Provided is a joint component manufacturing method for reducing occurrence of burrs upon bonding between a first member having a hole and a second member having a shaft portion and firmly bonding both members. In the method for manufacturing a joint component 100, a hole-side weak press-fit portion 112 is formed at a hole 111 of a flat plate ring-shaped first member 110. Moreover, each of a shaft-side weak press-fit portion 122 and a shaft-side strong press-fit portion 124 is formed at a shaft portion 121 of a cylindrical second member 120. The hole-side weak press-fit portion 112 and the shaft-side weak press-fit portion 122 are defined by a first weak press-fit interference Lw1 formed thinner than a first strong press-fit interference Ls1. The shaft-side strong press-fit portion 124 is defined by a first strong press-fit interference Ls1 as the minimum necessary press-fit interference for electric resistance welding upon electric resistance welding between the hole 111 and the shaft portion 121.

A method for manufacturing a joined member and a joined member manufacturing apparatus which can manufacture a joined member with a joint portion having an appropriate hardness. A method for manufacturing a joined member C by joining a first member D formed of a metal material having a possibility of undergoing quenching and a second member E formed of a metal material, the method includes a contact-placing step S1 of placing the first and second members D and E with joint target portions of the first and second members D and E respectively being in contact with each other; a joining step S2 of joining the first and second members D and E by passing a pulsed welding electric current A1 for joining through the joint target portions J of the first and second members D and E; a first tempering step S3 of tempering a joint portion F, where the first and second members D and E are joined, by passing a first tempering electric current A2 through the joint portion F; and a second tempering step S4 of tempering the joint portion F by passing a second tempering electric current A3 smaller than the first tempering electric current A2 through the joint portion F.

A method for manufacturing a joined member and a joined member manufacturing apparatus which can manufacture a joined member with a joint portion having an appropriate hardness. A method for manufacturing a joined member C by joining a first member D formed of a metal material having a possibility of undergoing quenching and a second member E formed of a metal material, the method includes a contact-placing step S1 of placing the first and second members D and E with joint target portions of the first and second members D and E respectively being in contact with each other; a joining step S2 of joining the first and second members D and E by passing a pulsed welding electric current A1 for joining through the joint target portions J of the first and second members D and E; a first tempering step S3 of tempering a joint portion F, where the first and second members D and E are joined, by passing a first tempering electric current A2 through the joint portion F; and a second tempering step S4 of tempering the joint portion F by passing a second tempering electric current A3 smaller than the first tempering electric current A2 through the joint portion F.

Provided is an electric resistance welded clad steel pipe or tube in which a region where solidification microstructure is formed, i.e. a region in a weld particularly having significant influence on properties, is reduced without impairing its function as a clad pipe or tube. An electric resistance welded clad steel pipe or tube comprises: a first layer made of carbon steel or low-alloy steel as base metal; and a second layer placed on one surface of the first layer, and made of stainless steel or a nickel-containing alloy as cladding metal, wherein the base metal is not exposed at a cladding metal-side surface of the electric resistance welded clad steel pipe or tube in a weld, and no solidification microstructure is contained in each of circular sections of 0.1 mm in radius respectively centered at specific three positions in a plane perpendicular to a pipe or tube longitudinal direction.

Provided is an electric resistance welded clad steel pipe or tube in which a region where solidification microstructure is formed, i.e. a region in a weld particularly having significant influence on properties, is reduced without impairing its function as a clad pipe or tube. An electric resistance welded clad steel pipe or tube comprises: a first layer made of carbon steel or low-alloy steel as base metal; and a second layer placed on one surface of the first layer, and made of stainless steel or a nickel-containing alloy as cladding metal, wherein the base metal is not exposed at a cladding metal-side surface of the electric resistance welded clad steel pipe or tube in a weld, and no solidification microstructure is contained in each of circular sections of 0.1 mm in radius respectively centered at specific three positions in a plane perpendicular to a pipe or tube longitudinal direction.

Disclosed are a joining structure of different kinds of conductors, a joining method of different kinds of conductors, and a joint of power cables capable of improving joining reliability of a junction of the different kinds of conductors.

A wire billet butt-welding apparatus and a wire billet butt-welding method, the method including: S1: preparing a stock, S2: rotating a butt-welding stock receiver to a stock receiving position, and feeding a first coil of wire billet to a stock receiving rod of the butt-welding stock receiver; S3: welding the first coil of wire billet and the second coil of wire billet on a rotary plate at the butt-welding position end-to-head; S4: rotating the butt-welding stock receiver and the second coil of wire billet to the stock receiving position; S5: rotating the stock receiving rod to rotate to tighten the wire billet between the first coil of wire billet and the second coil of wire billet; and S6: repeating steps S3 to S5 to complete butt-welding operations on the 3.sup.rd to n.sup.th coils of wire billet sequentially.

A method for manufacturing an integrated member and an integrated member manufactured by the method which can improve the joining strength and reduce the manufacturing cost. A method for manufacturing an integrated member by welding a first member formed of aluminum alloy material and a second member formed of ferrous-based material characterized in that the first member contains a predetermined amount of silicon and has a thickness larger than that of the second member. The second member can be pressed against the first member along the thickness direction, and by electrically energizing the pressed-in portion during the pressing period, electric resistance welding can be used. The pressing-in amount is set to a value larger than the thickness of the second member and less than that of the first member. The overlapping margin of the first and second members is set to a value of 0.5 mm or more.

A method for manufacturing an integrated member and an integrated member manufactured by the method which can improve the joining strength and reduce the manufacturing cost. A method for manufacturing an integrated member by welding a first member formed of aluminum alloy material and a second member formed of ferrous-based material characterized in that the first member contains a predetermined amount of silicon and has a thickness larger than that of the second member. The second member can be pressed against the first member along the thickness direction, and by electrically energizing the pressed-in portion during the pressing period, electric resistance welding can be used. The pressing-in amount is set to a value larger than the thickness of the second member and less than that of the first member. The overlapping margin of the first and second members is set to a value of 0.5 mm or more.

A welded portion forming structure forms a welded portion that joins a valve seat and a cylinder head main body. If the distance in a radial direction between a vertex of a corner, which is formed by a first surface and a second surface of the convex portion, and the first origin portion is assumed to be A, and the distance in the radial direction between the vertex and the second origin portion is assumed to be B, then a relation that satisfies all of A>0, AB, and B0 holds. Moreover, an angle which a first joint surface of the valve seat forms with an axial direction and an angle which the second joint surface forms with the axial direction are equal.