... :Butt-welded&Overlap 2.cold or hot water,gas series 3.ISO,CE,AENOR, EMI certificate 4.high ... .process :Butt-welded&Overlap2.cold or hot water,gas series3.ISO,CE,AENOR, EMI certificate4.top high quality ... 3. Pipe used for solar energy water heater;4. Coal gas and natural gas pipe;5. Drinking water within a ... in agriculture or garden;11. Pipes used for gas suction under condition of vacuum;12. Tubes used ...