新型转子钢25Cr2Ni4MoV的焊接性及接头性能

Weldability and joint performance of new type rotor steel 25Cr2Ni4MoV

根据新型转子25Cr2Ni4MoV成分和合金特点,分别进行HAZ硬度、斜Y坡口裂纹、冷裂纹插销试验等,由试验结果可知,该钢种的冷裂纹敏感性强,焊接时预热温度应大于300℃。对接头常温力学性能和高温短时拉伸测试,结果表明该钢焊后的接头强度接近母材,塑性较好,焊缝的冲击韧性较高,接头微观组织为回火贝氏体和少量铁素体组织,断口由脆性断裂区和纤维断裂区组成,脆性断裂区为沿晶和准解理,随着预热温度的提高,沿晶成分减少,准解理部分增多。

According to the constituents and alloy characteristics of the new type rotor25Cr2Ni4MoV,the tests of HAZ hardness,bevel Y groove crack and cold crack bolt are respectively carried out.The results show that the cold crack sensitivity of the steel is strong and the preheating temperature should be more than300℃.The normal temperature mechanical property and high temperature tensile strength of welded joints are also tested.The results show that the strength of postweld joint is close to that of the base metal,and the weld has high impact toughness,and the microstructure of the joints is temper bainite and a few ferrite.The fracture surface is composed of brittle fracture zone and fiber fracture zone,and the brittle fracture zone is intergranular fracture and quasi-cleavage.When the preheating temperature increases,the intergranular part decrease,while the quasi-cleavage part increase.