Method for locking a nut made of a material having a low capability of plastically deforming

摘要

A method for locking a nut with an inner thread, in which the ultimate tensile strength (Rm) and yield strength (Re) of the material constituting the nut are determined according to temperature. An optimal heating temperature is determined, at which a maximum of a relative plastic interval of the material is reached, said relative plastic interval being defined by the formula (Rm−Re)/Rm, and a maximum heating time is determined, above which the nut presents the risk of deterioration of its microstructure and/or of its initial mechanical strength. The nut is heated to a temperature substantially equal to said optimal temperature and for a heating time of less than said maximum time so that the initial microstructure and mechanical strength of the material constituting the nut are preserved, and a body of the nut is deformed locally by bending.

主权项

1. A method for locking a nut with an inner thread, comprising the steps of:
heating a nut having an inner thread and formed from a material having known values of ultimate tensile strength (Rm) and yield strength (Re) corresponding to a first plurality of temperatures, and wherein the material of the nut also has a relative plastic interval corresponding to each temperature of the first plurality of temperatures, said relative plastic interval being defined by the formula (Rm−Re)/Rm where Rm and Re are determined from the known values corresponding to temperatures, and wherein the material further has an optimal heating temperature at which a maximum of a relative plastic interval of the material of the nut occurs, obtaining a maximum heating time for a temperature within a first range of temperatures including the first plurality of temperatures, above which the nut presents a risk of deterioration of a microstructure of the nut or of an initial mechanical strength of the nut, wherein heating the nut includes heating the nut to a temperature within a second range of temperatures defined between 80% and 120% of the optimal heating temperature, the temperature being expressed in ° C., and for a heating time of less than said maximum heating time so that the initial microstructure and mechanical strength of the material constituting the nut are preserved, deforming a body of the nut locally by bending once the nut has been heated to the temperature within the second range of temperatures.