某型號(hào)接線盒支架沖壓模具設(shè)計(jì)-復(fù)合模含開(kāi)題及9張CAD圖
某型號(hào)接線盒支架沖壓模具設(shè)計(jì)-復(fù)合模含開(kāi)題及9張CAD圖,型號(hào),接線,支架,沖壓,模具設(shè)計(jì),復(fù)合,開(kāi)題,cad
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XX設(shè)計(jì)（XX）中期報(bào)告
題目：某型號(hào)接線盒支架沖壓模具設(shè)計(jì)
系 別
專 業(yè)
班 級(jí)
姓 名
學(xué) 號(hào)
導(dǎo) 師
20XX年 3 月 15 日
撰寫內(nèi)容要求（可加頁(yè)）：
1. 設(shè)計(jì)（論文）進(jìn)展?fàn)顩r
翻譯了外國(guó)文獻(xiàn)（利用一種新的沖模磨損試驗(yàn)方法體系測(cè)試對(duì)基本材料磨損性能的影響）。
查閱了一些沖壓技術(shù)的相關(guān)資料，重點(diǎn)關(guān)注了本設(shè)計(jì)的關(guān)于排樣，沖裁，沖孔，拉伸等工藝。得出如下的一些數(shù)據(jù)：
普通碳素鋼Q235-A，未經(jīng)退火，抗剪強(qiáng)度：310-380 MPa.抗拉強(qiáng)度：440-470 MPa
伸長(zhǎng)率：21-25%。屈服點(diǎn)：240 MPa。
做了相關(guān)的數(shù)據(jù)計(jì)算如下：
如圖所示，材料厚度t=3mm，零件高度H=13mm，未標(biāo)注圓角都為3mm。
l 確定拉伸次數(shù)：
一次拉伸成形的條件（1）拉伸高度H≤（0.3-0.8）B.（2）盒子轉(zhuǎn)角的圓角半徑r=(0.05-0.2)B.（3）底部圓角半徑rр ≥（2-4）t。根據(jù)所定的參數(shù)，以上條件滿足，所以此零件可以一次拉深成形。
l 計(jì)算毛坯的形狀及尺寸：
將低盒形拉深件展開(kāi)，計(jì)算尺寸：本次設(shè)計(jì)中，工件圖帶凸緣，取修邊余量為0.4mm，所以計(jì)算:
所以代入數(shù)據(jù)得：
L=13+3-0.43×6=13.42mm
R===12.32mm
R取12.32mm
所以尺寸80和50展開(kāi)長(zhǎng)度計(jì)算分別為：
L1=74+13.42×2=100.84mm
L2=46+13.42×2=72.84mm
分別取值為101mm和73mm。
l 材料利用率的計(jì)算：
一個(gè)步距內(nèi)的材料利用率：
η＝Ａ/BS×100%
式中： A—一個(gè)步距內(nèi)沖裁件的實(shí)際面積；
B—條料寬度；
S—步距；
一個(gè)步距內(nèi)沖裁件的實(shí)際面積，CAD軟件-工具-查詢-面積：
A=7687mm2
所以一個(gè)步距內(nèi)的材料利用率：
Η=Ａ／BS×100%
=7687／157×75×100%
=65.28%
根據(jù)計(jì)算結(jié)果知道選用直排材料利用率可達(dá)65.28%，滿足要求。
2. 存在問(wèn)題及解決措施
在確定毛坯尺寸及確定毛坯形狀的時(shí)候出現(xiàn)了一些不太理解的問(wèn)題。由于這個(gè)零件是盒形的拉深，不是回轉(zhuǎn)體，比較特殊，所以在計(jì)算其毛坯尺寸的時(shí)候計(jì)算方法較為繁瑣，有一種為作圖法
這個(gè)作圖法在計(jì)算毛坯尺寸的時(shí)候相當(dāng)繁瑣，后來(lái)經(jīng)過(guò)查閱很多本資料解決了這個(gè)問(wèn)題，通過(guò)計(jì)算的方法去解決，從而避開(kāi)了較為繁瑣且不太準(zhǔn)確的作圖法。
在排樣方式上是不是可以選擇無(wú)間隙排樣。
零件面積的計(jì)算比較繁瑣，對(duì)沖裁的面積不好確定。
3. 后期工作安排
第九周至第十二周：對(duì)各套沖壓模具機(jī)構(gòu)尺寸、強(qiáng)度等進(jìn)行具體計(jì)算。
第十三周至第十六周：繪制沖壓模具機(jī)械工程圖及相應(yīng)零件圖，完成畢業(yè)設(shè)計(jì)
論文，做好畢業(yè)答辯準(zhǔn)備。
指導(dǎo)教師簽字：
年 月 日
注：1. 正文：宋體小四號(hào)字，行距22磅；標(biāo)題：加粗 宋體四號(hào)字
2. 中期報(bào)告由各系集中歸檔保存，不裝訂入冊(cè)。
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XX設(shè)計(jì)(XX)開(kāi)題報(bào)告
題目： 某型號(hào)接線盒支架沖壓模具設(shè)計(jì)
系 別
專 業(yè)
班 級(jí)
姓 名
學(xué) 號(hào)
導(dǎo) 師
20XX年 11 月 29 日
6
1、畢業(yè)設(shè)計(jì)（論文）綜述：
由于冷沖壓有許多突出的優(yōu)點(diǎn)，因此，在機(jī)械制造，電子電器等各個(gè)行業(yè)中，都得到了廣泛的應(yīng)用。大到汽車的覆蓋件，大多是由冷沖壓方法制成的。目前，采用冷沖壓工藝所獲得的沖壓制品，在現(xiàn)代汽車，拖拉機(jī)，電機(jī)電器，儀器儀表及各種電子產(chǎn)品和人們?nèi)粘Ｉ畹确矫妫颊加惺种匾牡匚?。在電子產(chǎn)品中，沖壓件的數(shù)量占零件總數(shù)的85%以上。在飛機(jī)。導(dǎo)彈，各種槍彈與炮彈的生產(chǎn)中，沖壓件所占的比例也相當(dāng)大。人們?nèi)粘Ｉ钪械慕饘僦破?，沖壓件所占的比例更大，如鋁鍋，不銹鋼餐具，搪瓷盆，都是冷沖壓制品。今年許多模具企業(yè)加大了用于技術(shù)進(jìn)步的投資力度，一些多內(nèi)模具企業(yè)已普及了二維CAD，并陸續(xù)開(kāi)始使用UG,PRO/E等國(guó)際通用軟件，并成功應(yīng)用于沖壓模的設(shè)計(jì)中。
近年來(lái)，隨著工業(yè)和高科技產(chǎn)業(yè)的飛速發(fā)展，我國(guó)沖壓模具的設(shè)計(jì)與制造能力已經(jīng)達(dá)到較高的水平，雖然如此，我國(guó)的沖壓模具設(shè)計(jì)制造能力與市場(chǎng)需要和國(guó)際先進(jìn)水平相比仍然有很大差距，這主要表現(xiàn)在高檔轎車和大中型汽車覆蓋件模具及高精度沖模方面，無(wú)論在設(shè)計(jì)還是加工工藝和能力方面，都存在較大差距。轎車覆蓋件模具，具有設(shè)計(jì)和制造難度大，質(zhì)量和精度要求高的特點(diǎn)，可代表覆蓋件模具的水平。雖然在設(shè)計(jì)制造方法和手段反面已基本達(dá)到了國(guó)際水平，模具結(jié)構(gòu)功能方面也接近國(guó)際水平，在轎車模具國(guó)產(chǎn)化進(jìn)程中前進(jìn)了一大步，但在制造質(zhì)量，精度，制造周期等反面，與國(guó)外相比還存在一定的差距。
