首先想了解不銹鋼沖壓、彎曲和連續沖裁加工工藝,必須要知道以下幾點:


 a. 極限拉深比--拉深加工時,相對于容器直徑d可能拉深的最大原料板直徑為Dmax時,Dmax/d則稱為極限拉深比(LDR).


  b. 平(ping)均(jun)r值--塑性(xing)為(wei)異向性(xing)的(de)材料(liao)深(shen)拉深(shen)成形特性(xing)評(ping)價的(de)重要指標(biao)。鐵素體(ti)系列不(bu)銹鋼中,其平(ping)均(jun)r值越大,其極(ji)限拉深(shen)比就越高。


  c. 拉深皺折-鐵素體(ti)系(xi)列不銹鋼在沖床上(shang)進行深拉深加工(gong)時,在其表(biao)面(mian)上(shang)容易產生凹凸(tu)不平的(de)(de)皺折。可(ke)認(ren)為是組合結(jie)構不同(tong)而引起的(de)(de)塑性(xing)異向性(xing)。


  d. 時(shi)效性(xing)(xing)斷裂(lie)-奧氏(shi)(shi)體系列(lie)不(bu)銹鋼SUS304等(deng)準穩定型奧氏(shi)(shi)體系列(lie)不(bu)銹鋼,在加工后有(you)發生(sheng)時(shi)效性(xing)(xing)裂(lie)紋的現象。它與(yu)晶界晶粒(li)無關。一般認為是由于加工感應(ying)而引起的馬(ma)氏(shi)(shi)體、氫(qing)和殘余應(ying)力(li)所致。



1. 沖壓加工(gong)


    沖(chong)壓加(jia)(jia)工(gong)(gong)(gong)行業(ye)是家庭式作坊工(gong)(gong)(gong)業(ye)的(de)代(dai)表(biao)性產(chan)(chan)業(ye),多是從單獨一(yi)(yi)個一(yi)(yi)個地加(jia)(jia)工(gong)(gong)(gong)西餐具(ju)、器(qi)皿等(deng)(deng)所謂(wei)的(de)“洋人筷子”等(deng)(deng)開始,發展到餐飲業(ye)的(de)廚(chu)房(fang)用(yong)具(ju)以(yi)及廚(chu)房(fang)中所使(shi)(shi)用(yong)的(de)水槽、洗滌盆、深拉(la)深加(jia)(jia)工(gong)(gong)(gong)的(de)澡盆以(yi)及汽車、電機(ji)領域中的(de)零部件等(deng)(deng)。主要工(gong)(gong)(gong)藝方法(fa)是采用(yong)剪切、沖(chong)孔、拉(la)深等(deng)(deng)進行連(lian)續加(jia)(jia)工(gong)(gong)(gong)。洋餐具(ju)、器(qi)皿和(he)鍋的(de)沖(chong)壓加(jia)(jia)工(gong)(gong)(gong),基(ji)本上是屬于圓筒(tong)拉(la)深制成。原材料板(ban)直(zhi)徑(jing)D對容器(qi)(產(chan)(chan)品(pin))直(zhi)徑(jing)d之比(bi),D/d稱(cheng)為(wei)拉(la)深比(bi)。以(yi)可(ke)能拉(la)深的(de)最大原材料板(ban)直(zhi)徑(jing)為(wei)Dmax時,則(ze)Dmax/d稱(cheng)為(wei)極限(xian)拉(la)深比(bi)(LDR: Limiting Drawing Ratio)作為(wei)衡量加(jia)(jia)工(gong)(gong)(gong)性的(de)指(zhi)標。不(bu)銹(xiu)鋼產(chan)(chan)品(pin)得以(yi)大幅度(du)的(de)增(zeng)加(jia)(jia)需(xu)求與沖(chong)壓加(jia)(jia)工(gong)(gong)(gong)技(ji)(ji)術(shu)的(de)發展有很(hen)大關系(xi)。不(bu)銹(xiu)鋼產(chan)(chan)品(pin)生產(chan)(chan)廠家在深拉(la)深加(jia)(jia)工(gong)(gong)(gong)等(deng)(deng)方面,由于塑性加(jia)(jia)工(gong)(gong)(gong)技(ji)(ji)術(shu)和(he)材料技(ji)(ji)術(shu)的(de)進展。使(shi)(shi)得鐵素體系(xi)列不(bu)銹(xiu)鋼高加(jia)(jia)工(gong)(gong)(gong)性鋼種,已經產(chan)(chan)品(pin)化(hua)了。可(ke)以(yi)選定(ding)平均r值在1.2~1.8,LDR為(wei)2.2~2.5的(de)鋼種。


