Abstract
In order to study the effects of age and of heat-treatment etc., after rolling, on the repeated impact tensile strength of rolled screw bolts, we have conducted repeated impact tensile test of 3"/8 rolled screw bolts, made of SS41-, S55C-and SCM3-steels.
The results obtained are outlined as follows.
(1) The repeated impact tensile strength of rolled screw bolts is larger than that of cut screw bolts.
(2) The age increases the repeated impact tensile strength of rolled screw bolts made of SS41-steel, after rolling.
(3) The heat-treatment (quenched and tempered) decreases the repeated impact tensile strength of rolled screw bolts remarkably after rolling.
(4) The screw rolling increases the repeated impact tensile strength of heat-treated screw bolt made of SCM3-steel, after heat-treatment.
(5) The hot dip zinc plating decreases the repeated impact tensile strength of heat-treated screw bolts slightly after heat-treatment.
