Page 202 - Mechanical Engineer's Data Handbook

190 MECHANICAL ENGINEER’S DATA HANDBOOK

1.6.6 Characteristics of steel tools

Carboo steels (for softer metals and wood; poor perfomace above 250°C)
Composition Characteristics Applications

Plain carbon steel, O.Z%Mn, High toughness, low hardness Shear blades, chisels, turning
water hardening mandrels
0.7-0.8%c
0.9%c General purpose. Best combination Large taps and reamers
of toughness and hardness
High hardness, keen edge, low Taps, screw dies, twist drills, mills
shock resistance for soft metals, files

Carbon steel + vanadium
0.8-1 .O%C, 0.2%Mn, Water hardening, takes keen edge, Screw taps and dies, twist drills,
0.2%Va more shock resistant than plain reamers, broaches
carbon steel
Chrome steel
0.9%C, 0.2%Mn, O.S%Cr Water hardening, good abrasion Drawing dies, wood planes, chisels
resistance, takes high compression
High manganese steel
OSM.8%C, 0.6-0.8Y0Mn Oil hardening, tougher but less Bending form dies, hammers, tool
hard, high shock resistance shanks

High-speed steels

Composition (%)
C W Cr Va Co Mo Characteristics
- ~-
~ ~~
Super 0.8 18/22 4.5 1.5 10112 - Highest temperature of HSS. Very hard
but not so tough. Most expensive.
For materials with tensile strength
=- 1225 MPa
General purpose 0.75 18 4.15 1.2 - - Tougher than super and cheaper, for
materials over 1225 MPa tensile
strength
General purpose 1.25 7 4.3 2.8 6 5.5 Better impact resistance and cheaper
tungsten/molybdenum than general purpose HSS. High
wear resistance

High vanadium 1.55 12.5 4.75 5.0 5 - Best abrasion resistance. Used for
hinhlv abrasive materials

HSS, high-speed steels.