Abstract: A machine component includes a first region having a first linear expansion coefficient, and a second region having a second linear expansion coefficient greater than the first linear expansion coefficient and joined to the first region. A region including an outer periphery of an interface between the first region and the second region is inclined toward the second region side over the entire periphery. On a surface of the first region, a groove is formed to extend along the outer periphery of the interface.

Abstract: The method includes a step of preparing a first member made of a first metal and a second member made of a second metal having a smaller deformation resistance than the first metal, and a step of joining the first member and the second member. The step of joining includes a step of disposing the second member in a cavity of a mold, a step of heating the first member and the second member by relatively rotating the first member with respect to the second member, while pressing the first member against the second member, without changing a positional relationship, and a step of cooling the first member and the second member with the members being in contact with each other. In the step of disposing, the second member is disposed such that a second member contact surface is surrounded by the sidewall of the cavity.

Abstract: The method for producing a metal member includes a step of preparing a first member made of a first metal and having a recessed portion formed therein, and a second member made of a second metal having a smaller deformation resistance than the first metal, and a step of joining the first member and the second member. The step of joining includes a step of increasing temperatures of the first member and the second member by relatively rotating the second member with respect to the first member while pressing the second member against the first member with at least a part of the second member being received in the recessed portion, and a step of stopping the relative rotation of the second member with respect to the first member and cooling the first member and the second member with the members being pressed against each other.

Abstract: A sprocket wheel, which is a machine component configured to slide relative to a bushing while being in contact with the bushing in an outer peripheral surface, includes a base made of a first metal, and an overlay that covers the base so as to constitute the outer peripheral surface. The surface of the overlay constituting the outer peripheral surface has been smoothed. Such a smoothed surface of the overlay makes the sprocket wheel less damaging to the bushing.

Abstract: A tooth, which is a wear-resistant component, includes a core, and a body made of a first metal and disposed to enclose the core. The core includes a matrix made of a second metal, first hard particles dispersed in the matrix, and a hard structure extending from the corresponding first hard particle in a direction along the grain flow in the body, the hard structure being higher in hardness than the matrix.

Abstract: A sprocket wheel, which is an example of the machine component, includes a base made of a first metal, and an overlay disposed in contact with the base to cover at least a part of a surface of the base. The overlay includes a matrix made of a second metal, and hard particles dispersed in the matrix. The overlay includes a protrusion that protrudes toward the base in a region including the interface between the overlay and the base.

Abstract: A sprocket wheel has an annular shape. The sprocket wheel has a plurality of projections formed on an outer peripheral surface for transmitting a driving force to a track. The sprocket wheel includes a base made of a first metal, and an overlay including a second metal that covers the base so as to constitute at least a part of the outer peripheral surface. The overlay is formed with a metallic structure that is continuous in the circumferential direction so as to connect between adjacent ones of the projections.

Abstract: A sprocket wheel, which is an example of the machine component, includes a base made of a first metal, and an overlay disposed in contact with the base to cover at least a part of a surface of the base. The overlay includes a matrix made of a second metal, and hard particles dispersed in the matrix. The surface of the overlay is a forged surface. The hard particles located in an overlay surface region within an average particle diameter of the hard particles from the surface of the overlay are arranged side by side while being embedded in the overlay.

Abstract: The method includes a step of preparing a first member made of a first metal and a second member made of a second metal having a smaller deformation resistance than the first metal, and a step of joining the first member and the second member. The step of joining includes a step of heating the first member and the second member by relatively rotating the first member and the second member, while pressing the first member and the second member against each other, without changing a relative positional relationship therebetween, and a step of cooling the first member and the second member heated, while being pressed against each other. In a first contact surface which is a surface of the first member coming into contact with the second member, a recess is formed so as to include a region intersecting the axis of rotation.

Abstract: The method for producing a metal member includes a step of preparing a first member made of a first metal, a second member made of a second metal, and a third member made of a third metal, and a step of joining the first member and the second member via the third member. The step of joining includes a step of heating the first member, the second member, and the third member by stacking the first member, the third member, and the second member in this order and relatively rotating the first member about an axis of rotation, while pressing the first member against the third member, without changing a positional relationship, and a step of cooling the first member, the second member, and the third member heated, with the members being in the stacked state.

