Specification for white pvc - u extruded hollow profiles with heat welded corner joints for plastics windows : materials type b 塑料窗用带热焊拐角连接的聚氯乙烯u型挤压空心型材外型规范: b型材料
2.
Railway rolling stock . art and resistance welded joints of steels . part 1 : acceptance criteria for defects in welded butt and corner joints 铁路车辆.钢的电弧和电阻焊接接头.第1部分:对接焊点和角焊接点中缺陷的验收准则