Page 21 - MetalForming-Jul-2018-issue
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 Heavy-gauge, high-strength structures can be produced using hot-forming.
strength and steep cyclic stress-strain response, which creates excellent fatigue performance.
• It offers high potential for weight reduction, resulting in significant mass reductions in vehicles, helping to achieve fuel-economy targets.
• Laser-welded (or tailor-welded) blanks with different combinations of thickness, properties and surface coat-
ings can be hot- formed as a single stamp- ing, achieving optimal strength and ductility in vehi- cle-safety components such as door- reinforcement beams, frame supports and crossbeams, or complete door-
opening rings.
• Temperature control using partially
heated blanks or quench-rate adjust- ments can create zones with different strength levels in the final stamping, providing energy-absorbing crush zones.
• Deep cross-sectional shapes can be formed due to elongation of 25 to 50 percent during forming, allowing a
reduction of the number of stampings in the vehicle and associated assembly cost.
• Excellent corrosion resistance is made possible due to improved coat- ings and alloys.
There is, however, a price to pay in order to achieve these capabilities in terms of equipment considerations. Hardware musts include:
• Furnace located before the press line’s forming station to heat the blanks to about 930 C;
• Hydraulic or servo-mechanical press and hot-form stamping dies with internal cooling channels and dwell capabilities to maintain tonnage at
MetalForming/July 2018 19
Locator holes in blanks help control the part during forming and in many cases, eliminate the need to laser trim.

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