GB/T 12770-2002 机械结构用不锈钢焊接钢管 GB/T 12771-2000 流体输送用不锈钢焊接钢管 GB/T 13793-1992 直缝电焊钢管 GB/T 14975-2002 结构用不锈钢无缝钢管 GB/T 14976-2002 流体输送用不锈钢无缝钢管 GB/T 18984-2003 低温管道用无缝钢管 GB/T 3639-2000 冷拔或冷轧精密无缝钢管 GB 3087-1999 低中压锅炉用无缝钢管 GB/T 3091-2001 低压流体输送用焊接钢管 GB 5310-1995 高压锅炉用无缝钢管 GB/T 5312-1999 船舶用碳钢和碳锰钢无缝钢管 GB 6479-2000 高压化肥设备用无缝钢管 GB/T 8162-1999 结构用无缝钢管 GB/T 8163-1999 输送流体用无缝钢管 GB 9948-2006 石油裂化用无缝钢管 GB/T 14
uarantee for t he great struggl e. T his aspe cts XI Ge neral Secretary of speech main i ncl udi ng exercise thrift, against extravagance mass line i s party of lifeline and fundame ntal work r oute a ccurate grasp party of mass li ne educati on practi ce a ctivities of gui deli ne a nd target requirements set and develop "thre e strict t hree real" of style put power shut into system of cage i n