Introduction of surface treatment process of die parts - NITONI, China Precision Mould parts(components) manufactur and supplier

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Introduction of surface treatment process of die parts

Return list Reffer:NITONI Click number:- Release time:2018-04-20

How many kinds of surface treatment technologies are available for mold parts?As you know, the application of surface treatment in mold is the most effective way to improve mold quality and service life and reduce cost.Through the adoption of different surface treatment technology, only change the mould surface composition, microstructure, properties, thereby significantly improve and enhance the surface properties of the mould, such as hardness, wear resistance, friction properties, demoulding performance, insulation performance, corrosion resistance and high temperature oxidation resistance, improve the ability of cavity surface scratch resistance, demoulding, anti-seizure special performance, such as several times, several times to improve the service life of the die.This is of great significance to improve mold quality, reduce production cost, improve production efficiency and make full use of the potential of mold materials.

There are dozens of surface treatment processes used in mold parts, which can be summarized as physical surface treatment, chemical surface treatment and surface coating.Next, changsha borun introduced several surface treatment technologies for mold parts:

1. Chemical heat treatment on carburizing surface.

Carburizing technology is one of the more commonly used (more than 80%) of mold surface strengthening technology, which is mainly aimed at the surface reinforcement of plastic mold cavity.After carburizing treatment of mold parts, can achieve the effect of the "outer hard inner toughness", namely the work parts surface hardness, wear resistance, fatigue strength and other performance boost, while the heart is still kept the original plastic toughness, strength, meet the requirements of the mold working parts of use function has the faster, the permeability layer depth, low cost, and permeability layer and the substrate has a perfect combination of performance between parts, combining to realize smooth transition between layers.But higher operating temperature (900-950 ?), especially ion carburizing temperature can reach 1100 ?, and after carburizing and corresponding heat treatment, leading to the possibility of mold deformation increase, therefore, high precision plastic mold the technology is not recommended.

Gas carburizing temperature generally is 920-950 ?, the comprehensive evaluation of test: the most reasonable carburizing layer surface carbon content for w (C) 0.85% 0.95%, permeability layer outside-in carbon mass fraction gradient should be uniform flat, quenching in the organization is not allowed to have a thick strips martensite, residual austenite, carbide network and too much black troostite.The high carbon mass fraction were molded parts organization carbide network in malignant tissue, such as, affecting the service life of die quality and liable to occur in the subsequent process of stress concentration, the phenomenon such as cracks.

Ion carburizing temperature generally is 900-960 ?, compared with gas carburizing, ion carburizing with high efficiency, small deformation, pollution and can handle any shape of surface mould parts, etc, is more suitable for the plastic mould and stamping die surface strengthening processing of the application.

2. Flame surface thermal spraying technology.

Thermal spraying technology is a new surface strengthening technology development is very rapid, it is the use of heat sources (electric arc, arc ion, flame, etc.) will be heated to melt coating material or partially molten state, and make it spray, spray at a certain speed to after pretreatment of substrate surface, relying on the physical and chemical changes, combined with the matrix of process method, the binding layer, can improve the wear resistance of mold parts, corrosion resistant, heat resistant, such as performance, and easy operation, low cost.

In recent years, the application of this technology in the surface strengthening of mould has been further developed and improved.Guangzhou non-ferrous metal research institute adopts supersonic spraying hard alloy craft, make Cr12 stainless steel drawing die to increase the life of the die 3-10 times.At the same time, the technology also made great progress in the mold repair, such as huazhong university of science and technology, material forming and mould technology state key laboratory of the supersonic flame spraying (HVOF) technology, in Cr12MoV die steel surface preparation of the nanometer structure WC12Co metal ceramic coating, coating can be measured the average shear strength of 150.8 MPa, the coating bond strength of more than 80 MPa, the coating hardness is higher than 1000 hv.The application of HVOF technology to the cold extrusion mould can meet the requirements of the enterprise.

3. Composite surface plating technology.

Electroplating technology is an electrochemical method for the deposition of metal or metallization on the substrate surface.

And hard hard chromium electroplating nickel is China's traditional plastic mold surface treatment technology, the technology in close to room temperature, mould performance is almost unaffected, also won't appear serious distortion, at the same time, the plating with low surface roughness, higher hardness is 800 hv.But there are still many problems, such as corrosion resistance is not high, groove, deep hole can't handle, make its application in the mold reinforced by certain restrictions, only can be used to strengthen the common plastic mould wearability, shall not be applicable to complicated shape and high corrosion resistance requirements of plastic mold.

