Enhancement Of Hardenability And Performance With Addition Of Master Alloy Powder In PM Steels: Effect Of Different Atomisation Techniques

In PM steels, alloying through master alloy (MA) addition enables the introduction of oxygen-sensitive elements such as Cr, Mn, and Si. These elements offer cost-effective and sustainable alternatives to Cu and Ni, enhancing hardenability and performance. This study investigates the atomisation of Fe-Cr-Mn-Si-C MA powders using three different techniques: water atomisation, gas atomisation, and gas atomisation-water cooling. The MA powders were sieved into two size fractions and mixed with Fe – 0.85 wt.% Mo pre-alloyed base powder and graphite. MA powder characterisation, compressibility, and dilatometry-sintering experiments were performed to evaluate the different atomisation techniques, and liquid phase formation at various sintering temperatures. Additionally, industrial sintering trials were conducted, and mechanical properties were assessed to understand the behaviour of sintered samples. The results indicate that MA addition improves the hardenability and performance, especially after sintering above 1200°C, once the MA melting and alloy homogenisation have occurred.