In the common problems of seamless steel pipe, wall thickness difference (eccentricity) is the most important. Wall thickness difference, as the name implies, is the difference between the maximum wall thickness and the minimum wall thickness. As long as it is seamless steel pipe, there will be wall thickness deviation, but how much can this deviation be controlled? If
Wall thickness deviation of seamless steel pipe If it is too large, what impact will it have on customers' products? Have you ever met the seamless steel pipe with serious wall thickness deviation as shown in the figure below? I'll take you to find out.
The wall thickness deviation of seamless steel pipe is large
1. Wall thickness deviation specified in national standard
What is the allowable deviation of wall thickness of seamless steel pipe? According to the national standard: GB / t8162-2008, the national standard of seamless steel pipe for structure is as follows:
According to the above national standards for allowable wall thickness deviation of seamless steel pipe, such as:
ask : what is the allowable deviation of wall thickness of 25 * 5 seamless steel pipe?
answer If the wall thickness s is 5mm, and the allowable deviation range of corresponding ＞ 3 ~ 10 is - 10% s to + 12.5% s, then the allowable wall thickness deviation of 25 * 5 seamless steel pipe is -0.5~+0.625mm。
2. The influence caused by uneven wall thickness of seamless steel pipe
In some machining applications, Wall thickness deviation of seamless steel pipe It is a very important indicator. If the wall thickness deviation is too large, it is necessary to put more margin, waste materials and increase cost, so it is difficult to accept orders and has no market competitiveness.
Large wall thickness deviation leads to uneven chamfering
The wall thickness deviation is large, and the cylindrical part cannot be machined
3. How to control wall thickness deviation and help customers save cost
(1) Steel pipe manufacturing source - perforation
· With excellent perforation equipment (lengthened type), the furnace length is equipped with preheating, heating and high temperature zone. Natural gas nozzle is used in the whole process to ensure the quality of perforation.
· With high quality alloy plug, the piercing quality is better and more stable.
· The sampling inspection record should be made in the whole process of perforation, and the root inspection of capillary after perforation should be carried out to ensure the quality of capillary.
· For the general small steel pipe plant (processing workshop), the perforated capillary is generally purchased by outsourcing, and the quality of the capillary can not be guaranteed from the source.
Wall thickness difference of perforation inspection
(2) Tianzhan - 16 years of thick wall pipe manufacturing experience, the process is mature and stable.
The thick wall steel pipe is the characteristic product of Tianzhan, especially various carbon steel and alloy thick wall steel pipe, such as: 32 * 12 (wall thickness), 20 * 8 (wall thickness).
Tianzhan has two processes of cold drawing and cold rolling, which can be customized according to the requirements of customers Wall thickness deviation of seamless steel pipe , precision and performance, to help customers save costs, with high cost-effective products.
Finishing rolling process precise deviation correction
The above are some answers and opinions on the allowable wall thickness deviation of seamless steel pipe. If you want to customize high-precision seamless steel pipe, please go to Tianzhan.