Tensile, bending, room temperature and low temperature-40 ℃ impact and hardness tests were performed on Q450NQR1 high-strength weathering steel MAG welded 45°, 50°, 60° HV grooved butt joints, and the fractures of the tensile and impact specimens were scanned and the microstructure for analysis. The results showed that the tensile properties of the three different included angle joints were good, and the tensile properties of the 45° bevel joint were the best, the 45°, 50°, 60° HV included angle joints had good bending properties. The room temperature impact performance was good, but the low temperature impact performance was significantly reduced. The room temperature and low temperature impact performance of the 50° included angle joint was higher than that of the other two included angle joints. Observing the fracture surface showed that the specimens at different temperatures were all ductile fractures, the hardness distribution of the three different included angle joints was roughly the same. The hardness value near the fusion line of the 60° included angle joint was higher than that of the other two included angle joints, and the hardness values were all in line with the standard, the 60° included angle was pre-eutectoid in the joint weld due to the large included angle and slow heat dissipation. The amount of ferrite was more than the other two groove joints.
To effectively improve the exothermic welding effect of the subway copper grounding grid, it was necessary to reasonably set the exothermic welding process parameters. Therefore, the optimization method of the exothermic welding process parameters of the subway copper grounding grid was studied. Taking T2 type copper tube with a diameter of 35 mm, a wall thickness of 3 mm, a length of 1 800 mm, and w（Cu）99. 98% as an example, the exothermic welding process was selected, and the three main exothermic welding process parameters, namely preheating temperature, welding speed and welding time, were analyzed by orthogonal experiment to optimize the exothermic welding process parameters of copper tube. The experimental results showed that the order of the primary and secondary factors affecting the exothermic welding effect of the subway copper grounding grid was: welding speed, preheating temperature, compaction pressure, and the corresponding optimal process parameters were 0. 6 mm∕s, 100 ℃, 0. 43 MPa respectively. After optimizing the exothermic welding process parameters, the exothermic welded joints of the welded metro copper grounding grid were neat and beautiful, without burrs and solution splashing, and there were almost no cavities on the welding cutting surface. The surface was relatively flat and dense. The maximum impact energy at the welding point could reach 91. 6 J, and the maximum compressive strength could reach 481. 5 MPa. It had good toughness and compression resistance, and the welding effect was good.
在实际生产中,650轧机2000kW电机轴发生了突然断裂,从断裂看,断口有10％旧裂纹.电机轴材质为35CrMo钢,因没有备品,需要尽快修复.为了防止变形,采用芯轴热装对接的方法,精准对中;同时,为防止长轴产生焊接变形,采取了预热和消除应力的措施,成功进行了修复,及时恢复了生产.
为满足国家对海洋油气生产装备制造业的战略需求,同时适应集团公司"建设国际一流能源公司"的总体布局,结合公司发展战略和转型升级需要及滨海新区场地现状,本公司拟在天津港保税区临港区域建设一个海洋工程装备制造基地.利用此次契机,同时为了盘活国有闲置资产,经过考察、论证,决定重新启用原上海振华港机制造的1台900 t门式起重机,通过拆解、运输、合龙、安装、调试,达到重新启用的目的.龙门吊主体的合龙、安装主要采用手工焊接的方法,安装、调试完成后经过第三方的质检和特检所的验收,各方面均合格,一次性通过验收,完全可以重新投入使用.经过一段时间的试运营,设备各方面指标、性能都得到充分的验证,性能稳定,运行平稳,受到使用方和业主的高度评价和赞扬.
通过对不锈钢药芯焊丝E308LT1-1在使用防飞溅剂时,焊接后容易产生气孔进行分析,发现防飞溅剂污染焊接坡口后焊接时产生了大量的气体,导致不锈钢药芯焊丝E308LT1-1焊缝容易产生氢气孔.合理控制氟化物和氧化物的加入量能够提高不锈钢药芯焊丝对防飞溅剂的适应性,使焊缝不产生气孔;合理加入氧化铁和氧化铈不会对该药芯焊丝工艺性能和力学性能产生不良影响.
