There are two reasons.
Defects in steel sheets.
When sheet metal is rolled the width doesn t change but since the thickness is dramatically reduced the length must increase by a similar percentage.
The shape defect of the steel coil is higher or lower than the one end of the coil and is continuous like a pagoda which appears in the inner outer ring portion of the coil.
The rolling process is used to made plates steel sheets etc.
Apart from that in the rolling applications there are two types of rolling products.
6 common steel defects encountered during quality assurance bare spots galvanized coated bruises roll marks buckle dross on galvanized strip edge wave pinchers.
Lamination defect in steel plates is highly undesirable for dynamically loaded elements of steel structure such as high pressure temperature storage tanks vessels.
The weight doesn t change.
1 coiling machine centering device failure strip steel deviation.
The surface unevenness is mainly caused by the unqualified stamping die.
The presence of these defects results.
Crown and wedge when sheet metal is rolled down to your ordered thickness the center width position of the master coil is slightly thicker and the coil edges are slightly thinner than the body of the coil.
Corner cracks these are cracks present in the edge of.
6 common defects in sheet metal forming uneven surface appearance.
Incorrect blank shape and or size.
Surface defects in rolling can be categorized into following types and those are.
Detecting identifying defects in steel during surface preparation coatings shrink as they cure resulting in low film thickness over sharp edges and welds which is a classic cause of coatings failure.
Longitudinal cracks they are formed in the direction of extraction of the steel.
It isn t practical to handle this when it s flat so it is coiled as it s produced.
The sheet metal forming parts will collide with the surrounding objects in the process of raw material.
Springback or final part deviation from nominal incorrect process or number of forming tools.
Transverse cracks these cracks usually appear due to the tensions in the longitudinal direction of the strand.
Excessive thinning thickening of the sheet during forming.
2 strip steel is not straight such as sickle bending narrowing etc.
Those are as follows.
This means the length of your sheet metal can be over a mile long.
This effect is called crown.