    在不(bu)(bu)銹(xiu)鋼(gang)(gang)制品的沖壓加工中,如(ru)果(guo)使用奧氏體(ti)系列不(bu)(bu)銹(xiu)鋼(gang)(gang)或(huo)鐵素體(ti)系列不(bu)(bu)銹(xiu)鋼(gang)(gang)的高加工性能鋼(gang)(gang)種時,可以進行一(yi)定(ding)程度的深(shen)拉深(shen)加工。奧氏體(ti)系列不(bu)(bu)銹(xiu)鋼(gang)(gang)的代(dai)表型鋼(gang)(gang)種 SUS 304(18Cr -18Ni),因為它(ta)的LDR為2.5,可以進行相對較大的深(shen)拉深(shen)加工。


   但(dan)由于加(jia)工(gong)硬化(hua)傾向(xiang)大而急劇地增加(jia)了(le)加(jia)工(gong)難度,有時(shi)竟發生(sheng)裂(lie)(lie)紋或斷裂(lie)(lie)。為此,沖(chong)壓廠家(jia)就在中間(jian)加(jia)上一道熱處理工(gong)序之后(hou)(hou)再進行深拉(la)深加(jia)工(gong)。還(huan)必須注意(yi),奧氏體(ti)系列不銹(xiu)鋼的奧氏體(ti)穩定度低的鋼種經過拉(la)深后(hou)(hou),有可能發生(sheng)時(shi)效斷裂(lie)(lie)現象。


圖 9.jpg


   近(jin)年來,新潟縣(xian)燕市的(de)沖壓加工(gong)(gong)廠(chang)和新鴻縣(xian)工(gong)(gong)業(ye)技術中(zhong)心共(gong)同開(kai)發(fa)不銹鋼熱(re)沖壓技術,實現了超深(shen)拉深(shen)加工(gong)(gong)。熱(re)沖壓技術就是將凹(ao)模(mo)或者凸(tu)模(mo)其(qi)(qi)中(zhong)之一進行加熱(re),這(zhe)樣(yang)不銹鋼原來的(de)拉深(shen)程度就可以提高1.5~2.0倍。熱(re)沖壓加工(gong)(gong)設備的(de)工(gong)(gong)作原理(li)如(ru)圖6-9所(suo)示(shi)。其(qi)(qi)加工(gong)(gong)特性如(ru)圖6-10所(suo)示(shi)。



