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. 平均(jun)r值--塑性為異向性的材(cai)料深拉深成(cheng)形特性評價(jia)的重要指(zhi)標。鐵素體系列不銹鋼中,其(qi)平均(jun)r值越大,其(qi)極限(xian)拉深比就越高。


  c. 拉(la)深皺折(zhe)-鐵素(su)體系列不(bu)(bu)銹鋼在沖床(chuang)上進行深拉(la)深加工(gong)時,在其表(biao)面上容易產生(sheng)凹凸不(bu)(bu)平的皺折(zhe)。可認為是(shi)組合結構不(bu)(bu)同而引起的塑性異(yi)向性。


  d. 時(shi)效(xiao)性(xing)斷裂-奧氏體系(xi)列不(bu)銹(xiu)鋼SUS304等(deng)準穩定型奧氏體系(xi)列不(bu)銹(xiu)鋼,在加工后有發生時(shi)效(xiao)性(xing)裂紋的(de)現(xian)象(xiang)。它與晶界晶粒無關。一般認(ren)為是由于加工感應而(er)引起(qi)的(de)馬氏體、氫和殘余應力所致。



1. 沖壓加工


    沖(chong)壓(ya)加(jia)(jia)(jia)(jia)工(gong)(gong)(gong)(gong)(gong)行業(ye)是家庭式作坊工(gong)(gong)(gong)(gong)(gong)業(ye)的代(dai)表性產(chan)業(ye),多是從單獨(du)一個一個地加(jia)(jia)(jia)(jia)工(gong)(gong)(gong)(gong)(gong)西餐具(ju)、器(qi)(qi)皿(min)等(deng)所謂的“洋人筷(kuai)子”等(deng)開始,發(fa)展(zhan)到餐飲業(ye)的廚房用具(ju)以(yi)及廚房中所使(shi)用的水槽、洗滌盆、深(shen)拉(la)深(shen)加(jia)(jia)(jia)(jia)工(gong)(gong)(gong)(gong)(gong)的澡盆以(yi)及汽車、電機領域中的零部(bu)件等(deng)。主要工(gong)(gong)(gong)(gong)(gong)藝方法(fa)是采用剪切(qie)、沖(chong)孔、拉(la)深(shen)等(deng)進(jin)(jin)行連續加(jia)(jia)(jia)(jia)工(gong)(gong)(gong)(gong)(gong)。洋餐具(ju)、器(qi)(qi)皿(min)和(he)鍋的沖(chong)壓(ya)加(jia)(jia)(jia)(jia)工(gong)(gong)(gong)(gong)(gong),基本上是屬于圓筒拉(la)深(shen)制成。原(yuan)材料(liao)板直(zhi)徑(jing)D對容(rong)器(qi)(qi)(產(chan)品)直(zhi)徑(jing)d之比(bi),D/d稱(cheng)為(wei)拉(la)深(shen)比(bi)。以(yi)可能(neng)拉(la)深(shen)的最大原(yuan)材料(liao)板直(zhi)徑(jing)為(wei)Dmax時,則(ze)Dmax/d稱(cheng)為(wei)極限拉(la)深(shen)比(bi)(LDR: Limiting Drawing Ratio)作為(wei)衡量加(jia)(jia)(jia)(jia)工(gong)(gong)(gong)(gong)(gong)性的指標。不銹鋼(gang)產(chan)品得(de)以(yi)大幅度的增(zeng)加(jia)(jia)(jia)(jia)需求(qiu)與沖(chong)壓(ya)加(jia)(jia)(jia)(jia)工(gong)(gong)(gong)(gong)(gong)技(ji)術的發(fa)展(zhan)有很(hen)大關系(xi)。不銹鋼(gang)產(chan)品生產(chan)廠家在(zai)深(shen)拉(la)深(shen)加(jia)(jia)(jia)(jia)工(gong)(gong)(gong)(gong)(gong)等(deng)方面,由于塑(su)性加(jia)(jia)(jia)(jia)工(gong)(gong)(gong)(gong)(gong)技(ji)術和(he)材料(liao)技(ji)術的進(jin)(jin)展(zhan)。使(shi)得(de)鐵(tie)素體系(xi)列不銹鋼(gang)高加(jia)(jia)(jia)(jia)工(gong)(gong)(gong)(gong)(gong)性鋼(gang)種(zhong)(zhong),已(yi)經產(chan)品化了。可以(yi)選定平均r值在(zai)1.2~1.8,LDR為(wei)2.2~2.5的鋼(gang)種(zhong)(zhong)。


