喷丸对低压铸造A356铝合金转向节组织与性能影响

Effects of Partial Shot Peening on Microstructure and Properties of Low Pressure Casting A356 Aluminum Alloy Steering Knuckle

在低压铸造A365铸造铝合金转向节过程中引入局部表面喷丸强化工艺,测试并分析表层残余应力分布情况及加热温度对其影响、表层显微硬度并观察喷丸截面的金相组织。结果表明,通过喷丸处理可使表层组织中的共晶Si细化并显著提高铝合金的表层硬度。喷丸时间为0~30 min时,随喷丸时间延长铝合金表层硬度逐渐增大,喷丸30 min时表层硬度(HV)约为230,与合金心部相比提高了约1.35倍。由于喷丸效果在超过100℃时会消失,因此喷丸处理后的铸件工作温度建议不超过100℃。

The partial surface shot peening process was introduced to the low pressure casting A365 aluminum alloy steering knuckle. The effects of distribution of surface residual stress and the heat temperature on the alloy as well as the microhardness were tested and analyzed. The cross-section microstructure of the shot peening section was observed. The results indicate that the eutectic Si grains in the surface microstructure is refined and the surface hardness of aluminum alloy is improved significantly by shot peening. In the range of 0~30 min, the hardness of the aluminum alloy surface is increased gradually with the extension of the shot peening time. When the shot peening time is 30 min, the surface hardness is about 230 HV, which is about 1.35 times higher than that of the center material. Considering that the shot peening effect disappears over 100 ℃, it is not recommended that the working temperature of the casting after shot peening exceed 100 ℃.