... stress crackingProduction standard :execute GB/T 13663-2000 'PE pipes for water supply'Production process:Automatic feeding → heating extrusion ... 5.Inside sleek, low resistance, water circulation ability, the construction cost6.Good abrasion resistance, abrasion resistance7.Low- ... , etc, to an new non-excavation technology,10.The PE material contains carbon, hydrogen, two elements of harmless11. ...