A cemented carbide comprising 55-90 parts by mass of WC particles and 10-45 parts by mass of a Fe-based binder phase; the binder phase having a composition comprising 0.5-10% by mass of Ni, 0.2-2% by mass of C, 0.5-5% by mass of Cr, 0.2-2.0% by mass of Si, and 0.1-5% by mass of W, the balance being Fe and inevitable impurities, and containing 0.05-2.0% by area of Fe—Si—O-based particles.

A cemented carbide comprising 55-90 parts by mass of WC particles and 10-45 parts by mass of a Fe-based binder phase; the binder phase having a composition comprising 0.5-10% by mass of Ni, 0.2-2% by mass of C, 0.5-5% by mass of Cr, 0.2-2.0% by mass of Si, and 0.1-5% by mass of W, the balance being Fe and inevitable impurities, and containing 0.05-2.0% by area of Fe—Si—O-based particles.

The present invention relates to the technical field of material processing and provides a method for making a metal material composite, including: contacting a first surface of a first plate with a second surface of a second plate; placing the first plate and the second plate in a recess in a circumferential direction of a first roller such that a third surface of the second plate contacts a bottom wall of the recess in a circumferential, the third surface being opposite the second surface, the first plate having a greater hardness than the second plate; and controlling a first roller and a second roller to rotate, thereby rolling to combine the first plate and the second plate into a composite plate, where a fourth surface of the first plate contacts a surface of the second roller and the fourth surface is opposite the first surface during the rolling. According to the method for making a metal material composite in the present invention, flashings and burr on the side edges of a composite plate are avoided by placing the first plate and the second plate in a recess for machining.

A centrifugally cast composite roll comprising an outer layer formed by a centrifugal casting method, and an inner layer made of ductile cast iron and integrally fused to the outer layer, the outer layer being made of an Fe-based alloy comprising by mass 1.3-3.7% of C, 0.3-3% of Si, 0.1-3% of Mn, 1-7% of Cr, 1-8% of Mo, at least one of 2.5-7% of V, 0.1-3% of Nb and 0.1-5% of W (V is indispensable), and 0.01-0.2% of B and/or 0.05-0.3% of S, the balance being substantially Fe and inevitable impurities, the outer layer having a structure containing no graphite; the inner layer comprising a core portion fused to the outer layer, and a drive-side shaft portion and a free-side shaft portion integrally extending from both ends of the core portion; the total amount of Cr, Mo, V, Nb and W being 0.35-2% by mass in an end portion of the drive-side shaft portion and 0.15-1.8% by mass in an end portion of the free-side shaft portion, the former being larger than the latter by 0.2% or more by mass.

A centrifugally cast, hot-rolling composite roll comprising an outer layer formed by a centrifugal casting method, and an inner layer made of ductile cast iron and integrally fused to the outer layer; the outer layer having a chemical composition comprising by mass 1-3% of C, 0.4-3% of Si, 0.3-3% of Mn, 1-5% of Ni, 2-7% of Cr, 3-8% of Mo, 3-7% of V, and 0.01-0.12% of B, the balance being Fe and inevitable impurities, and meeting the relation expressed by Cr/(Mo+0.5W)<−2/3[C−0.2(V+1.19Nb)]+11/6, wherein W=0, and Nb=0, when W and Nb are not contained; and containing by area 1-15% of MC carbide, 0.5-20% of carboboride, and 0.5-20% of Mo-based carbide.

A centrifugally cast, hot-rolling composite roll comprising an outer layer formed by a centrifugal casting method, and an inner layer made of ductile cast iron and integrally fused to the outer layer; the outer layer having a chemical composition comprising by mass 1.6-3% of C, 0.3-2.5% of Si, 0.3-2.5% of Mn, 0.1-5% of Ni, 2.8-7% of Cr, 1.8-6% of Mo, 3.3-6.5% of V, and 0.02-0.12% of B (or 0.01-0.12% of B, and 0.05-02% of S), the balance being Fe and inevitable impurities, and meeting the relation expressed by Cr/(Mo+0.5W)≥−2/3[C−0.2(V+1.19Nb)]+11/6, wherein W=0, and Nb=0, when W and Nb are not contained, and containing by area 1-15% of MC carbide, 0.5-20% of carboboride, and 1-25% of Cr-based carbide.

A centrifugally cast composite roll for hot rolling comprising an outer layer having a composition comprising by mass 0.8-3.5% of C, 0.1-2.5% of Si, 0.1-2.5% of Mn, 1.2-15% of Cr, 1-5% of Ni, and 1-10% of Mo+0.5×W, the balance being substantially Fe and inevitable impurities, and an inner layer made of an iron-based alloy and integrally fused to the outer layer; the outer layer having Shore hardness of 67-82 at the initial diameter of the composite roll; and the maximum Shore hardness of the outer layer in a range 30 mm or more deep from the initial diameter being higher by 1 or more than the Shore hardness of the outer layer at the initial diameter.

[PROBLEM] The invention provides a roll for hot rolling process having various types of more excellent durability performances than conventional rolls, and provides also a method for manufacturing the same. [SOLUTION] A cladding layer 4 is formed on an outer circumference portion of a roll for hot rolling process 1, where the cladding layer 4 comprises: 0.5 to 0.7% by mass of C, 2.8 to 4.0% by mass of Si, 0.9 to 1.1% by mass of Cu, 1.4 to 1.6% by mass of Mn, 2.7 to 3.3% by mass of Ni, 13.5 to 14.5% by mass of Cr, 0.8 to 1.1% by mass of Mo, 0.9 to 1.1% by mass of Co, and 0.2 to 0.4% by mass of Nb, with a balance being Fe and inevitable impurities, and has a thickness of 5 mm or more.

[PROBLEM] The invention provides a roll for hot rolling process having various types of more excellent durability performances than conventional rolls, and provides also a method for manufacturing the same. [SOLUTION] A cladding layer 4 is formed on an outer circumference portion of a roll for hot rolling process 1, where the cladding layer 4 comprises: 0.5 to 0.7% by mass of C, 2.8 to 4.0% by mass of Si, 0.9 to 1.1% by mass of Cu, 1.4 to 1.6% by mass of Mn, 2.7 to 3.3% by mass of Ni, 13.5 to 14.5% by mass of Cr, 0.8 to 1.1% by mass of Mo, 0.9 to 1.1% by mass of Co, and 0.2 to 0.4% by mass of Nb, with a balance being Fe and inevitable impurities, and has a thickness of 5 mm or more.

A composite roll for rolling comprising an outer layer and an inner layer integrally fused to each other; the outer layer being made of an Fe-based alloy comprising by mass 1-3% of C, 0.3-3% of Si, 0.1-3% of Mn, 0.1-5% of Ni, 1-7% of Cr, 1-8% of Mo, 4-7% of V, 0.005-0.15% of N, and 0.05-0.2% of B; the inner layer being made of graphite cast iron comprising by mass 2.4-3.6% of C, 1.5-3.5% of Si, 0.1-2% of Mn, 0.1-2% of Ni, less than 0.7% of Cr, less than 0.7% of Mo, 0.05-1% of V, and 0.01-0.1% of Mg; the inner layer comprising a core portion fused to the outer layer, and shaft portions integrally extending from both ends of the core portion; at least one of the shaft portions containing 200/cm.sup.2 or more of hard MC carbides having circle-equivalent diameters of 5 μm or more.