PDH Engineer     PE PDH
PDH Online

How to Visually Detect Flaws and Characteristics in Rolled Aluminum

Quiz Questions

1. Measurement of flatness, especially for thin sheet, is often made in terms of:
“I” units
2. Longitudinal bow is usually caused by :
Bad handling of the roll during the shipping
Unbalanced stresses between the top and bottom surfaces of the rolled aluminum
3. Arbor buckles are caused by plastic bending over a coil and in contact with:
The mandrel
The longitude edge laying underneath the roll
The cross edge laying underneath the roll
4. Bond blisters are caused by:
Expansion of gas from a localized incomplete bond
Rolling against the material grain direction
Dropping the roll during the shipping
5. Burr is :
Rolled surface rubbing against each other
A thin ridge of roughness left by a cutting operation such as slitting, trimming, shearing, blanking or sawing
6. Repeating dent on a roll can be caused by a particle adhering to a rotating roll across which the metal has passed.
7. Edge containing crack, split, and/or tear which is caused by;
defective material
too short of a roll radius
Inability to deform without fracturing
8. An embossed pattern distortion is caused due to:
Misalignment of the male and female embossing rolls
Substandard material
9. Rolled-in metal is an extraneous chip or particle or metal rolled into the surface of the product.
10. Surface discoloration which may vary from dark brown to white is produced:
During thermal treatment by incomplete evaporation and /or oxidation of lubricants on the surface
Oil leak from the rolling machine
Discrepancies in the ingot during solidification