Factors affecting the quality of seamless tubes

There are two categories of factors that affect the quality of seamless tubes: steel quality and rolling process factors.

Many factors of the rolling process are discussed here. The main influencing factors are: temperature, process adjustment, tool quality, process cooling and lubrication, removal and control of sundries on the surface of rolled pieces, etc.

1. Temperature

Temperature is the most important factor affecting the quality of seamless tubes. First of all, the uniformity of the heating temperature of the tube blank directly affects the uniform wall thickness and inner surface quality of the perforated capillary, which in turn affects the wall thickness quality of the product. Secondly, the temperature level and uniformity of the seamless steel tube during rolling (especially the final rolling temperature) are related to the mechanical properties, dimensional accuracy and surface quality of the product delivered in the hot-rolled state, especially when the steel billet or tube blank When it is overheated or even overburned, it will cause waste products. Therefore, in the production process of hot-rolled seamless tubes, heating and controlling the deformation temperature strictly according to the process requirements must be done first.
2. Process adjustment
The quality of process adjustment and work quality mainly affects the geometric and appearance quality of seamless steel tubes.
For example, the adjustment of the piercing machine and the rolling mill affects the wall thickness accuracy of the product, and the adjustment of the sizing machine is related to the outer diameter accuracy and straightness of the product. Moreover, process adjustment also affects whether the rolling process can be carried out normally.

3. Tool quality
Whether the tool quality is good or bad, stable or not, is directly related to whether the dimensional accuracy, surface quality and tool consumption of the product can be effectively controlled; Surface, the second is to affect mandrel consumption and production costs.

4. Process cooling and lubrication
The cooling quality of piercing plugs and rolls not only affects their life, but also affects the quality control of the inner and outer surfaces of finished products. The cooling and lubrication quality of the mandrel first affects the inner surface quality, wall thickness accuracy and mandrel consumption of the seamless steel tube; at the same time, it will also affect the load during rolling.

5. Removal and control of impurities on the surface of the rolled piece
This refers to the timely and effective removal of oxide scale on the inner and outer surfaces of capillary and barren pipes and the control of re-oxidation before rolling deformation. Nitrogen blowing and borax spraying treatment on the inner hole of the capillary tube, high-pressure water descaling at the entrance of the rolled tube and the fixed (reduced) diameter can effectively improve and improve the quality of the inner and outer surfaces.

In short, there are many factors that affect the quality of seamless steel tubes, and they are often the combined effect of various factors. Therefore, the above-mentioned main influencing factors must be effectively controlled. Only in this way can we control the quality of seamless steel tubes and produce hot-rolled seamless steel tubes with high dimensional accuracy, good performance and excellent quality.