UNS #T11342

M42® is a premium cobalt high-speed steel with high hardness and superior hot hardness. The combination of composition and properties allows for machining high-strength and pre-hardened steels, high-hardness alloys, and the difficult-to-machine, nonferrous superalloys. This steel exhibits excellent wear resistance and hot hardness with cutting edges on tools remain sharp and hard in heavy-duty and high-production cutting applications.

Type Analysis

  • Carbon (Nominal) 1.08
  • Silicon (Maximum) 0.25
  • Tungsten (Nominal) 1.5
  • Manganese (Maximum) 0.25
  • Chromium (Nominal) 3.75
  • Cobalt (Nominal) 8
  • Molybdenum (Nominal) 9.5
  • Iron (Nominal) Balance
  • Vanadium (Nominal) 1.15


twist drills, taps, milling cutters, reamers, broaches, saws, knives, thread rolling dies, chasers, counterbores, form cutters, gear cutters, hobs, milling cutters.

Applicable Specifications

  • ASTM A600
  • QQ-T-590




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