THE EFFECT OF FORGING RATIO ON MECHANICAL STRENGTH OF 13% Cr STEEL

Abstract

It is well known that forging ratio affects on the mechanical strength of steel, yet a necessary forging ratio as structural steel varies with different kinds of steels and ingot size. The experiments herein introduced were made to clarify the effect of forging ratio on the mechanical strength of 13% Cr steel. Eight specimens were used which had various forging ratios from 1 to 73, and test pieces were prepared being taken from two directions (i.e. forging direction and the direction at right angles to it.).
The results were summarised as follows.
(1) Tensile strength was not affected by forging ratio.
(2) With increase of forging ratio, reduction of area and impact value increased to the forging ratio of 18 and then decreased slightly, however those in the direction at right angles to forging decreased considerably to 10.5 forging ratio and then increased slightly.
(3) At room temperature, variation of fatigue strength had analogy to impact value etc., however, at 400°C, it showed different tendency.