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对800 MPa水电用钢进行了模拟焊后热处理,研究了焊后热处理对试验钢组织和性能的影响。结果表明:试验钢经模拟焊后热处理后,组织以贝氏体为主,但较回火态,粒状贝氏体等平衡态组织增多;在焊后热处理过程中,回火过程中析出的析出物未发生明显长大,且有部分较细小的析出物均匀、弥散地在基体上析出。经模拟焊后热处理后,钢板屈服强度和抗拉强度均有所下降,其中,屈服强度下降30~100 MPa,抗拉强度下降20~80 MPa;伸长率均有不同程度的上升,上升幅度在0.5%~2.0%范围内;模拟焊后热处理并未对试验钢的冲击性能产生明显的影响,试验钢模拟焊后热处理前后韧脆转变温度均在-45~-50℃之间
The 800-MPa hydropower steel was simulated after-welding heat treatment, and the effect of postweld heat treatment on the microstructure and properties of the test steel was studied. The results show that the microstructure of bainite is dominated by bainite after simulated post-weld heat treatment, but the equilibrium microstructure is more than that of tempered and granular bainite. During the post-weld heat treatment, the precipitated precipitates The material did not significantly grow up, and some of the smaller precipitates evenly dispersed in the matrix precipitation. After simulating post-weld heat treatment, the yield strength and tensile strength of the steel plate decreased, of which the yield strength decreased 30 ~ 100 MPa, the tensile strength decreased 20 ~ 80 MPa; elongation increased in varying degrees, the increase In the range of 0.5% ~ 2.0%. Simulated post-weld heat treatment had no significant effect on the impact properties of the test steels. The ductile-brittle transition temperatures of the test steels before and after the heat treatment were between -45 and -50 ℃