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通过力学性能测试及微观组织分析研究了传统中板及低碳、Nb-Ti微合金化Q345R热连轧压力容器板在手工焊、气保焊及埋弧焊3种焊接工艺下的接头性能,测定了不同焊接工艺下接头各区域的硬度分布,评价了Q345R接头力学性能。试验结果表明,连轧Q345R板焊接接头具有更好的综合性能,其接头冲击韧性明显好于传统中板,粗晶区淬硬程度低。连轧板良好的性能来源于TMCP工艺下碳当量降低及Nb-Ti微合金化处理改善了基体及接头的微观组织。
The joint performance of traditional mid-plate and low-carbon, Nb-Ti microalloyed Q345R hot rolling pressure vessel plates under three kinds of welding processes, ie manual welding, gas-shielded welding and submerged arc welding, was studied through mechanical properties test and microstructure analysis. The hardness distribution of joints in different welding processes was measured, and the mechanical properties of Q345R joints were evaluated. The test results show that the continuous rolling Q345R plate welded joint has better overall performance, the impact toughness of the joint is obviously better than the traditional plate, the coarse grain region hardened low. The good performance of the continuous rolling plate comes from the reduction of carbon equivalent and the micro-alloying treatment of Nb-Ti under the TMCP process to improve the microstructure of the matrix and the joint.