2. 彎曲(qu)與連續沖(chong)裁


   奧氏體(ti)系(xi)列不銹(xiu)鋼(gang)(gang)進(jin)行(xing)彎(wan)曲(qu)加(jia)(jia)(jia)(jia)工(gong)(gong)(gong)是件(jian)簡單之事,可以(yi)制作角鋼(gang)(gang)、槽鋼(gang)(gang)等型材(cai)使用。鐵(tie)素體(ti)系(xi)列,馬(ma)(ma)氏體(ti)系(xi)列不銹(xiu)鋼(gang)(gang)作為型材(cai)加(jia)(jia)(jia)(jia)工(gong)(gong)(gong),一(yi)(yi)般情況下(xia)沒有問題(ti),但當彎(wan)曲(qu)半徑(jing)R小的(de)(de)時候,在(zai)(zai)折彎(wan)處有時會發生斷裂。在(zai)(zai)JIS標準中,對(dui)鐵(tie)素體(ti)、馬(ma)(ma)氏體(ti)系(xi)列的(de)(de)不銹(xiu)鋼(gang)(gang)彎(wan)曲(qu)試驗標準規定,彎(wan)曲(qu)半徑(jing)R為1.0t(t為板材(cai)厚度)不應發生彎(wan)曲(qu)斷裂。還有,必須注意(yi)不銹(xiu)鋼(gang)(gang)彎(wan)曲(qu)加(jia)(jia)(jia)(jia)工(gong)(gong)(gong)回彈量(liang)大(da)的(de)(de)特(te)點。落(luo)料(俗稱(cheng)下(xia)料)或(huo)(huo)稱(cheng)為沖(chong)裁加(jia)(jia)(jia)(jia)工(gong)(gong)(gong),大(da)多數是采用沖(chong)床(chuang)連續加(jia)(jia)(jia)(jia)工(gong)(gong)(gong)的(de)(de)方(fang)式,有時在(zai)(zai)沖(chong)切斷面(mian)上,發生塌(ta)邊(bian)現(xian)象(即沖(chong)切面(mian)與基準平面(mian)不垂直)。精(jing)密(mi)(mi)落(luo)料是從變(bian)壓(ya)器等使用疊層的(de)(de)電磁鋼(gang)(gang)板的(de)(de)加(jia)(jia)(jia)(jia)工(gong)(gong)(gong)技(ji)術開展起來(lai)的(de)(de)技(ji)術,對(dui)粒子(zi)加(jia)(jia)(jia)(jia)速器的(de)(de)套環(collar)或(huo)(huo)電子(zi)零部件(jian)中的(de)(de)引(yin)線(xian)框(kuang)(lead frame)等等,從較厚的(de)(de)板材(cai)到超薄(bo)材(cai),精(jing)密(mi)(mi)落(luo)料得到廣泛應用。沖(chong)壓(ya)加(jia)(jia)(jia)(jia)工(gong)(gong)(gong)機(ji)械(xie)亦可以(yi)進(jin)行(xing)精(jing)密(mi)(mi)沖(chong)壓(ya)(落(luo)料)加(jia)(jia)(jia)(jia)工(gong)(gong)(gong),但由于沖(chong)壓(ya)塌(ta)邊(bian)的(de)(de)問題(ti),一(yi)(yi)般不能作為成品(pin)(pin)直接使用。在(zai)(zai)精(jing)密(mi)(mi)沖(chong)壓(ya)中,為控制塌(ta)邊(bian),就需加(jia)(jia)(jia)(jia)一(yi)(yi)道機(ji)械(xie)控制的(de)(de)工(gong)(gong)(gong)藝措施,這需要按(an)產品(pin)(pin)用途(tu)以(yi)及(ji)成本兩方(fang)面(mian)來(lai)權衡。在(zai)(zai)加(jia)(jia)(jia)(jia)工(gong)(gong)(gong)方(fang)法競爭上,還有一(yi)(yi)種“蝕刻”方(fang)法,在(zai)(zai)電子(zi)產品(pin)(pin)的(de)(de)接線(xian)框(kuang)等超薄(bo)產品(pin)(pin)中,在(zai)(zai)加(jia)(jia)(jia)(jia)工(gong)(gong)(gong)廠家的(de)(de)技(ji)術競爭中,兩者幾乎各占一(yi)(yi)半。


 

 3. 加工油、表面保(bao)護薄膜和其他潤滑


   a. 表面保護薄膜-為了保持不銹鋼的(de)匠藝性、防止產生瑕(xia)疵(ci)以及作為潤滑而敷于材料表面的(de)聚氯乙烯或(huo)聚乙烯等薄膜。


   b. 揮(hui)發(fa)性加工油(you)--加工時有潤(run)滑效果而后又能(neng)揮(hui)發(fa)掉的(de)加工油(you)。使用完全(quan)揮(hui)發(fa)型的(de),可以省掉清洗(xi)工序(xu)。


    c. 潤滑(hua)不銹鋼板-具有透明石蠟涂裝的(de)不銹鋼,它(ta)比(bi)加(jia)(jia)工油或(huo)表面(mian)保護膜(mo)有更好的(de)加(jia)(jia)工性(xing)。


