双液双金属高Cr合金/钢复合材料性能优化热力学研究

Thermodynamic Study on Performance Optimization of Two-liquid Bimetal High Cr-containing Alloy/Steel Composite Materials

对不同企业生产的双液双金属高Cr合金，钢复合材料进行了热力学分析，研究其钢中微量元素的固溶与沉淀析出规律，并根据具体工况优化了复合材料化学成分，改善其性能。研究表明：Ti／Nb基微合金钢中各微量元素固溶量随温度的减小而降低。尤其是元素Nb、Ti变化较明显，且Ti元素在全固溶温度～1050℃范围内，其固溶量急速下降；系数k1，k2，m1及№随温度的变化较复杂，各材料中系数№随温度降低而减小，系数k1随温度降低而增大，可见在冷却过程中析出的第二相所占的比例是随时改变。在高温阶段以TiN析出为主，低温阶段以NbC析出为主；优化后的复合材料，其高Cr合金锤头处存在条带状碳化物。硬度平均为HRC62．6。碳钢锤柄组织为贝氏体＋细致的回火屈氏体，硬度平均为HRC43．6；改进后材料的使用性能得到了大幅改善．提高了企业的市场满意度和产品的竞争力。

Thermodynamic analysis was conducted for the two-liquid bimetal high Cr-containing alloy/steel com- posite materials manufactured by different companies, and the equilibrium solid solution and precipitation be- havior of trace elements in steel was studied in different temperature and chemical composition. The chemical composition of composite materials was optimized according to the specific engineering conditions, and the per- formance was then improved. This study shows： the solid solution quantity of each trace element decreases as the temperature decreases in Ti/Nb microalloyed steels, and the effects of Ti and Nb are more significant, the solid solution quantity of Ti declines rapidly in the range of carbonitride full dissolution temperature, until to 10509; the changing rule of kl, k2, ml and ma with temperature is complicated and the m2 decreases as the temperature decreases, but the kl increases as the temperature decreases, so the proportion of second-phase changes at any time in the process of steel cooling; at high temperature phase, the precipitated mainly is TiN and at low temper- ature phase, the precipitated mainly is NbC; the composite material after optimizing has banded carbide in high Cr-containing alloy hammerhead with the mean hardness HRC62.6; the organization is bainite and refined tem- pered troostite in carbon steel hammerhandle with the mean hardness HRC43.6; the material application perfor- mance is significantly improved after optimizing, and the enterprise＇s market satisfaction and the competitiveness of products are thus enhanced.