隨著我國(guó)經(jīng)濟(jì)的騰飛和產(chǎn)品制造業(yè)的蓬勃發(fā)展，模具制造業(yè)也相應(yīng)進(jìn)入了高速發(fā)展的時(shí)期，據(jù)中國(guó)牌模具工業(yè)協(xié)會(huì)統(tǒng)計(jì)，2003年我國(guó)模具工業(yè)總產(chǎn)值約為145億元，年均增長(zhǎng)14%。另?yè)?jù)統(tǒng)計(jì)，我國(guó)現(xiàn)有模具生產(chǎn)廠點(diǎn)以超過(guò)20000家，從業(yè)人員有60多萬(wàn)人，模具年產(chǎn)值在1億元以上的企業(yè)已達(dá)十多家?？梢杂鲆?jiàn)我國(guó)經(jīng)濟(jì)的高速發(fā)展將對(duì)模具提出更為大量，更為迫切的需求，特別需要發(fā)展大型精密，復(fù)雜，長(zhǎng)壽命的模具。同時(shí)要求模具設(shè)計(jì)，制造生產(chǎn)周期達(dá)到全新的水平。
2、 本課題研究的主要內(nèi)容和擬采用的研究方案、研究方法或措施
本課題的研究?jī)?nèi)容為某型號(hào)接線盒支架沖壓模具設(shè)計(jì)，要求是1。能沖出符合技術(shù)要求的工件。2。能提高生產(chǎn)率。3。模具制造和維修方便。4。模具有足夠的壽命。5。模具易于安裝調(diào)整，且操作方便，安全，模具裝配圖一張，零件圖若干張，設(shè)計(jì)計(jì)算說(shuō)明書一份。
零件圖如下：
擬采用的研究方案：材料的選擇，沖壓設(shè)備的選擇，排樣的設(shè)計(jì)，分析制件的沖壓工藝性，制定合理的工藝方案，根據(jù)工藝方案設(shè)計(jì)相應(yīng)的模具，選擇合理的沖壓類型及結(jié)構(gòu)等。
擬定的工藝方案：
方案一：①落料，沖裁出零件毛坯料；②拉深，加工接線盒中間40*32的盒形凹槽；③沖孔，分別沖直徑為10的孔和直徑為6的孔。
方案二：①落料，沖裁出零件毛坯料；②沖孔，分別沖直徑為10的孔和直徑為6的孔；③拉深，加工接線盒中間40*32的盒形凹槽。
方案三：①落料，沖裁出零件毛坯料；②使用級(jí)進(jìn)模具。
三種方案優(yōu)缺點(diǎn)分析如下：
方案一：使用簡(jiǎn)單沖裁模具，結(jié)構(gòu)簡(jiǎn)單，易于制造和維修，沖裁件的精度也較高,不受送料誤差影響,內(nèi)外形相對(duì)位置一致性好,沖件表面較為平整,適宜沖薄料。但由于都是單件完成一個(gè)工序，所以效率較低，步驟較多。
方案二：由于先使用的是沖孔，而后使用拉伸工藝，會(huì)導(dǎo)致孔的變形程度較大，尺寸與位置難以保證。
方案三：多工位級(jí)進(jìn)模在壓力機(jī)的一次行程內(nèi)能完成多個(gè)工序(包括落料,拉伸,沖孔),所以生產(chǎn)效率高,并容易實(shí)現(xiàn)操作機(jī)械化和自動(dòng)化,尤其適用于單機(jī)上實(shí)現(xiàn)現(xiàn)代化,可采用高速壓力機(jī)生產(chǎn),操作安全,工人的勞動(dòng)強(qiáng)度低,模具強(qiáng)度較高,壽命較長(zhǎng)。但是通用性較差,僅適用于中小型零件的大批量生產(chǎn),模具制造與價(jià)格都較高,要求沖床的運(yùn)動(dòng)精度高,剛度好,振動(dòng)小,對(duì)沖壓的運(yùn)動(dòng)精度高,板料的要求高,模具結(jié)構(gòu)復(fù)雜,制造精度高,調(diào)試,維修困難,價(jià)格昂貴。
3、 本課題研究的重點(diǎn)及難點(diǎn)，前期已開(kāi)展工作
本課題主要是對(duì)某接線盒的支架進(jìn)行沖壓模具設(shè)計(jì)，根據(jù)圖示，重點(diǎn)與難點(diǎn)在于中間40*32的盒形凹槽的加工，首先要根據(jù)設(shè)計(jì)的一些參數(shù)的確定來(lái)計(jì)算拉伸的次數(shù)，其次在拉伸后要保證其精度，以及沖孔之后孔的精度。
近期我的主要工作是查找相關(guān)資料，補(bǔ)充自己在沖壓模具設(shè)計(jì)中的知識(shí)，同時(shí)對(duì)零件結(jié)構(gòu)、尺寸進(jìn)行認(rèn)真分析。
4、完成本課題的工作方案及進(jìn)度計(jì)劃
第一周至第三周：做畢業(yè)設(shè)計(jì)準(zhǔn)備工作，查找相關(guān)資料，補(bǔ)充設(shè)計(jì)知識(shí)，確定加工方案做好開(kāi)題答辯工作。
第四周至第八周：根據(jù)前期補(bǔ)充的知識(shí)，進(jìn)行模具結(jié)構(gòu)的簡(jiǎn)單設(shè)計(jì)，完成中期報(bào)告。
第九周至第十二周：對(duì)各套沖壓模具機(jī)構(gòu)尺寸、強(qiáng)度等進(jìn)行具體計(jì)算。
第十三周至第十六周：繪制沖壓模具機(jī)械工程圖及相應(yīng)零件圖，完成畢業(yè)設(shè)計(jì)論文，做好畢業(yè)答辯準(zhǔn)備
5 指導(dǎo)教師意見(jiàn)（對(duì)課題的深度、廣度及工作量的意見(jiàn)）
指導(dǎo)教師： 年 月 日
6 所在系審查意見(jiàn)：
系主管領(lǐng)導(dǎo)： 年 月 日
注：1. 正文：宋體小四號(hào)字，行距22磅。
2. 開(kāi)題報(bào)告由各系集中歸檔保存。
參考文獻(xiàn)：
【1】王孝培主編.沖壓手冊(cè).北京：機(jī)械工業(yè)出版社，1990
【2】《沖壓模具設(shè)計(jì)與制造》.劉建超、張寶忠主編.高等教育出版社
【3】《模具設(shè)計(jì)與制造簡(jiǎn)明手冊(cè)》(第二版).馮炳堯編.上?？茖W(xué)技術(shù)出版社
【4】李碩本主編. 沖壓工藝學(xué). 北京：機(jī)械工業(yè)出版社，1982
【5】模具實(shí)用技術(shù)叢書編委會(huì).沖壓設(shè)計(jì)應(yīng)用實(shí)例.北京：機(jī)械工業(yè)出版社，1994
【6】高鴻庭，劉建超主編.冷沖壓設(shè)計(jì)及制造.北京：機(jī)械工業(yè)出版社，2002
【7】《沖模圖冊(cè)》李天佑主編.北京：機(jī)械工業(yè)出版社，2002
【8】丁松聚主編. 冷沖模設(shè)計(jì).北京：機(jī)械工業(yè)出版社，1994
【9】成虹主編.沖壓工藝與模具設(shè)計(jì). 北京：高等教育出版社，2000
【10】李天佑主編. 沖模圖冊(cè). 北京：機(jī)械工業(yè)出版社，1988
【11】國(guó)家技術(shù)監(jiān)督局.沖模模架. 北京：中國(guó)標(biāo)準(zhǔn)出版社，1991
【12】中國(guó)機(jī)械工程學(xué)會(huì)鍛壓學(xué)會(huì)編.鍛壓手冊(cè) 第2冊(cè). 北京：機(jī)械工業(yè)出版社，1993
【13】Friction factor measurement for sheet metal forming.Xu, S.C. (Tangshan Econ. and Trade Comm., Tangshan 063000, China); Wang, X.J. Source: Kang T'ieh/Iron and Steel (Peking), v 36, n 2, p 37-40, February 2001 Language: Chinese
