For producing a welded ring, a band of a length corresponding to the circumference of the ring is bent into a ring and its two ends are welded together. The band ends to be welded together have an offset in the circumferential direction of the ring, the offset lying in the plane of the band. The welding is performed from both lateral edges of the ring, from the outside to the inside up to the offset. Welding having an overall improved welding quality and a higher tensile strength is thus obtained.

A method of producing an endless metal ring includes welding ends of a maraging steel plate such that the maraging steel plate has a ring shape, annealing the maraging steel plate with the ring shape in a furnace at 845 C. or higher, and nitriding the annealed maraging steel plate, wherein, during the annealing, a dew point temperature indicating an amount of water in the furnace is adjusted such that a value of the dew point temperature [ C.] is equal to or higher than a value obtained by subtracting 35 from time [min] at an annealing temperature of 845 C. or higher.

A method of producing an endless metal ring includes welding ends of a maraging steel plate such that the maraging steel plate has a ring shape, annealing the maraging steel plate with the ring shape in a furnace at 845 C. or higher, and nitriding the annealed maraging steel plate, wherein, during the annealing, a dew point temperature indicating an amount of water in the furnace is adjusted such that a value of the dew point temperature [ C.] is equal to or higher than a value obtained by subtracting 35 from time [min] at an annealing temperature of 845 C. or higher.

Provided is a method for manufacturing a cylindrical member which includes end bending of respective end portions of a plate material in a longitudinal direction, primary grooving of respective end surfaces of the plate material subjected to end bending, bending of the plate material to a ring shape, secondary grooving of respective end surfaces of the plate material subjected to bending in a ring shape, and joining of respective end surfaces of the plate material. Therefore, it is possible to manufacture a high-quality cylindrical member.

Provided is a method for manufacturing a cylindrical member which includes end bending of respective end portions of a plate material in a longitudinal direction, primary grooving of respective end surfaces of the plate material subjected to end bending, bending of the plate material to a ring shape, secondary grooving of respective end surfaces of the plate material subjected to bending in a ring shape, and joining of respective end surfaces of the plate material. Therefore, it is possible to manufacture a high-quality cylindrical member.

A method and a system for producing a ring-shaped member. A punching process is carried out on an axial intermediate part of a first intermediate annular material so as to produce a pair of ring-shaped members. A punching step includes a step in which a first punching process is carried out over a first range of the axial intermediate part in the circumferential direction, and a step in which a second punching process is carried out over a second range of the axially-oriented intermediate part, which is at least partially different than the first range, in the circumferential direction. The first punching process is carried out such that at least one tab is formed. The second punching process is carried out such that at least one separate tab is formed, thereby producing the pair of ring-shaped members.

A method and a system for producing a ring-shaped member. A punching process is carried out on an axial intermediate part of a first intermediate annular material so as to produce a pair of ring-shaped members. A punching step includes a step in which a first punching process is carried out over a first range of the axial intermediate part in the circumferential direction, and a step in which a second punching process is carried out over a second range of the axially-oriented intermediate part, which is at least partially different than the first range, in the circumferential direction. The first punching process is carried out such that at least one tab is formed. The second punching process is carried out such that at least one separate tab is formed, thereby producing the pair of ring-shaped members.

In a case of a mark left type, a slit is formed on a line side (slit side) of a joint portion. The slit is formed, for example, with a scroll saw. By the formation of the slit, a length of the joint portion in a direction orthogonal to an axial direction of a single ring is set to approximately 0.7 mm. In a case of a mark removed type, a slit and a slit are formed respectively on the line side (slit side) and a side opposite thereto of the joint portion. Those slits are formed, for example, with the scroll saw. By the formation of those slits, the length of the joint portion in the direction orthogonal to the axial direction of the single ring is set to approximately 0.8 mm.

In a case of a mark left type, a slit is formed on a line side (slit side) of a joint portion. The slit is formed, for example, with a scroll saw. By the formation of the slit, a length of the joint portion in a direction orthogonal to an axial direction of a single ring is set to approximately 0.7 mm. In a case of a mark removed type, a slit and a slit are formed respectively on the line side (slit side) and a side opposite thereto of the joint portion. Those slits are formed, for example, with the scroll saw. By the formation of those slits, the length of the joint portion in the direction orthogonal to the axial direction of the single ring is set to approximately 0.8 mm.

This method for manufacturing a ring is a method for manufacturing an endless metal ring for a continuously variable transmission using a transmission belt that is formed by binding a plurality of elements with the ring. The method includes: a welding step of butt welding ends of a metal strip to form an endless tubular body; a solution treatment step of solution-treating the welded tubular body; a cutting step of cutting the solution-treated tubular body with laser light into ring bodies with a predetermined width; a lateral end processing step of pressing a grinding wheel against a lateral end of the cut ring body to remove a heat-affected zone formed by the cutting step and form the lateral end into a convex arc shape; and a rolling step of adjusting the ring body with the processed lateral end to a predetermined thickness.