °C for 1, 2, 3, 4, and 5 h. Orthogonal analysis was carried out to study the microstructure, yield strength, tensile strength, elongation to fracture, reduction of area, and product of strength and plasticity under different temperatures and holding time, in order to find the best heat treatment temperature and time for the test steel. The results show that Cr₂N precipitates in the samples without solution treatment and after solution treatment at 800 and 900 °C, and ferrite precipitates in the samples after solution treatment at 1200 °C. The materials treated at 1000 and 1100 °C are pure austenite. The specimen held at 1000 °C for 4 h has the best plasticity and high strength, and its section shrinkage and post-fracture elongation can reach 67.5% and 69.5%, respectively. The strength of the samples without heat treatment is the highest, and the reduction of section and elongation after fracture remains at 42% and 49.9%. The comprehensive mechanical properties of the samples held at 1000 °C for 1 h are the best, and the product of strength and plasticity can reach 58.59 GPa%.