軟鋼板のn値におよぼす材質的要因

抄録

Metallurgical factors affecting the work hardening exponents (n-values) of low carbon rimmed steels were studied. The following results have been obtained;
(1) In the tension test, the amount of work per unit volume which was done on the specimen to the maximum load showed 8.3±0.4 kg/mm² in the low carbon rimmed steel samples, while those of the sample containing 0.1 wt% of phosphorus showed about 9.2 kg/mm².
(2) Theoretical equations concerning n-value, and σ₀ and K (which were obtained in a relationship σ=σ₀+K.εnear the maximum load) were obtained considering (1), and agreed well with experimental results.
(3) Effects of grain diameter on n-value shown by the next equation, was obtained by using (1) and (2).n=10/(10+σ₁+1.3d^-1/2) where d (mm) is average grain diameter and σi (kg/mm²) is intrinsic strength.(4) The true effect of the content of a chemical element on n-value, eliminating the effect of grain size, was determined by using (1) and (2).
Mn: the effect is related to manganese content in solid solution.
N: the effect is dependent on manganese content.
C.: the effect is saturated above about 0.03 wt%.
S: the effect is far smaller than those of carbon, nitrogen and manganese.
O: the effect is negligible.
(5) Singularity of n-values of the samples containing phosphorus above about 0.05 wt% was foundand explained well by using (1).