Cold burst refers to cold rolling in the roll burst, not stainless steel strip burst. Broken strip is cold rolled stainless steel strip breakage, into a discontinuous section of the scrap. Cold burst and broken strip is not the same thing, but there is a connection, the roll burst will directly lead to broken strip.
Q: What are the causes of roll bursting?
A: 1. Cracks exist inside the roll, which will produce bursting when rolling at high speed with large rolling force.
2. Cracks on the surface of the rolls are not hollowed out during the grinding process to eliminate the cracks, and the cracks expand during the rolling process, resulting in bursting.
3. Operating factors: the new roll warm-up time is too short, the first volume of steel speed is too fast, the sudden increase in rolling pressure, as well as the discovery of cracks in the rolling process did not change rolls in time, rolling rolls continuous rolling fatigue, resulting in the expansion of internal cracks, easy to produce roll burst.
Q: What are the causes of strip breakage?
A: In the rolling process caused by broken strip in the following areas: 1.
1. Incoming material causes. The incoming material has serious quality defects, such as waste edge pressed into, serious overflow edge and serious under or over pickling, serious uneven thickness, plate shape edge wave or middle wave will lead to broken strip.
2. Equipment failure. Electrical, control system failure or hydraulic system failure, common are tension fluctuation, tension disappearance, hydraulic system parking, etc.
3. Operation failure. Operation accidents caused by the broken strip is more common, such as the discovery of strip runaway, incoming material defects not in time to reduce the speed or parking; Road time plan is not reasonable selection, road deformation is too large, resulting in large rolling pressure, plate shape is difficult to control, the road before and after the tension is too large, the strip will be pulled off; before the road time strip thickness fluctuations somewhere (thinning or super-thick), after the road time is not timely deceleration or will be cut off tension control, resulting in broken strip.
Q: How to deal with the broken strip after rolling?
A：Breakage caused by roll burst, after the broken strip, should immediately stop, pull out the strip in the rack, and the work roll, intermediate roll out, check whether the work roll, intermediate roll sticky roll or damaged, minor sticky roll available oil stone to smooth the surface, serious damage, should be replaced by the support roll. In addition, the rack must be cleaned of broken belt debris, if the mill main drive shaft safety ring broken should immediately notify the mechanical personnel to replace the safety ring, otherwise it can not be extracted from the work roll. If necessary, the emulsion injection can be opened, the residual in the rack of broken small strip flushed clean. After replacing the rolls, the first roll of steel should not be rolled too fast, and carefully check its surface quality.