【14】Incremental sheet metal forming on CNC milling machine-tool
Kopac, J. (University of Ljubljana, Faculty of Mechanical Engineering, A?kerceva 6, 1000 Ljubljana, Slovenia); Kampus, Z. Source: Journal of Materials Processing Technology, v 162-163, n SPEC. ISS., p 622-628, May 15, 2005
【15】Sheet metal forming simulation using EAS solid-shell finite elements.Parente, M.P.L. (Department of Mechanical Engineering, Faculty of Engineering, University of Porto, 4200-465 Porto, Portugal); Fontes Valente, R.A.; Natal Jorge, R.M.; Cardoso, R.P.R.; Alves de Sousa, R.J. Source: Finite Elements in Analysis and Design, v 42, n 13, p 1137-1149, September 2006
INFLUENCE OF SUBSTRATE MATERIAL ON WEAR PERFORMANCE OF STAMPING DIES UTILIZING A NEW DIE WEAR TEST SYSTEM mer N. Cora and Muammer Ko NSF I/UCR Center for Precision Forming / Department of Mechanical Engineering Virginia Commonwealth University Richmond, VA KEYWORDS U/AHSS, Stamping, Die Wear Test, Die Materials, Coatings ABSTRACT Stamping of Ultra/Advanced High Strength Steel (U/AHSS) sheets results in high contact stresses and non-uniform strains. These, in turn, cause high wear rates and springback. In order to prevent the excessive wear effect in stamping dies, various countermeasures have been proposed such as alternative coatings, modified surface enhancements in addition to the use of newer die materials including cast, cold work tool, powder metallurgical tool steels. A new, slider type of test system was developed to replicate the actual stamping conditions including the contact pressure state, sliding velocity level and continuous and fresh contact pairs (blank-die surfaces). A vertical machining centre, with vertical and normal force sensors mounted on its spindle, was employed to generate the contact pressure and controlled movement of die samples on sheet blank. Several alternative die materials in coated or uncoated conditions were tested against different AHSS and stainless steel blanks under certain load, sliding velocity, and lubrication circumstances. This paper briefly describes the test system and experimental methodology; and presents wear resistance performance of four different substrate materials namely DC 53, SKD 11, DRM 3, DRM 51 coated with same thermal diffusion (TD) technique. All the die samples were tested against a type of advanced high strength steel (AHSS) which is dual-phase (DP) 600 (UTS is 600 MPa). INTRODUCTION Die wear is an undesired and unpredictable failure and downtime reason in metal forming operations. It directly affects the part formability and surface quality, and causes production loss, cost increase and delays. AISI D2 die material has been a widely used tool steel for various forming applications in the stamping industry. However, it is found to be not suitable for stamping of Advanced High Strength Steel (AHSS) grades (DP, TRIP, etc.) because of excessive wear/galling and toughness issues. Several attempts have been sought to find alternative solutions for die wear issues including development of different die