    在不(bu)銹鋼(gang)制(zhi)品的(de)沖(chong)壓(ya)加(jia)工中,如果使用奧(ao)氏體(ti)系列(lie)不(bu)銹鋼(gang)或鐵素體(ti)系列(lie)不(bu)銹鋼(gang)的(de)高加(jia)工性(xing)能鋼(gang)種時(shi),可以進行(xing)一定(ding)程度的(de)深(shen)拉深(shen)加(jia)工。奧(ao)氏體(ti)系列(lie)不(bu)銹鋼(gang)的(de)代表型鋼(gang)種 SUS 304(18Cr -18Ni),因為它(ta)的(de)LDR為2.5,可以進行(xing)相對較(jiao)大(da)的(de)深(shen)拉深(shen)加(jia)工。


   但由(you)于加(jia)(jia)(jia)工(gong)(gong)硬化傾向大而急劇地(di)增(zeng)加(jia)(jia)(jia)了加(jia)(jia)(jia)工(gong)(gong)難度,有時竟發(fa)生裂紋或斷裂。為(wei)此,沖壓(ya)廠家就在中間(jian)加(jia)(jia)(jia)上一(yi)道(dao)熱處理工(gong)(gong)序之后再進行深(shen)拉深(shen)加(jia)(jia)(jia)工(gong)(gong)。還必(bi)須注意,奧氏體(ti)系(xi)列不銹鋼(gang)的奧氏體(ti)穩定度低的鋼(gang)種(zhong)經過拉深(shen)后,有可能發(fa)生時效斷裂現象。


圖 9.jpg


   近年來(lai),新潟(xi)縣(xian)燕市(shi)的(de)(de)沖壓加(jia)工(gong)廠和新鴻縣(xian)工(gong)業技術(shu)中(zhong)心共同(tong)開發不銹鋼(gang)熱沖壓技術(shu),實(shi)現了超深(shen)拉深(shen)加(jia)工(gong)。熱沖壓技術(shu)就(jiu)是將凹模或(huo)者凸模其(qi)中(zhong)之一(yi)進行加(jia)熱,這樣不銹鋼(gang)原來(lai)的(de)(de)拉深(shen)程度就(jiu)可(ke)以(yi)提(ti)高1.5~2.0倍(bei)。熱沖壓加(jia)工(gong)設備的(de)(de)工(gong)作原理如(ru)圖6-9所示。其(qi)加(jia)工(gong)特性(xing)如(ru)圖6-10所示。



