新型气膜约束成形铝合金连续铸锭的研究

设计了一种新型气膜约束铝合金连铸结晶器,在结晶器与初凝壳之间可以形成气膜.设计思想是减少结晶器内的横向散热,形成连铸坯近似单向散热的条件,降低结晶器内的液穴深度,缩短初凝壳长度,从而减少或消除铝合金连铸坯内部缺陷,提高铝合金连铸坯内外品质.对新型结晶器与传统结晶器进行了传热数值模拟,证明凝固温度场发生很大变化.利用新型结晶器对7075铝合金进行了连铸试验,在气膜稳定平衡的条件下,连铸坯表面光滑.探讨了拉速、气体流量和气体压力的关系及其对连铸坯品质的影响,在液面高度稳定时,控制气体流量可以控制气膜的稳定性.

Preparation of Aluminum Alloy Ingot by Continuous Casting with New Gas Film Definition

A mould with new gas film definition for aluminum alloy in continuous casting was designed,in which the gas film was formed between mould and initial solidified shell,which can decrease the transverse heat transfer in the mould to form approximately single direction heat transfer condition in the billets and to decrease the liquid front depth and to shorten the length of initial solidified shell to eliminate the inner defects in aluminum alloy ingot and to improve the quality of the ingot.The numerical simulation of heat transfer in new mould and conventional mould has been conducted,showing that the remarkable change of temperature field can be observed in the new mould.The continuous casting 7075 aluminum alloy billets with smooth surface can be produced with new mould in the condition of stability and balance of gas film.The relationship of drawing velocity and gas flux with gas pressure as well as their effects on the billet quality have been described.The stability of gas film can be controlled by gas flux in the condition of a constant liquid surface height.