Method of straightening metal bars having extremely low levels of residual stress after straightening operations are completed
AssigneeSlater Steels Corporation
InventorJon S. Schumacher
Life of this patent
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Abstract
Method of straightening a metal bar in which the metal bar is straightened by transporting the metal bar between a pair of rollers at a first straightening pressure. An outer layer portion of the metal bar is then removed in order to provide the metal bar with a reduced diameter and a substantially round cross-section. The metal bar is then again straightened by transporting the metal bar between a pair of rollers at a second straightening pressure. Subsequent to such straightening step, the metal bar desirably is heat treated under stress relieving conditions.
Claims33
A method of straightening a metal bar having a longitudinal axis, comprising the steps of:
- (a) straightening the metal bar by transporting the metal bar between a pair of rollers at a first straightening pressure;
- (b) removing an outer layer portion of the straightened metal bar in order to provide the metal bar with a reduced diameter and a substantially circular cross-section;
- (c) straightening the metal bar by transporting the metal bar between a pair of rollers at a second straightening pressure, wherein the second straightening pressure is less than the first straightening pressure.
A method of straightening a thermally hardenable metal bar having a longitudinal axis, comprising the steps of:
- (a) providing the thermally hardenable metal bar;
- (b) subjecting the metal bar to a heat treating operation in order to thermally harden the bar;
- (c) straightening the thermally hardened metal bar at a first straightening pressure;
- (d) removing an outer layer of the straightened metal bar in order to provide the metal bar with a reduced diameter and a substantially circular cross-section;
- (e) subsequent to the removing step, straightening the metal bar a second time at a second straightening pressure, wherein the second straightening pressure is less than the first straightening pressure;
- and
- (f) subsequent to the second straightening step, heat treating the metal bar under stress relieving conditions.
A method of straightening a metal bar, comprising the steps of:
- (a) subjecting the metal bar to a first heat treating operation effective to increase the hardness of the metal bar;
- (b) subsequent to said first heat treating operation, subjecting the metal bar to a first straightening operation, wherein said first straightening operation comprises:
- (i) rotary straightening the metal bar at a first straightening pressure;
- and
- (ii) removing an outer surface layer portion of the metal bar in order to provide the metal bar with a reduced diameter and a substantially round cross section;
- and
- (c) subsequent to said first straightening operation, subjecting the metal bar to a second heat treating operation.
Dependencies are inferred from the claim text.