Akira Sawamoto

Influence of Solution Treatment Temperature on the Rolling Contact Fatigue Strength of Mild Steel.

The effect of solution treatment temperature on the rolling contact fatigue strength of mild steel with carbon 0.17%, was studied by using specimens which were annealed, age-hardened at room temperature (20°C) after keeping for 20 minutes at solution temperatures of 700°C, 650°C, 600°C and 500°C, and tempered at 670°C to have almost the same hardness as the specimen solution treated at 700°C.Rolling contact fatigue tests were carried out with each pair of the same specimens by a Nishihara-type wear testing machine under pure rolling contact with lubricant.The results obtained are as follows;(1) The rolling contact fatigue strength of rolled steel for general structure (SS34) is increased markedly by the age-hardening treatment.(2) In order to produce the maximum rolling contact fatigue endurance limit of rolled steel for general structure (SS34), a solution treatment temperature of 600°C is necessary.(3) The propagation depth of crack formed in rolled steel for general structure by repeated contact stress tends to be in the vicinity of the region (Z0) where the maximum shear stress value becomes maximum.