700MPa级高强度调质钢板焊接性能研究

从低成本700 MPa级调质中厚钢板的焊接性能着手,分析了母材的成分、组织及性能特点,研究了其焊接冷裂纹敏感性、焊接过程中的热输入量以及焊后热处理过程对试验钢焊接接头组织和性能的影响。结果表明,针对50 mm厚的700 MPa级高强度调质钢板,在中等拘束条件下,采用BHG-4M焊丝富氩混合气体保护焊、预热100℃的工艺进行焊接可以防止冷裂纹产生;在苛刻拘束条件下,最低预热温度在120℃以上才能防止裂纹产生;试验钢对焊接工艺规范有较强的适应性,焊接热输入量在8.85~24.17 kJ/cm范围内变化时,试验钢焊接接头的综合力学性能保持在较高水平。

Investigation on Welding Performance of Quenched and Tempered Type 700 MPa Grade High Strength Steel Plate

On the basis of welding performance of quenched and tempered type 700 MPa grade high strength steel plate, the chemical composition, microstructure and mechanical properties of the steel are analyzed, crack sensitivity and effect of the heat input and post welding heat treatment on the microstructure and mechanical properties of welded joint are studied. The results show that cold cracking can be prevented from the 50 mm thickness quenched and tem pered type 700 MPa grade high strength steel plate when preheating at 100 ℃ and welding under moderate restraint conditions with BHG -4M wire and rich Ar gas shield welding process, while cracking can avoided on the same plate when preheating at min. 120 ℃ and welding under severe restraint conditions with the same welding process. The trial steel has strong adaptability to the welding specifications, i. e. , when welding heat input varies between 8.85 - 24.17 kJ/cm,the comprehensive mechanical properties of the weld joint maintain at relatively high level.