Why do seamless steel pipes crack?

Posted by zora li on December 14th, 2022

Why do seamless steel pipes crack?

Recently, our company's small partners often encounter customer feedback during the process of talking with customers. In their previous procurement experience, they often encountered cracking problems in purchased steel pipes, which led to serious problems in product quality and caused losses to the company. A big loss. The following permanent steel pipe manufacturing Co., Ltd. will give you an analysis of the main factors that cause the cracking of seamless steel pipes.

What are the main factors that cause seamless steel pipe cracking? There are mainly the following points:

1. Raw material selection

In order to save costs, some seamless steel pipe manufacturers will use round steel produced by small steel mills for processing, but the round steel produced by these small steel mills will contain many impurities, air bubbles, interlayers, pores, etc., which are easy to cause cracks after post-processing. question. PMC steel pipe round steel is purchased from high-quality round steel such as Baosteel and Huaiwu Steel, and the supply is reliable.

2. Improper heat treatment temperature control

Small manufacturers do not have professional production experience and technology. Workers in the workshop cannot only rely on the heating temperature and time to ensure whether the heat treatment of the steel pipe is in place. Heat treatment will change the mechanical properties of the steel pipe. However, general manufacturers do not have clear indicators for different steel types, wall thicknesses, mechanical properties, etc., and do not have testing equipment to judge whether the pipes meet the performance indicators required by customers.

How does PMC control production?

Each batch of steel pipes produced by PMC steel pipes has clear normalizing, annealing, tempering temperature and speed indicators, and tensile tests are carried out to determine whether the products meet the performance required by customers. These data parameters are used as the basis for production, so as to ensure the customer's product quality and the stability of the final use, rather than relying on the experience of a certain worker to determine, which is the main factor that PMC steel pipes have always been favored. Years left.

3. Straightening strength

Straightening is equivalent to secondary deformation. Bi-directional force is applied when straightening. If the operator is inexperienced, the straightening force is too large, and the strength of the thick-walled pipe is not well controlled, it will cause internal damage and cracks. This is also the reason for the later cracking of the steel pipe.

4. Stretch deformation

If the drawing deformation is too large, cracks in the steel pipe will also be formed, causing the steel pipe to crack in the later processing. The elongation rate of bright tube is low, generally 7-8%, the deformation is large, the elongation rate is low; the deformation is small, the elongation rate is high. Some small manufacturers cut corners and materials in order to save workmanship. Three deformations are changed to two, so that the deformation is enlarged, and the stress is too large to cause cracking.