Martensitic steels are designed to form martensite on normal air cooling of the weld deposit. As a result, these steels are often termed "self-hardening" or "air-hardening," and they resemble tool steels with hardnesses in the range of 45 to 60 HRC. The carbon content of the martensitic steels ranges up to 0.7%. Other elements such as molybdenum, tungsten, nickel, and chromium (up to 12%), are added to increase hardenability and strength and to promote martensite formation.
Manganese and silicon usually are added to aid weldability