经TMCP处理的ABS-EQ47海工厚板钢的组织性能

Microstructure and Mechanical Properties of TMCP Processed ABS-EQ47 Plate Steel for Offshore Platform

以工业生产的ABS-EQ47钢为对象,研究了奥氏体连续冷却相变行为,在中试工厂使用热机轧制(thermomechanical control process,TMCP)工艺成功开发出35mm和40mm厚钢板,考察了钢板经单道次模拟焊接热循环后的组织性能。结果表明,所开发钢板的组织为针状铁素体+细粒状贝氏体,屈服强度(Rp0.2)高于500MPa,抗拉强度(Rm)高于630MPa,伸长率(A)大于20%,在-60℃下横向Charpy冲击吸收能量(KV2)大于200J。TMCP型钢板的屈强比低于同成分调质(QT)钢板的屈强比,但其Rm高于QT型钢板。模拟焊接热输入为30kJ/cm时,粗晶区HAZ试样的KV2不低于40J。

Continuous cooling transformation behavior of commercial ABS-EQ47 grade platform plate steel was investigated under various austenitizing scenarios, i. e. , under the non-deformed, deformed, and simulated heat-affected zone （HAZ） conditions. Plates ranged from 35 to 40mm in thickness were rolled from blocks sectioned from the industrially cast EQ47 steel slab during test-scale rolling trials employing thermo-mechanical control processing （TMCP）. Single pass welding processes were also simulated on the TMCP treated plates. The microstructures of the plates consist of mainly acicular ferrite （AF） ＋ refined granular bainite （GB）. An excellent combination of strength and toughness is achieved showing yield strength （Rp0. 2 ） greater than 500 MPa, tensile strength （Rm） greater than 630 MPa, and Charpy impact toughness （KV2） greater than 200J even at -60 ℃. In comparison with a commercial steel plate with the same composition and, however, treated by conventional quenching and tempering （QT） process, the TMCP plates exhibit better yield ratio and higher tensile strength. The KVz of the simulated coarse-grained HAZ is higher then 40J at -40 ℃ as long as the heat input of the simulated heat input is less than 30kJ/cm.