Therefore, the finished product warehouse of mechanical ductile iron pipe of the material itself can be better improved, and it has the essence of iron and the performance of steel. The metallographic structure of the annealed ductile iron pipe is ferrite and a small amount of pearlite, which has good mechanical properties, excellent corrosion resistance, good ductility, good sealing effect and easy installation.

Casing in the production prone to outer folding defects, affect product quality improvement, it needs to be controlled.

Hydrostatic pressure test is conducted using a method for static characteristics of rock deformation measurement indicators.

ERW is the first letter abbreviation for electric resistance welding.
ERW tube and submerged arc welding pipe significantly different, using a pressure-free filler metal welding, the weld is not filled with other ingredients, relying on high-frequency cur