The effect of annealing temperature and time on microstructure and tensile properties of a carbide-contained medium Mn steel

• Main Authors: I-cheng Hung, 洪一正
• Other Authors: Chih-Pu Chang
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/22593885177108812006

碩士 === 國立中山大學 === 材料與光電科學學系研究所 === 104 === This study explores the effect of annealing temperature, time and amount of cold rolling on the microstructure and tensile properties of a medium manganese steel after two-stage annealing and cold rolling procedures. After the first stage annealing, the microstructure consists of ferrite and tiny carbides. During the second stage annealing, the carbides are dissolved and provide abundant manganese and carbon to the surrounding ferrite matrix, which then transforms into submicron austenite grains. The small grain size of the austenite increases the austenite stability, and let TRIP effect occurs during deformation.Diffirent cold roll reduction gave similar phase fraction, composition, grain size and aspect ratio, but 25% and 50% cold rolling followed by 750℃ annealing 1 hour gave diffirent tensile properties. Annealing temperature and time affect austenite fraction, alloy partition and grain size, which in turn affect the tensile properties of the steel. To make enough carbides to be dissolved, the annealing temperature should be higher than 700℃, and the annealing time should exceed 5 minutes.