经济型双相不锈钢2101中氮化物在基体中的平衡固溶度计算

Equilibrium solid solubility of nitrides in the matrix of lean duplex stainless steel 2101

为了解析出物对经济型双相不锈钢2101热塑性的影响机制,对比了相同工艺下2101和2205双相不锈钢在热变形过程中相界析出物产生的规律.结果表明:2101钢比2205钢的相界处更倾向于产生析出物,促使后续热变形过程中相界产生裂纹,进而影响材料的热塑性.根据热力学相关数据,通过Thermo-Calc和实验测试数据,推导出2101和2205双相不锈钢析出物Cr2N的平衡固溶度公式,计算实验钢中析出物Cr2N的全固溶温度,同时引入Wagner相互作用系数,考虑了Ni、Mn、Mo和Si对固溶度积公式的影响.发现2101双相不锈钢中Cr2N的全固溶温度比2205钢高100℃左右,计算结果和实验结果吻合较好.实际生产过程中必须控制双相不锈钢热轧的终轧温度到全固溶温度以上,否则相界容易产生氮化物析出,影响材料热塑性.

In order to improve the thermoplasticity of lean duplex stainless steel, the precipitation law and mechanism of lean du- plex stainless steel 2101 （ LDX2101 ） and duplex stainless steel 2205 （ DSS2205 ） were studied in hot rolling. It is found that LDX2101 is susceptible to nitride precipitation at phase boundaries compared with DSS2205, which causes microcracks and results in the thermoplasticity of specimens worsen. According to relevant thermodynamic data, the equilibrium solid solubility formulas of Cr2 N precipitation in LDX2101 and DSS2205 were deduced, and total solid solution temperatures of Cr2N precipitation were calculated through Thermo-Calc software and experimental data. Meanwhile, the Wagner interaction coefficient was introduced to consider the in- fluence of Ni, Mn, Mo and Si on the equilibrium solid solubility product formula. The results show that the total solid solution temper- ature of Cr2 N precipitation in LDX2101 is around 100 ℃ higher than that in DSS2205. The calculation results and experimental results are in good agreement. The finishing hot roiling temperature must be above the total solid solution temperature in the practical produc- tion process to prevent Cr2N precipitation. Otherwise, the nitride precipitation is prone to produce at phase boundaries, which influ- ences the thermoplasticity of the materials.