2. 彎曲與連續(xu)沖裁


   奧(ao)氏體(ti)系(xi)(xi)(xi)列(lie)不(bu)銹(xiu)鋼(gang)進(jin)行(xing)彎(wan)曲(qu)(qu)(qu)加(jia)(jia)(jia)(jia)工是件(jian)簡單之事,可以(yi)(yi)制(zhi)作角鋼(gang)、槽鋼(gang)等(deng)(deng)型材(cai)使(shi)用(yong)。鐵(tie)素體(ti)系(xi)(xi)(xi)列(lie),馬(ma)氏體(ti)系(xi)(xi)(xi)列(lie)不(bu)銹(xiu)鋼(gang)作為(wei)(wei)(wei)型材(cai)加(jia)(jia)(jia)(jia)工,一般情(qing)況(kuang)下沒有(you)(you)問題(ti),但當(dang)彎(wan)曲(qu)(qu)(qu)半(ban)徑R小的(de)(de)時候(hou),在(zai)(zai)折彎(wan)處(chu)有(you)(you)時會發生(sheng)斷裂(lie)。在(zai)(zai)JIS標(biao)準(zhun)中(zhong),對(dui)鐵(tie)素體(ti)、馬(ma)氏體(ti)系(xi)(xi)(xi)列(lie)的(de)(de)不(bu)銹(xiu)鋼(gang)彎(wan)曲(qu)(qu)(qu)試(shi)驗(yan)標(biao)準(zhun)規(gui)定,彎(wan)曲(qu)(qu)(qu)半(ban)徑R為(wei)(wei)(wei)1.0t(t為(wei)(wei)(wei)板材(cai)厚(hou)(hou)度(du))不(bu)應發生(sheng)彎(wan)曲(qu)(qu)(qu)斷裂(lie)。還(huan)有(you)(you),必須注(zhu)意不(bu)銹(xiu)鋼(gang)彎(wan)曲(qu)(qu)(qu)加(jia)(jia)(jia)(jia)工回(hui)彈量(liang)大的(de)(de)特點。落(luo)料(liao)(俗稱(cheng)下料(liao))或稱(cheng)為(wei)(wei)(wei)沖(chong)裁加(jia)(jia)(jia)(jia)工,大多(duo)數(shu)是采用(yong)沖(chong)床(chuang)連續加(jia)(jia)(jia)(jia)工的(de)(de)方式,有(you)(you)時在(zai)(zai)沖(chong)切斷面上,發生(sheng)塌(ta)邊現(xian)象(即沖(chong)切面與基準(zhun)平面不(bu)垂直)。精密落(luo)料(liao)是從(cong)(cong)變壓(ya)(ya)器等(deng)(deng)使(shi)用(yong)疊層的(de)(de)電(dian)磁鋼(gang)板的(de)(de)加(jia)(jia)(jia)(jia)工技(ji)術開展起來(lai)的(de)(de)技(ji)術,對(dui)粒(li)子(zi)加(jia)(jia)(jia)(jia)速器的(de)(de)套環(huan)(collar)或電(dian)子(zi)零部(bu)件(jian)中(zhong)的(de)(de)引線框(lead frame)等(deng)(deng)等(deng)(deng),從(cong)(cong)較厚(hou)(hou)的(de)(de)板材(cai)到超薄(bo)材(cai),精密落(luo)料(liao)得到廣泛應用(yong)。沖(chong)壓(ya)(ya)加(jia)(jia)(jia)(jia)工機(ji)械亦可以(yi)(yi)進(jin)行(xing)精密沖(chong)壓(ya)(ya)(落(luo)料(liao))加(jia)(jia)(jia)(jia)工,但由于沖(chong)壓(ya)(ya)塌(ta)邊的(de)(de)問題(ti),一般不(bu)能作為(wei)(wei)(wei)成品(pin)直接(jie)使(shi)用(yong)。在(zai)(zai)精密沖(chong)壓(ya)(ya)中(zhong),為(wei)(wei)(wei)控(kong)制(zhi)塌(ta)邊,就需(xu)加(jia)(jia)(jia)(jia)一道機(ji)械控(kong)制(zhi)的(de)(de)工藝措施(shi),這需(xu)要按(an)產(chan)品(pin)用(yong)途以(yi)(yi)及成本(ben)兩(liang)方面來(lai)權衡。在(zai)(zai)加(jia)(jia)(jia)(jia)工方法競(jing)爭上,還(huan)有(you)(you)一種(zhong)“蝕刻”方法,在(zai)(zai)電(dian)子(zi)產(chan)品(pin)的(de)(de)接(jie)線框等(deng)(deng)超薄(bo)產(chan)品(pin)中(zhong),在(zai)(zai)加(jia)(jia)(jia)(jia)工廠家的(de)(de)技(ji)術競(jing)爭中(zhong),兩(liang)者幾乎各(ge)占(zhan)一半(ban)。


 

 3. 加工油、表面保護薄膜和其他潤滑


   a. 表面保護(hu)薄膜(mo)-為(wei)了保持不銹鋼的(de)匠藝性、防止產生瑕疵以及作為(wei)潤滑而敷于(yu)材料表面的(de)聚(ju)氯乙(yi)烯或(huo)聚(ju)乙(yi)烯等(deng)薄膜(mo)。


   b. 揮(hui)發(fa)性加(jia)工(gong)油--加(jia)工(gong)時(shi)有潤(run)滑效果而后又(you)能揮(hui)發(fa)掉(diao)的加(jia)工(gong)油。使用完全揮(hui)發(fa)型的,可以省(sheng)掉(diao)清洗工(gong)序(xu)。


    c. 潤滑(hua)不銹(xiu)鋼板-具有透明(ming)石蠟(la)涂裝的不銹(xiu)鋼,它比(bi)加(jia)工油或表面保護(hu)膜有更好的加(jia)工性。


