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本文阐述了浇铸和压制铝合金活塞材料的特性。与造形可能性较大的浇铸活塞相比,压制活塞有较好的强度。因此,轿车上的汽油发动机以及较大的汽油和柴油发动机大部份均采用浇铸活塞。但是,在大马力柴油机上,压制活塞因其有较大的强度和延伸率, 因而使用比较安全。根据一些结构不同的发动机长时间的运转情况,以及活塞的损坏情况, 可以看出采用浇铸和压制活塞的可能性。压制活塞的造价一般比浇铸活塞的要高,然而, 由于进一步采用了自动化生产,使很经济地成批生产压制活塞成为可能。在谈到压制活塞时,多次的提到了锻造或压锻活塞以及活塞的材料。关于材料,在参考文献[1]中用代号P(=geprebt)来表示,而本文却用geprebe(压制的)表示。浇铸和压制活塞所用的铝合金,虽然成份相同,但其强度是不同的,而且压制的活塞,在20—35℃的温度范围内,承受作用在活塞上的动应力的情况比浇铸活塞好。因此,压制活塞适用于机械应力和热应力很大的汽油机上,尤其是用在柴油机上。在浇铸活塞上,铸入阻滞膨胀和耐磨的铸铁镶环是比较容易的。因此除了单金属活塞外,在大量的汽油机和柴油机上采用了带有热膨胀自动调节环(或称镶环)的双金属浇铸活塞。由于压制活塞有较高的屈服极限和延伸率,所以在几乎同样好的运转特性下,从损坏情况可以看到,这种活塞对活塞顶部裂纹、活塞环岸的破损和活塞销座支承筋的裂纹,没有浇铸活塞那么敏感,特别对大型发动机上承受高应力的活塞来说,压制活塞对裂纹具有极小的敏感性有着很重要的意义。
This article describes the characteristics of cast and pressed aluminum alloy piston materials. Compression pistons have a better strength than cast pistons that are more likely to be shaped. As a result, most of the petrol engines on cars and larger petrol and diesel engines use casting pistons. However, on high-powered diesel engines, the compression piston is safer to use because of its greater strength and elongation. Depending on the long-term operation of the engine with different configurations and the piston damage, the possibility of casting and pressing of the piston can be seen. Pressed pistons are generally cost more than cast pistons, however, because of the further use of automated production, it is possible to economically mass-produce pressing pistons. When it comes to pressing the piston, the material of the forging or pressing piston and the piston is mentioned several times. For the material, it is represented by the reference P (= geprebt) in reference [1], whereas geprebe is used in this paper. The aluminum alloy used for casting and pressing pistons, although of the same composition, has different strengths and the pressed piston withstands the dynamic stress acting on the piston better than the cast piston at a temperature in the range of 20-35 ° C. Therefore, the compression piston for mechanical and thermal stress great gasoline engine, especially for diesel engines. On cast pistons, it is easier to cast cast iron rings that block expansion and wear. Therefore, in addition to single-metal pistons, a large number of gasoline engines and diesel engines with a thermal expansion of the automatic adjustment ring (or ring) bimetallic casting piston. Due to the higher yield point and elongation of the compression piston, it is evident from the damage that, under the same good operating characteristics, the piston has cracks on the top of the piston, on the piston ring bank and on the piston pin bearing Cracks, which are not as sensitive as cast pistons, are especially important for pistons with high stress on large engines, where compression of pistons is extremely sensitive to cracking.