The object of the method is to obtain rolling mill rolls with a coating of tungsten carbide or of the alloys thereof, wherein the coating is a single layer and is carried out by means of high velocity thermal spraying.

The object of the method is to obtain rolling mill rolls with a coating of tungsten carbide or of the alloys thereof, wherein the coating is a single layer and is carried out by means of high velocity thermal spraying.

A composite cemented carbide roll comprising an inner layer made of an iron-based alloy, and an outer layer made of cemented carbide which is metallurgically bonded to an outer peripheral surface of the inner layer; the cemented carbide of the outer layer comprising 55-90 parts by mass of WC particles and 10-45 parts by mass of an Fe-based binder phase having a particular composition; a shaft member and a shaft end member being metallurgically bonded to at least one axial end of the inner layer; the inner layer being made of an iron-based alloy containing 2.0% or more in total by mass of at least one selected from the group consisting of Cr, Ni and Mo; and the shaft member and the shaft end member being made of an iron-based alloy containing 1.5% or less in total by mass of at least one selected from the group consisting of Cr, Ni and Mo.

A composite cemented carbide roll comprising an inner layer made of an iron-based alloy, and an outer layer made of cemented carbide which is metallurgically bonded to an outer peripheral surface of the inner layer; the cemented carbide of the outer layer comprising 55-90 parts by mass of WC particles and 10-45 parts by mass of an Fe-based binder phase having a particular composition; a shaft member and a shaft end member being metallurgically bonded to at least one axial end of the inner layer; the inner layer being made of an iron-based alloy containing 2.0% or more in total by mass of at least one selected from the group consisting of Cr, Ni and Mo; and the shaft member and the shaft end member being made of an iron-based alloy containing 1.5% or less in total by mass of at least one selected from the group consisting of Cr, Ni and Mo.

A centrifugally cast composite roll for hot rolling comprising an outer layer made of an Fe-based alloy having a chemical composition comprising by mass 2.6-3.6% of C, 0.1-3% of Si, 0.3-2% of Mn, 2.3-5.5% of Ni, 0.5-3.2% of Cr, 0.3-1.6% of Mo, 1.8-3.4% of V, and 0.7-2.4% of Nb, 1.4≤V/Nb≤2.7, a V equivalent (Veq=V+0.55Nb) being 2.60-4% by mass, and the balance being Fe and impurities, and an inner layer made of an iron-based alloy and integrally fused to the outer layer.

A method for manufacturing a roll mold by cutting a roll, includes generating a control waveform based on a signal corresponding to a rotary position of the roll, and making a plurality of cuts on a surface of the roll by, while the roll is rotated, reciprocating a cutting blade in a radial direction of the roll in accordance with the control waveform. Making the plurality of cuts includes at each of a plurality of predetermined locations, making a predetermined number of cuts of predetermined depth based on the control waveform. Generating the control waveform includes generating a control waveform dictating that the predetermined locations, the predetermined depths, or both are randomly selected. Generating the control waveform includes generating a control waveform dictating that, when multiple cuts are made at a predetermined location, each subsequent cut will have a smaller depth than a preceding cut.

A method for manufacturing a roll mold by cutting a roll, includes generating a control waveform based on a signal corresponding to a rotary position of the roll, and making a plurality of cuts on a surface of the roll by, while the roll is rotated, reciprocating a cutting blade in a radial direction of the roll in accordance with the control waveform. Making the plurality of cuts includes at each of a plurality of predetermined locations, making a predetermined number of cuts of predetermined depth based on the control waveform. Generating the control waveform includes generating a control waveform dictating that the predetermined locations, the predetermined depths, or both are randomly selected. Generating the control waveform includes generating a control waveform dictating that, when multiple cuts are made at a predetermined location, each subsequent cut will have a smaller depth than a preceding cut.

The method for obtaining rolling mill rolls with a coating of tungsten carbide or the alloy thereof, wherein the coating is a single layer and is carried out by high velocity thermal spraying is disclosed.

The method for obtaining rolling mill rolls with a coating of tungsten carbide or the alloy thereof, wherein the coating is a single layer and is carried out by high velocity thermal spraying is disclosed.

A rolling mill includes three or more rolling rolls aligned along a circumferential direction and arranged so each rotary shaft is skewed with respect to a pass line of a material to be rolled, wherein the material to be rolled made of a pipe or bar material passes between the rolling rolls while being rotated to undergo diameter reducing rolling. At least one rolling roll selected from the three or more rolling rolls is smaller in roll diameter than at least one other rolling roll. When at least one rolling roll having a relatively maximum roll diameter defined as a maximum diameter rolling roll and at least one rolling roll smaller in roll diameter than the maximum is defined as a small diameter rolling roll, the small diameter rolling roll has a roll diameter equal to or less than 90% of the roll diameter of the maximum diameter rolling roll.