   在(zai)沖床上進行(xing)不(bu)(bu)銹(xiu)鋼(gang)板(ban)彎(wan)曲、沖裁(落(luo)料(liao))等加(jia)(jia)(jia)工(gong)(gong)(gong)(gong)(gong)時,可使(shi)用(yong)(yong)加(jia)(jia)(jia)工(gong)(gong)(gong)(gong)(gong)油(you)、表(biao)面(mian)(mian)保(bao)護(hu)(hu)(hu)(hu)薄(bo)膜(mo)(mo)(mo)或直接使(shi)用(yong)(yong)潤滑(hua)鋼(gang)板(ban)。在(zai)表(biao)6-1中,對加(jia)(jia)(jia)工(gong)(gong)(gong)(gong)(gong)油(you)、表(biao)面(mian)(mian)保(bao)護(hu)(hu)(hu)(hu)薄(bo)膜(mo)(mo)(mo)和潤滑(hua)鋼(gang)板(ban)進行(xing)比較。表(biao)面(mian)(mian)保(bao)護(hu)(hu)(hu)(hu)薄(bo)膜(mo)(mo)(mo)是(shi)不(bu)(bu)銹(xiu)鋼(gang)保(bao)持(chi)匠(jiang)藝性的(de)一(yi)項重要措施。所(suo)用(yong)(yong)樹脂為聚氯乙(yi)(yi)烯系(xi)列或聚乙(yi)(yi)烯系(xi)列。材料(liao)運(yun)轉自始至終都是(shi)用(yong)(yong)表(biao)面(mian)(mian)保(bao)護(hu)(hu)(hu)(hu)薄(bo)膜(mo)(mo)(mo)對材料(liao)表(biao)面(mian)(mian)施行(xing)保(bao)護(hu)(hu)(hu)(hu)。使(shi)用(yong)(yong)表(biao)面(mian)(mian)保(bao)護(hu)(hu)(hu)(hu)薄(bo)膜(mo)(mo)(mo),最(zui)容易發生的(de)問題就是(shi)殘(can)留糊狀物,貼附后(hou)長期保(bao)存(cun)在(zai)倉庫(ku)內的(de)或者是(shi)不(bu)(bu)具備耐(nai)候性能的(de)薄(bo)膜(mo)(mo)(mo)放置在(zai)室(shi)外(wai)的(de),則(ze)容易發生損壞。表(biao)面(mian)(mian)保(bao)護(hu)(hu)(hu)(hu)薄(bo)膜(mo)(mo)(mo)要根(gen)據(ju)用(yong)(yong)途和加(jia)(jia)(jia)工(gong)(gong)(gong)(gong)(gong)方法選定。主要廠家生產的(de)表(biao)面(mian)(mian)保(bao)護(hu)(hu)(hu)(hu)薄(bo)膜(mo)(mo)(mo)性能及(ji)其有關事項如表(biao)6-2所(suo)示。不(bu)(bu)使(shi)用(yong)(yong)表(biao)面(mian)(mian)保(bao)護(hu)(hu)(hu)(hu)薄(bo)膜(mo)(mo)(mo)時,一(yi)般情況下要使(shi)用(yong)(yong)加(jia)(jia)(jia)工(gong)(gong)(gong)(gong)(gong)油(you)。當使(shi)用(yong)(yong)加(jia)(jia)(jia)工(gong)(gong)(gong)(gong)(gong)油(you)加(jia)(jia)(jia)工(gong)(gong)(gong)(gong)(gong)后(hou),需進行(xing)洗凈。洗凈的(de)方法有多種,最(zui)近在(zai)保(bao)護(hu)(hu)(hu)(hu)地球環(huan)境問題當中,規定了(le)保(bao)護(hu)(hu)(hu)(hu)環(huan)境條(tiao)例,對于(yu)破(po)壞臭(chou)氧層(ceng)的(de)清洗劑做出了(le)限制。


