Thermal treatment process for plunger rod (piston rod) of nitrogen gas spring

Abstract

The invention discloses a thermal treatment process for a plunger rod (piston rod) of a nitrogen gas spring. The thermal treatment process comprises the following steps of: selecting 38CrMoAl(GB / T3077-1999) (GB / T3077-19999) high-grade nitriding steel as a base material of the nitrogen gas spring plunger rod (piston rod); cleaning to-be-nitrided workpieces by cleaning liquor to ensure that the surfaces of the workpieces are free of other foreign matters such as scrap iron, greasy dirt and oil paint; performing drying or air-curing, and wiping the surfaces of the workpieces by cotton cloth before charging; uniformly putting the workpieces onto a cathode disc in a glow ion nitriding system, stacking the workpieces layer by layer, ensuring a spacing distance between every two workpieces on the same layer to be greater than 15 mm, ensuring the workpieces in the same furnace to be the same in size to the greatest extent, prolonging heating time while mixed loading is needed if sizes of the workpieces are different, and enabling the workpieces to obtain sufficient heat exchange balance; and setting various process parameters for the glow ion nitriding system, wherein surface hardness of a nitriding layer of the spring plunger rod (piston rod) treated by the glow ion nitriding system is greater than 1000 HV, wear resistance of the plunger rod can be improved, and the service life of the plunger rod of the nitrogen gas spring can be prolonged.

Description

technical field [0001] The invention relates to material heat treatment technology, in particular to a heat treatment process for a nitrogen spring plunger rod (piston rod). Background technique [0002] With the vigorous development of the automobile and home appliance industries, the application of stamping dies and large plastic molds to nitrogen springs is becoming more and more extensive, and the requirements for the stability and service life of nitrogen springs are getting higher and higher. The wear resistance and smoothness of the rod (piston rod) put forward higher requirements. [0003] At present, the nitrogen spring generally adopts the process of bearing steel (such as GCr15, 42CrMo) + surface treatment (gas nitriding or PVD). Gas nitriding is easy to produce nitrogen white layer and peel off the surface, which will damage the seal and affect the service life. Although the PVD treatment has a high surface hardness and improves wear resistance, but due to the ...

AI Technical Summary

Problems solved by technology

Gas nitriding is easy to produce nitrogen white layer, which will cause surface peeling, damage the seal and affect the service life

Although the PVD treatment has a high surface hardness and improves wear resistance, it is prone to weak adhesion, blistering and peeling due to the large gap between the substrate and the surface hardness, which will damage the seal and affect the service life.