Microstructure and Mechanical Properties of HSLA-100 Steel
Abstract
Light microscopy, scanning electron microscopy, and transmission electron microscopy were employed to examine the microstructural basis for the mechanical properties of as-quenched and tempered HSLA-100 steel. Examination of the alloy revealed granular bainite with martensite and retained austenite in the as-quenched state which upon aging at temperatures below the lower transformation temperature, 677 C, formed tempered bainite with precipitates of copper and carbides. These results indicate the strength and toughness of HSLA- 100 steel aged below 677 C is based primarily on the fine prior austenite grain size and classic copper precipitation behavior but also on the bainite dislocation substructure and carbides. After tempering at 677 C, HSLA-100 steel has a dual-phase microstructure consisting of bainitic ferrite laths, fine ferrite grain clusters and martensite with precipitates of carbides and overaged copper. The results indicate the yield strength of the overaged alloy is based on the fine ferrite grain and bainite lath sizes, the fine carbide distribution and elastic moduli strengthening while the toughness is the result of the high- angle ferrite grain boundaries, the fine intralath carbides and the ductile overaged copper precipitates.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1990
- Accession Number
- ADA242937
Entities
People
- Victor R. Mattes
Organizations
- Naval Postgraduate School