Correct option is A
High-Speed Steel (HSS) is a tool steel known for its high hardness, wear resistance, and ability to retain hardness at high temperatures. To achieve these properties, HSS undergoes heat treatment, including hardening and tempering.
· The hardening temperature for HSS tools typically ranges from 1200°C to 1280°C depending on the exact composition.
· At this temperature, the alloying elements (such as tungsten, molybdenum, vanadium, and chromium) dissolve into the austenite phase, ensuring high hardness after quenching.
· The steel is then quenched in air, salt bath, or oil to rapidly cool it down and retain hardness.
