【摘要】 在不同的预热温度下,利用CO2激光器对6 mm厚的异种金属材料微合金钢Qste420TM和中碳钢XC45进行焊接。通过光学显微镜对焊缝的微观结构及成分进行观察,结合显微硬度测试手段,研究了预热温度对微观组织的影响。研究表明相比常温下进行的焊接,经过预热后焊缝热影响区粗晶区组织变得粗大,靠近XC45钢处的热影响区生成了更多的板条马氏体和粒状贝氏体,靠近Qste420TM处的热影响区由部分的板条马氏体转变成了无碳贝氏体和粒状贝氏体。200℃的预热温度下焊缝处板条马氏体中有碳化物析出,300℃时转变成回火马氏体。显微硬度测试结果与组织的规律一致。更多还原

【Abstract】 Dissimilar metal micro-alloy steel Qste420TM and medium carbon steel XC45 plates with 6 mm thickness were butt welded at different preheating temperatures by CO2 laser.Optical microscopy(OM),hardness equipment and tensile machine were employed to evaluate the properties of weld seam.Results show that compared with the weld seam at room temperature,the grains in the coarse grain zone get coarser.More lath martensite and granular bainite appear in the coarse grain zone of XC45.And some of the lath martensite in the coarse grain zone of Qste420TM transform to carbonless bainite and granular bainite.When the preheating temperature reaches 200 oC,carbide is precipitated in the form of lath martensite.And the weld seam shows a higher tensile strength and hardness.更多还原