Naresuan University; Suranaree University of Technology; National Science & Technology Development Agency - Thailand; National Metal & Materials Technology Center (MTEC)
Type
Article
Source Title
SCIENCEASIA
ISSN
1513-1874
Year
2021
Volume
47
Page
51-59
Open Access
gold
Publisher
SCIENCE SOCIETY THAILAND
DOI
10.2306/scienceasia1513-1874.2021.S008
Format
PDF
Abstract
Silicon and carbon are common alloying elements in wrought steel production. A judicious content of silicon can prevent carbide precipitation. So silicon is commonly used in the production of carbide-free bainitic steel, which is one of advanced high strength steels. It was found previously that both silicon and carbon elements from silicon carbide additives can be alloyed to form iron-based powder compacts via sintering process. In this study, sintered steels were produced from mixtures of pre-alloyed Fe-0.50Mo-0.15Mn powder and various silicon carbide contents (1.0, 2.0, 3.0, and 4.0 wt.%) using 'press and sinter' process. Microstructures of sintered steels changed in accordance with added silicon carbide content. The microstructure consisting of ferrite plate and martensite/austenite constituent in the low silicon carbide-added steel was changed to the microstructure with martensite matrix in high silicon carbide-added steel. Surprisingly, diffusional phase transformations resulting in the formations of pearlite and inverse bainite were occurred prior to diffusionless martensitic transformation in high silicon carbide-added steel. The ultimate tensile strength and hardness of the studied sintered steels increased with increasing martensite volume fraction but dropped with the presence of grain boundary carbide networks.