表 1.jpg

表 2.jpg


 因此(ci),當使用(yong)(yong)加(jia)(jia)(jia)(jia)工(gong)(gong)油(you)(you)(you)時(shi),要考慮到(dao)洗(xi)(xi)(xi)凈和存放(fang)問題。在(zai)加(jia)(jia)(jia)(jia)工(gong)(gong)油(you)(you)(you)選(xuan)定方面,從前認為由于不(bu)銹鋼(gang)(gang)硬度比普(pu)(pu)通(tong)鋼(gang)(gang)要高,加(jia)(jia)(jia)(jia)工(gong)(gong)不(bu)銹鋼(gang)(gang)比普(pu)(pu)通(tong)鋼(gang)(gang)困難,所以要選(xuan)用(yong)(yong)有黏性的(de)加(jia)(jia)(jia)(jia)工(gong)(gong)油(you)(you)(you)。具有黏性的(de)加(jia)(jia)(jia)(jia)工(gong)(gong)油(you)(you)(you)往往是黏糊(hu)(hu)糊(hu)(hu)的(de),在(zai)加(jia)(jia)(jia)(jia)工(gong)(gong)過程中(zhong)不(bu)但變(bian)黑而(er)且難以清洗(xi)(xi)(xi)。另外(wai),其中(zhong)多(duo)數情況下加(jia)(jia)(jia)(jia)入氯(lv)系列添加(jia)(jia)(jia)(jia)劑。因此(ci),更有必要進(jin)行充(chong)分地清洗(xi)(xi)(xi)。近(jin)年(nian)來,開發(fa)了許多(duo)水溶(rong)性加(jia)(jia)(jia)(jia)工(gong)(gong)油(you)(you)(you),在(zai)深(shen)拉深(shen)等加(jia)(jia)(jia)(jia)工(gong)(gong)中(zhong),其潤(run)滑性堪(kan)比原用(yong)(yong)油(you)(you)(you)性的(de)加(jia)(jia)(jia)(jia)工(gong)(gong)油(you)(you)(you)。水溶(rong)性加(jia)(jia)(jia)(jia)工(gong)(gong)油(you)(you)(you)比較容(rong)易清洗(xi)(xi)(xi),應用(yong)(yong)效果很(hen)好。作(zuo)為新技術(shu),雖然加(jia)(jia)(jia)(jia)工(gong)(gong)條件受到(dao)某(mou)種程度的(de)限制,免清洗(xi)(xi)(xi)的(de)揮發(fa)型加(jia)(jia)(jia)(jia)工(gong)(gong)油(you)(you)(you)仍得(de)到(dao)推廣。


  在(zai)揮發(fa)(fa)性(xing)加工(gong)油中(zhong)(zhong),有完全(quan)揮發(fa)(fa)型(xing)和(he)部分殘留型(xing)等產品。需根(gen)據加工(gong)條件選擇,使用(yong)完全(quan)揮發(fa)(fa)型(xing)的(de)可以省(sheng)掉加工(gong)后的(de)清(qing)洗。在(zai)家電生產廠中(zhong)(zhong),沖(chong)制全(quan)自動洗衣(yi)機不銹(xiu)鋼洗衣(yi)桶(tong)時就是(shi)采用(yong)完全(quan)揮發(fa)(fa)型(xing)加工(gong)油。在(zai)其他領域中(zhong)(zhong),完全(quan)揮發(fa)(fa)型(xing)加工(gong)油已實(shi)際運用(yong)到沖(chong)孔、內緣翻邊、壓(ya)(ya)制筋板、彎(wan)曲(qu)和(he)卷(juan)邊等沖(chong)壓(ya)(ya)工(gong)藝(yi)中(zhong)(zhong)。