Abstract: A tooth which is an example of a wear-resistant component includes a base made of a first metal, and an overlay disposed in contact with the base to cover a covered region that is a part of a surface of the base. In an overlay edge portion corresponding to a boundary between the covered region and an exposed region other than the covered region on the surface of the base, the exposed region and a surface of the overlay are flush with each other to form a forged surface.

Abstract: A sliding component and its producing method are provided. The sliding component includes a base section made of steel or cast iron, and a sliding section having a sliding surface, made of copper alloy including hard particles, and joined to the base section. The hard particles in the sliding section are arranged such that those in a region including an outer periphery of the interface with the base section have their longitudinal directions coinciding with the directions along the outer periphery as compared to those in an inner peripheral side. This improves the durability of the sliding section in its region including the outer periphery of the interface with the base section.

Abstract: A piston shoe as a sliding component includes a base section, which is made of steel, and a sliding section having a sliding surface, which is made of copper alloy and joined to the base section. The base section and the sliding section are joined, with a base section joint region being formed in the base section, the base section joint region including a base section joint surface that is a surface joined to the sliding section and having smaller grains than other regions in the base section.

Abstract: A tooth as the earth and sand abrasion resistant component includes a base, a first overlay layer disposed in contact with the base so as to cover a distal end face which is a part of a surface of the base, and a second overlay layer disposed on the first overlay layer. The first overlay layer and the second overlay layer each include a matrix made of iron or steel, and cermet particles made of cermet and dispersed in the matrix.

Abstract: A tooth, which is a wear-resistant component, includes a core, and a body made of a first metal and disposed to enclose the core. The core includes a matrix made of a second metal, first hard particles dispersed in the matrix, and a hard structure extending from the corresponding first hard particle in a direction along the grain flow in the body, the hard structure being higher in hardness than the matrix.

Abstract: A machine component includes a first region having a first linear expansion coefficient, and a second region having a second linear expansion coefficient greater than the first linear expansion coefficient and joined to the first region. A region including an outer periphery of an interface between the first region and the second region is inclined toward the second region side over the entire periphery. On a surface of the first region, a groove is formed to extend along the outer periphery of the interface.

Abstract: A metal member producing device includes a spindle, a base portion, and a driving portion which drives at least one of the spindle and the base portion in an axial direction of the spindle. Of the spindle and the base portion, one includes a first holding portion for holding a first member. The other has disposed thereon a mold for holding a second member to oppose the first holding portion. The mold includes a bottom wall and a sidewall that extends from the bottom wall in a direction intersecting the bottom wall. The sidewall has a resistive wall formed thereon, the resistive wall being a wall surface inclined with respect to a plane parallel to the axial direction of the spindle so as to face the bottom wall side.

Abstract: The method for producing a metal member includes a step of preparing a first member made of a first metal and having a recessed portion formed therein, and a second member made of a second metal having a smaller deformation resistance than the first metal, and a step of joining the first member and the second member. The step of joining includes a step of increasing temperatures of the first member and the second member by relatively rotating the second member with respect to the first member while pressing the second member against the first member with at least a part of the second member being received in the recessed portion, and a step of stopping the relative rotation of the second member with respect to the first member and cooling the first member and the second member with the members being pressed against each other.

Abstract: The method for producing a metal member includes a step of preparing a first member made of a first metal, a second member made of a second metal, and a third member made of a third metal, and a step of joining the first member and the second member via the third member. The step of joining includes a step of heating the first member, the second member, and the third member by stacking the first member, the third member, and the second member in this order and relatively rotating the first member about an axis of rotation, while pressing the first member against the third member, without changing a positional relationship, and a step of cooling the first member, the second member, and the third member heated, with the members being in the stacked state.

Abstract: The method includes a step of preparing a first member made of a first metal and a second member made of a second metal having a smaller deformation resistance than the first metal, and a step of joining the first member and the second member. The step of joining includes a step of disposing the second member in a cavity of a mold, a step of heating the first member and the second member by relatively rotating the first member with respect to the second member, while pressing the first member against the second member, without changing a positional relationship, and a step of cooling the first member and the second member with the members being in contact with each other. In the step of disposing, the second member is disposed such that a second member contact surface is surrounded by the sidewall of the cavity.