Effects of Heat-Treatment on Pre-Yield Burst Emissions of A533B Steel.
Abstract
Nonmetallic inclusions strongly affect the ductility and acoustic emission (AE) characteristics of A533B steel. Our present and previous studies have revealed highly anisotropic AE behavior during tensile and fracture testing, originating from the particular morphological features of MnS inclusions. In the present study, the effect of different heat-treatment practices on the role of MnS-matrix interfaces in generating AE has been investigated. Although both L and S orientations of ASTM A533B steel were examined, pre-yield, burst-type emissions were observed only in the S-orientation. The pre-yield, burst type AE activities increased drastically with tempering temperature (up to 750 C) for samples that were furnace-cooled after tempering. A maximum in this AE activity was noted, for specimens that were oil-quenched subsequent to tempering, around a tempering temperature of 600 C. This AE behavior is explained by the occurrence of two phenomena. First, some of the MnS-matrix interfaces debond due to thermal stresses set up during quenching. Second, during tempering, partial cohesion of debonded interfaces commences along with the segregation of sulfur to the interfaces. Upon tensile loading, these interfaces fracture at relatively low stresses and generate the observed, burst-type AE in the pre-yield region of the S-orientation tensile samples. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1982
- Accession Number
- ADA120067
Entities
People
- Hong-bee Teoh
- Itzhak Roman
- Kanji Ono
Organizations
- University of California, Los Angeles