materials, coatings, and surface enhancements. The literature is abundant in terms of various die wear test methods developed for different Transactions of NAMRI/SME 325 Volume 37, 2009 applications and wear conditions. However, they either do not reflect the actual stamping conditions or require special, cumbersome and costly preparations that are not applicable in small spaces such as laboratory environment. For example, in pin-on-disk test Rabinowicz 1995; Blau and Budinski 1999, the die material (in form of a very small pin) is in contact with the same disc surface (sheet metal of interest) during the entire the testing duration, which is not a true representation of the actual stamping operation conditions, because at every stamping stroke the die material gets in contact with new sheet metal surfaces (i.e., virgin surface conditions). In addition, as opposed to the actual stamping conditions, the contact surface area is very small in the pin-on-disk wear tests. SRV (Schwingung Reibung Verschlei: reciprocating friction and wear) tester is one of several configurations of pin-on-disk test systems, and the same surfaces of the die and sheet materials of interest are in contact during the whole test Wan et al. 1995; Hardell 2007. Similarly, the twist-compression test (TCT) Lenard, Medley, and Schey 1996; Costello and Riff 2005 is based on the repeated contact tracks on the same sheet material surface, and it is found to be suitable for comparing the test variables (such as lubricant) rather than obtaining an absolute measure of wear Dalton 2002. Likewise in load-scanner test, a stationary test cylinder is used as a tool sample, and it is contacting with another rotating cylinder which is the sheet material of interest Podgornik, Hogmark, and Pezdirnik 2004. In this test, the same contact surface is scanned repeatedly in every cycle; however, in a real stamping operation a die/punch is in contact with untouched blank surfaces continuously. On the other hand, other wear tests such as (a) strip pulling Attaf et al. 2002; Boher et al. 2005, (b) u-bending/deep drawing Sato and Besshi 1998; Schedin 1994; Nilsson, Gabrielson, and Stahl 2002, (c) strip drawing Schedin 1994; Jonasson et al. 1997; Hortig and Schmoeckel 2001, (d) draw bead Sanchez 1999, (e) combined draw-bead and strip pulling Dalton 2004, and (f) bending under tension or radial strip drawing Schedin 1994; Eriksen 1997 are more representative of the actual stamping conditions; however, they are lengthy (e.g. 15-70 km strip length is needed in combined draw-bead and strip pulling test), costly and require special arrangements such as specially slit coils, large test area and extra equipment like hydraulic clamps, presses, coilers/de-coilers, etc. With an increasing demand to introduce new lightweight materials into the auto body components, newer and alternative die materials, coatings, surface treatment and enhancements, lubricants become necessary to ensure prolonged die life, competitive part cost and consistent high part quality. Accurate and rapid testing of all possible combinations of die material, coating and surface treatment using