Due to the superior performance and low cost of powder metallurgy materials, powder metallurgy parts are used more and more widely in the automobile, including shock absorber parts, guide, piston and low valve seat in the automobile chassis;The brake system has ABS sensor, brake pad and so on;Pump parts are mainly fuel pump, oil pump and transmission pump in the key parts;The engine has a conduit, seat ring, connecting rod, bearing seat, key components of variable valve timing system (VVT) and exhaust pipe support, etc.The transmission has synchronous hub and planetary gear frame and other parts.
I. Development of powder metallurgy auto parts
With the rapid development of China’s auto industry, the auto parts market has also maintained a rapid trend.In 2015, China’s auto output reached 24.5033 million units, ranking first in the world.China’s auto parts manufacturing industry achieved sales revenue of 3.23 trillion yuan, up about 10 percent from last year.On the other hand, after China’s entry into the world trade organization, not only form a complete set of foreign automobile industry such as hosts, and in the domestic large orders of powder metallurgy parts, each products, and foreign host companies invest in our country, to form a complete set of powder metallurgy products supply localization of growing demand, the demand for expanding to the development of powder metallurgy enterprises in China has brought a rare opportunity.
From the point of view of sales output value of powder metallurgy auto parts, sales output value increased from 876.21 million yuan in 2006 to 367.826 million yuan in 2015, with a compound annual growth rate of 17.28%, and maintained a trend of continuous rapid growth, and powder metallurgy auto parts market demand maintained a trend of rapid growth.
The density of common atomized powder (including carbon steel and copper-carbon alloy steel) is above 6.9, and the quenching hardness can be controlled around HRC30.
In general, the density of the pre-alloyed powder (AB powder) exceeds 6.95, and the quenching hardness can be controlled around HRC35.
High prealloyed powders with density greater than 6.95 and quenching hardness controlled at HRC40.
Powder metallurgy products made of the above materials have stable density and material, and the hardness after heat treatment meets the corresponding requirements, so their tensile strength and compressive strength will reach a better peak.
However, because the density of PM products is not as high as that of No. 45 steel, the highest density of PM pressing parts is usually 7.2 g/cm, while the density of No. 45 steel is 7.9 g/cm.Forced carburizing of powder metallurgy or high frequency heat treatment exceeding HRC45 will make the powder metallurgy products brittle due to high quenching, resulting in the strength of the powder metallurgy products.
1. High material utilization rate, up to more than 95%
2. No or only a little cutting is required
3. Good dimensional consistency of parts, good stability and high precision.
4. Strength comparison: professional powder metallurgy manufacturers have optimized the powder metallurgy mold design, and the tensile strength and compressive strength of the gear produced are close to that of the hobbing gear.For example, the driven gear of the automobile gearbox with high transmission intensity is also powder metallurgy gear.Visible, powder metallurgy gear is practical and extensive.
5. Powder pressing molding using mold molding, can produce other cutting hobbing technology can not produce complex shapes.
6. Because it is suitable for mass production, the production efficiency is high and the cost is lower than cutting.
7. Suitable for mass production, so the price is absolutely competitive.