Abstract
Tensile properties and their strain rate sensitivity have been investigated on 245kg/mm2 grade and 280kg/mm2 grade maraging steels as a function of testing temperature. Tensile test was carried out at temperatures ranging from -76°to 150°C, and a crosshead travel speed was varied from 0.005 to 30 mm/min. The strain rate sensitivity in the maraging steels was produced by selecting aging temperature and time.
It was found that temperature range where the tensile properties were very sensitive to strain rate was from about -40°to about 75°C. As the strain rate decreased, tensile elongation decreased. Tensile elongation at a decreased strain rate was increased in tensile tests at temperatures where no strain rate sensitivity was observed. It was also found that tensile elongation at room temperature was increased by increasing the strain rate. Accordingly, hydrogen embrittlement is vitally concerned with the strain rate sensitivity of the tensile properties.