the existing wear testing methods is not feasible in terms of time, cost and reliability. The main motivation in this study was to establish a test system that provides reliable results, in a rapid manner and also to simulate/control the parameters as much as possible to real conditions. The test system we proposed eliminates the repeated contact surface issues by continuous sweeping of fresh/untouched blank surface by means of tool/die sample. This paper presents the results of a study for which the aim was to investigate the effect of different substrate materials, recently introduced tool steel DC 53, conventional tool steel SKD 11 (equivalence of AISI D2/DIN 1.2379), cold forging tool steel DRM 3, DRM 51, on die wear resistance under stamping conditions of DP 600 AHSS grade sheet blanks. The test system, experimental conditions, die material, and sheet blank properties are presented in detail. Experimental measurements and results are described and conclusions and recommended future work discussed. TEST SYSTEM An alternative die wear test system was developed with the premise of rapid and accurate wear performance assessment of alternative die materials for newer stamping materials. Its earlier design and comparison with existing die wear test methods were discussed in previous work of the authors Cora, Usta, and Ko 2007, a brief description of the updated test system is as follows: This die wear test system is based on the use of precise and controlled motion of a vertical machining centers (Haa VF- 3 CNC) x, y, and z-axes and spindle (no rotation). A load sensor was mounted on the Transactions of NAMRI/SME 326 Volume 37, 2009 spindle through a holder that also houses the die sample of interest. AHSS sheet blanks are laid on the x-y table with clamps at four corners as can be seen in Figure 1. CNC was programmed for the precise pressing of die sample and one- way scratching/sweeping on the AHSS sheet blank. Normal and friction force occurring at the die and blank interface was recorded during the tests. Figure 2 shows the die sample dimension and an actual picture with the wear tracks on the sheet blank. FIGURE 1. TEST SYSTEM. FIGURE 2. DIE SAMPLE DIMENSIONS (TOP) AND ITS ACTUAL PHOTO ON WEAR TRACKS (BOTTOM). Experimental Procedure and Test Materials Each die sample was tested along 2.2 km track distance under an average normal load of 220N with a sliding speed of 0.33 m/s utilizing the above mentioned system. DP 600 (Dual- Phase, 600MPa UTS) sheet blanks of 330 x330 x1mm were used in tests. Chemical compositions for die and sheet blanks, tested material-coating combination, and hardness values for the die samples and sheet blanks are tabulated in Tables 1 through 4. TABLE 1. CHEMICAL COMPOSITIONS OF THE TESTED DIE SAMPLES. Material C Cr Mo W V Cr Mo DC 53 0.95 8 2 - 0.3 8.0 2.0 SKD 11 1.50 12 1 - 0.3 8.0 2.0 DRM 3 0.60 4 2Mo+W 1.0 8.0 2.0 DRM 51 Patent pending by DAIDO TABLE 2. TESTED MATERIAL CONFIGURATION, SUBSTRATE HARDNESS, AND DENSITY VALUES. TABLE 3. TYPICAL CHEMICAL COMPOSITION OF DP600 STEEL SHEET BLANKS Cuddy et al. 2005. TABLE 4. HARDNESS AND AVERAGE SURFACE ROUGHNESS (RA) VALUES