The Influence of Nitrogen on The Wear Resistance of Ferritic Stainless Steel

摘要

Ferritic stainless steel has low properties of wear resistance and hardness. Normal heat treatment on AISI 430 Ferritic Stainless Steel cannot be treated utilised to achieve this task. However, it can be treated through nitriding method. Nitrogen is well known to improve mechanical, wear and corrosion resistance of stainless steels. Normal heat treatment on AISI Ferritic Stainless Steel is not suitable to achieve this task. Thus, the aim of this work is to investigate the influence of nitriding on wear resistance properties of AISI 430 Ferritic Stainless Steel. The influence of nitriding on the steel were observed. Microstructures, hardness test and scratch resistance analysis for wear resistance were conducted and analysed. Nitriding was carried out at 1200°C for 1 h, 3 h and 5h using nitrogen gas as a medium. Martensitic transformation from ferrite was observed on the as-received samples. From microstructure observations, the influence of nitriding also could be seen. Martensite structure shows higher hardness compare to ferrite structure. Therefore, the hardness for 5 h nitrided sample is higher than 1 and 3 h nitrided sample as more martensite structures was formed at 5 h nitrided sample. Scratch resistance was conducted to analyse the influence of nitriding for wear resistance properties. The depth of penetration obtained shows how much improvement on tribology properties are made. Results from testing conducted shows that the improvement of wear resistance properties is dependent on nitriding time. The longer the nitriding time, the more nitrogen is diffused into the sample. As more nitrogen atoms diffused into the steel, improvement on wear resistance properties are higher.