1. Scratch
Reason:The guide plate, roller table, tools and rollers are not clean, there are adherents or angular burrs, etc., rolling and scratching the surface; the operation is not careful, causing them to collide with each other to form a scratched surface.
Measures: Before rolling, check the tools, guide plates, roller tables and rolls, etc., and clear the problems in time; operate carefully, and don't pull and bump.
2. Metal indentation
Reason:The edge burr and tail slag of the rolled piece are pressed into the surface of the product.
Measures: Eliminate burrs and surface foreign bodies on the slab edge in time. Cut off the cracked edge and the cracked head in time.
3. Non-metallic indentation
Reason:Poor environmental sanitation, dust and foreign matter fall on the surface of the rolled piece; after pickling, the cleaning is not clean.
Measures: Do a good job of sanitation and promptly remove the adhesions on the surface of the rolling piece.
4. Ma Hang Pock
Reason:There is dust and foreign matter on the surface of the pressing plate or the backing plate during the press-correction annealing.
Measures: Clear the surface of the pressing plate and backing plate in time before entering the furnace.
5. Roll marks
Reason:The surface of the roll is severely worn, with pits, pitted surface, scratches, etc.; the surface of the roll is pressed out of the pit by the plate corner.
Measures: If roll marks are found, grinding or replacing rolls is required.
Unconventional defects are:
1. Surface crack
Reason:The incoming material is unqualified, the surface cracks are not cleaned, or the brittle getter layer on the incoming material surface is not cleaned. In addition, the reduction procedure is unreasonable, the pass processing rate is small, the pass is too many, or the pass processing rate distribution is uneven.
Measures: Strictly control the surface quality of the incoming materials, reasonably distribute the processing rate of the passes, ensure the uniform annealing temperature of the slab, and enhance the rolling lubrication.
2. Acid spots
Reason:One is that the residual acid is not rinsed out during pickling, and the board is dried and formed. One is the uneven surface oxidation of the sheet during stack annealing, and the inconsistent surface corrosion after pickling.
Measures: The pickling must be clean to ensure that there is no residual acid on the surface of the plates before drying; reduce the stacking thickness to ensure uniform annealing of the plates; sanding treatment can also be used for later salvage treatment.
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