   在(zai)(zai)沖(chong)床上進(jin)行不(bu)銹(xiu)鋼(gang)板(ban)彎曲、沖(chong)裁(cai)(落料(liao))等加(jia)(jia)工(gong)時,可使(shi)用(yong)(yong)(yong)加(jia)(jia)工(gong)油(you)、表(biao)(biao)(biao)面保(bao)(bao)(bao)護(hu)(hu)薄(bo)膜(mo)(mo)或直接使(shi)用(yong)(yong)(yong)潤滑鋼(gang)板(ban)。在(zai)(zai)表(biao)(biao)(biao)6-1中,對(dui)加(jia)(jia)工(gong)油(you)、表(biao)(biao)(biao)面保(bao)(bao)(bao)護(hu)(hu)薄(bo)膜(mo)(mo)和潤滑鋼(gang)板(ban)進(jin)行比較。表(biao)(biao)(biao)面保(bao)(bao)(bao)護(hu)(hu)薄(bo)膜(mo)(mo)是(shi)不(bu)銹(xiu)鋼(gang)保(bao)(bao)(bao)持匠藝性的(de)一項(xiang)重要(yao)措施。所用(yong)(yong)(yong)樹(shu)脂(zhi)為聚氯乙烯(xi)系列(lie)或聚乙烯(xi)系列(lie)。材(cai)料(liao)運轉自始至終都是(shi)用(yong)(yong)(yong)表(biao)(biao)(biao)面保(bao)(bao)(bao)護(hu)(hu)薄(bo)膜(mo)(mo)對(dui)材(cai)料(liao)表(biao)(biao)(biao)面施行保(bao)(bao)(bao)護(hu)(hu)。使(shi)用(yong)(yong)(yong)表(biao)(biao)(biao)面保(bao)(bao)(bao)護(hu)(hu)薄(bo)膜(mo)(mo),最容(rong)易(yi)發(fa)生的(de)問(wen)題就(jiu)是(shi)殘留糊狀(zhuang)物,貼附后長期保(bao)(bao)(bao)存在(zai)(zai)倉庫內的(de)或者是(shi)不(bu)具備耐候(hou)性能的(de)薄(bo)膜(mo)(mo)放置在(zai)(zai)室外的(de),則容(rong)易(yi)發(fa)生損壞。表(biao)(biao)(biao)面保(bao)(bao)(bao)護(hu)(hu)薄(bo)膜(mo)(mo)要(yao)根據用(yong)(yong)(yong)途和加(jia)(jia)工(gong)方法選定(ding)。主要(yao)廠家生產的(de)表(biao)(biao)(biao)面保(bao)(bao)(bao)護(hu)(hu)薄(bo)膜(mo)(mo)性能及其有關事項(xiang)如(ru)表(biao)(biao)(biao)6-2所示。不(bu)使(shi)用(yong)(yong)(yong)表(biao)(biao)(biao)面保(bao)(bao)(bao)護(hu)(hu)薄(bo)膜(mo)(mo)時,一般情況下(xia)要(yao)使(shi)用(yong)(yong)(yong)加(jia)(jia)工(gong)油(you)。當使(shi)用(yong)(yong)(yong)加(jia)(jia)工(gong)油(you)加(jia)(jia)工(gong)后,需進(jin)行洗凈(jing)。洗凈(jing)的(de)方法有多種,最近(jin)在(zai)(zai)保(bao)(bao)(bao)護(hu)(hu)地球環(huan)境問(wen)題當中,規定(ding)了保(bao)(bao)(bao)護(hu)(hu)環(huan)境條例(li),對(dui)于破壞臭(chou)氧層的(de)清洗劑做出(chu)了限制。