At present, composite plating is the most dynamic application of coating technology in die industry.Composite brush plating can strengthen mold cavity surface, also can be used to repair mold cavity surface.The study found that the non-crystalline coating (0.01-0.02mm) was brushed on the surface of the mold cavity, and the life span was 0.5-1.0 times.There are many kinds of particles in the composite coating, and the range of parameter adjustment is wide and operable, which fully reflects the diversity and comprehensiveness of the coating.

Dalian university of technology will be Ni - P - PTFE composite plating for UPVC pipe fittings mold surface strengthening, solve the UPVC material corrosion on the surface of the mould has obvious effect, achieve molding surface wear-resisting corrosion resistance comprehensive performance requirements, but the hardness is a bit low.Therefore, Harbin industrial university van will jade on the basis of Ni - P, PTFE and SiC particles in the composite application in glass fiber reinforced plastic molding mold, the practice shows that can make its life by about 10 times.

4. PVD, CVD, PCVD surface coating technology.

Coating technology is vapor deposition technology, is to have special performance of stable compounds deposited on the working parts of the mold surface, formation of hard coating, make the mould work part has excellent performance.The stable compounds with high frequency in industry mainly include TiC, TiN and sine.

Physical vapor deposition (PVD) is a practical technique for the deposition of coating materials on the substrate surface by means of physical method.The technology application in the beginning of the 20th century, is developing rapidly in the recent 30 years, as a door has a broad application prospect of new technology, and gradually to the development trend of environmental protection, clean type, mainly used in the manufacture of high precision cold work mould.

The application of multi-arc ion coating method for the actual service life of 20 cold extruded convex dies treated by TiN coating was conducted by the institute of applied physics of jiangxi academy of sciences.Guangzhou non-ferrous metal research institute of physical vapor deposition of hard film on advanced application has carried on the detailed research, pointed out that the technology can significantly improve the quality of the service life of die and workpiece processing, but also exist, such as winding plating and PVD law such as faults, the complex shape of the surface of the mold parts processing there is a certain limit.

Chemical vapor deposition (CVD) is within 900-2000 ? with chemical method makes gas reaction on the surface of substrate material and form layer of practical technology.The technology deposition combined with strong, high temperature, coating surface shape of molded parts almost no requirements, such as complex shape parts or with grooves and holes are evenly coated, make up the physical vapor deposition related defects, for example, is frequently used in the mold surface strengthening of the TiC coating high hardness, good wear resistance, low friction factor, anti-friction and bite resistance is strong, increase the service life of mould.However, CVD method has high temperature and still needs to be hardened, which can lead to large deformation and other defects. Therefore, in the manufacture of high-precision molds, the use of this technology is limited.

Plasma enhanced chemical vapor deposition (PCVD), is the use of glow discharge to enhance the chemical activity of reactants, promote the gas phase chemical reactions, with high quality at low temperature deposition coating of practical technology, is a kind of processing between CVD and PVD method.The coating was coated on the surface of the mold working parts with PCVD method, and the economic benefits were proved to be considerable.

Chongqing institute of technology of PCVD technology application in the mould reinforcement are studied, found using PCVD technology in W18Cr4V deposits a layer of TiC in cold extrusion die, die life than no deposited film layer increased by more than 10 times;The PCVD method can be used to improve the mould life of plastic products 1-4 times.

Beijing university of aeronautics and astronautics professor mold set up PCVD surface strengthening technology research laboratory, to design and manufacture of the test equipment and auxiliary facilities, the project team based on composite plating PCVD method was developed mold surface strengthening technology, a low temperature, are good plating processes and high bonding strength, etc. Suitable for all the preparation of high temperature tempering mould and parts of low temperature tempering mould, is currently the only applicable to cutting tool as well as a way of strengthening and is suitable for the shape of the complex mold surface strengthening vapor deposition surface strengthening technology.

Therefore, the application of PCVD technology in the field of mold parts strengthening has been achieved, and the application prospect is very broad.

5. High-energy beam strengthening technology.

High energy beam reinforcement technology with non contact material, control precision, wide adaptability, strong flexibility, quality, resource saving and environment friendly and other comprehensive advantages, can be used for both mass efficient automation production, and is applicable to many varieties, small batch processing, custom-made personalized products, even is an important and indispensable technologies in mould manufacturing.Among them, the ion implantation technology in its almost perfect strengthening effect in cold work mould, hot-work die and plastic mould is widely used in areas such as, its life expectancy can improve the general 2 to 10 times, has great application value.


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