Effect of Repeated Quenching Heat Treatment on Microstructure and Dry Sliding Wear Behavior of Low Carbon PM Steel

摘要

The effect of repeated quenching heat treatment on microstructure and dry sliding wear behavior of low carbon PM steel was investigated. For this purpose, atomized iron powder was mixed with 0.3 % graphite and 1 % Ni powders. The mixed powders were cold pressed and sintered at 1200°C for 30 min under pure Ar gas atmosphere. Some of the sintered specimens were intercritically annealed at 760°C and quenched in water (single quenching). The other sintered specimens were first fully austenized at 890°C and water quenched. These specimens were then intercritically annealed at 760°C and re-quenched in water. The martensite volume fraction in the double quenched specimens was higher than that of the single quenched specimen. Wear tests were carried out on the single and double quenched specimens under dry sliding wear condition using a pin-on-disk type machine at constant load and speed. The experimental results showed that the wear coefficient effectively decreased in the double quenched specimen.