Household appliances are closely related to people’s daily life, such as household air conditioners, household air conditioners, refrigerators, washing machines, household kitchen appliances, household beauty care appliances, household sanitary appliances, etc. In 2019, the accumulated main business income of 1-8 home appliance industry reached 1.05 trillion yuan, an increase of 4.7% year-on-year, and the total accumulated profit reached 79.897 billion yuan, an increase of 14.9% year-on-year. All kinds of products maintained the growth trend. There is an indispensable part in household appliances, which is, powder metallurgy parts: sintered metal oil bearing and sintered metal mechanical structure parts.

According to the statistics of powder metallurgy Association of China Machinery Association, in 2018, the accumulated main business income of powder metallurgy parts was 703 million yuan, the total accumulated profit reached 829.66 million yuan, and the accumulated sales volume was 190000 tons, including 1176.86 million yuan and 40998 tons of accumulated sales volume of home appliance industry. See Figure 1 for the accumulated main business income and sales volume of P / M parts from January to September 2019. The above data shows that in the current economic situation, the P / M industry is still against the trend and finding a trace of vitality in the difficulties, in which the P / M parts of the household electrical appliances industry account for 16.7% of the total and 20.6% of the sales volume, and the P / M parts of the household electrical appliances industry are also an important part of the P / M industry.

Powder metallurgy is a kind of material saving and energy saving technology. It can be used to manufacture household electrical appliances with special properties. As a big country in the production and consumption of household appliances, there is a big gap between China and the world in the quantity and quality of PM products used in household appliances. In order to increase the application and development of powder metallurgy materials in household appliances, it is an arduous task in front of us. In the air conditioning compressor, the parts of powder metallurgy household appliances mainly include: cylinder block, lower cylinder head, upper cylinder head, etc.; in the washing machine, they mainly include: all kinds of bearings, variable speed gears, central gears, planetary gear reducers, etc.; in the refrigerator compressor, they mainly include: connecting rod, piston, valve plate, bottom valve seat, etc.; in the air conditioner, they mainly include: transmission gears, all kinds of bearings, etc.

The development of powder metallurgy in the field of home appliances

In the development of household electrical appliances, the early stage of powder metallurgy was mainly to make copper based oil-bearing. Difficult parts, such as compressor cylinder head, cylinder liner with high precision and complex shape, and some products with special performance requirements have also been developed successfully. In China, the demand for PM structural parts is very large for all kinds of compressors. For example, the annual output of rotary compressors used in air conditioners and refrigerators is about 3.55 million, and each compressor needs 80-350g PM structural parts. The annual output of the connecting rod compressor used in the refrigerator is about 8.27 million, and each one needs 100g of P / M structural parts; the annual output of the sliding rod compressor used in the air conditioner and refrigerator is about 3.1 million, and each one needs 30-200g of P / M structural parts. Household electrical products are a big market of P / M structural parts, but these parts are not only complex in shape, but also require high temperature and high pressure resistance, rust proof, air tightness and good machinability. It is also very beneficial for the P / M manufacturers to further improve the technological equipment and design level.

Application of powder metallurgy in household appliances

In order to reduce the noise, PM oil-bearing has been used in washing machines and electric fan motors, especially the iron-based oil-bearing with low noise, which can replace copper. The noise of the whole machine is ~ 40dB PM oil-bearing. Due to its self-lubricating, low noise, low price, suitable for mass production, PM precision oil bearing is also widely used in cameras, tape recorders and other micro electrical appliances.

P / M stainless steel structural parts, such as parts of automatic dishwasher and washing machine made of 304L P / M materials, push out plate of refrigerator ice maker made of 316L P / M materials, limit switch and clutch made of 410L P / M materials, etc Powder metallurgy copper base alloy is widely used in dishwasher, clothes dryer, washing machine, sewing machine, vacuum cleaner, refrigerator, food mixer fan, etc.

Washing machine industry is mainly automatic washing machine at present. The full-automatic washing machines sold on the market are generally divided into three categories: the front-end side opening roller washing machine invented in Europe, the wave wheel top opening washing machine invented by Asians, and the “agitated” washing machine invented in North America. Many powder metallurgy parts are used in the middle, and some steel parts are changed into powder metallurgy parts For example, General Electric Company of the United States has redesigned two steel parts in the gearbox of the “agitated” automatic washing machine: lock tube and spin tube into powder metallurgy parts, which has improved the production cost and product quality, reduced the production cost of materials, labor, management cost and waste loss, and saved more than 250000 US dollars annually Yuan.

At present, China’s household appliances have entered a stage of steady development. The quality of household appliances and their materials is becoming increasingly important, especially the powder metallurgy materials widely used in household appliances. Because, some home appliance materials and parts can only be made by powder metallurgy, such as porous self-lubricating bearings of refrigerator compressors, washing machines, electric fans, etc.; some home appliance materials and parts are made by powder metallurgy with better quality and lower price, such as complex shape gears and magnets in the exhaust fans of home air conditioners and vacuum cleaners, etc. In addition, powder metallurgy plays an important role in maintaining ecology, protecting environment and saving materials and energy.