The Application of Aluminium Alloys in Automotive Parts
一、 Engine Body
Automotive engine body points on the cylinder body—cylinder head and cylinder block.
The manufacture form could roughly divide into die casting, low pressure casting and gravity casting. For Japanese cars, they always choose aluminium alloys to cast cylinder body and cylinder block, but sometimes they will choose cast iron material to make cylinder head.
The aluminium alloy ingot casting brand code is difference in all countries of the world. The codes which we always use and see in the market are: American codes A390、390、ASM380 etc; Japanese codes AC2B、ADC10 etc; Chinese codes ZL104、ZL106 etc; French codes ALSI9Cu3; Germany codes ALSI8CuNiMg、ALSi12Cu etc.
The aluminium alloy part of the automotive is not a single strength requirement or a single plasticity requirement, the combination of strength & plasticity of comprehensive performance is what it really needs. Low thermal expansion rate and good abrasion resistance are what it needs, too. If the aluminium alloy parts need heat treatment in the post-procedure process, it needs to put forward special requirement to calcium, titanium alloy element content in the aluminium alloy ingot. In the technical requirements, it needs to rule clearly the content of the impurity and whether require modification treatment. Doing above, we could avoid to material defects such as surface stains and bad air tightness, which cause by the excessive impurities and strontium modification.
Composition is not the unique factor which causing parts of product defects, the material organizational structure is the key point. The unclear requirements of the downstream enterprises are unfair to the upstream enterprises. In order to avoid defects, the material must be complied with the organizational structure demands: ALFeMn is less than 200 microns, ALFeMnSi is less than 200 microns, Silicon bronze agglomerate is less than 50 microns, Large area of gas bearing defects—pinhole degree is less than level 2, Copper agglomerate is less than 50 microns.
Cylinder head is the second big part of the engine parts. The feature of this part is that it’s with complex structure and high technology demand. When making cylinder head, we always will use gravity casting or low pressure casting technique. For material, we will choose A356、AC2A、ALSi6Cu4、ALSi7Mg、ZL106、ZL107 etc. For cylinder head, they will ask for high heat resistance, impact resistance and high fatigue strength of comprehensive performance requirements. Because of it, the cast material must be strict with the pinhole degree, grain size and modification treatment, they should be in line with the material structure requirements. The material must be with good tensile strength & yield strength, too.
The organizational structure of any materials, they will more or less have some defects. For these defects, we should control them within the corresponding scope according to cylinder head performance requirements: the primary silicon size less than 50 microns, aluminum silicon phase of acicular iron is less than 90 microns, the average grain size greater than level 7, Pinhole degree is less than level 2.
According to the metallurgical properties & processability of the piston material, we always use eutectic alloy material to make. But for the products which asked for low expansion coefficient, they always will use hypereutectic alloy material. We always will mainly use ALSi12CuMgNi、ZL109 ALSiCu1、AC8Aetc material to make piston parts. The feature of this kinds of material is that they includes nickel, the composition is more than 1 percent. For piston parts, they ask for high strength and toughness, heat resistance and impact resistance of comprehensive performance requirements.
四、End cap、bracket、valve body、manifold
We mainly use ADC12、ADC10、ALSi12Cu、ZL102、ZLD10 etc alunimiun alloys to make automotive parts such as end cap、bracket、valve body、manifold. For this kinds of automotive parts material, they always require the aluminium alloys have the strength & toughness combined comprehensive performance.
We mainly use ADC12、ADC10、390、ZL102、G-ALSi10、1016 etc alunimiun alloys to make Gearbox Housing.
Always we will use ADT6、ALMg2Mn etc alunimiun alloys to make steering wheel. For the steering wheel material, it demands high impact resistance、high strength & high corrosion resistance. So, for this kinds of aluminium alloy material, they always function as solution strengthening.