What does the amount of strain, introduced during cold rolling, have on the rolled metal?
The amount of strain introduced determines the hardness and other material properties of the finished product. • Cold rolled steel can be produced in various ‘conditions’. Compare some of the characteristics and differences of ‘skin rolling’ and ‘quarter hard rolled’ stock. In skin rolling, the metal is reduced by 0.5 to 1.0% and results in a surface that is smooth. It is more ductile and further forming and stretching operations can be performed. ‘Quarter hard’ has higher reductions, up to 50%. This increaes the yield point; grain orientations and material properties assume differnece properties along the grain orientation. Ductility decreases. • Describe some of the ‘bend’ possibilites for ‘quarter hard’, ‘half hard’ and ‘full hard’ meterial. ‘Quarter hard’ material can be bent (perpendicular to the direction rolling) on itself without fracturing. ‘Half hard’ can be bent 90°, ‘full hard’ can be bent 45°, giving these materials great amounts of bending deformation, without fracturing.
