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 plants for processing, but the round steel produced by these small steel plants will contain many impurities, bubbles, interlayers, pores, etc., which will easily cause cracks after post-processing. problem. PMC steel pipe round bars are purchased from Baosteel, Huaigang and other high-quality round bars, and the source is reliable.
2. Inadequate heat treatment temperature control
Small manufacturers do not have professional production experience and technology. Workshop workers cannot guarantee whether the heat treatment of the steel pipe is in place based on the heating temperature and duration alone, and the heat treatment will change the mechanical properties of the steel pipe. However, general manufacturers do not have clear indicators for different steel grades, wall thicknesses, mechanical properties, etc., and no testing equipment to determine whether the pipe has reached the performance indicators required by the customer.
How does PMC control production?
Each batch of steel pipes produced by PMC steel pipes has clear temperature and speed indicators for normalizing, annealing and tempering, and a tensile test will be carried out to determine whether the product meets the performance required by the customer. These data parameters are used as the basis for production So as to ensure the stability of the customer’s product quality and end use, rather than just relying on the experience of a certain worker to determine, this is the main factor why PMC steel pipe has been cooperating with many well-known enterprises in the industry for more than ten years.
3. Straightening strength
Straightening is equivalent to secondary deformation. Two-way force is applied during straightening. If the operator is not experienced enough, the straightening force is too strong, and the thick-walled pipe will cause internal damage and cracks if the strength of the thick-walled pipe is not well controlled. This is also the reason for the cracking of the steel pipe in the later stage.
4. Drawing deformation
If the drawing deformation is too large, steel pipe cracks will also be formed, causing the steel pipe to crack during the later processing. Bright tube has low elongation, generally 7-8%, large deformation, low elongation; small deformation, high elongation. Some small manufacturers cut corners and cut corners to save craftsmanship. The three deformations were changed to two, which expanded the deformation and caused excessive stress to cause cracking.