... CNG pipe: resist high press from outside,no leak on tube, tested by 1500kg water press;smooth and tough,advanced ... oil system, fuel system,etc2. Raw materials: low carbon steel tube, copper tube, seamless steel pipe3. Speciation:φ6.00mm × 1±0.1mmφ8 ... System-ISO155005. Products functions: our materials single/double wall steel tube conform to Country YB/T4164-2007 standards6. Mechanical functions: Good ...