G0300-1-2 Effect of Loading Rate and Tempering Temperature on Fracture Toughness of Hydrogen Charged Low Alloy Steel

Abstract

J-R curves under continuous hydrogen charge were obtained to evaluate the effect of absorbed hydrogen on fracture toughness of low alloy steel. The effect of absorbed hydrogen, loading rate and tempering temperature were investigated. J_<IC> under continuous hydrogen charge condition drastically decreased in the case of very low loading rate. The materials which were tempered at 803K and 843K showed significant reduction of J_<IC>, but reduction of the material tempered at 903K was small. Dimple fracture surface was observed when the loading rate was high. Quasi-cleavage fracture surface was predominantly observed in the tests which resulted in low J_<IC>.