调质工艺对Q390E海洋工程用管组织与性能的影响

Effect by Quenching and Tempering Process on Microstructure and Properties of Q390E Steel Pipe for Offshore Engineering

用力学性能测试和微观组织分析等方法,研究了不同调质工艺对Q390E海洋工程用管微观组织和力学性能的影响。结果表明:Q390E海洋工程用管在890℃淬火+690℃回火可获得全部贝氏体,其强韧性匹配最佳;Q390E海洋工程用管实际的A_(c1)温度在690~710℃;在相同淬火温度时,当回火温度升高至710℃,Q390E海洋工程用管在两相区回火,基体组织出现明显的先共析铁素体,材料的低温冲击韧性严重恶化,且抗拉强度上升,屈强比降低。

Investigated are the effects by different quenching and tempering processes on the microstructure and mechanical properties of the Q390E steel pipe for offshore engineering by means of mechanical property testing and microstructure analysis.The results indicate that after being quenched at 890 ℃ and tempered at 690 ℃, the microstructure of the Q390E pipe is completely bainite, and has the best strength-low temperature toughness matching; and that the actual Ac1 temperature of the pipe is about 690~710 ℃, and at the same quenching tempera- ture, when the tempering temperature is going up to 710 ℃, and the pipe is tempered at a two-phase zone, and proeutectoid ferrite obviously developed in the matrix microstructure, which leads to seriously deteriorated lowtem- perature impact toughness, increased tensile strength, and decreased yield ratio of the material.