Question

Make a list of the alloying elements used in high-speed steels. Explain what their functions are and why they are so effective in cutting tools.

Please answer me in computer-typing format. Thanks!

Answer 1

General Composition of High Speed Steel is given below =

(A) (18-4-1) =

Tungsten = 18 %

Chromium = 4 %

Vanadium = 1 %

Carbon =  0.65 to 0.8 %

(B) Cobalt high speed steel =

Tungsten = 20 %

Chromium = 4 %

Vanadium = 2 %

Cobalt = 2 – 15 % ( 12%)

Carbon = upto 1.5 %

( C ) Molybdenum high speed steel =

Tungsten = 6 %

Molybdenum = 6 %

Chromium = 4 %

Vanadium = 2 %

Cobalt = 2 – 15 % ( 12%)

Carbon = upto 1.5 %

Fuction and Effectivness of alloying elements =

(a) Carbon = For hardenability of steel, increases wear resistance, high hot hardness.

(b) Tungsten and Molybdenum = Improves red hardnesss, wear resistance, retention of hardness and high temperature strength of the matrix, form special carbides of great hardness. Cutting performance of the steels increases in a linear manner as the percentage of either element increases.

(c) Chromium = Prime purpose of promoting depth hardening, produces readily soluble carbides.

(d) Vanadium =  Forms special carbides of supreme hardness, increase high temperature wear resistance, retention of hardness and high temperature strength of the matrix. Always present to a minimum of 1 wt. % and generally up to 2 wt. % or 3 wt. %.

(e) Cobalt = Improves red hardness and retention of hardness of the matrix, Increases heat resistance, and can give a Rockwell hardness up to 67 Min..

Due to High Temperature sustainability, High Hardness, High wear resistance, High Corrosion resistance, High melting points these are used in Cutting tool bits, Milling cutters, Gear cutter, Saw blades, Punches.