表 1.jpg

表 2.jpg


 因此,當使(shi)用加(jia)工(gong)(gong)(gong)(gong)油(you)(you)(you)時,要(yao)考慮到洗(xi)凈(jing)和(he)存(cun)放問(wen)題。在(zai)加(jia)工(gong)(gong)(gong)(gong)油(you)(you)(you)選(xuan)(xuan)定方面,從前認為(wei)由于不銹鋼(gang)(gang)硬度比(bi)(bi)普通(tong)鋼(gang)(gang)要(yao)高(gao),加(jia)工(gong)(gong)(gong)(gong)不銹鋼(gang)(gang)比(bi)(bi)普通(tong)鋼(gang)(gang)困難(nan),所以(yi)要(yao)選(xuan)(xuan)用有黏(nian)性(xing)的(de)(de)(de)加(jia)工(gong)(gong)(gong)(gong)油(you)(you)(you)。具有黏(nian)性(xing)的(de)(de)(de)加(jia)工(gong)(gong)(gong)(gong)油(you)(you)(you)往(wang)往(wang)是(shi)黏(nian)糊(hu)糊(hu)的(de)(de)(de),在(zai)加(jia)工(gong)(gong)(gong)(gong)過程(cheng)中不但(dan)變黑而且難(nan)以(yi)清(qing)洗(xi)。另外,其(qi)中多數(shu)情況下加(jia)入氯系(xi)列(lie)添加(jia)劑。因此,更有必要(yao)進行(xing)充分地清(qing)洗(xi)。近年來,開(kai)發(fa)(fa)了許多水溶性(xing)加(jia)工(gong)(gong)(gong)(gong)油(you)(you)(you),在(zai)深拉(la)深等加(jia)工(gong)(gong)(gong)(gong)中,其(qi)潤滑性(xing)堪比(bi)(bi)原用油(you)(you)(you)性(xing)的(de)(de)(de)加(jia)工(gong)(gong)(gong)(gong)油(you)(you)(you)。水溶性(xing)加(jia)工(gong)(gong)(gong)(gong)油(you)(you)(you)比(bi)(bi)較容(rong)易(yi)清(qing)洗(xi),應(ying)用效果很好。作為(wei)新技術,雖(sui)然(ran)加(jia)工(gong)(gong)(gong)(gong)條件受到某種(zhong)程(cheng)度的(de)(de)(de)限制,免清(qing)洗(xi)的(de)(de)(de)揮發(fa)(fa)型加(jia)工(gong)(gong)(gong)(gong)油(you)(you)(you)仍(reng)得到推(tui)廣。


  在揮發(fa)性(xing)加(jia)工油(you)(you)中(zhong),有完(wan)全(quan)揮發(fa)型(xing)和(he)部分殘留(liu)型(xing)等產品。需(xu)根據加(jia)工條件選擇,使(shi)用(yong)完(wan)全(quan)揮發(fa)型(xing)的(de)可以省掉加(jia)工后(hou)的(de)清洗(xi)。在家電生產廠中(zhong),沖制全(quan)自動洗(xi)衣機(ji)不銹鋼(gang)洗(xi)衣桶時就是(shi)采用(yong)完(wan)全(quan)揮發(fa)型(xing)加(jia)工油(you)(you)。在其他領域中(zhong),完(wan)全(quan)揮發(fa)型(xing)加(jia)工油(you)(you)已實際運用(yong)到沖孔、內緣翻邊、壓制筋板、彎(wan)曲和(he)卷(juan)邊等沖壓工藝中(zhong)。


