(1. 北京科技大學(xué) 材料先進(jìn)制備技術(shù)教育部重點(diǎn)實(shí)驗(yàn)室，北京 100083;
2. 北京科技大學(xué) 新材料技術(shù)研究院，北京 100083)
摘 要: 將結(jié)晶器移出感應(yīng)加熱器，使連續(xù)定向凝固時固液界面控制在結(jié)晶器出口；結(jié)合傳熱邊界條件，求解連續(xù)定向凝固熔體區(qū)、液/固界面、空冷區(qū)和水冷區(qū)的一維穩(wěn)態(tài)溫度場方程，得出線坯最大穩(wěn)態(tài)拉坯速度隨熔體溫度、結(jié)晶器長度、冷卻距離和冷卻水流量的變化規(guī)律；并基于直徑為6 mm的Cu-12%Al(質(zhì)量分?jǐn)?shù))線材制備的工藝條件，對理論解進(jìn)行實(shí)驗(yàn)驗(yàn)證和討論。結(jié)果表明：Cu-12%Al線材的最大穩(wěn)態(tài)拉坯速度隨熔體溫度升高而降低，且降低速率逐漸減小，其中在1 150~1 300 ℃范圍內(nèi)降低37.3%；最大穩(wěn)態(tài)拉坯速度隨結(jié)晶器長度增加而增加，且增加速率逐漸減小，其中在20~40 mm范圍內(nèi)增加28.5%；最大穩(wěn)態(tài)拉坯速度隨冷卻距離增加而降低，且降低速率逐漸減小，其中在4~12 mm范圍內(nèi)降低68.8%；冷卻水流量在100~400 L/h范圍內(nèi)最大穩(wěn)態(tài)拉坯速度變化不明顯。當(dāng)固液界面前沿溫度梯度小于2.02 ℃/mm時，實(shí)際拉坯速度無法達(dá)到理論最大穩(wěn)態(tài)拉坯速度；當(dāng)固液界面前沿溫度梯度大于4.17 ℃/mm時，最大穩(wěn)態(tài)拉坯速度實(shí)驗(yàn)值和理論值吻合較好。
關(guān)鍵字: Cu-12%Al線材；拉坯速度；溫度場；結(jié)晶器長度；溫度梯度
Cu-12%Al wires during OCC
（1. Key Laboratory of Advanced Materials and Manufacturing Technologies, Ministry of Education,
University of Science and Technology Beijing, Beijing 100083, China;
2. Institute for Advanced Materials and Technologies,
University of Science and Technology Beijing, Beijing 100083, China）
Abstract:By moving out of induction heater for crystallizer, the solid-liquid interface was controlled at the exit of crystallizer during Ohno continuous casting(OCC). Based on the temperature field equations of melt region, liquid/solid interface, air cooling region and water cooling region, the relationship was deduced among the maximum steady-state drawing velocity, melt temperature, crystallizer length, cooling distance and water flow rate by using thermal boundary conditions. Through the solidification process of Cu-12%Al(mass fraction) wires with a diameter of 6 mm, the theoretical solutions were verified and discussed. The results show that, the maximum steady-state drawing velocity for Cu-12%Al wire decreases by 37.3% in the range of 1 150−1 300 ℃ with increment of melt temperature, increases by 28.5% in the scope of 20−30 mm with increment of crystallizer length, and decreases by 68.8% in the range of 4−12 mm with increment of cooling distance, changes weakly with cooling water flow rate in the range of 100−400 L/h. When the thermal gradient at solid-liquid interfaces is lower than 2.02 ℃/mm, the experimental drawing velocity cannot reach the theoretical maximum steady-state drawing velocity. When the thermal gradient at solid-liquid interface is higher than 4.17 ℃/mm, there is a good agreement between the experimental and theoretical values of the maximum steady-state drawing velocity.
Key words: Cu-12%Al wire; drawing velocity; temperature field; crystallizer length; thermal gradient
