Effects of pulsed Nd: YAG laser welding parameters and subsequent post- weld heat treatment on microstructure and hardness of AISI 420 stainless steel
Effects of pulsed Nd: YAG laser welding parameters and subsequent post- weld heat treatment on microstructure and hardness of AISI 420 stainless steel
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DOI：
10.1016/j.matdes.2012.06.027
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发表时间：
2013-01-01
影响因子：
8.4
通讯作者：
Mousavi, S. A. A. Akbari
中科院分区：
文献类型：
--
作者：
Baghjari, S. H.;Mousavi, S. A. A. Akbari
马氏体不锈钢常用于需要高强度和中等耐腐蚀性的场合。在这项研究中，脉冲Nd：YAG激光焊接AISI 420马氏体不锈钢被认为是。试样的焊接是自动进行的。样本之间的间隔几乎为零。所有样品均为对焊。研究了电压、激光束直径、频率、脉冲宽度和焊接速度等焊接参数对焊缝尺寸的影响，得到了最佳焊接参数：电压450 V，激光束直径0.6 mm，频率6 Hz，脉冲宽度5 ms，焊接速度1.5 mm/s。采用光学显微镜和扫描电镜对熔池和热影响区的微观组织进行了观察。还进行了显微硬度研究。结果表明，焊缝马氏体组织中存在少量残余δ铁素体，热影响区中M23 C6碳化物粗化。热影响区的硬度值高于焊缝区。为了降低焊缝和热影响区的硬度并增加这些区域的韧性，进行了两种类型的焊后热处理（PWHTs）。在类型1中，样品回火2 h。在类型2中，样品在1010摄氏度下回火0.5小时，然后回火2小时。为了实现高强度和韧性，类型1和2热处理的最佳回火温度分别为595和537 ℃。结果表明，类型2比类型1具有更高的韧性。(c)2012爱思唯尔有限公司保留所有权利。
Martensitic stainless steels are often used in cases where high strength and medium corrosion resistance are required. In this study, pulsed Nd: YAG laser welding of AISI 420 martensitic stainless steel is considered. Welding of samples were carried out autogenously. The spacing between samples was set to almost zero. All samples were butt welded. The effect of welding parameters such as voltage, laser beam diameter, frequency, pulse duration, and welding speed on the weld dimensions were investigated and the optimum values were obtained for the 450 V voltage, 0.6 mm focal diameter, 6 Hz frequency, 5 ms pulse duration and 1.5 mm/s welding speed. Microstructure of weld pool and heat affected zone (HAZ) were investigated by optical microscopy (OM) and scanning electron microscopy (SEM). Micro-hardness studies were also carried out. The results showed the presence of some remaining delta-ferrite in the martensitic weld structure and coarsening of M23C6 carbides in HAZ. The magnitude of hardness in the HAZ was higher than that of the weld zone. To reduce the hardness of weld and HAZ and to increase the toughness in these regions, two types of post-weld heat treatments (PWHTs) were carried out. In type 1, samples tempered for 2 h. In type 2, samples austenitizied for 0.5 h at 1010 degrees C and then tempered for 2 h. In order to achieve high strength and toughness, optimum temper temperatures for type 1 and 2 heat treatments were obtained for 595 and 537 degrees C, respectively. The results showed higher toughness for type 2 than type 1. (c) 2012 Elsevier Ltd. All rights reserved.