表 3.jpg


  由于(yu)使用揮(hui)發(fa)性(xing)加(jia)(jia)(jia)工(gong)(gong)(gong)(gong)油(you)(you)可以(yi)省掉清洗工(gong)(gong)(gong)(gong)序,在(zai)流水(shui)加(jia)(jia)(jia)工(gong)(gong)(gong)(gong)作業(ye)線上(shang)使用,可以(yi)降低成本。主要生產(chan)廠家的(de)揮(hui)發(fa)性(xing)加(jia)(jia)(jia)工(gong)(gong)(gong)(gong)油(you)(you)產(chan)品如(ru)表6-3所示。如(ru)將揮(hui)發(fa)性(xing)加(jia)(jia)(jia)工(gong)(gong)(gong)(gong)油(you)(you)的(de)涂敷(fu)方式和(he)加(jia)(jia)(jia)工(gong)(gong)(gong)(gong)條件進(jin)(jin)行改(gai)進(jin)(jin)時,即可以(yi)完全省掉清洗工(gong)(gong)(gong)(gong)作。但是,揮(hui)發(fa)性(xing)加(jia)(jia)(jia)工(gong)(gong)(gong)(gong)油(you)(you)涂敷(fu)方式、加(jia)(jia)(jia)工(gong)(gong)(gong)(gong)條件及加(jia)(jia)(jia)工(gong)(gong)(gong)(gong)夾具的(de)質(zhi)量管理(li)不(bu)善時,由于(yu)加(jia)(jia)(jia)工(gong)(gong)(gong)(gong)夾具的(de)磨損等(deng)可能產(chan)生對不(bu)銹(xiu)(xiu)鋼的(de)鐵(tie)粉銹(xiu)(xiu)蝕事(shi)故。關于(yu)鐵(tie)粉銹(xiu)(xiu)蝕檢(jian)查方法,可參照本書后部章節中的(de)“使用時注意重占日惠執(zhi)處理(li)”由的(de)說明。


先(xian)前在沖壓加(jia)工過(guo)程中(zhong)使用加(jia)工油。為(wei)了洗凈這(zhe)(zhe)些加(jia)工油而使用了破壞臭(chou)氧層的(de)三氯(lv)(lv)乙烷,三氯(lv)(lv)乙烯等。后(hou)來(lai),洗凈方法改為(wei)堿性洗凈方法。在1995年,考慮到保護地球環境問(wen)題,開發了潤(run)滑(hua)(hua)(hua)不(bu)(bu)銹(xiu)(xiu)鋼(gang)板。在汽車(che)、電機、燃氣(qi)器具領域中(zhong),積極推廣了省掉清洗工序的(de)潤(run)滑(hua)(hua)(hua)不(bu)(bu)銹(xiu)(xiu)鋼(gang)板。特別是(shi)在汽車(che)領域中(zhong)的(de)排(pai)氣(qi)分支管的(de)不(bu)(bu)銹(xiu)(xiu)鋼(gang)化過(guo)程中(zhong),實踐證明,加(jia)工這(zhe)(zhe)種(zhong)形狀復雜的(de)工件,認(ren)為(wei)潤(run)滑(hua)(hua)(hua)不(bu)(bu)銹(xiu)(xiu)鋼(gang)板比以前使用潤(run)滑(hua)(hua)(hua)油的(de)加(jia)工性更優越。所以,潤(run)滑(hua)(hua)(hua)不(bu)(bu)銹(xiu)(xiu)鋼(gang)板的(de)需要量(liang)大幅(fu)度增加(jia)。


表 4.jpg


  潤(run)滑不銹(xiu)(xiu)鋼(gang)板,根據用途(tu)亦有不涂薄膜(mo)(mo)的(de)。非(fei)脫(tuo)膜(mo)(mo)型(xing)和(he)脫(tuo)膜(mo)(mo)型(xing)兩類(lei)已經(jing)產品化了(le)。潤(run)滑不銹(xiu)(xiu)鋼(gang)板種類(lei)和(he)特性如(ru)表6-4所示(shi)。在建筑材(cai)料領域中,使用潤(run)滑不銹(xiu)(xiu)鋼(gang)板做屋頂時,非(fei)脫(tuo)膜(mo)(mo)型(xing)和(he)脫(tuo)膜(mo)(mo)型(xing)一樣(yang),其薄膜(mo)(mo)經(jing)過1~2年的(de)紫外線照射就消失(shi)了(le)。作為工(gong)(gong)程實例,用于西(xi)武百貨大樓(lou)和(he)福岡機場(chang)候(hou)機大廳。實踐證明,潤(run)滑不銹(xiu)(xiu)鋼(gang)板的(de)加工(gong)(gong)性比加工(gong)(gong)油還要優越,見表6-5。


  不(bu)銹鋼板生(sheng)產廠家的(de)潤滑不(bu)銹鋼板產品,在透明(ming)涂裝不(bu)銹鋼項(xiang)目中有介紹。