There is provided a roll surface layer material including a roll surface layer with excellent fatigue resistance. The roll surface layer material has a composition including, on a mass % basis, C: 2.3% to 2.9%, Si: 0.2% to 0.8%, Mn: 0.2% to 1.0%, Cr: 5.0% to 7.5%, Mo: 4.4% to 6.5%, V: 5.3% to 7.0%, Nb: 0.6% to 1.5%, and Co: 0.1% to 4.0% so as to satisfy 14.0(Mo+1.7V)17.0 (where Mo represents a content (mass %) of Mo and V represents a content (mass %) of V) and further including Al: 0.001% to 0.03% and/or REM: 0.001% to 0.03%, wherein a carbide is contained at an area fraction of 13% to 40%. A composite roll obtained by integrally welding a shaft member to the roll surface layer member is treated as a centrifugal cast roll that includes a surface layer with excellent fatigue resistance.

A method for installing a first machine part into a second machine part includes press fitting the first machine part into the second machine part in its intended final position. The method also includes disposing an exothermically reactive substance on or in the first machine part and activating the exothermically reactive substance to cause a thermal structural change, stress relief, for example, in a part of the first machine part.

A method for installing a first machine part into a second machine part includes press fitting the first machine part into the second machine part in its intended final position. The method also includes disposing an exothermically reactive substance on or in the first machine part and activating the exothermically reactive substance to cause a thermal structural change, stress relief, for example, in a part of the first machine part.

A method of forming a component from a powder metal includes forming the component to a desired shape from the powder metal, heating the component to a burnishing temperature of 900 to 1300 degrees Fahrenheit, and burnishing a surface of the component while the component is at the burnishing temperature to densify the surface.

[Problem to be Solved]

To provide a novel briquetting roll having excellent performance such as providing both abrasion resistance and spalling resistance, which can also be manufactured at low cost and in a short period of time, and a method for manufacturing the same.

[Means for Solving the Problem]

A briquetting roll 1 integrally has an inner layer material 4 and an outer layer material 5, which comprise mutually different materials and are in contact with each other at the respective exterior and interior thereof, and has pockets 6 formed at the outer circumference of the outer layer material 5. A chromium-molybdenum forged steel material is used for the inner layer material 4 and a high-carbon high-speed steel material is used for the outer layer material 5. The outer layer material 5 may be formed on the outside of the inner layer material 4 by a continuous pouring process.

[Problem to be Solved]

To provide a novel briquetting roll having excellent performance such as providing both abrasion resistance and spalling resistance, which can also be manufactured at low cost and in a short period of time, and a method for manufacturing the same.

[Means for Solving the Problem]

A briquetting roll 1 integrally has an inner layer material 4 and an outer layer material 5, which comprise mutually different materials and are in contact with each other at the respective exterior and interior thereof, and has pockets 6 formed at the outer circumference of the outer layer material 5. A chromium-molybdenum forged steel material is used for the inner layer material 4 and a high-carbon high-speed steel material is used for the outer layer material 5. The outer layer material 5 may be formed on the outside of the inner layer material 4 by a continuous pouring process.

A method of forming a component includes heating the component to a burnishing temperature above 500 degrees Fahrenheit, and burnishing a surface of the component while the component is at the burnishing temperature to densify the surface. The burnishing process at an elevated temperature may be integrated into other processes, such as the sintering or heat treating processes.

A method of forming a component includes heating the component to a burnishing temperature above 500 degrees Fahrenheit, and burnishing a surface of the component while the component is at the burnishing temperature to densify the surface. The burnishing process at an elevated temperature may be integrated into other processes, such as the sintering or heat treating processes.

A roll outer layer material contains small-size carbides having a circle equivalent diameter of 3 to 30 m in a number of 500 to 2500 pieces/mm.sup.2 and large-size carbides having a circle equivalent diameter of 50 m or more in a number of 20 pieces/mm.sup.2 or less, preferably having a chemical composition containing, by mass %, C: 2.4% or more and 2.9% or less, Si: 0.2% or more and 1.0% or less, Mn: 0.2% or more and 1.0% or less, Cr: 4.0% or more and 7.5% or less, Mo: 4.0% or more and 6.5% or less, V: 5.3% or more and 7.0% or less, Nb: 0.5% or more and 3.0% or less, and the balance being Fe and inevitable impurities, in which the contents of Cr, Mo, and V satisfy the relationship 1.5(Cr+Mo)/V2.4.

A method of forming a component includes heating the component to a burnishing temperature above 500 degrees Fahrenheit, and burnishing a surface of the component while the component is at the burnishing temperature to densify the surface. The burnishing process at an elevated temperature may be integrated into other processes, such as the sintering or heat treating processes.