FOR DP 600 SHEET BLANK. Die specimens provided by DAIDO Steel Co. Ltd were prepared with the following procedure: First, all the samples are roughly machined before pre-heat treatment. In the heat treatment DC 53 die samples were exposed to gas Substrate material + Coating configuration Substrate Hardness (HRC) Substrate Density (kg/m 3 ) DC 53 + TD Coating 60.4 7870 SKD 11+TD Coating 57.2 7730 DRM 3 +TD Coating 62.7 7920 DRM 51+TD Coating 60.0 7970 Chemical Composition Material Grade C Mn Si Al S P DP 600 0.106 0.800 0.310 0.044 0.005 0.01 Hardness Measured (HV 1 ) Average Surface Roughness Ra (m) 203 0.24 Transactions of NAMRI/SME 327 Volume 37, 2009 quenching at 1030C, then tempered for 1 hour at 550C. After the heat treatment applied; the die samples are machined to final dimensions and polished prior to thermal diffusion (TD) coating process. TD coated samples are heat treated after coating process again for improved performance. The final procedure for the sample preparation is polishing. EXPERIMENTAL RESULTS AND DISCUSSION Performance evaluation of die samples was based on the following measurements (1) mass loss, (2) surface profile (roughness) and (3) microscopic evaluations. To have information about surface roughness, contact surface of die samples are measured with a stylus (Ambios XP-1, Ambios Tech., CA), which is a contact- type of profilometer. All the measurements are taken normal to the sliding direction which was followed during the test. Figures 3 to 6 show the micrographs for contact surfaces of the tested materials before and after tests. Sliding directions were unidentifiable on the contact surfaces except barely visible tracks on DRM 3 sample. FIGURE 3. MICROGRAPHS FOR DC 53 DIE SAMPLE CONTACT SURFACE BEFORE TEST (LEFT) AND AFTER TEST (RIGHT). FIGURE 4. MICROGRAPHS FOR SKD 11 DIE SAMPLE CONTACT SURFACE BEFORE TEST (LEFT) AND AFTER TEST (RIGHT). FIGURE 5. MICROGRAPHS FOR DRM 3 DIE SAMPLE CONTACT SURFACE BEFORE TEST (LEFT) AND AFTER TEST (RIGHT). FIGURE 6. MICROGRAPHS FOR DRM 51 DIE SAMPLE CONTACT SURFACE BEFORE TEST (LEFT) AND AFTER TEST (RIGHT). Specific wear rate (k) was used to asses the wear resistance performance. It is defined as follows: n V k sF = (Eq. 1) where V is wear volume, s stands for sliding distance, F n is applied normal load, and k is for specific wear rate (mm 3 /N.m). The specific wear rates of the test samples are given in Figure 7. The smaller value stands for higher wear resistance and as can be inferred from the table that the performances of the DRM 3 and DRM 51 are close to each other, slightly higher than DC 53, and less than SKD 11. For repetition purposes, 3 replications were performed with the DC 53 sample. Based on good results obtained from replications as depicted in Figure 7, repetitions for other cases were not performed. The coating was not removed from the substrate completely in any replication test, which strengthened the consistency of test results. This test group is one of planned test phases in our test matrix. The effect of different substrate hardness for DC 53 material, effect of different coating types on DC 53 substrate material