表 3.jpg


  由(you)于(yu)使用(yong)揮(hui)發(fa)性加(jia)(jia)工(gong)油(you)可(ke)(ke)以(yi)省掉清洗工(gong)序(xu),在流(liu)水(shui)加(jia)(jia)工(gong)作(zuo)業線上使用(yong),可(ke)(ke)以(yi)降低成(cheng)本。主(zhu)要生(sheng)(sheng)產廠家的(de)(de)揮(hui)發(fa)性加(jia)(jia)工(gong)油(you)產品如(ru)表(biao)6-3所示。如(ru)將揮(hui)發(fa)性加(jia)(jia)工(gong)油(you)的(de)(de)涂敷方式和加(jia)(jia)工(gong)條件(jian)進(jin)行改進(jin)時,即可(ke)(ke)以(yi)完(wan)全省掉清洗工(gong)作(zuo)。但(dan)是,揮(hui)發(fa)性加(jia)(jia)工(gong)油(you)涂敷方式、加(jia)(jia)工(gong)條件(jian)及加(jia)(jia)工(gong)夾具的(de)(de)質量管理不(bu)善時,由(you)于(yu)加(jia)(jia)工(gong)夾具的(de)(de)磨(mo)損等可(ke)(ke)能(neng)產生(sheng)(sheng)對不(bu)銹(xiu)(xiu)鋼的(de)(de)鐵(tie)粉銹(xiu)(xiu)蝕事故。關于(yu)鐵(tie)粉銹(xiu)(xiu)蝕檢查方法,可(ke)(ke)參(can)照本書后(hou)部(bu)章節中的(de)(de)“使用(yong)時注(zhu)意重(zhong)占日(ri)惠(hui)執處理”由(you)的(de)(de)說(shuo)明。


先前在(zai)沖壓加(jia)工(gong)過程中(zhong)使(shi)用加(jia)工(gong)油(you)。為(wei)(wei)了(le)洗(xi)(xi)(xi)凈這(zhe)些加(jia)工(gong)油(you)而使(shi)用了(le)破壞臭氧層(ceng)的(de)三氯(lv)乙烷,三氯(lv)乙烯(xi)等。后來,洗(xi)(xi)(xi)凈方法(fa)改為(wei)(wei)堿性洗(xi)(xi)(xi)凈方法(fa)。在(zai)1995年(nian),考慮到保護地球環境(jing)問題,開發了(le)潤滑不(bu)銹鋼板。在(zai)汽(qi)車(che)、電(dian)機、燃氣器具領(ling)域中(zhong),積極推廣了(le)省(sheng)掉(diao)清(qing)洗(xi)(xi)(xi)工(gong)序(xu)的(de)潤滑不(bu)銹鋼板。特別(bie)是(shi)在(zai)汽(qi)車(che)領(ling)域中(zhong)的(de)排氣分支管的(de)不(bu)銹鋼化過程中(zhong),實踐證明(ming),加(jia)工(gong)這(zhe)種形(xing)狀復(fu)雜的(de)工(gong)件(jian),認(ren)為(wei)(wei)潤滑不(bu)銹鋼板比以(yi)前使(shi)用潤滑油(you)的(de)加(jia)工(gong)性更優越(yue)。所以(yi),潤滑不(bu)銹鋼板的(de)需要量大幅度增加(jia)。


表 4.jpg


  潤(run)滑不銹鋼板(ban),根據用(yong)途亦有不涂薄(bo)膜(mo)的(de)。非脫(tuo)膜(mo)型和(he)脫(tuo)膜(mo)型兩類已經(jing)產品化了。潤(run)滑不銹鋼板(ban)種類和(he)特性如表6-4所示。在建筑材(cai)料領域中,使用(yong)潤(run)滑不銹鋼板(ban)做屋頂時(shi),非脫(tuo)膜(mo)型和(he)脫(tuo)膜(mo)型一樣,其薄(bo)膜(mo)經(jing)過1~2年的(de)紫外(wai)線(xian)照射就(jiu)消失了。作為(wei)工程實例,用(yong)于(yu)西武百貨大(da)樓和(he)福岡機場候(hou)機大(da)廳。實踐(jian)證(zheng)明,潤(run)滑不銹鋼板(ban)的(de)加工性比加工油還要優越,見表6-5。


  不銹鋼板生產廠(chang)家的潤滑不銹鋼板產品,在透明(ming)涂(tu)裝不銹鋼項目中有(you)介紹(shao)。