ER307Si is an austenitic stainless steel with added manganese and silicon compared to the AWS 307 grades. Used for joining and surfacing applications involving work-hardenable steels, armor plate, heat resistant
steels and subjected to temperatures up to 1560 F and dissimilar steels such as austenitic manganese steels to carbon steel forgings and  castings. Weld deposits are porosity free, crack and corrosion resistant. 

(Tri-mix gas = 90%He+7.5%Ar+2.5%CO2)