The roundness of the eccentric pipe should not exceed 1% of the corresponding outer diameter at the ends, with allowable deviation of ±3mm. The material of the eccentric pipe conforms to SY/T5037, GB/T9711, GB/T8163, ASTM A106/A53 GRB, API 5L, APT5CT, ASTM A105, ASTM A234, ASTM A106, DIN German standards, and customer-specified standards. The eccentric pipe (reducer) is a type of pipe fitting used at pipe diameter changes. The commonly used forming processes include reducing and expanding, or reducing and then expanding, and for certain specifications, stamping can also be employed.