摘要:利用激光冲击波对X70管线钢焊接接头进行了改性处理,通过慢应变速率法(SSRT)研究了其在NACE(national association of corrosion engineers)标准饱和H2S溶液中应力腐蚀的敏感性,并对其断口进行SEM观察,分析了激光冲击处理对X70管线钢焊接接头抗H2S应力腐蚀开裂(SCC)行为的影响.结果表明,原始状态的X70管线钢焊接接头为脆性断裂,断口为应力腐蚀裂纹;经激光冲击处理后X70管线钢焊接接头,韧窝尺寸与深度变小,断口形式为韧性断裂;SCC是X70管线钢焊接接头应力腐蚀断裂的主要机制,激光冲击处理降低了氢致开裂和SCC的倾向,提高了焊接接头抗H2S应力腐蚀的能力.
摘要:焊缝跟踪是实现焊接自动化的前提条件.间隙的变化会影响基于熔化极气体保护焊(metal active gas,MAG)的管道自动打底焊的焊接质量,为此设计了基于电荷耦合器件(charge-coupled device,CCD)视觉传感的MAG打底焊焊接过程监控系统.但从CCD获取的焊接过程的图像通常具有很大噪声,亟需设计出有效的焊缝边缘提取方法,提出了一种新的焊缝边缘提取方法,使用预处理方法获取熔池区域,然后使用Sobel算子检测出候选左(下)焊缝位置作为贪婪Snake模型的初始轮廓控制点,使用贪婪Snake模型拟合焊缝边缘.结果表明,即使在出现噪声的图像中,该方法提取焊缝边缘也是有效的.
摘要:Dissimilar metal joining between 5A02 aluminum alloy and AISI 304 stainless steel was conducted by gas tungsten arc welding with ZnAl15 and AlSi12 flux-cored filler metals,and the effect of the filler metal composition on the microstructures and mechanical properties of the joints were investigated.The results revealed that the tensile strength of as-welded joints made with ZnAl15 and AlSi12 flux-cored filler metals was 121 MPa and 162 MPa respectively.After annealed at 280 ℃ for 30 min,the tensile strength of joints made with ZnAl15 flux-cored filler metal reached 180 MPa,while that with AlSi12 flux-cored filler metal was 166 MPa.The interfacial layer in the weld made with ZnAl15 filler metal was comprised of Znx and [Fe2Al5]Znx,and ternary intermetallic compound Al7.4Fe2Si was found in the interfacial layer in the joint made with AlSi12 flux-cored filler metal.The thickness of the interfacial layers made with both filler metal was less than 10 μm.
摘要:Study on pores in TIG welding of oxide dispersion strength ened(ODS) alloys MGH956 LEI Yucheng, REN Wenjie,Xie Weifeng, HUANG Wei, ZHU Qian, ZHANG Qi ( School of Material Science and Engineering, Jiangsu University, Zhenjiang 212013, China). p 1 -4