Defects of stainless steel coil in slitting process

Generally speaking, the supply state of stainless steel in the rolling mill is coil, but when processing in the hardware factory, due to the small workpiece of the manufacturer, in order to facilitate processing, automatic feeding, especially the high-speed automatic feeding punch, divides the coil into several coils with a certain width to meet the processing requirements.

In the process of stainless steel slitting, various defects will occur due to various factors. According to different follow-up process requirements, it is mainly divided into surface defects and edge defects.

Striped stainless steel strips are used to make pipes, such as automobile exhaust pipes, decorative pipes, corrugated pipes, etc. due to the welding of subsequent processes, the requirements for edges are particularly high.

1. The burr is too big. Burr will seriously affect the subsequent pipe production, so the burr size must be controlled in the cutting process. Burr is inevitable, but the size can be controlled. With the increase of tool clearance, the burr will become larger. Therefore, it is necessary to select a suitable gap. According to the author's experience, for the high hardness gap of 300 series, 12% plate thickness is generally adopted, while for 400 series, 10% plate thickness is adopted. In addition, the passivation of the cutting edge of the tool will also cause too many burrs. The tool tube should grind the blade regularly.

2. Local burrs protrude. When periodic burrs protrude at the edge, the tool is usually broken. At this time, stop the machine for inspection, find the damaged tool and replace it. The tool setter shall check the tool before tool arrangement to avoid tool collapse.

3. Uneven burr size indicates that the burr on the same side is large and small, or the burr size on both sides of the same strip is different. The tool clearance is unstable due to the deviation of the tool axis and the non parallelism of the upper and lower tool axes. At this time, calibrate the tool axis.

4. Edge wave. When the tool clearance is too small, the strip steel is pressed too tightly by the tool side, resulting in edge extrusion and waveform. In addition, when the side of the tool is uneven and the side pressure is unstable, side waves will also be generated. Therefore, the tool layout clearance cannot be too small. In addition, before placing the tool, check whether the side of the tool is damaged or uneven.

Strip stainless steel strip is used for processing and stamping parts. Since the edges will be removed in subsequent processing, the requirements for edges are low. Basically, only cutting is required, but the requirements for the plate surface are relatively high. In addition to the common surface defects of stainless steel, some defects will also appear in the process of longitudinal cutting and strip steel.

1. Surface scratches. If the surface of the whole slitting production line is in contact with the plate surface, there are foreign matters, such as pressing roller, feeding roller, etc., which are easy to scratch. Therefore, in case of surface scratch, pay attention to check all parts and remove foreign matters in time.

2. Knife indentation. The overlapping amount of upper and lower knives, that is, if the pressing amount of knife shaft is too small, the strip steel will be cut continuously, and if it is too large, there will be knife indentation. If it is local knife indentation, it may be that the knife axis is not parallel, resulting in excessive local indentation. The knife axis should be calibrated, which can be temporarily solved on the knife adhesive tape. If the indentation area of the knife is large, the indentation amount shall be adjusted.