Factors affecting the quality of seamless steel tube

Factors affecting the quality of seamless steel tube

Seamless steel tube is a kind of high performance industrial material, its quality is affected by many factors. From the selection of raw materials to the implementation of the production process, and then to the subsequent treatment, each step can have a significant impact on the performance of seamless tubes. The following are the main factors affecting the quality of seamless steel tubes:

1. Selection of raw materials
The quality of seamless steel tube is closely related to raw materials, mainly including the chemical composition of the billet and the quality of the billet.

Chemical composition: Seamless steel pipes for different purposes have strict requirements for the content of each element, and the proportion of elements determines the strength, toughness and corrosion resistance of the steel pipe. In the selection of raw materials, the proportion of each element should be strictly controlled to avoid that the proportion of elements is not the same as the specified proportion, resulting in problems in the quality of the steel pipe.
Quality of billet: When selecting materials, attention should be paid to whether there are defects on the surface of the billet, and ultrasonic or X-ray detection should be used to detect whether there are impurities or uneven organizational structure in the billet to avoid quality problems caused by defects and impurities.

2. Temperature control
(1) During heating
The temperature uniformity of the billet should be maintained during the heating process. The temperature uniformity of the billet during the heating stage plays an important role in the wall thickness and the inner and outer surface quality of the subsequent perforated tube. Uneven heating may lead to wall thickness deviation and surface defects, while too high temperature or even over-burning will cause the steel pipe to lose its performance, directly leading to the scrap of the steel pipe.
(2) During rolling
In the steel pipe rolling stage, it is very important to keep the proper rolling temperature. In particular, the final rolling temperature is directly related to the stability of the outer diameter of the steel pipe and the surface finish. Improper temperature control may lead to mechanical degradation and dimensional deviation.
(3) Cooling link
The cooling speed and method in the production process must be reasonable, and the cooling should be slow to reduce the internal stress of the steel pipe and improve its structural stability. Too fast cooling may lead to changes in the internal stress of the steel pipe, resulting in deformation or cracking of the steel pipe.

3. Adjustment of process and equipment
(1) Adjustment of equipment parameters
The adjustment of piercing machine and tube rolling machine has a direct influence on the geometric accuracy and surface quality of the product. For example, the adjustment of the caliper will affect the accuracy of the outer diameter of the steel pipe, while the adjustment of the details of the perforation process determines whether the wall thickness is uniform.
(2) Optimization of process flow
Scientific and reasonable process design can effectively improve production efficiency and reduce scrap rate. Especially in core processes such as perforation, rolling and shaping, deviations in any step may cause product defects.

4. Equipment and tools
(1) Aging of equipment
The stability of equipment performance has a significant impact on the quality of seamless steel pipe. Surface defects of the perforating head or roll may lead to a decline in the surface quality of the finished product, and timely maintenance and upgrading of the equipment is the basis for ensuring production efficiency and product quality.
(2) The accuracy of the tool becomes low
The quality of tools such as mandrel and roll is directly related to the dimensional accuracy and surface finish of the product. High-quality, chromium-treated mandrel not only reduces friction, but also reduces tool consumption.

5. Surface cleaning and protection
(1) The oxide is not removed
The surface of the steel pipe is easy to generate oxide skin, if not cleaned in time, these impurities will be embedded in the surface, affecting the appearance and performance of the product. The surface quality can be effectively improved by high pressure water descaling, sand blasting and other processes.
(2) No surface protection
No protective material is sprayed on the steel pipe, which makes the steel pipe secondary oxidation in a high temperature environment. Nitrogen protection or sprayed protective materials should be used to reduce the secondary oxidation of the steel pipe in a high temperature environment, further improving its surface performance and durability.

Conclusion

The high-quality production of seamless steel tubes depends on the fine management of the whole process. From temperature control to tool performance, from process optimization to surface treatment, the optimization of every link is the key to improving quality. By improving equipment, strengthening process monitoring and strictly implementing process standards, the product performance of seamless steel tubes can be effectively improved to meet the diversified needs of the market.

read more :What is a seamless steel pipe?