Introduction of defects formed during re-rolling of stainless steel plates

When the austenitic stainless steel sheet is re-rolled, due to the properties of the plate itself, in the process of re-rolling, with the increase of the degree of deformation during the re-rolling process, the internal austenite structure of the plate will be continuously induced to become a martensite structure, which will affect the rolling process. The re-roll forming of stainless steel plate causes defects such as wrinkles and dents. Let's talk about these common defects of stainless steel sheet during re-rolling

When the austenitic stainless steel sheet is re-rolled, due to the properties of the plate itself, in the process of re-rolling, with the increase of the degree of deformation during the re-rolling process, the internal austenite structure of the plate will be continuously induced to become a martensite structure, which will affect the rolling process. The re-roll forming of stainless steel plate causes defects such as wrinkles and dents. Let's talk about these common defects of stainless steel sheet during re-rolling
Re-rolling of stainless steel sheet
Wrinkle defects include flange wrinkles and wall wrinkles.
The former is that when the stainless steel sheet passes through the mold, in addition to the blank holder force, the flange part is also subjected to radial tensile stress and tangential tensile stress. Whenever the tangential compressive stress is relatively large, plastic instability may be formed in the flange part of the sheet, resulting in tangential bending, resulting in slight waves in the vertical direction of the flange part of the stainless steel sheet, that is, the flange is wrinkled. . The reason for the formation of flange wrinkles is that the blank holder force is too small and the radius of the die fillet is not suitable.
When the blank holder force is too small, the outer edge of the stainless steel sheet will be thickened due to the action of the vertical compressive force and radial tensile force in the fillet direction, and wrinkles will occur when the stainless steel sheet is modified. During rolling, one can add and modify the rolling bead to remedy, and the other is to adjust the blank holder force.
As for the wall wrinkle, it is formed because the flange wrinkle is re-rolled to the cylinder wall when the stainless steel sheet is re-rolled. The method of correction is to adjust the rolling gap in time, and to form a tension in the direction perpendicular to the rolling direction.
Let's talk about scratches. When the stainless steel sheet passes through the rounded part of the die during the re-rolling process, there may be many small slip scratches, also called scratches. This is because the rounded part of the die is the place where the maximum deformation force of the sheet occurs, and the viscosity of the stainless steel sheet during the deformation process is strong, so this defect will become more and more serious. It will scratch stainless steel products and affect the smoothness of the products. There will also be scratches, pits, dents, etc. on the working surface of the punch and die. In the actual production process, it can be overcome by chrome-plating the punch, adjusting the rolling gap, and using a suitable lubricant.
The fourth is cracks and ruptures. When the stainless steel plate is changed to rolling, it is very common to break the bottom of the product. The way to avoid it is to increase the radius of the convex and concave die, reduce the anti-wrinkle blank holder force, strengthen the lubrication, and change the finishing die to the concave die. work surfaces, etc. to prevent it.


The bottom concave is when the modified rolling piece has not broken, but the material in contact with the punch fillet is necked due to the modified rolling, and the bottom of the stainless steel product is concave due to the existence of residual stress after the processing is completed. The solution is to adjust the radius of the convex and concave die fillets, so that the stainless steel sheet is in a reasonable stress state when rolling.