Typical application of powder metallurgy technology in automobile industry

The improvement of automobile quality requires the use of more powder metallurgy parts, which is reflected in the increase in the output of powder metallurgy industry and the increasing proportion of powder metallurgy products in automobile parts.
 
A large number of powder sintered materials have been used in automobiles. According to statistics, there is about one sintered part in each automobile in Japan. The powder metallurgy materials used in American automobile manufacturing have reached the number of automobiles in 2018, and their applications range from mechanical parts, sliding parts, friction parts, porous materials, magnetic materials. Superhard tool materials, electrical materials, etc.
Sensor core wire in engine ignition system and exhaust system.
In a word, powder metallurgy parts have various performance advantages over traditional forged steel parts, which will make powder metallurgy materials occupy a dominant position in automotive materials.
Pure iron powder is pre-mixed lubricant, alloy is pressed and re-pressed under another program. The application trend of powder metallurgy in automobiles In order to make the automobile structure meet higher standard requirements, the powder metallurgy process has been designed more and more And materials engineers have studied and adopted, which is recognized as an important way to save energy and reduce costs. The powder metallurgy process flow diagram is shown in the figure.
Powder metallurgy products have been widely used in engine chassis and other parts by many domestic and foreign automobile manufacturers.
Moreover, as countries pay more and more attention to environmental protection.
The requirements for gasoline components are also becoming more and more stringent. The heat-resistant steel and heat-resistant cast iron used in automobiles can no longer rely on the lead in gasoline for lubrication, which greatly reduces the wear resistance. Powder metallurgy materials are due to Integrating the advantages of various metal powders, it has good wear resistance and machinability.
In addition, various powder metallurgy materials have also been widely used with the birth of EFI engines. These materials are usually used in various finished powders due to their high temperature resistance, ablation resistance and low thread loss. Typical applications of metallurgical technology in automobiles Sintered alloys are used in a large amount in automobiles, which can reduce fuel costs and improve vehicle performance. Metal powder is the raw material for sintered metal products. There are many advantages of powder metal sintering. Due to the use of different metals Mixing the powder not only has few inclusions, it is easy to adjust the composition, but also the insoluble components can be compounded. The parts produced have high machining accuracy and less unnecessary loss of materials.
a) The valve guide supports the high-speed reciprocating valve stem, and the end on the combustion chamber side is exposed to high temperature. It is an important part that requires heat-resistant research and development.
A company in Japan has developed a material that disperses the lubricious solid lubricating component lead and low-melting glass in a solid solution-strengthened matrix, which is equivalent to having excellent wear resistance at high temperatures. It can be used in flake graphite in unleaded gasoline cast iron and free graphite in sorbite or by engine, and can also be used in diesel and liquefied petroleum gas engines. Oil-filled pores composed of P-, its wear resistance is the same as that of ordinary alloys. Casting these excellent properties, heat resistance, wear resistance, machinability is twice that of ordinary iron.
Casting materials cannot be satisfied at the same time.
The valve seat valve seat is a sintered valve seat that is valued and developed by many countries. The composition of the valve seat announced by the Japanese Piston Ring Development Department is shown in the table. In order to ensure the tightness of the combustion chamber, the valve seat needs to withstand high temperature. The fuel cylinder head material is used to select the friction of the reciprocating valve, and to maintain a certain clearance.
So it must be decided.
Due to the different lead content in the fuel, the wear pattern of the material has a great need to have excellent heat resistance and wear resistance.
difference.
The lead oxide, lead sulfide, lead halide, etc. produced in the combustion, Japan Powder Metallurgy Company will contain the lead compound in an appropriate amount, which acts as a lubricant, but too much sintered steel is used as the base material, and there are residual pores in it. In the case of medium infiltration, corrosion and wear will be caused due to molten salt. In this case, this sintered material has excellent wear resistance and high use. The temperature of the valve needs to be lowered to a temperature lower than that of the melting zone, so need life.
In addition, with the improvement of engine performance, the valve seat with good thermal conductivity is used for the above-mentioned valve seat heat resistance.
What the company developed is to disperse hard particles in the steel-resistant matrix material while improving the manufacturing method. The worn material is used as the matrix, and the hole is sealed with copper, thus forming a series of materials.
To improve the thermal conductivity of the material, the powder metallurgy division of Sumitomo Electric Industries, Ltd., which is used to manufacture leaded gasoline engines, is in the heat-resistant alloy valve seat.
The hard carbide phase is dispersed in the matrix and the applicable conditions of the stuffy seat material announced by the Japanese Huoxinhuan Technology Development Department are chemical composition density, hardness, crush strength, thermal conductivity, and the grade is lead-free.
For exhaust, one for suction, the lower part of the double-layer valve seat has its own lead, and the cast iron cylinder head for exhaust uses a power steering device.
Generally, vane type hydraulic pump is used, and its main parts are rotor, cam ring, stator and other parts. Sintered alloy is a suitable material.
A sintered body can be used for rotors with tensile strength requirements above and cam rings are produced in large quantities.
However, with the acceleration of the engine, it is turning to a series of materials with better wear resistance.
Gear for starter motor.
The gear requires high impact strength. In the past, air carburizing and quenching was used. Now, high-density forming and extreme high-temperature sintering can greatly improve the impact value.
Sintered parts with complex shapes often need to be divided into several parts that can be sintered and formed, and then combined.
Traditional welding and brazing should not be used.
A special brazing material and the combination technology of brazing at the same time of sintering a plurality of powder moldings effectively ensure that the sintered parts can be hardened during the sintering process, and can control the deep power steering of the penetration of the brazing material into the pores of the sintered body. The device is the rotor on the automobile air-conditioning compressor manufactured by this method. In the past, the rotor was made of steel by cutting, and now the sintering welding technology is used. Due to the gap, the quality can be reduced. Conclusion The development of modern powder metallurgy technology has also made this field In the future development of the automobile industry, powder metallurgy technology will play an increasingly important role.
Paying attention to the research of powder metallurgy technology and developing typical powder metallurgy parts is an important way to improve the quality of vehicle products.
The editor of this article, Gong Tiejie, notes that the hard dispersing particles and the hard particles play a role in the dispersion strengthening of the soft particles when the direct contact point produces high temperature.
The low melting point element is melted and flattened on the rubbing surface under the action of friction, forming a thin lubricating layer with good plasticity.
This layer not only lubricates, but also helps to reduce the pressure on the contact point and reduce the mechanical resistance of the staggered peaks and valleys of the rubbing contact surface.