基于某宽厚板生产线,采用调质工艺开发了一种屈服强度690 MPa级高强度工程机械用钢,钢板微观组织为板条状贝氏体,晶粒均匀、板条束尺寸细小.经检验,钢板的屈服强度Rp0.2达到780 MPa,抗拉强度Rm达到864 MPa,延伸率A达到18%.此外,钢板具有优良的低温冲击韧性,-20 ℃条件下冲击吸收功可以达到260 J以上;-40 ℃条件下冲击吸收功可以达到250 J以上;-60 ℃的超低温条件下其最低冲击吸收功依然可以达到238 J.钢板也具有良好的冷成型性能,可以满足严格的加工和严苛的服役要求.%A high strength plate with yield strength of 690 MPa was developed based on a heavy plate mill by quenching and tempering process.The microstructure of the plate is bainite.All grains were small and uniform.The size of bainite lath is thin.The yield strength Rp0.2, tensile strength Rm, and elongation A of the plate reached 780 MPa, 864 MPa, and 18.0%,respectively.The Charpy absorbed energy is higher than 260 J at-20℃ and also higher than 250 J at-40℃.The lowest Charpy absorbed energy can reach 238 J even at-60 ℃.Especially, the plate also has good cold-bending properties.
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