压铸_挤压铸造_液态模锻_及半固态加工的适应性分析_罗守靖
压铸、挤压铸造(液态模锻)及半固态加工的适应性分析
罗守靖
(哈尔滨工业大学材料科学与工程学院)
摘 要 对压铸、挤压铸造(液态模锻)和半固态加工工艺性、适应性范围进行了比较分析。结果表明,3种工艺均有优势,但亦有不足,而在成形难易和形状复杂性、尺寸精确性、满足对制件力学性能要求等方面,均不能同时兼顾,但却能相互补充,扬长避短。主张充分发挥3种工艺的潜能,为金属加工合理选用工艺、提升工艺水平提供一条可供参考的依据。关键词 压铸;挤压铸造(液态模锻);半固态加工;工艺适应性
中图分类号 T G249.2 文献标志码 A 文章编号 1001-2249(2007)08-0600-03
收稿日期:2007-04-13
作者简介:罗守靖,男,1939年出生,教授,哈尔滨工业大学材料科学与工程学院,哈尔滨(150001),电话:0451-********,E-m ail:luosj@https://www.360docs.net/doc/b114974046.html,
材料成形方法多种多样。但人们总希望材料加工方法容易操作,适用性强,而且制件质量高,以满足科技发展对制件形状尺寸和材料性能的要求。目前应用较多的压铸、挤压铸造(液态模锻)、半固态成形和固态模锻,很难在成形性和性能两方面均得到满足。基于此,笔者根据多年研究的实践,对这3种工艺的特点、适应性进行分析,目的在充分发挥各工艺本身的最大优势,精确成形其得心应手的制件,并使其制件使用性和经济性完美统一。
1 3种工艺性、适应性分析
1.1 压铸
压铸工艺实质是在高压作用下,液态金属以极高的速度,经内浇道输送至封闭型腔,实现充填、凝固成形。这里所谓在压力作用下凝固成形很难办到。压铸分热室压铸(见图1)和冷室压铸(见图2)。其特点:压铸前,型腔全封闭;设备配有高速的压射系统和合模系统,保证有足够大的压射力、压射速度和锁模力。适用范围:薄壁壳体类制件。
压铸工艺不足之处:对于厚壁件、壁厚不均匀件和随后进行热处理制件,
不适用。
图1 热室压铸示意图
图2 冷室压铸示意图
1.2 挤压铸造(液态模锻)
基于压铸工艺之不足,前苏联压铸大师 . . ??é?è?在18世纪末,提出一种新的成形工艺,即挤压铸造(液态模锻)[1]。1964年,他出版了一本专著《 ?±?áà3?±è1 èé?à′à ??±??±》,一年之后美国将其翻译成英文版《Squeeze casting 》,即《挤压铸造》[2]
。其工艺过程:敞口模上注,合模充填成形,随后加压凝固和塑性变形。其过程见图3
。
图3 挤压铸造(液态模锻)示意图
挤压铸造的工艺特点:模具是敞口,结构简单,在通用或专用液压机上,实现快速合模和开模;慢速加压。适用范围:它是压铸和热模锻的一种工艺补充。即对于形状复杂(或厚壁件)而性能有一定要求的制件,采用热模锻难以成形,而采用压铸或因铸造缺陷难以消除(如
壁厚不均匀)件,或因力学性能达不到的这类制件要求,完全可以选用挤压铸造(液态模锻)[2]。
600
专题论述特种铸造及有色合金 2007年第27卷第8期
1.3 半固态成形
半固态模锻:将半固态坯料经加热重熔,置于模腔,合模充填,加压凝固和塑性变形(见图4)
。
图4 触变锻压工艺流程图
1.凝固
2.坯料
3.加热
4.模锻
5.挤压
6.轧制
7.机械搅拌
8.电磁搅拌
9.SIM A 法
半固态压铸:将坯料加热至半固态,置于压射室,在高压下,高速充填型腔,实现凝固成形(见图5)。
图5 半固态压铸工艺图
半固态成形与压铸和挤压铸造(液态模锻)的区别:半固态成形对象是半固态坯,其坯在半固态温度下,由球状晶和包覆其周围的液相组成,在加工前可搬运,但压力作用下,粘度大大下降,具有与压铸和挤压铸造(液态模锻)相近的流动性。这就使得其加工温度低,变形抗力低,凝固时间短,凝固收缩小,大大提高制件加工精度和生产效率,其质量与热模锻相近,并大大降低能耗。
