半固态连铸工艺参数设计

提出了半固态连铸的主要工艺参数设计原则浇注温度为浇入制浆室后的熔体温度恰好等于液相线的温度;制浆室预热温度保证熔体浇入后,其界面温度不小于停止流动的临界温度,不大于熔体的初始温度;开拉时间在保证开拉时引锭不滑脱的前提下越短越好;拉坯速度既保证金属熔体通过制浆室的时间不小于非技晶球状组织的形成时间,又要保证熔体在通过结晶器的时间内能够形成不小于安全厚度的凝固层.     

半固态连铸过程拉漏(断)机理研究

利用自行设计制造的半固态连铸机对Fe-Cr-C系及Fe-Mn-C系合金进行了半固态连铸试验。着重研究了工艺参数对拉漏及拉断现象的影响,探讨了拉漏拉断的条件及机理,提出了防止拉漏拉断的技术途径。     

无柱状晶钢坯的连铸技术——半固态连铸

无柱状晶钢坯连铸技术是现代连铸技术的一个新发展，所得钢坯具有优异的成形加工性能。其基本过程包括合金熔炼，预结晶器预热，熔体搅拌和振动，凝固拉坯等基本环节。论述半固态连铸的基本概念，目前的应用，坯料的组织和性能以及今后的发展方向。     

半固态连铸技术研究现状与展望

分析了半固态连铸技术研究现状和存在的主要问题 ,提出了该领域今后的主要研究课题 ,并对半固态连铸的应用前景进行了探讨     

工艺参数对半固态连铸过程稳定性影响的数值模拟

在已有模拟半固态连铸过程温度场和流场软件的基础上,开发了一个可预测半固态连铸过程能否稳定进行的软件.利用这个软件研究了主要工艺参数对半固态连铸过程拉漏、拉断的影响,结果表明结晶器热流密度及开拉时间对半固态连铸过程稳定性影响最大,热流密度越大及开拉时间越短,半固态连铸过程越趋于稳定.     

倾斜冷却半固态连铸A356铝合金过程稳定性研究

研究了浇注温度、拉坯速度、倾斜板长度和倾斜角度对倾斜冷却半固态连铸A356铝合金过程稳定性的影响。结果表明:浇注温度、拉坯速度对连铸过程稳定性有显著影响,倾斜板上熔体的横截面积与拉坯速度成正比,拉坯速度的变化将导致倾斜板上熔体冷却强度发生相应的变化,实验表明合适的浇注温度和拉坯速度分别为630～660℃、400～600mm/min,此时连铸过程能稳定进行;而倾斜板长度在500～900mm、倾斜角度在30°～60°内变化对连铸过程稳定性并无显著影响。     

半固态连铸过程拉漏(断)机理研究

利用自行设计制造的半固态连铸机对Fe Cr C系及Fe Mn C系合金进行了半固态连铸试验。着重研究了工艺参数对拉漏及拉断现象的影响 ,探讨了拉漏拉断的条件及机理 ,提出了防止拉漏拉断的技术途径。     

半固态连铸技术经济分析与研究进展

半固成连铸是半固态加工技术的一个重要分支,也是制备高质量年用坯料的一种新技术。文章介绍了半固态连铸的基本概念、工艺流程及其与普通连铸的区别,并进行了技术经济分析。通过对现有机型的分析比较,指出立式半固态连铸机只是一种初期机型,将来应当发展半固态弧形连铸机。在对研究现状进行分析比较的基础上,指出今后的主要研究方向是半固态合金连铸性能研究、半固态连铸工艺稳定性理论研究、半固态成形用坯料的质量标准及生产     

AlSi7Mg合金半固态连铸坯料和组织形成研究

研究了电磁搅拌对半固态ＡｌＳｉ７Ｍｇ合金连铸坯料组织的影响,研究结果表明,电磁搅拌功率是重要的影响因素,搅拌功率越大,球状的初生α－Ａｌ端部形态越圆整,蔷薇状的初生α－Ａｌ越少,尺寸越小,宫铸坯表层的枝晶层越薄;连铸坯料中的出现大量球状初生α－Ａｌ是蔷薇状初生α－Ａｌ二次臂熔断的结果,连铸坯料中出现许多蔷薇状初生α－Ａｌ结果是其二次臂未充分熔断所致。     

