A stainless steel and copper joined body is provided. A fillet welded lap joint that is a joined portion of stainless steel and copper is formed at an end of the copper. The Cu/Fe ratio of the fillet welded lap joint is 2.3 or more. The fillet welded lap joint includes multiple welding points that are continuous in the welding direction. The average diameter D.sub.mean (mm) of the welding points and the copper thickness (mm) satisfy the relationship of the following Formula (1). The overlap ratio OR of welding points is 10% or more and 80% or less.

[00001]$\begin{array}{cc}2t^{0.5}{D}_{\mathrm{mean}}10t^{0.5}& \left(1\right)\end{array}$

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.

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.

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.

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.

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.

A pyrolysis surface such as a rotating retort is provided by copper sheet supported by a nickel alloy framework. Pyrolysis is used to destroy calorific waste and/or to produce gas therefrom.

A negative electrode collector using a copper-covered steel foil for carrying a negative electrode active material for lithium ion secondary batteries has a steel sheet as the core material thereof and has, on both surfaces thereof, a copper covering layer having a mean thickness t.sub.Cu of from 0.02 to 5.0 m on each surface, and of which the total mean thickness, t, including the copper covering layer 7 is from 3 to 100 m with t.sub.Cu/t of at most 0.3. The steel sheet can be common steel, austenitic stainless steel, or ferritic stainless steel. The copper covering layer can be a copper electroplating layer (including one rolled after plating). On the surface of the copper covering layer, for example, a carbon-based active material layer that has been densified through strong roll pressing is formed, and the copper-covered steel foil and the carbon-based active material layer constitute the negative electrode collector.

The method comprises applying a spot load to a joint part between a first metal material and a second metal material in a state where sites to form the joint part are superposed on each other. When a total thickness of the first metal material and the second metal material at the joint part before bonding is defined as T.sub.0 mm, the total thickness thereof after bonding is defined as T.sub.1 mm, and T.sub.0/T.sub.1=R is defined as a reduction ratio, the reduction ratio R is 1.4 or more.

The present invention describes a brazing process in copper and steel parts for several equipment, using a zinc alloy as an additive material, and a device produced according do said process. Specifically, the present invention includes a brazing process between a copper pipe and a steel part, using an alloy composed mainly by zinc as addiction material. Said brazing process is applied to exhaust copper pipes and steel exhaust system, both present in the compressors. The present invention is situated on the industrial field of compressors, metallurgy, mechanical engineering and materials engineering.