半固态加工的适应性:①半固态加工温度与压铸和挤压铸造(液态模锻)相比,要低得多,适用于加工高熔点合金,如钛合金、铁基合金等;②适于成形形状复杂、厚或薄壁件;③受制坯(浆)限制,不宜采用半固态加工成形大尺寸制件;④受力结构件宜采用半固态加工[3~6]。
2 工艺适应性与成本比较
2.1 压铸和挤压铸造(液态模锻)的比较
充填性:挤压铸造(液态模锻)不如压铸,因为压铸
是在高压下,快速充填,而挤压铸造(液态模锻)是模具自身作用下慢速充填。
加压效果:挤压铸造(液态模锻)最优。因为挤压铸造(液态模锻)的压力直接作用在金属液上,不仅发生压
力下结晶凝固所产生的很多优异特性,而且产生少量塑性变形,获得很好的密实效果。
挤压铸造(液态模锻)的局限性:挤压铸造(液态模锻)尽管融入了力学变形,有很好的加压效果。但由于塑性变形很小,其组织还是一种有所改善的铸造组织,力学性能改善还有限。另外,制件形状太复杂或壁太薄(<5m m),也不适用。2.2 压铸与半固态加工的比较
压铸是有色金属大批量生产最常用的工艺方法,成
本不高,且尺寸范围大,大至汽车发动机缸体[7~10]
,小至微小链状制件,这是压铸的优势,而半固态加工在这方面却逊色得多;半固态加工技术与压铸工艺一样,可生产薄壁件、复杂件及尺寸精确件,但由于半固态加工技术有高的制坯成本,因此与压铸相比这方面无优势可言。
然而要同时确保制件完整性(无缺陷)和可靠性,压铸就无法达到,而半固态加工具有优势。
3 两点启示
3.1 汽车轻量化趋势
在过去的20年中,全球汽车工业致力于减小尺寸
和轻量化,以达到政府和市场的要求
[11~13]
。为了达到
轻量化的目标,汽车制造商已经逐渐将铸造铝合金和镁合金应用到汽车行业,并且利用新的技术来进行净成形铝合金和镁合金制件。这里包括压铸、挤压铸造(液态模锻)和半固态加工,及热模锻(等温锻、超塑性成形)
等。
图6 挤压铸造(液态模锻)设备
3.2 韩国釜山近净成形厂工艺配置的启示
在2006年9月韩国釜山举行的第九届合金与复合材料半固态加工国际学术会议上,笔者所参观的韩国的一个有色金属近净成形厂,在压铸车间里,既布置有大小不等的压铸设备,亦有压铸设备改装的挤压铸造(液态模锻)设备(见图6)。其特点:把压射缸改为加压缸,慢速输送金属,填充结束后,直接加压和保压,生产铝合金汽车件(见图7a 、图7b)。同时,该厂还另外设置了一个半固态加工车间(见图8和图9)。图10为采用半固态加工工艺生产的铝合金汽车零件。
601
压铸、挤压铸造(液态模锻)及半固态加工的适应性分析 罗守靖
(a)发动机端盖
(b)控制曲柄
图7 挤压铸造(液态模锻)
成形件
(a)转向节(触变压铸)(b)下曲柄(流变压铸)
图10 采用半固态加工生产的汽车零件
釜山近净成形厂工艺配置:以压铸为主体,辅以挤压铸造(液态模锻)和半固态加工,兼顾使用性和经济性,使产品成形工艺有极大的选择空间。在推进交通运输机械零件轻量化方面,极具竞争力。
4结论
(1)压铸适用于各种尺寸的复杂薄壁壳体件;挤压铸造(液态模锻)适用于中等尺寸的较简单的厚壁件;半固态加工适用于中等尺寸的复杂结构件。
(2)压铸生产厂家为了提升自己的竞争力(包括产
品性能和成本),可适当配有挤压铸造(液态模锻)和半固态加工生产能力。
(3)大力开展压铸、挤压铸造(液态模锻)和半固态加工的适用性研究,乃是充分发挥3种工艺的潜能、合理选用工艺、提升工艺水平所必须。
参 考 文 献
[1] 罗守靖,何绍元,王尔德,等.钢质液态模锻[M ].哈尔滨:哈尔滨
工业大学出版社,1990.
[2] ? 1 ?±?áà3?±è1?èé?à′à ??±??±[M ]. ±êo?à-??à??o?,1964.
[3] 谢水生,黄声宏.半固态金属加工技术及其应用[M ].北京:冶金
工业出版社,1999.
