raise
To cause to rise; to lift or elevate.
raise: lift metal stock vertically during forging
In forging, to raise means to draw metal upward and lengthen it vertically between hammer and anvil or dies. The workpiece sits on the anvil face; repeated blows from above stretch it along its height while compressing its cross-section. This is distinct from drawing, which lengthens material horizontally. Raising is essential for converting ingots into blooms and billets, and for tapering round or square stock.
The technique works because metal under compressive stress flows away from the point of impact. By striking repeatedly along the length of a piece held vertically, the smith or machine operator guides deformation upward and outward. On a power hammer or press, the operator positions the workpiece so each blow lifts and extends it further. Hand-forging raises are done with pein (wedge-shaped) hammer ends or by tilting the workpiece slightly between strikes.
Variants and equipment
Raising happens on flat anvils with hand hammers, on power hammers with shaped dies, and in hydraulic forging presses. On friction screw presses, a raised workpiece thickens as it rises because the metal has nowhere to go laterally; the operator may need to turn the stock or use spreading dies to control the profile. On power hammers with helve arms or frame pivots, the raising motion is fast and repetitive, ideal for mills processing long billets.
Temperature control is critical: raising cold or undersized stock causes surface checking and internal cracking. Most raising happens at red to bright-cherry heat, roughly 700 to 900 degrees Celsius for steel. The metal must be hot enough to flow but not so hot that it becomes too plastic and tears. Oxidation (scale) forms rapidly at forging temperature; scale particles embed in the raised surface and must be removed by pickling or grinding later.
Raising is one of the primary forging operations, taught before drawing or upsetting because it combines compression with directional flow. It appears in the sequence of breaking down heavy ingots, refining bloom structure, and preparing stock for finishing operations. A raised billet has reduced segregation compared to an as-cast ingot because the deformation redistributes dissolved impurities and shrinkage voids through the metal.