JP2017509788A5 - - Google Patents

Claims (7)

A method of nitriding a metal ring (32) for a drive belt (3) for a continuously variable transmission, wherein the ring (32) is disposed in an oven chamber (50), and at least ammonia is placed in the oven chamber (50). Supply gas,
The equilibrium constant K _N of the reversible chemical reaction from ammonia to hydrogen and nitrogen in the oven chamber (50) and vice versa, the equilibrium constant K _N is the equation K _N = (p [NH ₃ ]) _{/ (p [H 2] ^} 1.5) (2)
P [NH ₃ ] represents the partial pressure of the ammonia gas, p [H ₂ ] represents the partial pressure of the hydrogen gas,
The equilibrium constant K _N is controlled to a desired value that is at least 4 bar ^−1/2 smaller than the equilibrium constant K _N when the iron nitride compound layer is formed on the surface of the ring (32). A method of nitriding a metal ring (32) for a drive belt (3) for a continuously variable transmission. The method of nitriding a metal ring (32) according to claim 1, wherein the equilibrium constant K _N is controlled to a value between 4 and 8 bar ^-1/2 .   The method of nitriding a metal ring (32) according to claim 1 or 2, wherein the temperature of the ammonia gas in the oven chamber (50) is at most 505 ° C.   The method of nitriding a metal ring (32) according to claim 3, wherein the temperature of the ammonia gas in the oven chamber (50) is controlled to a value between 465 and 475 ° C.   A metal ring (32) according to any one of claims 1 to 4, wherein an iron nitride compound layer can be linked to a discoloration of the surface of the metal ring (32) after etching with a suitable etchant. Nitriding method. A method of nitriding a metal ring (32) for a drive belt (3) for a continuously variable transmission, wherein the ring (32) is disposed in an oven chamber (50), and at least ammonia is placed in the oven chamber (50). Supply gas,
The equilibrium constant K _N of the reversible chemical reaction from ammonia to hydrogen and nitrogen in the oven chamber (50) and vice versa, the equilibrium constant K _N is the equation K _N = (p [NH ₃ ] ) / (P [H ₂ ] ^ ^1.5 ) (2)
P [NH ₃ ] represents the partial pressure of the ammonia gas, p [H ₂ ] represents the partial pressure of the hydrogen gas,
A method for nitriding a metal ring (32) for a drive belt (3) for a continuously variable transmission, wherein the equilibrium constant K _N is controlled to a value of 4 to 8 bar ^-1/2 .   The method of nitriding a metal ring (32) according to claim 6, wherein the temperature in the oven chamber (50) is controlled to a value between 465 and 475 ° C.