ENDLESS METAL RING AND METHOD OF PRODUCING THE SAME

• US 20190331197A1
• Filed: 04/22/2019
• Published: 10/31/2019
• Est. Priority Date: 04/27/2018
• Status: Abandoned Application

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Maekawa, Yoshihiro, Nishida, Koji
• Application Number:
  US16/390,054
• Publication Number:
  US 20190331197A1
• Time in Patent Office: Days
• CPC Class Codes: B21D 53/14 belts, e.g. machine-gun belts
• CPC Class Codes: B21D 53/16 rings, e.g. barrel hoops
• CPC Class Codes: C21D 1/06 Surface hardening
• CPC Class Codes: C21D 1/26 Methods of annealing
• CPC Class Codes: C21D 1/76 Adjusting the composition of the atmosphere
• CPC Class Codes: C21D 6/02 Hardening by precipitation
• CPC Class Codes: C21D 9/40 for rings; for bearing races
• CPC Class Codes: C21D 9/50 for welded joints
• CPC Class Codes: C22C 38/06 containing aluminium
• CPC Class Codes: C22C 38/105 containing Co and Ni
• CPC Class Codes: C22C 38/12 containing tungsten, tantalum, molybdenum, vanadium, or niobium
• CPC Class Codes: C22C 38/14 containing titanium or zirconium
• CPC Class Codes: C23C 8/02 Pretreatment of the material to be coated C23C8/04 takes precedence
• CPC Class Codes: C23C 8/26 of ferrous surfaces
• CPC Class Codes: C23C 8/80 After-treatment
• CPC Class Codes: F16G 5/16 consisting of several parts

Abstract

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.

Claims

1. A method of producing an endless metal ring, comprising:

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 maraging steel plate that is annealed,

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.

2. The method according to claim 1, wherein

the furnace has a nitrogen gas supply path and a hydrogen gas supply path,

the nitrogen gas supply path has a branch path with a water supply source, and

the dew point temperature is adjusted by adjusting a flow rate of nitrogen gas that passes through the branch path.

3. An endless metal ring, comprising:

a maraging steel plate including 5.75 mass % to 6.05 mass % of molybdenum, 12.0 mass % to 17.0 mass % of cobalt, 17.0 mass % to 20.0 mass % of nickel, 0.4 mass % to 0.5 mass % of titanium, 0 mass % to 0.15 mass % of aluminum, and a remainder including iron and inevitable impurities,

wherein a thickness of a titanium nitride layer in the maraging steel plate is 2 μ

m or less.