PRODUCT CATEGORIES

Vacuum Heat Treatment Furnace

Vacuum Sintering Furnace

Vacuum Brazing Furnace

Vacuum Carburizing of Extrusion Die for Wire Take-up Connecting Rod Made of Base Steel 65Nb

Material: 65Nb steel

Technical requirements: the mass fraction of carbon in the carburized layer is not more than 0.95%,

Not more than 1.25% and about one-third of 1.6%, mesh and massive carbides are not allowed, and the depth of the carburized layer is about 0.6mm.

The internal combustion type small vacuum carburizing furnace is used for vacuum carburizing, and the vacuum carburizing process curve of the extrusion die of 65Nb steel wire take-up connecting rod is shown in Figure 1.

The main points of the vacuum carburizing process: ① The carburizing medium adopts a volume fraction of 70% CH4 + 30% H2 as the diluent gas; ② The initial vacuum degree is usually 1.33Pa, and the low initial vacuum degree is beneficial to prevent oxidation and rapid increase of the parts during heating Furnace gas carbon potential; 3. The vacuum degree during carburizing is usually 2.7X104Pa~4X104Pa. After the carburizing medium is filled in the furnace, the vacuum degree decreases. If the vacuum degree is low, the carbon potential of the furnace gas is high, so it should be determined according to the carbon potential requirements. The size of the vacuum degree in the furnace during the strong infiltration period; ④ The infiltration and expansion ratio has a certain relationship with the furnace pressure. The ratio of the strong infiltration and diffusion time during strong infiltration determines the carbon concentration of the carburized layer. The layer carbon concentration is also high. When the low concentration carburizing (the mass fraction of the carburizing layer is less than or equal to 0.95%), the infiltration and expansion ratio is 1: 5~1: 4, and the medium concentration carburizing (the mass fraction of the carburizing layer is less than or equal to 1.25%) When the infiltration and expansion ratio is 1: 3~1: 2; ⑤When the base steel is carburized, generally no grain coarsening will occur, so direct quenching after carburization is often used. In order to obtain the red hardness of the steel, normal temperature should be used. Quenching, tempering temperature and times are the same as ordinary tempering requirements.

After carburizing, quenching and tempering, the 65Nb steel wire take-up connecting rod extrusion die has a lifespan that is 2.5 higher than that of the non-carburized die
times, and 7.5 times longer life than Cr12MoV steel molds.