Abstract
Tensile, crack opening displacement (COD), blunt notch, and Charpy impact tests were used to investigate cleavage initiation in the intercritically reheated coarse-grained heat-affected zone (IC CG HAZ) of three steels. The steels were chosen to provide different distributions and morphologies of MA (high-carbon martensite with some retained austenite) particles within the IC CG HAZ structure. Observation of minimum impact toughness values for the IC CG HAZ was found to be associated with a particular microstructure containing a near-connected grain boundary network of blocky MA particles, the MA particles being significantly harder than the internal grain microstructure. The initiation mechanism for this structure was determined to be from a combination of an overlap of residual transformational induced stress fields, due to the formation of the MA particles, between two closely spaced particles and stress concentration effects resulting from debonding of the particles. © 1994 The Minerals, Metals and Materials Society, and ASM International.
| Original language | English |
|---|---|
| Pages (from-to) | 563-573 |
| Number of pages | 11 |
| Journal | Metallurgical and Materials Transactions A |
| Volume | 25 |
| Issue number | 3 |
| DOIs | |
| Publication status | Published - Mar 1994 |
Keywords
- austenite
- cracks
- grain size and shape
- impact testing
- martensite
- metallographic microstructure
- morphology
- particles (particulate matter)
- phase transitions
- steel metallography
- stresses
- tensile testing
- cleavage initiation
- crack opening displacement
- fractographic evidence
- intercritically reheated coarse grained heat affected zone
- heat affected zone