Strength and toughness of T42 high-speed steel

AbstractHardness and compressive strength, Young's modulus, bend strength, and fracture toughness were measured in wrought and commercially sintered T42 high-speed steel. After identical heat treatments, no significant differences were found between wrought and sintered materials in hardness (800–1010 HV50), Young's modulus (∼220 GN m−2), or fracture toughness (9−18 MN m−3/2). The four-point bend strengths in the wrought material were slightly higher in specimens cut longitudinal to the working direction than in transverse specimens (1·3–2·4 GN m−2), and both were markedly superior in strength to the sintered material (1·0–1·2 GN m−2). For three-point bend tests with laboratory-sintered material, the stresses for brittle fracture were in the range 1·9–3·0 GN m−2, a level comparable to the wrought specimens. Wrought material contained carbide stringers with a scattering of large Me carbides, whereas in the sintered material pores and incomplete bonding could be detected, albeit infrequently. Fracture initi...