[4] 罗守靖,田文彤,谢水生,等.半固态加工技术及其应用[J].中国
有色金属学报,2000,10(6):765-773.
[5] 吴春苗.压铸实用技术[M ].广州:广州科技出版社,2003.
[6] ANACLE TO D F.Science and Technology S em-i s olid M etal
Process[M ].U SA:W orcester Polytechnic Ins titu te,2004.
[7] 罗守靖,田文彤,李金平.21世纪最具发展前景的近净成形技术-半
固态加工[J].特种铸造及有色合金,2001(压铸专刊):175-180.[8] 罗守靖,姜巨福,杜之明,等.半固态加工技术的新控索[J].特种铸
造及有色合金,2003(S ):285-289.
[9] T OSH IO H,SH INSUKE S.Prkdu ction of alumin um alloy ingots
for thixoforming by the s em-i solid casting u sing a cooling slopw [C].In:Proc.6th Inter.Conf.on S em-i Solid Pr oceessing of Alloys and Composites,T orin o Italy,Sw pt.,2000:735-740.
[10] T OSH IO H ,S HINS UKE S.Sem-i solid s trip casting lf alumin um
alloy usin g a melt drag twin roll cas ter equipment w ith a cooling s lope[C].In:Proc.6th Inter.Con f.on Sem-i S olid Procees sing of Alloys and Composites,T orino Italy,Sw pt.,2000:221-225.
[11] 王益志.半固态成形中的某些关键技术[J].特种铸造及有色合金,
2002(压铸专刊):192-194.
[12] 罗守靖,杜之明,姜巨福.复合材料和半固态加工技术[J].特种铸
造及有色合金,2003(S):290-292.
[13] 陈威,罗守靖,刘刚.液态连挤硅线石粒子/铝复合材料摩损行为
[J].中国有色金属学报,2004,14(2):238-243.
(编辑:袁振国)
借名办展之风日盛铸协发布律师声明
据中国铸造协会统计,今年举办的各类铸造专业展览会将达40多个,平均每月4个,其中3月份竟高达8个。中国铸造协会秘书长张立波认为,铸造展会近几年层出不穷的原因与我国铸造行业迅猛发展、市场火爆密不可分。自2000年开始,中国铸件的产量已连续7年稳居世界第一,铸造企业达3万家,成为名副其实的铸造大国。现在我们的铸造展会太多,其中难免有鱼目混珠和滥竽充数的,有的在未经许可的情况下,借中国铸协、地方协会、一些专业媒体名义招展,侵犯了相关方面的权利,也让企业难辩真伪。
据张立波介绍,中国铸协的联合维权行动已经开始。北京某展览公司承办的国际铸造、锻压展览会就将中国铸协主办的杂志和一些行业比较熟悉的杂志列为支持媒体,但张立波称,中国铸协和相关媒体此前并不知情,保留追究办展单位法律责任的权利。
在律师声明出来后不久,北京这家展览公司的负责人与协会进行了沟通,还亲自上门,写了书面材料,表示歉意并及时予以更正。
张立波说,他对联合维权行动所取得的成效表示满意,并将把维权行动进行到底。他希望,协会、学会、媒体、企业乃至展览公司都行动起来,加强自律,加强合作,共同规范铸造展会市场。
(摘自《铸造世界报》2007年第7期)
602
特种铸造及有色合金 2007年第27卷第8期
w ho se y ield strength,tensile streng th and elo ng ation ar e impr oved by56.9%,19.2%and69.3%respec-tively,and w hose hardness and impact energy ar e in-creased by16.4%and18.8%,respectively,compared w ith those of the original alloy.T he mechanism of streng thening and toug hening o f mag nesium alloy s containing SiC nano-particles are also appro ached. Key Words:Magnesium Alloy,SiC Nano-particles, Sem-i solid,Microstructure,Mechanical Properties
Numerical Simulation of Porous A-l Cu Metaloceramics in Squeezing-infiltration Method Chen W eiping, H uang D a n,Liang Zeqin,He Zengxian(School of Mechanical Engineering,South China University of Technolog y,Guangzho u,China)2007,27(8)586~ 589
Abstract Num erical simulation of por ous A-l Cu m eta-loceramics in squeezing-infiltr ation method has been conducted by the Procast so ftw are,and the ex per-i m ent has been made.The results verify that so lidified tim e and solid-liquid phase structur e in numerical sim-ulatio n results are w ell in agreement w ith that in the ex periment and m etallog raphic observatio n,show ing the availability of the sim plified model in simulation of por ous A-l Cu metalo ceramics in squeezing-infiltration method.The infiltrated form ation of the A-l Cu m eta-loceramics is totally different fro m the formation of com mon allo ys.T he defects in the metalo ceramics are attributed to the com plex ity of internal structure in por ous m etalocer am ics perform s.
