Side Trimming Line

The Process of Shear Deformation

Shear deformation involves the processes of elastic deformation, crack propagation, plastic deformation, and material fracture. During the elastic deformation phase, the upper and lower blades of the shearing line squeeze the steel plate, causing it to elastically flatten and bend slightly. As the distance between the cutting edges continues to decrease, the steel reaches its yield limit, leading to plastic deformation within the metal and resulting in a bright cut section. As shearing continues, stress concentration occurs at the cutting edge, inducing small cracks. These upper and lower cracks expand and overlap, eventually disconnecting the steel plate and completing the shearing process. Typically, the shoulders and burrs are relatively small, with the cut-off layer and tear-off layer occupying most of the shear section.

The Relationship of Blade Clearance And Cutting Edge Quality

• Firstly, the standard of cut to length line quality: the cross-section is about 1/5-1/3 of the thickness of the steel slitting line. The dividing line between the cutting surface and the tearing surface is continuous and straight, and the whole shearing is smooth and no notch and big burr.

• And secondly, the relationship between blade clearance and cutting edge quality: the lateral clearance of the cutting edge is the most important factor affecting the shearing quality of the steel slitting line. Practice shows that the size of the lateral clearance is more sensitive than the overlapping amount; therefore, it is crucial for cut to length line manufacturers to set a reasonable value for the side clearance when adjusting the chopper. From the cutting section of the strip, the cut-off layer ratio will be significantly reduced with the increase of the lateral clearance, while there is no basic change in shoulders and burrs. When the lateral clearance increases to a certain extent, the trend of cutting layer reduction is not obvious, but the shoulders and burrs increase. This will cause severe wear of the cutting blade, overload the equipment, and result in a large proportion of the cut surface and meat staining or secondary shearing on some sections due to the small adjustment of the backlash of the cutting blade. Conversely, if the crack cannot be closed, the center part is forcibly broken, leading to serious burrs and shoulder collapse.

• Thirdly, the relationship of overlap amount and cutting edge quality: the overlap amount of the shear should be determined by the thickness of the strip and the situation of shearing. Generally, when the overlap is too large, the shearing force will be too large. And the edge wire will be bent and the buckle will be caused, if, in the converse condition, the steel plate will not be cut.