The manufacturer of S355J2H pipe tells you that in the production of seamless steel pipes, we must follow the key points and matters of the production process to avoid flaws in seamless steel pipes, which will have a fatal impact on the quality of our products. So how to avoid these defects? S355J2H pipe manufacturer tells you that you need to understand the reasons for these defects:

1. Seamless steel pipe folding
The manufacturer of S355J2H pipe tells you that it is a kind of pipe that exists on the outer or inner surface of seamless steel pipe, in a straight line or spiral, continuous or discontinuous state. The main reason for the folding is that the quality of the pipe material is not good, there are folds, or there are inclusions, serious scratches and cracks on the surface, and edges and corners at the grinding place, and folds appear after being drawn. In order to avoid folding, the quality of the pipe material should be improved and attention should be paid to inspection and grinding.
2. Seamless steel pipe cracks
Refers to the small cracks on the inner and outer surfaces of seamless steel pipes that are distributed in straight lines or spirals, with a depth of 1 mm or more, and there are continuous and discontinuous. The manufacturer of S355J2H pipe tells you that according to the analysis of Shandong Jute Pipe Industry, the reason is: the hot-rolled pipe blank has subcutaneous bubbles and subcutaneous inclusions, and there are cracks or deep pits on the steel pipe before drawing. Longitudinal scribes or scratches occurred during the pulling operation. The manufacturer of S355J2H pipe tells you that preventing the formation of cracks is also to improve the quality of the tube blank and strengthen the inspection and grinding of the tube material. At the same time, it is necessary to avoid pitting, scratches and scratches on the pipe during the cold drawing production process.
3. Seamless steel pipe scratches
The characteristic of the defect is that there are longitudinally linear scratches of varying lengths on the inner and outer surfaces of the seamless pipe. Most of them are groove-shaped, but they may also be raised stripes. The main reason for the scratches (cutting) is: there are internal markings on the pipe material, which cannot be eliminated during drawing, the iron oxide skin remains on the steel pipe and the mold sticks to the steel, and the strength and hardness of the mold are insufficient or uneven. Fragmentation and wear occur, the hammer head is defective, and the sharp edges and corners of the hammer head transition part damage the mold. The manufacturer of S355J2H pipe tells you that in order to prevent scratches and scratches, the quality of each preparation process before drawing should be improved, and molds with high strength and hardness and good smoothness should be used.
4. Seamless steel pipe pits
The manufacturer of S355J2H pipe tells you that this is one of the common surface defects of seamless pipes. Local depressions with different areas are distributed on the surface of the steel pipe. Some of them are distributed periodically and some are irregular. The pits are caused by the iron oxide scale or other hard dirt pressed into the surface of the steel pipe during the drawing or straightening process, or the peeling of the original peeling on the surface of the steel pipe. The manufacturer of S355J2H pipe tells you that the measures to prevent pits are to carefully inspect the pipe material and remove defects such as warped skin, keep the work site, tools and lubricants clean, and prevent oxide scale and dirt from falling on the surface of the steel pipe.
The manufacturer of S355J2H pipe tells you that when there are smooth or sharp spiral marks on the outer surface of the seamless steel pipe, you should check the straightening machine. Due to the incorrect position of the straightening roller and the incorrect angle, the steel pipe rubbed the shoulders on the edge of the straightening roller during straightening, and there are worn grooves on the straightening roller, and excessive bending at both ends of the steel pipe may appear on the outer surface of the steel pipe. Pits.
5. Seamless steel pipe pitted surface
It is characterized by small pits in flakes and dots on the surface of the steel pipe. The manufacturer of S355J2H pipe tells you that the main reason for the pitted surface is pitting corrosion during pickling. After annealing, the iron oxide scale is too thick and straightened and pressed into the surface of the steel pipe to form a pitted surface; the steel pipe is kept in a humid environment, and even pitted corrosion occurs after water has entered. , After removing the rust spots, a pitted surface is formed.