不同N含量的EH36钢中第二相粒子在焊接热循环过程中的变化规律….pdfVIP

不同 N 含量的 EH36 钢中第二相粒子在焊接热循环过程 中的变化规律 吕 冬 徐荣杰 魏世同 刘仁东 （鞍钢股份技术中心汽车与家电用钢研究所，鞍山 114009 ） 摘 要 利用萃取复型和焊接热模拟技术，对不同 N 含量的 EH36 钢母材和热模拟粗晶区第二相粒子的形态、尺寸 及分布情况进行分析。结果表明，高 N 含量钢中的第二相粒子数量多于低 N 含量钢，并且粒子分布更加弥散。经 过热模拟后钢中粒子的平均尺寸增加，数量减少。分析表明，t8/5 时间对粒子在热循环过程中的溶解和析出行为有 较大影响，t8/5=50s 时，粒子变化以小粒子的消失为主要特征，t8/5=150s 时，粒子不仅发生溶解和长大，在钢中还出 现了独立形核的第二相粒子。热模拟和实际焊接接头的冲击检验结果表明，高 N 含量钢冲击韧性好于低 N 含量钢。 关键词 第二相粒子 热模拟 焊接1 Variation of Precipitates in EH36 Steel with Different Nitrogen Contents during Weld Themal Cycle Lv Dong Xu Rongjie Wei Shitong Liu Rendong (Automobile and Home Appliance Steel Institute, Technology Center of Angang Steel Co. Ltd., Anshan, 114009) Abstract The morphology, size and distribution of precipitates in the base metal and coarse grain heat affected zone (CGHAZ) of EH36 steel with different nitrogen contents have been studied using carbon extraction replica and thermal simulation technology. The result shows that the quantity of precipitates in high nitrogen steel is more than that in low nitrogen steel, and the precipitates distribution is more dispersive in high nitrogen steel. After weld thermal cycle, the mean size of particles increases and the quantity decreases. It is concluded that t8/5 has a great effect on the dissolution and precipitation behaviors of particles in the steel. When t8/5 is 50s, the main characteristic is the dissolution of the small particles. When t8/5 is 150s, the precipitates dissolve or grow up, and particles nucleating independently can be found. The results of thermal simulation and impact tests indicate that the impact toughness of the high nitrogen steel is