Key Words:Numerical Simulation,Porous Metalloce-ramics,Infiltration,C omposites
Numerical Simulation of Microstructure Formation in Metal Solidification Ya ng Fushua ng1,Ni Feng2,Duan Zongyin1,Zhang Jinbia o1,Zha ng Hongyun1,Luo La ihui1,Xu Xiangqi1(1.Department of M echanical Eng ineer ing,T ongling Co lleg e,To ng ling,China; 2. School of M aterials Science and Engineering,H enan Univer sity of Science and T echnolo gy,Luo yang,Ch-i na)2007,27(8)589~592
Abstract A stochastic mo del of nucleation and grow th has been established w ith continuous co oling,in w hich tim e facto r is taken into consider ation to gener ate the direct relativity of time w ith the function of nucleation and grow th model,based o n the Oldfield co ntinuum nucleation and g row th mo del by m eans o f basic theor y on metal so lidification to simulate the evo lution of metal microstructure during so lidification pro cess. The m icrostructure evo lution of eutectic Zn-5Al allo y has been simulated by the m odel,and the verificatio n exper im ent has been per for med.The results show that the sim ulated results ar e w ell in ag reem ent w ith the ex perimental o nes,revealing the availability of the mo del.
Key Words:Microstructure Simulation,Solidification, Nucleation,Growth
Progress in Technologies for preparation of Ti Alloy and Ti Alloy Parts with Ti Alloy Powder by Hydrogen Allo-ying Zha o Jia qi,Nan Hai,Hua ng Dong(Beijing In-stitute o f Aeronautical M ater ials,Beijing,China) 2007,27(8)593~595
Abstract Prog ress in technolog ies for preparation of Ti alloy and T i alloy parts by T i alloy pow der metallurg y w ith hydrog en alloy ing w as sur vey ed.T he for matio n techno logies of T i alloy pow der w ith hydr ogen,prop-erties of formed parts as w ell as the w ork mechanism of hydrogen in the T i alloy pow der w ere described. The future of the Ti alloy parts w ith high properties and low cost by Ti alloy pow der w ith hy dro gen w as review ed.
Key Words:Ti Alloy,Hydrogen,Mechanical Proper-ties,Powder Metallurgy,Porosity
A Review of the Surface Engineering Technologies for Light Alloy Qia n H a ncheng,Li Jun(College o f Me-chanical Engineering,Chongqing Univ er sity, Cho ng qing,China)2007,27(8)596~599
Abstract The light allo y w as w idely used for aero-space,automobiles,motorcycles,optical instrument, mechanical equipment,medical apparatus as w ell as e-lectronic parts due to its character istics o f lo w w eight, hig h specific intensity and thermal conductivity as w ell as ant-i electr omagnetic pro perties.H ow ever,the lig ht alloy has som e disadv antages,such as low hardness, w orse w ear r esistance and corrosion r esistance,so it is necessary to perfo rm surface treatment to im pro ve the co rrosio n resistance,w ear r esistance,ant-i frictio n as w ell as ox idizatio n resistance at a high temperature. Key Words:Light Alloy,Surface Treatment,Hardness Adaptability Analysis of Die C asting,Squeezing Casting and Sem-i solid Forming Luo Shoujing(School o f M ate-rials Science and Engineering,H arbin Institute o f Technolo gy,H arbin,China)2007,27(8)600~602 Abstract The com parativ e analy sis o f processing per-fo rmance and adaptability of die casting,squeezing casting and sem-i so lid forming w as conducted.T he re-sults rev eal that each o f these thr ee pro cessing has its
Ⅱ
advantages and disadvantag es,and no one can m eet all the desired dem ands including complexity,accuracy of size and mechanical pr operties of component.H ow ev-er,they can bring out its strengths to make up for the others w eakness.So it w ould be important to ex plode the potential of each pro cessing enough to im pro ve the pro cessing level.
