Grain growth of austenite in case hardening structural steels produced by vacuum-arc and electroslag remelting

Abstract

1. Vacuum-arc remelting of steel 15KhGNTA leads to grain growth with the same difference in grain sizes as in the original melt. Electroslag remelting of steel 15KhGNTA eliminates the difference in grain sizes up to 1000°C. Grains differing in size by approximately two grades are observed at 1050 and 1100°C. At higher temperatures the grains are uniform and somewhat larger than in the original metal or after vacuum-arc remelting at corresponding temperatures. 2. The grain size of steel 12Kh2N4A does not change after vacuum-arc or electroslag remelting at temperatures up to 900°C. At 950°C grains differing in size by 4 grades are observed in all melts, such grains occurring on holding 1 h in the original melt and after electroslag remelting and on holding 20 min after vacuum-arc remelting. In the original melt and after vacuum-arc remelting a difference in grain size is observed at all temperatures. After electroslag remelting of steel 12Kh2N4A at 1000, 1050, and 1150°C the grains are uniform (grade 5-4).