Casting mould heat treatment furnace will affect life
Views: 6 Author: Site Editor Publish Time: 2016-08-29 Origin: Site
Casting mold heat treatment correctly or not directly related to the mold service life.Caused by heat treatment process and procedure is not correct, mold deformation, cracking and scrap, and heat treatment of the residual stresses leads to failure of mould in use about which accounts for half of the mould invalidation.
Casting die cavity are made from high quality alloy steel, the material price is higher, plus the processing fee, the cost is high.If due to improper heat treatment or heat treatment quality is not high, lead to scrap or life can not meet the design requirements, the big economic loss.Therefore, when the heat treatment should be paid attention to the following:
(1) substrate is strong, is to improve the strength and toughness of the matrix, reduce deformation and fracture, therefore its conventional heat treatment must be strictly according to the process.
(2) the surface strengthening processing, its main purpose is to improve the mold surface lubrication and wear resistance, corrosion resistance performance.Surface strengthening treatment method are many, mainly include the carburizing, nitriding, sulfurizing, boronizing, nitrogen, carbon altogether permeability, metallic cementation, etc.
With different surface strengthening treatment technology, can make the mould service life increase several times or even more, in recent years, there have been some surface strengthening technology, such as the following three processes:
1. The ion nitriding
In order to improve the corrosion resistance and wear resistance of molds, thermal fatigue and prevent adhesion, ion nitriding can be used.Outstanding advantage of ion nitriding is significantly shortened the time nitriding, carbonitriding layer can be adjusted by different gas components control organization, reduces the surface brittleness of nitrided case, small deformation, seepage layer hardness distribution curve is smooth, not easy to produce flake and thermal fatigue.Permeable base material than gas nitriding, non-toxic, does not explode, production safety, but for complex shape mould, it is difficult to obtain uniform heating and uniform permeability layer, and infiltration shallow layer, transition layer is steep, temperature measurement and temperature uniformity are still to be solved.Ion nitriding temperature at 450-520 ℃ advisable, after treatment 6-9 h, nitriding layer depth is about 0.2-0.3 mm.Temperature is too low, permeability layer is too thin;Temperature is too high, the surface easy to appear osteoporosis layer, reduce the ability to resist sticking later.Ion nitriding the carbonitriding layer thickness to 0.2 0.3 mm is advisable.After wear and tear of the mold, ion nitriding by repair and ion nitriding again later, can be put into use, which can greatly improve the total service life of mould.
2. Carbon nitrogen altogether permeability
Low carbon and nitrogen altogether permeability process temperature (560 ~ 570 ℃), the deformation is small, the processing of the surface of the steel hardness up to 900-1000 hv, good wear resistance, corrosion resistance is strong, have higher hot hardness, can be used in die mold, cold heading die, cold extrusion molding, hot extrusion die, high speed forging die and plastic mould, can improve the service life of the 1-9 times respectively.But often occur after nitrogen gas carbon altogether permeability deformation, expansion volume accounts for some 25% of the thickness of the compound, should not be used for precision mold.Only to annealing and eliminate the residual before processing.For example, Cr12MoV steel leaf spring hole punching die, the nitrogen gas carbon altogether permeability and permeability vanadium salt bath treatment after 3 times can improve die life.Again, such as: 60 si2 steel cooling heading screws punch, adopt advance nitriding, short-term carbonitriding, direct quenching oil, low temperature quenching and high temperature tempering process, can improve the core toughness, improve life cold heading punch more than 2 times.
3. The carbon and nitrogen boron ternary permeability
Three yuan altogether permeability can be done in nitriding furnace, impregnation agent for organic boron ooze agent and ammonia, the ratio of 1:7, a total of infiltration temperature is 600 ℃, a total of infiltration time 4 h, carbonitriding layer compound layer thick 3-4 microns, the depth of diffusion layer is 0.23 mm, the surface hardness of HV011050.After a total infiltration treatment casting mould life improved significantly.
That is about the impact of casting mould heat treatment for life related introduction, hope to be able to help you.