Key Words:Die Casting,Squeezing Casting,Sem-i so-l id,Adaptability of Processing
Application Research on Sem-i solid Processing Techno-l ogies for Aluminum Alloys Xu Jun,Tian Zha nfeng, Zeng Yida n,Zha ng Zhifeng,Shi Likai(Gener al Re-search Institute for Non-fer rous Metals,Beijing,Ch-i na)2007,27(8)603~607
Abstract T he last progr ess in sem-i solid aluminum a-l loy billet preparation technolog ies and comm ercial ap-plication o f sem-i so lid thix o-form ing techno logy have been described em phatically,focusing on compound e-lectr omagnetic preparation,sem-i so lid continuous casting w ith m ult-i stream electrom ag netic stirring, sem-i solid thix o-fo rming die casting,sem-i solid thixo-fo rming forg ing,and so on.In addition,the po tential applied field and dev elo ping future o f sem-i solid alum-i num alloy pro cessing techno logies have been ex po un-ded including the form ing of non-easy casting alloy, direct casting of w ro ug ht aluminum alloy,w orking fo rming of piston alloy and defo rmatio n treatment of w rought alloy.
Key Words:Aluminum Alloy,Sem-i solid,Thixo-form-ing,Rheo-forming
Finite Element Simulation of Temperature Field in Sem-i solid Thixoforming ZL112Y Aluminum Alloy Billets in C ontinuous Induction Heating Zha ng Lei,Liu Chang-ming,W ang Yun(Scho ol of M echanical Eng ineering, Chong qing U niv ersity,Chong qing,China)2007,27 (8)608~612
Abstract We have designed an ex perimental horizo ntal continuous induction r eheating device based on sem-i solid thix oform ing principle.T he sim ulation o f tem-perature field in the ZL112Y alum inum allo y billets has been conducted w ith the ANASYS so ftw are w ith different heating pow er of three induction heating de-v ices.T he o ptimized heating po w er and heating time of different induction heating devices hav e been g iv en fo r the process of heating from ro om tem peratur e to sem-i solid tem peratur e of the billets.
Key Words:C ontinuous Thixoforming,Induction Heat-ing,Numerical Simulation,ZL112Y Aluminum Alloy Research and Application of JZ458Type Low Pressure Die Casting Machine Ka ng Jingle1,Ding Supei1, Chen Guoshi2,Sun Guofa1,Shi Xueqian1(1.Jinan Research Institute of Foundry and Forging,Jinan, China; 2.Yantai Lutong Precision Alloy Co.,Ltd. Yantai,China)2007,27(8)613~615
Abstract J458ty pe low pressure die casting machine is used to produce w ho le aluminum alloy w heel for auto-mobile,in w hich the controlling precision of liquid surface applied-pressur e system is low er than0.2% w ith the repeating precision lo w er than3%,the con-trol pr ecision of ho lding temperature o f liquid alum-i num allo y in ho lding fur nace is about680~720e,and the dimension precision in cavity of die is?0.1m m. The qualified rate of the w hole aluminum w heel r ea-ches up to95%using the low pressure die casting ma-chine.
Key Words:Low Pressure Die C asting Machine,Alum-i num Alloy,Wheel
2007Developing Tendency of Die C asting Industry in Guangdong Province W u Chunm iao(Schoo l of M echan-i cal Engineering,South China o f Technolog y,Guang-zhou,China)2007,27(8)615~617
Abstract T he present status o f die casting industry in Guangdo ng province w as sur vey ed.T he total die cast-ing product v olume is328000to ns in2006,in which the fiv e enterpr ises hav e the capacity o f mo re than 10000to ns pr oduction vo lum e.Som e leading com pa-nies is ex plo ring new developing paths,such as explo-i ting capital market to ex pand production scale,explo-ring o ut-m arket and for eign market,changing conven-tio nal manufacture m ode,and apply ing new save-ener-gy technologies and so on.The prom inent achievement can be o btained based o n above-m entioned measures as w ell as building up green die casting idea,enhancing enviro nm ental protection and implem enting cleaning pr oduction.
Key W ords:Guangdong,Die C asting Industry,Produc-tion,Technology,Market
Measures of Effectively Eliminating C rack in Investment Castings W u M i ng(Dey ang Jiny ang Special Casting Co.,Ltd.,Deyang,China)2007,27(8)618~619 Abstract The crack in investment casting s is com monly cr eated aro und ing ate due to easily form ing superhea-ting at r oot of ingate.For the investment casting re-quired for X-detection,the liquid steel sho uld be sm oothly filled in designing g ating sy stem.Through adopting turn-ingate to effectively reduce the filling
Ⅲ