630℃汽轮机用铸钢材料CW2热处理工艺研究

Research on Heat Treatment Process of Cast Steel Material CW2 for 630℃Steam Turbine

通过热力学计算和热处理工艺试验,研究了630℃等级汽轮机铸钢材料CW2合金的力学性能和显微组织,最终确定1130℃和750℃是CW2合金最佳的正火温度和回火温度,材料的强度和塑韧性都能够达到技术指标要求,经过630℃高温长时时效,材料仍能保持较好的强度和稳定的组织。当正火温度超过1150℃时,组织中析出δ-铁素体对铸钢材料的冲击韧性产生不利影响。

Through thermodynamic calculation and heat treatment process test,the mechanical properties and microstructure of 630°C grade steam turbine cast steel material CW2 alloy have been studied.Finally,it has been determined that 1130°C and 750°C are the best normalizing temperature and tempering temperature of CW2 alloy.The strength and plasticity and toughness of the material can meet the technical requirements.After high temperature and long aging at 630°C,the material can still maintain good strength and stable structure.When the normalizing temperature exceeds 1150°C,the precipitation ofδ-ferrite in the microstructure has an adverse effect on the impact toughness of the cast steel material.