PURPOSE:To improve the rolling life of a roll and to manufacture the roll economically, by diffusion joining a rolling annular body, formed by sintered hard metal or high speed steel, etc. to a ring base body, formed by a low-carbon low-alloy steel consisting of a matrix of ferrite, under a hot hydrostatic pressure. CONSTITUTION:A composite roll 1 is constituted of rolling annular-bodies 2 having desired calibers, formed in its outer peripheral surface, and a ring base body 3 having the bodies 2, built in it by exposing their outer peripheral surfaces. The bodies 2 and the body 3 are diffusion joined together under a hot hydrostatic pressure. That is, the powder of high wear-resistant material to be formed into the annular body 2 for rolling, is press packed in the recessed grooves 4 formed along the outer peripheral surface of body 3, and is provided with canning treatment before HIP treatment, to obtain a composite ring stock 1', which is formed into a composite ring roll 1 by providing it with desired caliber work. In this way, a roll excellent in durability is economically manufactured.

Composite ring roll

A forged roll for use, inter alia, in the cold rolling industry and a method of producing a forged roll as described. The roll has a steel composition, by weight, with 0.8 to less than 1% C, 0.2 to 0.5% Mn, 0.2 to 2.0% Si, 7.0 to 13.0% Cr, 0.6 to 1.6% Mo, more than 1.0 to 3.0% V, the remainder being Fe and impurities. The steel is tempered martensite with retained austenite at less than 5% per volume with eutectic carbides of less than 5% by volume, a hardness between 780-840 HV, and internal compressive stresses of between −300 to −500 MPa.

Forged roll meeting the requirements of the cold rolling industry and a method for production of such a roll

A method of producing a long-life roll for a rolling mill manufacturing a rolled sheet having brightness. At least the surface of the roll barrel is made of steel containing carbide, the average grain size of which is not greater than 0.6 μm, and the areal ratio of the carbide in the matrix is 6-30%. The roll is manufactured by canning steel powder produced by an RST process into a metal cylindrical container in a vacuum, sintering the powder in the cylindrical container by hot isostatic pressing, working the sintered body into the cnfiguration of a roll by machining and further giving it a heat treatment and finishing work. The roll and a rolling mill incorporating the roll are also disclosed.

Roll for a rolling mill, method of producing the same and the rolling mill incorporating the roll

PURPOSE:To allow a composite roll to combine high thermal shock cracking resistance with high wear resistance by constituting the composite roll of a core material made of low alloy steel having a specific hardness lower than that of outer layer material and an outer layer material made of high alloy steel in which hardness, structure, and residual stress are specified, respectively. CONSTITUTION:This composite roll is constituted of a core material made of low alloy steel having a hardness of >=35 Shore hardness and lower than the hardness of outer layer material and an outer layer material made of high alloy steel having a martensitic structure of >=80 Shore hardness and =70kg/mm residual stress at the outermost surface. In order to produce this roll, progressive hardening in which, while applying progressive heating to the outer layer material alone up to a temp. not lower than the austenite transformation point, a liquid refrigerant is sprayed on the heated part is performed. Then, high-temp. tempering treatment in which the amount of retained austenite phase in the outer layer material is regulated to =300 deg.C is made possible even if the surface hardness is regulated to a value equal to that of the conventional roll, resistance to thermal shock can be improved while maintaining wear resistance equal to that of the conventional roll.

Composite roll for rolling metal and its production

PROBLEM TO BE SOLVED: To provide a forging roll for use in cold rolling industry in the field of forging roll, and method for manufacturing the forging roll.SOLUTION: The forging roll for use in the cold rolling industry and the method for manufacturing such the roll are provided. The forging roll comprises a steel composition and a microstructure that comprises: tempered martensite with retained austenite at a ratio of less than 5% per volume; and an open eutectic carbide network with eutectic carbides of less than 5% per volume. The roll exhibits a hardness of from 780 to 840 HV and an internal compressive stress of -300 to -500 MPa in absolute values.

Forging roll meeting requirement of cold rolling industry and method for manufacturing the same

PURPOSE:To make a work roll for hot rolling withstand large Hertz stress during rolling and to enhance the wear resistance by manufacturing the roll with a Cr-Mo-V cast steel contg. a specified amount of V. CONSTITUTION:A work roll for hot rolling is manufactured with a cast steel contg. 0.6-1.2% C, =0.65. The roll is heat treated by oil hardening at 1,050-1,075 deg.C and tempering at 510 or 550 deg.C. Fine V carbide particles are uniformly dispersed in the tempered martensite structure, and a work roll for hot rolling with >=61 HRC hardness and superior wear resistance is obtd. This roll withstands >=200kg/ mm. Hertz stress.

Yasuo Nanbu

Papers

Work roll for hot rolling