ZL101A铝合金半固态连铸坯料的组织和力学性能

用电磁搅拌水平连铸设备制备ＺＬ１０１Ａ铝合金半固态连铸坯料，获得了两种非种非树枝晶组织，一种是初晶α－Ａｌ呈短棒状的组织；另一种是初晶α－Ａｌ呈短棒状和等轴状的混合组织。对短棒状组织连铸坯料进行Ｔ６热处理及力学性能测试，结果表明热处理使用σｂ和δ提高。     

Numerical simulation of semisolid continuous casting process

1　ＩＮＴＲＯＤＵＣＴＩＯＮＳｅｍｉｓｏｌｉｄｃｏｎｔｉｎｕｏｕｓｃａｓｔｉｎｇ(ＳＣＣ)ｉｓｓｔｉｌｌｉｎｔｈｅｅｘｐｅｒｉｍｅｎｔａｌｓｔｕｄｙｓｔａｇｅｉｎＣｈｉｎａ[1～ 3] .Ｔｈｅｒｅｆｏｒｅ ,ｍａｎｙｐｒｏｂｌｅｍｓａｒｅｎｅｅｄｅｄｔｏｂｅｅｘｐｌｏｒｅｄｃｏｎｔｉｎｕｏｕｓ ｌｙ .Ａｍｏｎｇｔｈｅｍ ,ｔｈｅｂｒｅａｋａｇｅａｎｄｂｒｅａｋｏｕｔａｒｅｔｈｅｋｅｙｂｌｏｃｋｓｔｏｌｉｍｉｔｔｈｅｉｎｄｕｓｔｒｉａｌａｐｐｌｉｃａｔｉｏｎｏｆｔｈｅｐｒｏｃｅｓｓ.Ｂｅｃａｕｓｅｏｆｔｈｅｃｏ…     

Stability condition of semisolid continuous casting process

1　ＩＮＴＲＯＤＵＣＴＩＯＮＴｈｅｓｅｍｉｓｏｌｉｄｃｏｎｔｉｎｕｏｕｓｃａｓｔｉｎｇ ,ＳＳＣＣｆｏｒｓｈｏｒｔ,ｉｓａｎｅｗ ｐｒｏｃｅｓｓｗｉｔｈｌｏｗｃｏｎｓｕｍｐｔｉｏｎａｎｄｈｉｇｈｐｒｏｄｕｃｔｉｖｉｔｙｔｏ ｐｒｏｄｕｃｅｈｉｇｈ ｑｕａｌｉｔｙｂｉｌｌｅｔｆｏｒｓｅｍｉｓｏｌｉｄａｌｌｏｙｓｆｏｒｍｉｎｇ .Ｈｏｗｅｖｅｒ ,ｔｈｅｂｒｅａｋｏｕｔａｎｄｂｒｅａｋａｇｅｏｆｔｅｎｏｃｃｕｒｉｎｔｈｅｐｒｏｃｅｓｓｂｅｃａｕｓｅｏｆｌａｃｋｉｎｇｓｕｆｆｉｃｉｅｎｔｒｅｓｅａｒｃｈｏｎｔｈ…     

Rheologic behaviors of A356 aluminum alloy billet produced by semisolid continuous casting process

The experiments for rheologic behaviors of semisolid continuous casting billets of A356 alloy in semisolid state had been carried out with a multifunctional rheometer. The results show that the deformation rate increases with loading time, the maximum strain reaches to 120％ (which is one time larger than that of traditional mold casting billet) and the strain can be rapidly eliminated to 10％ after unloading. Moreover, there is a critic stress for billet deformation even in semisolid state, which is named as critic shear stress. This stress increases with the decreasing of heating time. The theologic behaviors can be expressed by five elements mechanical model (H_2- [N_1|H_2]-[N_2|S]) and can be modified with the increasing of heating time.     

