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在砂型中浇注ZL201合金板形铸件,用XWT-604型多点记录仪测定铸件上各点的冷却曲线。采用X射线照相、金相试验和切取试样测定机械性能的方法,研究凝固过程中冷却速度和温度梯度对合金的组织和性能的影响。 高的冷却速度和温度梯度,可获得高致密度和高机械性能的铸件。当冷却速度大于14℃/min,平均温度梯度大于4℃/cm时,铸件切取试样的σ_b≥294MPa,δ_5≥8％,比一般铝合金铸件要求的σ_b高25％以上,δ_5高50％以上。机械性能与冷却速度(X)的关系,可用经验公式表达为: σ_b y=140+135logx δ_5 y=11.0logx-1.1 提高冷却速度和温度梯度,对改善结晶间隔宽的高强度铝合金铸件的冶金质量,充分发挥高强度铝合金的优势,有更为重要的意义。
Casting ZL201 alloy plate casting in sand mold, and measuring the cooling curve of each point on the casting by XWT-604 multi-point recorder. The effects of cooling rate and temperature gradient on the microstructure and properties of the alloy were studied by X-ray radiography, metallographic test and mechanical test. High cooling rate and temperature gradient, to obtain high density and high mechanical properties of the casting. When the cooling rate is more than 14 ℃ / min and the average temperature gradient is more than 4 ℃ / cm, the σ_b≥294MPa and δ_5≥8% of the specimens cut by the castings are more than 25% higher than the σ_b required by the ordinary aluminum alloy castings and the δ_5 is 50% the above. The relationship between mechanical properties and cooling rate (X) can be expressed empirically by the following formula: σ_b y = 140 + 135logx δ_5 y = 11.0logx-1.1 Increasing the cooling rate and temperature gradient improves the metallurgical properties of high strength aluminum alloy castings Quality, give full play to the advantages of high-strength aluminum alloy, there is more significance.