on wear resistance were investigated prior to this study Cora and Ko 2008a,b. In general, increasing mass losses are expected Transactions of NAMRI/SME 328 Volume 37, 2009 for the same material with the increasing contact normal forces/stresses. It is concluded that the combination of tested substrate material and coating type performed better then the previous tests samples. FIGURE 7. SPECIFIC WEAR RATES FOR TESTED MATERIALS. Tables 5 and 6 show the average and root- mean-square surface roughness values before and after experiments. Similarly, Figure 8 depicts the variation of average surface roughness value (Ra) with error bars. Variation tendency of average and root mean square roughness values is the same and this is an expected situation in most cases. The surface roughness values (Ra,Rq) for die samples contact surfaces are improved when compared with the surface roughness values measured before tests. TABLE 5. AVERAGE SURFACE ROUGHNESS VALUES (Ra) PRIOR TO AND AFTER TESTS. Die sample Ra Before Test (m) Ra After Test (m) DC 53 0.035 0.033 SKD 11 0.032 0.018 DRM 3 0.020 0.014 DRM 51 0.030 0.029 TABLE 6. ROOT-MEAN SQUARE ROUGHNESS VALUES (Rq) BEFORE AND AFTER TESTS. Die sample Rq Before Test (m) Rq After Test (m) DC 53 0.05 0.043 SKD 11 0.048 0.023 DRM 3 0.028 0.019 DRM 51 0.047 0.041 FIGURE 8. VARIATION OF AVERAGE SURFACE ROUGHNESS VALUE FOR TESTED DIE SAMPLES. Improved surface roughness is verified when the evolution of coefficient of friction during the tests is examined. In particular, friction coefficient for SKD 11 die sample was measured as 0.04 (mean value). It is noticed that the friction coefficient decreases with the increasing load. The stability of coefficient of friction can be explained by the lack of coating removal from the substrate and insignificant topography change on the contact surface. SKD 11 is Japanese standard tool steel and is known as equivalent of AISI D2 (DIN 1.2379). It has been one of the most commonly used tool steel materials in cold forming, blanking, trimming, and calibration dies in the past 3-4 decades. When forming of advanced high strength steels are started, using D2 as a tool /die material caused excessive problems in forming the material such as surface quality defects because of excessive wear galling issues. The other experienced problems were shortened tool life, unexpected failures of tools, shutdowns, and production losses consequently. These problems initiated quests for alternative die materials and surface treatment technologies in industry. Several alloyed steels and powder metallurgically produced tool steels have been developed for extended tool life applications without or reduced severe wear problems. As reported in the previous study of the authors Cora and Ko 2008a bare D2 is the least wear resistant tool steel among the tested uncoated alternative die materials. Contrary to weak performance of uncoated D2 tool steels, extended tool lives have been practiced with the coated D2 samples Miller 2008. Similar Transactions of NAMRI/SME 329 Volume 37, 2009 improved performance for the SKD 11 sample was witnessed after the tests. The acceptable