Preventive Measures for Defects in Stainless Steel Pipes During Cold Rolling or Cold Drawing

When stainless steel pipes are cold drawn or cold rolled, some defects will inevitably occur. These defects will affect the quality of the finished stainless steel pipes, so preventive measures need to be taken to prevent the causes of these defects.
The main quality defects of cold-drawn stainless steel pipes include uneven wall thickness, out-of-tolerance outer diameter, surface cracks, surface straight lines and scratches. The uneven wall thickness of cold-drawn stainless steel tubes is affected by factors such as the wall thickness accuracy of the tube blank, the tube drawing method, the drawing centerline offset, the hole shape, the deformation process parameters, and the lubrication conditions.
During the forming process, attention should be paid to the degree of wear of the fit and draft. In addition, in order to reduce the formation of cracks on the surface of the stainless steel pipe after drawing, it is necessary to select a suitable stainless steel pipe blank and grind the surface defects of the stainless steel pipe blank. When pickling the stainless steel pipe blank, it is necessary to avoid over-pickling to avoid the formation of pits or hydrogen brittle, avoid under-pickling, prevent the oxide scale from not being cleaned, ensure the annealing quality of the stainless steel tube blank during use, use a reasonable tube drawing method, select suitable deformation process parameters and tool shapes, and improve the drawing center Line adjustment and inspection. Enhancing the pickling quality and lubrication quality of stainless steel pipe blanks, ensuring tool hardness, uniformity and surface finish will help reduce the formation of straight lines and scratches on stainless steel pipes.
Quality defects and prevention of cold-rolled stainless steel pipes. The main quality defects of cold-rolled stainless steel pipes include uneven wall thickness of stainless steel pipes, excessive outer diameter, surface cracks, wrinkles and folds, etc. Enhancing the wall thickness accuracy of stainless steel pipe blanks is to ensure the cold An important condition for uniform wall thickness of rolled stainless steel pipes. Ensuring the wall thickness accuracy of the stainless steel tube blank and the pickling quality, lubrication quality and surface finish of the tube rolling tool are important guarantees for enhancing the wall thickness accuracy of the cold-rolled stainless steel tube. Over-pickling or under-pickling of the stainless steel tube blank should be avoided to prevent stainless steel If pitting or residual iron oxide scale is formed on the surface of the tube blank, the cooling of the tube rolling tool and the inspection of the surface quality of the tool should be carried out, and the mandrel rods and rolling groove blocks that do not meet the requirements should be replaced in a timely manner.
Therefore, measures to reduce rolling force are beneficial to increasing the outer diameter accuracy of stainless steel pipes, including annealing stainless steel pipe blanks, reducing rolling deformation, enhancing the lubrication quality of stainless steel pipe blanks and the surface finish of pipe rolling tools, etc., using Use materials with high strength and hardness to produce pipe rolling tools, and strengthen the cooling and inspection of pipe rolling tools. If the pipe rolling tools are found to be severely worn, they must be replaced in time to avoid the outer diameter of the stainless steel pipe being out of tolerance.