4TH International Congress on Technology - Engineering & SCIENCE - Kuala Lumpur - Malaysia (2017-08-05)

An Evaluation Of Fracture Toughness And Fatigue Crack Growth Behaviour Of Die Steels

In hot forging, die cracks happen due to cyclic impact and thermal loading faced during its operation. In the present work, tensile strength (room temperature and high temperature), Charpy impact value, fracture toughness (JIC) and Fatigue Crack Growth Rate tests of two die steels, AISI L6 and a new die steel denoted as ND, are evaluated. Results indicate that, despite being at higher hardness, the values of all tests for ND are higher than that of L6. Range of YS, UTS and Charpy strength are approximately 6-14%, 6-11% and 60-80% higher respectively, when compared in longitudinal, transverse and short transverse directions. Fracture toughness is approximately 8% and 27% higher in LS and TS orientation, respectively. The threshold stress intensity factor range of ND is 18.5 % higher than that of L6. Metallography and SEM was done to establish reasons behind the better performance of ND steel.
Santosh Kumar, Sachin Patil, Pravin Jadhav, Shreyas Kirwai, Atul Patil