Seamless steel pipes/tubes sometimes crack during production and use, which not only increases the loss of raw materials, but also affects their service life and the normal operation of related equipment. This article will discuss the causes of seamless steel pipe cracking and provide reference for relevant companies and personnel.
1. Selection of materials
Seamless steel pipes are made of perforated steel billets, so the quality of the material has a crucial impact on the quality of the steel pipes. If the steel billet has quality problems, such as uneven composition, high impurity content, etc., it will cause cracking during the perforation process. In addition, brittle inclusions, carbide segregation, etc. contained in the material will also affect the toughness of seamless steel pipes, making them prone to cracking.
In order to save costs, some seamless steel pipe manufacturers use round steel produced by small steel mills for processing. However, the round steel produced by these small steel mills contains many impurities, bubbles, interlayers, pores, etc., which are prone to cracks after post-processing.
2. Improper heat treatment control
Heat treatment is an important step in the production process of seamless steel pipes. If heat treatment is improper, it will also cause the steel pipes to crack. For example, during the quenching process, if the cooling rate is too fast or the temperature is too low, stress concentration will occur inside the steel pipe, causing cracking. In addition, if the tempering temperature is too low or the tempering time is insufficient, it will also affect the toughness of the steel pipe and make it prone to cracking.
The manufacturer does not have professional production experience and technology. Workshop workers cannot ensure whether the heat treatment of the steel pipe is in place simply by relying on heating temperature and time. Heat treatment will change the mechanical properties of the steel pipe. However, generally some small manufacturers do not have clear indicators for different steel types, wall thicknesses, mechanical properties, etc., and they do not have testing equipment to determine whether the pipes meet the performance indicators required by customers.
3. Straightening strength
Straightening is equivalent to secondary deformation. Bidirectional force is applied during 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 in the thick-walled pipe. This is also the reason for the later cracking of steel pipes.
4. Processing issues
Seamless steel pipes also have a risk of cracking during processing. For example, during the perforation process, if the perforation speed is too fast or the perforation temperature is too low, cracks will occur on the surface of the steel pipe, resulting in cracking. In addition, if the extrusion speed is too fast or the bending radius is too small, stress concentration will occur inside the steel pipe, causing cracking.
For faults caused by the above reasons, you can solve them according to the following solutions:
1. Failures caused by the selection of raw materials: We can start by strengthening cognition, so that merchants can fully understand the pros and cons of raw material selection, so as to solve the problem of seamless steel pipe cracking at the root.
2. For failures caused by improper heat treatment control: Relevant indicators can be clearly specified for processing and production, so as to avoid steel pipe cracking caused by improper heat treatment control.
3. For failures caused by processing reasons such as straightening strength: The operator's practical experience can be used to avoid later cracking of the steel pipe caused by the operator's lack of practical experience and excessive straightening force.
The reasons why seamless pipes crack during practical application-use environment issues:
Seamless steel pipes will be affected by environmental factors during use. For example, in harsh environments such as high temperature, high pressure, and corrosion, steel pipes will corrode and oxidize faster, making them prone to cracking. In addition, steel pipes may also crack or break under the influence of natural disasters such as earthquakes and sandstorms.
Conclusion:
There are various reasons for cracking of seamless steel pipes, including material problems, heat treatment problems, processing problems and environmental factors. In order to reduce the risk of cracking of seamless steel pipes, it is necessary to strengthen quality management and monitoring during production and use, and take corresponding measures to prevent and repair different problems. Only in this way can the normal use of seamless steel pipes and extend their service life be ensured.
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