Influence of nitrogen as grain refiner in low carbon and microalloyed steels

International Conference on Advances in Metallurgy, Materials and Manufacturing

冶金学;材料科学;机械制造

Hasan, B.M.^1 ; Sathyamurthy, P.^1

JSW Steel Limited, Salem Works, Tamilnadu, India^1

关键词: Carburizing temperature;    Grain coarsening;    High temperature;    Medium-carbon steels;    Micro-alloyed steels;    Micro-alloying elements;    Nitrogen content;    Property requirements;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/314/1/012008/pdf
DOI  :  10.1088/1757-899X/314/1/012008

学科分类：材料科学（综合）

来源: IOP

【 摘 要 】

Microalloyed steel is replacing using of low alloy steel in automotive industry. Microalloying elements like vanadium, niobium and titanium are used to enhance the steel property. The current work is focused on using nitrogen as a strengthening element in existing steel grade. Nitrogen in free form acts as solid solution strengthener and in combined form as precipitates acts as grain refiner for enhancing strength. The problem of grain coarsening at high temperature in case carburizing steel was avoided by increasing nitrogen level from 60ppm to 200ppm. Grain size of ASTM no 10 is obtained at carburizing temperature of 950 °C by increasing nitrogen content from grain size no 6 with lower nitrogen. Mostly crankshaft is made from Cr-Mo alloyed steel. At JSW, nitrogen in the level of 130-200ppm is added to medium carbon steel to meet property requirement for crankshaft application.