The roundness of the eccentric pipe should not exceed 1% of the corresponding outer diameter at the ends, and the allowable deviation is ±3mm. The material of the eccentric pipe complies with 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 for eccentric pipes ( reducers). Eccentric pipes are a type of piping fitting used at pipe diameter changes. The commonly used forming processes include reducing and pressing, expanding and pressing, or a combination of both. For certain sizes of eccentric pipes, stamping forming can also be employed.