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Main factors affecting quality of seamless steel tube and quality control scheme
- Jul 10, 2018 -

There are two kinds of factors affecting steel tube quality: Steel and rolling process. The factors of the rolling process are discussed here. 

The main influencing factors to seamless pipe are: Temperature, process adjustment, tool quality, process cooling and lubrication, the removal and control of debris on the surface of the workpiece.

(1) Temperature is the main factor affecting the quality of steel tube. First of all, the uniformity of the heating temperature of the tube directly affects the thickness uniformity and inner surface quality of the perforated capillary tube, and then affects the wall thickness quality of the product. Secondly, the temperature and uniformity of the steel pipe during rolling (especially the final rolling temperature) are related to the mechanical properties, outer diameter and the surface quality of the products delivered in hot rolling condition, especially when the billet or tube is overheated or even burnt, it will cause the waste product. 

Therefore, in the hot-rolled seamless pipe production process, strictly according to the technical requirements of heating and control deformation temperature is the first thing to do a good job. 

(2) The adjustment of process.

The adjustment and the quality of work mainly affect the geometry and appearance quality of the steel pipe. such as piercing machine and the adjustment of the pipe mill affect the thickness of the product precision, sizing machine adjustment related to the product OD accuracy and straightness. 

Moreover, the process adjustment also affects whether the rolling process can be carried out normally. 

(3) Tool quality

Tool quality of good and bad, stability or not, directly related to the size of the product and surface quality and tool consumption of effective control; core rod surface treatment (chrome) quality status, one is to affect the inner surface of steel tube, the second is to affect the core consumption and production costs. 

(4) The process cooling and lubrication

Perforation of the head, roll cooling quality not only affect its life, but also the quality control of finished products inside and outside the impact. 

The cooling and lubrication quality of the mandrel first affects the inner surface quality, wall thickness precision and mandrel consumption of the steel pipe, and also affects the load during rolling. 

(5) Removal and control of debris on the surface of rolled pieces

This refers to the timely, effective removal and control of the oxidation of the capillary, the inner and outer surface of the pipe before rolling deformation. 

The high pressure water descaling at the inlet of the pipe and the fixed (reduced) diameter can effectively improve the inner and outer surface quality of the capillary hole by blowing nitrogen and spraying borax treatment. In a word, the factors affecting the quality of steel tube are manifold, and often are the comprehensive action of various factors. Therefore, the main influencing factors must be controlled effectively. 

Only in this way can we control the quality of steel pipe and produce hot-rolled seamless steel pipe with high precision, good performance and excellent quality.