坯壳导电性对电磁制动结晶器多物理场的影响

采用雷诺时均方法,标准k-ε模型研究电磁制动下凝固坯壳导电性对板坯连铸结晶器内流场和电磁场的影响。计算了3种不同工况,1—忽略凝固坯壳导电性,2—凝固坯壳电导率取定值,该值等于钢液电导率,3—凝固坯壳电导率随温度变化,并对比了3种工况下感应电流、洛伦兹力、焦耳热及速度分布。结果表明,相较于凝固坯壳绝缘的情况,坯壳导电时,上环流减弱,下环流增强,环流涡心区域扩大;洛伦兹力、感应电流密度、焦耳热最大值出现在水口和射流区域,在制动区域内数值较高,随着远离制动区域而迅速衰减;坯壳导电时,数值和分布范围较坯壳绝缘时均有明显提高;电磁制动下坯壳导电性影响显著,因此模拟计算时凝固坏壳的导电性不应被忽略;由于凝固坯壳电导率接近钢液,因此工况2、3差异微小,由凝固坯壳导电引起的流场、感应电流密度分布和焦耳热分布的变化在工况2下变化幅度略大于工况3。     

连铸结晶器内坯壳凝固过程的广义热力耦合分析

本文对连铸结晶器内的铸坯早期凝固过程做了热力耦合分析 ,该分析过程不涉及具体的连铸形式 ,因而适用范围广。根据所建立的数学模型编制了有限元程序 ,并以圆坯连铸过程为例进行了计算     

Solidification modeling of continuous casting process

The aim of the present work was to utilize a new systematic mathematical-informational approach based on informational macrodynamics (IMD) to model and optimize the casting process, taking as an example horizontal continuous casting (HCC). The IMD model takes into account the interrelated thermal, diffusion, kinetic, hydrodynamic, and mechanical effects that are essential for the given casting process. The optimum technological process parameters are determined by the simultaneous solution of problems of identification and optimal control. The control functions of the synthesized optimal model are found from the extremum of the entropy functional having a particular sense of an integrated assessment of the continuous cast bar physicochemical properties. For the physical system considered, the IMD structures of the optimal model are connected with controllable equations of nonequilibrium thermodynamics. This approach was applied to the HCC of ductile iron, and the results were compared with experimental data and numerical simulation. Good agreement was confirmed between the predicted and practical data, as well as between new and traditional methods.     

铝合金壳盖压铸工艺优化研究

通过对铝合金壳盖压铸件进行实体造型,采用铸造数值模拟软件Z-Cast对铝合金壳盖压铸过程的压力场、速度场和温度场进行数值模拟,根据模拟结果分析浇注系统和溢流槽尺寸的合理性,重新设计、优化浇注系统的形状和布置位置,得到合理的压铸方案。对于铝合金压铸件结构和压铸工艺设计有着重要的指导意义。     

稀土处理与低温浇注制备半固态铝合金

本文采用稀土处理与低温浇注工艺制备ZL104铝合金半固态坯料,研究了坯料在重熔加热过程中组织的变化.实验结果表明:稀土处理和低温浇注有效地细化了合金的铸态组织,半固态重熔过程中可获得球形初生α-Al晶粒.当605℃浇注的坯料在580℃下半固态保温30～90min时,获得的球形初生α-Al晶粒组织最佳.     

Preparation and mechanical properties of SiC／2024 composite by semisolid casting

A SiC/2024 composite was made by semisolid casting.The wetting between SiC and Al matrix is improved by treating SiC particles at a high temperature,coating K2ZrF6,and adding Mg to the Al melt,An effective way to remove the gas around SiC particles was also found.Microstructures were observed under optical microscope(OM) and scanning electron microscopy(SEM).The results show that SiC particles and Al matrix are well bonded and no gaps or cavities around the particles are observed.SiC particles distribute homogeneously in the Al matrix.The existence of SiC particles results in the increase of wear resistance and strength.