河南铸铝件生产厂家为你讲诉铸坯内部裂纹液芯压下技术

河南铸铝件生产厂家为你讲诉铸坯内部裂纹液芯压下技术

      ，生产的铜套、离心铸造铜套、铜螺母、铜涡轮产品现已销往河南、安阳、邯郸、郑州等地，欢迎咨询

    　铸铝件生产厂家表示一般认为，其中对铸坯内部裂纹影响较大的主要参数有单辊压下量，压下量的分配和总压下量，因此液芯压下需制订正确的工艺参数。
第1、单辊压下量。对带液芯的铸坯来说，因为温度很高，坯壳强度低，特别是在坯壳的凝固前沿处的强度和塑性都很低。在这个区域内很容易因坯壳受力变形而在枝晶间的切口处形成裂纹。家指出当这些裂纹被残余的钢液充填后，因为偏析的作用会增加晶界的脆性，使裂纹继续扩展，最终在铸坯中形成内裂。因此带液芯的铸坯在二冷区运行过程中应尽量避免发生较大的变形，将变形限制在允许的范围内。
第2、压下量的分配。按照不同的工艺条件，液芯压下常常需要实施连续的压下来完成。这样总压下量在各扇形段中的分配对控制铸坯内部质量很重要。铸坯距离结晶器近的区段其凝壳较薄，在相同的变形率条件下，允许的压下量可以较大，且因为坯壳的温度较高，针对抑制应变和应力的积累较有利,因此,在液芯压下的前期应采用较大的压缩速率。在液芯压下的后期，因为凝壳厚,凝固前沿的应变较大，同时因为铸坯温度降低，针对抑制应变和应力的积累不利,因此应采用较小的压缩速率。
第3、最大形变量和形变速率。厂家表示最大形变量越大，对铸坯连铸连轧越有利，但同时导致铸坯产生内裂纹的危险性增大。针对不同的冶金条件，如何确保不产生内裂纹的情况下最大限度提高生产率、获得最佳的最大变形量等问题有待深入研究解决。此外，侧边变形速度分配也很重要，压下区段内辊列的对数、行程、辊列的锥度等必须满足内部及侧边铸坯质量要求。

Henan aluminum casting manufacturers, production of copper sleeve, a centrifugal casting copper sleeve, a copper nut, copper turbine products has been sold to Henan, Anyang, Handan, Zhengzhou and other places, welcomed the Advisory
Cast aluminum parts manufacturers said is generally believed that the crack of billet on the effect of main parameters of large single roll, the distribution and total pressure pressure, so liquid core reduction need to formulate the correct process parameters.
First, single reduction. For the casting billet with liquid core, because the temperature is high, the strength of the shell is low, especially the strength and plasticity at the front of the shell is very low. In this area it is easy to form a crack at the notch of the branch where the shell is subjected to force deformation. The casting manufacturers pointed out that when the cracks are remnants of the steel liquid filling, because of the segregation effect will increase the grain boundary brittleness, the cracking continues to expand, eventually in casting billet formed within the cleft. Therefore, in the process of operation of the liquid core of the casting slab in the two cold zone, the large deformation should be avoided, and the deformation is limited in the allowable range.
Second, the amount of pressure distribution. According to different process conditions, the liquid core is often required to implement a continuous pressure to complete. The distribution of total pressure in each sector is important to control the quality of casting billet. In the same deformation rate, the amount of pressure can be larger, and the temperature of the shell is higher, and the compression rate is higher than that of the liquid core. In the late period of the liquid core, the strain of the shell is thick and the strain of the solidification front is larger, and the temperature of the slab is decreased, which is unfavorable for the accumulation of strain and stress.
Third, maximum shape variable and variable rate. The casting manufacturers said maximum deformation is large, slab continuous casting and rolling of the more favorable, but also lead to cast billet crack increases the risk. For different metallurgical conditions, how to ensure the maximum productivity and the maximum deformation of the maximum deformation in the case of no internal cracks are needed to be further studied. In addition, the lateral deformation velocity distribution is also very important, the number of roller columns in the section, the travel of the roller, the taper of the roll, etc..