Abstract
The purpose of the present study is to derive an equation which gives the specific work for fracture in tension of sintered iron. Electrolytic iron powder was pressed into compacts with the density range of 5.8-7.5 g/cm3, and sintered at 1200°C for 1 hr in hydrogen.
The volume increased in the amount of 4-5% before fracture, but was regarded as constant for the following calculation. True stress-true strain curves were approximated by an equation, a=A⋅εn, where n was 0.33. This value of n was independent of as-sintered density and considered to be equal to that of cast materials with the same matrix.
Based on the above conditions, the specific work for fracture, Wfr, of sintered iron was given by the following equation,
Wfτ=σnfr⋅(1+efr)⋅1n(1+efr)⋅(n+1)-1.
Where arfr was ultimate tensile strength and efr was elongation.
The following relation between the charpy shelf value I.V. and Wfr was proposed;
I.V.∝Wfr⋅x.
Where, x was the width of the deformed zone adjacent to the fracture surface. This value was supposed to become greater with the increase of the work hardening exponent n and to be independent of the as-sintered density.
