Common problems and solutions of round steel shears

1. Cause analysis of end shear bending:
When the round steel shears are used to cut low carbon steel, such as 20# steel, 20CrMo, etc., it is easy to bend the end when cutting the end at the end. The length of the bending saw end is about 100~200mm, and the bending degree exceeds 4 ‰, which exceeds the requirements of the national standard. The straightening machine can not straighten, and can only be treated by secondary sawing at the rear, which increases the cost of subsequent treatment.
Corresponding solutions:
The end shear bending is mainly concentrated in low carbon steel and low alloy structural steel. The main reason is that the high shear temperature makes the deformation resistance of rolled piece small, and the shear impact force causes the end to bend downward. Through many tests, the shear temperature is controlled at about 150 ℃. At this time, the end phase transformation of the steel is completed, forming a small amount of bainite structure, increasing the end hardness and reducing the shear bending.
2. Cause analysis of end burr:
First of all, due to the large gap between the cutting blades of the round steel shears, the steel slides during the shearing process, and then tongue shaped burrs are brought out from the gap. Secondly, when the flat shear process is adopted, the flattened metal volume is accumulated at the cutting edge along the longitudinal direction of the rolled piece due to the influence of the bending of the rolled piece, and the rolled piece is separated and torn to form burrs during shearing. Third, in the process of accepting the cutting, the cutting edge of the cutting slice is not sharp enough, resulting in burrs at the cutting end of the round steel.
Corresponding solutions:
First, the gap between the upper and lower blades should be scientifically and reasonably controlled within 0.1~0.4mm. At the same time, the gap difference between the two ends of the blade head and tail should be less than or equal to 0.2mm. Before the round steel shears are officially used for cutting, once the clearance value of the cutting blade does not conform to the normal value range, it should be adjusted in time. The deviation of the cutting edge can be compensated by adding copper gaskets between the cutting edge and the wear-resistant lining plate, so as to make the clearance between the head and tail of the cutting edge consistent. Secondly, it is necessary to ensure the integrity of the blade. Once wear is found, it is necessary to replace new parts in time.