Deep cryogenic treatment (DCT) has been performed in 300M aeronautic steel quenched and tempered in conventional heat treatment parameters, in order to assess its effect on fracture toughness K_(IC) using circumferentially notched technique. DCT heat treatment was applied in one group of quenched and tempered specimens, before tempering, and fracture toughness was compared to other group, quenched and tempered, without DCT treatment. The results show a high influence of DCT treatment on fracture toughness of specimens and hardness too. It can be see a 16.37 MPa{the square root of}m loss on toughness and an increase around 2 HRC on hardness, for specimens that were submitted to DCT treatment in comparison with specimens without DCT.
展开▼
