WEAR-RESISTANT STEEL STRIP AND PRODUCTION METHOD THEREOF Russian patent published in 2016 - IPC C22C38/50 C21D8/02 

FIELD: metallurgy.

SUBSTANCE: invention relates to high-strength steel strip, in particular, to high-strength wear-resistant steel strip with Brinell hardness ≥HB 420, and method of its production. Strip has following chemical composition, wt%: C 0.205-0.25, Si 0.20-1.00, Mn 1.0-1.5, Al 0.02-0.04, Ti 0.01-0.03, N≤0.006, Ca≤0.005, more than one element from following: Cr≤0.70, Ni≤0.50, Mo≤0.30, unavoidable inclusion P≤0.015, S≤0.010, Fe - balance. Method for production of strip includes vacuum degassing of steel, continuous casting or injection moulding of molten steel. During continuous casting slab is obtained, and in casting under pressure bar is obtained. Heating of slab or bar is carried out at 1,150-1,250 °C, single-pass or multiple-pass rolling in more than three passes is performed in recrystallisation zone of austenite, wherein total reduction factor is ≥70 %, and rolling end temperature is ≥860 °C. Water cooling of rolling steel strip is performed with minimum speed to obtain martensite Vmin about 50 °C/s to temperature of martensite Ms in range of 145-185 °C, further cooling air to room temperature, coefficient of quenching P =2.7C+0.4Si+Mn+0.45Ni+0.8Cr+0.45Cu+2Mo, minimum cooling rate for producing martensite Vmin is equal to lgVmin = 2.94-0.75P, and initial temperature of formation of martensite Ms=561-474C-33Mn-17Cr-17Ni-21Mo.

EFFECT: production of high wear resistance strip with thickness of 6-25 mm, having a structure of martensite and residual austenite (5-10 %), hardness ≥HB 420, yield strength ≥1,000 MPa, elongation ≥18 %, A_kv≥27 J at -40 °C, better bend under cool conditions and self-quenching effect during operation thereof.

19 cl, 5 tbl, 3 dwg