upper limit of specific wear rate for engineering sliding surfaces is regarded by some researchers as 1x10 -6 mm 3 /m.N, and all the tested samples performed well above when compared to given value van der Heide et al. 2006. Conclusion and Future Work The effect of substrate material on die wear resistance has been investigated for four different steels against advanced high strength steel sheet blanks of DP 600. The proposed test system enables fast, cost-effective, reliable wear resistance assessment especially for the die materials used in forming of advanced high strength steel sheet blanks. Test results showed that the combination of substrate material and coating technique applied can significantly change the wear resistance compared to performance of the bare/uncoated material. The optimum hardness value for the substrate material and the coating technique applied are the other important factors for improved performance. As can be seen from Table 3, the substrate hardness values for the tested materials varied from 57 to 62 HRc, however, the superiority of the one of tested die sample to another is undistinguishable. It is also worth to mention that TD coating contributed to improved performance of the tested materials as experienced in previous test stages Cora and Ko 2008a,b. In application of TD coating, two separate heat treatments are applied before and after coating process. It is reported by the sample provider that the secondary heat treatment provides higher performance. The future studies will include the effect of lubricated /unlubricated tests, and performance assessment of different lubricants in addition to continuation of testing other alternative die materials. ACKNOWLEDGMENT This study is partially funded by NSF IIP grant #0638588 (NSF I/UCRC Center for Precision Forming). The authors are grateful to International Mold Steel Inc. and Daido Steel Inc. for providing die samples and to US Steel and SSAB for providing AHSS sheet blanks. REFERENCES Attaf, D., L. Penazzi, C. Boher, and C. Levaillant (2002). “Mechanical Study of a Sheet Metal Forming Dies Wear.” Proceedings of the Sixth International Tooling Conference, 1013 September 2002, Karlstad University, Germany. Blau, P.J. and K.G. Budinski (1999). “Development and Use of ASTM Standards for Wear Testing.” Wear Vol. 225-229 pp. 1159- 1170. Boher, C., D. Attaf, L. Penazzi, and C. Levaillant (2005), “Wear Behaviour on the Radius Portion of a Die in Deep-Drawing: Identification, Localisation and Evolution of the Surface Damage.” Wear, Vol. 259, pp. 10971108. Cora, .N., Y. Usta, and M. Ko (2007). “Experimental Investigations on Development of Rapid Die Wear Tests for Stamping of Advanced High Strength Steels.” Proceedings of the 2007 International Manufacturing Science And Engineering Conference - MSEC2007, October 15-17, 2007, Atlanta, Georgia, USA. Cora, .N. and M. 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Schedin (1997). “Comparative Study of Shotblasted and Electrical-discharge-textured Rolls.” Wear, Vol. 207, pp. 34-40. Lenard, J.G., J.B. Medley, and J.A
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