The reason for the cracking of seamless steel pipe
Posted by chase Liu on May 9th, 2023
The seamless pipe has a hollow cross-section and is widely used as a pipeline for conveying fluids, such as octg pipes for conveying oil, natural gas, gas, water, and pipes for certain solid materials. Compared with welded pipes, seamless pipes have higher bending and torsional strength and better compression resistance, and are economical section steels. Widely used in oil, natural gas, water, steam, gas and other high, medium and low pressure fluid transmission pipelines and steel pipes for piling, bridges, buildings and other structures
The root causes of seamless steel pipe cracking mainly include the following points:
1. Raw materials
In order to save costs, some seamless steel pipe manufacturers will choose round steel produced by small steel mills for processing. However, the round steel produced by these small steel factories will contain a lot of impurities, bubbles and other problems. The seamless steel pipe produced by using this kind of round steel will have interlayers, pores, etc. inside, and after post-processing, cracking problems will occur.
2. Heat treatment temperature control is not in place
Some manufacturers do not have rich production experience, and the heating temperature and duration can only be judged by the experience of workshop workers, which cannot guarantee whether the heat treatment of seamless steel pipes is in place. However, heat treatment will change the mechanical properties of seamless steel pipes, and general manufacturers do not have testing equipment to judge whether seamless steel pipes have reached the performance indicators required by customers.
3. Straightening
In the process of straightening, excessive straightening force will also cause internal damage and cracks in the steel pipe, and it will be packaged and shipped without flaw detection in the later stage, which is also the reason for the cracking of the steel pipe in the later stage.
4. Pulling
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.
