Page 40 - MetalForming Magazine April 2023

A welded blank, such as the one shown here from an ArcelorMittal tailored blanks catalogue, places strength, thickness and corrosion protection only where the properties are needed.
variable thickness and strength down the length of the coil rather than across its width. The gap between rolls in traditional sheet rolling mills decreases in sequential stands to produce progres- sively thinner sheets. Each roll stand contains structurally supported components to ensure the most uniform thickness possible. In contrast, when producing TRCs, the gap between the rolls used
tubes (TRTs) and tailor welded tubes (TWTs). Each of these can be cold formed, and when appropriately designed, may be hot formed as well.
Patchwork blanks consist of a smaller patch blank spot welded to a main blank underneath; the two components may differ in strength and thickness. The spot welds hold the blanks together to prevent shifting during forming oper- ations. One reason to deploy a patchwork blank rather than a LWTB: if the reinforcement is located within the boundaries of the main blank.
Butt welding at the sub-blank edges creates a LWTB; sim- ilarly, welds can join entire coils together edge-to-edge, cre- ating tailor welded coils. The new strip either is directly blanked, or recoiled for future blanking or for use as feedstock for continuous coil-fed operations such as progressive-die and transfer-press stamping, and rollforming. Variations in strength, thickness and coating occur across the coil width.
Another option: tailor rolled coils (TRCs), which feature
THREE-PART SERIES
JULY 11—Precision Stamping
JULY 18—Automation in the Pressroom JULY 25—Fabrication for Metal Stampers
for thickness reduction is intentionally varied smaller and larger in a controlled sequence, allowing for different strip thicknesses in the direction of rolling. TRCs usually require annealing after rolling due to the high degree of cold work. Controlling the amount of thickness reduction in certain areas may allow for local strengthening in the thinner regions after annealing.
TRCs are the feedstock used to produce tailor rolled blanks and variable-thickness TRTs, or as the feedstock for a roll- forming line. In the case of TRTs, properties and thickness vary down the length of tube but are consistent radially.
Conventional welded-tube production starts with roll- forming monolithic strips to the desired shape and welding the free ends together to create a closed section. The TWT production process allows the designer to create complex variations in shape, thickness, strength and coating as a function of the starting LWTB. These tubes can be hydro- formed to further expand design options. MF
ON THE SHOP FLOOR
APRIL 25—LIVE ON THE SHOP FLOOR
Case studies showcase automation of press tending and of secondary processes including cold heading, coining and piercing at Clips & Clamps Industries. Also on the agenda: a press-tending robot at work in the pressroom of Sukup Manufacturing Co., Sheffield, IA. There, a six-axis robot destacks blanks and tends to two stamping presses.
An expert-panel discussion will follow.
For information and to register visit: https://www.metalformingmagazine.com/event/?/metalforming-live
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