【摘要】：本課題采用機(jī)械振動(dòng)和低壓鑄造相結(jié)合的原理自主研究設(shè)計(jì)了低壓振動(dòng)鑄造平臺(tái)。利用數(shù)值模擬手段,研究了波動(dòng)載荷對(duì)低壓鑄造溫度場(chǎng)、應(yīng)力場(chǎng)和熱裂形成傾向的影響。以ZL205A合金作為實(shí)驗(yàn)材料,研究了不同振動(dòng)參數(shù)下的機(jī)械振動(dòng)對(duì)ZL205A合金鑄件低壓鑄造熱裂的影響規(guī)律。低壓振動(dòng)鑄造平臺(tái)包括振動(dòng)模塊、低壓模塊、測(cè)溫模塊和模具模塊四個(gè)主要部分。振動(dòng)模塊以慣性式偏心輪振動(dòng)電機(jī)作為振源,可以按需求調(diào)節(jié)機(jī)械振動(dòng)的頻率、振幅,利用測(cè)溫模塊控制起振溫度。通過(guò)對(duì)ZL205A低壓鑄造過(guò)程施加波動(dòng)載荷的數(shù)值模擬,預(yù)測(cè)了鑄件熱裂傾向最大的位置。通過(guò)比較不施加波動(dòng)載荷和施加振動(dòng)載荷鑄件的應(yīng)力分布,發(fā)現(xiàn)施加波動(dòng)載荷后,熱節(jié)處應(yīng)力減小,以此減小鑄件的熱裂傾向。通過(guò)在低壓條件下澆注了12組振動(dòng)試樣,對(duì)鑄件的裂紋深度進(jìn)行分別測(cè)量,利用正交分析手段得到了振動(dòng)頻率、振動(dòng)振幅、鑄件尺寸和起振溫度對(duì)鑄件表面裂紋的大小影響規(guī)律。研究發(fā)現(xiàn):細(xì)桿的直徑大小對(duì)裂紋的影響最大,其次是振動(dòng)頻率,對(duì)裂紋深度影響最小的是振動(dòng)振幅。從正交實(shí)驗(yàn)表中我們可以十分容易的找到低壓鑄造施加機(jī)械振動(dòng)的最佳振動(dòng)參數(shù),即當(dāng)振動(dòng)頻率為15Hz、振幅為0.5mm、細(xì)桿直徑為30mm、起振溫度為650℃的時(shí)候,鑄件產(chǎn)生熱裂紋的傾向最小。通過(guò)測(cè)量鑄件的收縮量,得到鑄件內(nèi)部應(yīng)力隨振動(dòng)參數(shù)不同而產(chǎn)生的變化大小,從而進(jìn)一步判斷鑄件內(nèi)部的熱裂傾向。綜合分析來(lái)看,機(jī)械振動(dòng)對(duì)低壓鑄件熱裂影響傾向最小的工藝為頻率15Hz、振幅0.5mm、高溫下澆注。
[Abstract]:Based on the principle of mechanical vibration and low-pressure casting, the platform of low-pressure vibration casting is designed. The influence of fluctuating load on temperature field, stress field and hot crack forming tendency of low pressure casting was studied by numerical simulation. The effect of mechanical vibration on hot cracking of ZL205A alloy castings in low pressure casting was studied with ZL205A alloy as experimental material. Low-pressure vibration casting platform consists of four main parts: vibration module, low pressure module, temperature measurement module and die module. The vibration module takes the inertial eccentric wheel vibration motor as the vibration source, can adjust the frequency and amplitude of the mechanical vibration according to the demand, and use the temperature measurement module to control the starting temperature. By numerical simulation of fluctuating load applied in ZL205A low pressure casting process, the position of the largest hot cracking tendency was predicted. By comparing the stress distribution of castings with no wave load and vibration load, it is found that the stress at hot joint decreases after the application of fluctuating load, thereby reducing the hot cracking tendency of castings. By pouring 12 groups of vibrating samples at low pressure, the crack depth of castings was measured, and the vibration frequency and vibration amplitude were obtained by means of orthogonal analysis. The influence of casting size and vibration temperature on the surface crack size of castings. It is found that the diameter of the rod has the greatest influence on the crack, followed by the vibration frequency, and the vibration amplitude has the least effect on the crack depth. From the orthogonal test table, we can easily find the best vibration parameters applied in low pressure casting, that is, when the vibration frequency is 15 Hz, the amplitude is 0.5 mm, the diameter of the rod is 30 mm, the starting temperature is 650 鈩，

本文編號(hào)：2314066