What are the reasons for the cracking of seamless steel pipes?

What are the main factors causing cracking of carbon seamless steel pipes? There are mainly the following points:

1. Raw material selection

Some seamless steel pipe manufacturers will choose round steel produced by small steel mills for processing in order to save costs, but the round steel produced by these small steel mills will contain many impurities, air bubbles, interlayers, pores, etc., which will easily cause cracking after post-processing The problem is that Husteel steel pipe round steel is purchased from high-quality large manufacturers such as Baosteel, Huaigang, Zhongtian, etc., and the source is reliable.

2. Heat treatment temperature control is not in place

Small manufacturers do not have professional production experience and technology, and workshop workers cannot guarantee whether the heat treatment of steel pipes is in place based on the heating temperature and duration alone, and heat treatment will change the mechanical properties of steel pipes. However, general manufacturers do not have clear indicators for different steel grades, wall thicknesses, and mechanical properties, nor do they have testing equipment to judge whether the pipes have reached the performance indicators required by customers.

How does Husteel control the quality?

Each batch of steel pipes produced by Husteel Steel Pipe has clear temperature and speed indicators for normalizing, annealing, and tempering, and tensile tests will be carried out to determine whether the product meets the performance required by customers. These data parameters are used as the basis for production. Guarantee the stability of the customer's product quality and end use, rather than relying solely on the experience of a certain worker, this is the main factor why Husteel Steel Pipe has cooperated with many well-known companies in the industry for many years.

3. Drawing deformation

If the amount of deformation in drawing 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 amount is large, and the elongation rate is low; the deformation amount is small, and the elongation rate is high. Some small manufacturers cut corners and materials. In order to save the process, the three deformations were changed to two, which enlarged the deformation and caused cracking due to excessive stress.

4. Straightening strength

Straightening is equivalent to secondary deformation, and two-way force is applied during straightening. If the operator is inexperienced, the straightening force is too harsh, and the thick-walled pipe does not control the force well, it will cause internal damage and cracks in the steel pipe. It is also the reason for the cracking of the steel pipe in the later period.

5. Both ends of the steel pipe are not cut clean

Many manufacturers blindly pursue the yield rate, only cut a few centimeters at both ends of the steel pipe, and the hidden danger of cracking at both ends of the steel pipe has not been removed, which is also one of the factors that lead to cracking in later use.

Seamless vs Welded Pipes

In terms of performance, seamless steel pipes have greatly improved the pressure bearing capacity compared with welded steel pipes, so they are often used in high-pressure equipment. Such as the pipeline connection of hydraulic equipment, etc. The weld seam part of the welded steel pipe is its weak link, and the quality of the weld seam is also the main factor affecting its overall performance.