... process :Butt-welded&Overlap 2.cold or hot water,gas series 3.ISO,CE,AENOR, EMI certificate ... .1.process :Butt-welded&Overlap2.cold or hot water,gas series3.ISO,CE,AENOR, EMI certificate4.top ... . Hot water and cold water pipe for production and domestic use;2. Heating pipe, pipes used for heating installation on ... on;3. Pipe used for solar energy water heater;4. Coal gas and natural gas pipe;5. Drinking ...