Carbon alloy steel- designed for maintenance-type shearing; when long blade life is not a nessescity.
Mid-Range alloy steel- the workhorse of the line; when shearing 3/8" and thicker. Longer life than standard carbon.
High Carbon, High Chrome alloy steel- Designed specifically for light gauge shearing of no more than 3/8" on hydraulic machines, 1/4" on mechanical controlled machines.
High Speed Steel- recommended for use as single edge shear blades when long life between sharpenings is critical. Most applications are light capacity shearing.
Here's a list of some of the major brands supplied:
Accurpress/Accurshear * Allsteel * Amanda * American Hercules * Atlantic * Besco * Betenbender * Century * Cincinnati * Cleveland Crane * Deem * Di-Acro/Elga * Dreis & Krump * Edwards * Engel Industries * Famco * HTC * Henry Corporation * Herr-Voss * Hydrapower/Rockwell * Lodge & Shipley * National Sheet Metal * Niagra * Pacific * Pearson * Pexto * Powermatic * Promecam/Verrina * Pullmax * Red Bud Industries * Roper Whitney * Spatanics * Standard Industrial * Steelweld * Summit * Tennsmith * Weir * Welty Way * Wysong & Miles