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r值(zhi)(zhi)--塑(su)性(xing)為異向性(xing)的材料(liao)深(shen)拉(la)深(shen)成形特(te)性(xing)評(ping)價(jia)的重要指標。鐵素體系列不(bu)銹鋼(gang)中,其平(ping)均r值(zhi)(zhi)越大,其極限拉(la)深(shen)比(bi)就(jiu)越高。
c. 拉深皺折-鐵素體系列不(bu)銹鋼(gang)在沖床上進行深拉深加工時,在其表面上容易(yi)產生(sheng)凹凸不(bu)平的(de)皺折。可認為是組合結構不(bu)同而(er)引(yin)起(qi)的(de)塑性異向性。
d. 時(shi)效(xiao)性(xing)斷裂(lie)-奧(ao)(ao)氏體系列不銹(xiu)鋼(gang)SUS304等準穩定型奧(ao)(ao)氏體系列不銹(xiu)鋼(gang),在(zai)加工后有發(fa)生時(shi)效(xiao)性(xing)裂(lie)紋的現象(xiang)。它與晶界晶粒(li)無關。一般認為是由于加工感應而(er)引起的馬氏體、氫和殘余應力所致。
1. 沖壓加工(gong)
沖(chong)壓(ya)加(jia)(jia)(jia)(jia)工行業是家庭式作(zuo)坊工業的(de)(de)(de)(de)(de)(de)代表性產業,多是從單獨一(yi)個一(yi)個地(di)加(jia)(jia)(jia)(jia)工西餐具(ju)、器(qi)(qi)皿等所謂的(de)(de)(de)(de)(de)(de)“洋人(ren)筷(kuai)子”等開始,發展到餐飲業的(de)(de)(de)(de)(de)(de)廚房用具(ju)以(yi)(yi)(yi)及(ji)廚房中所使用的(de)(de)(de)(de)(de)(de)水槽、洗滌盆、深(shen)(shen)拉深(shen)(shen)加(jia)(jia)(jia)(jia)工的(de)(de)(de)(de)(de)(de)澡盆以(yi)(yi)(yi)及(ji)汽(qi)車、電機領域中的(de)(de)(de)(de)(de)(de)零(ling)部(bu)件等。主要工藝方(fang)法(fa)是采用剪切、沖(chong)孔、拉深(shen)(shen)等進(jin)行連續加(jia)(jia)(jia)(jia)工。洋餐具(ju)、器(qi)(qi)皿和(he)鍋的(de)(de)(de)(de)(de)(de)沖(chong)壓(ya)加(jia)(jia)(jia)(jia)工,基(ji)本上(shang)是屬于圓(yuan)筒拉深(shen)(shen)制(zhi)成(cheng)。原材料板直(zhi)(zhi)徑D對容(rong)器(qi)(qi)(產品(pin))直(zhi)(zhi)徑d之(zhi)比,D/d稱為(wei)(wei)拉深(shen)(shen)比。以(yi)(yi)(yi)可(ke)能拉深(shen)(shen)的(de)(de)(de)(de)(de)(de)最大原材料板直(zhi)(zhi)徑為(wei)(wei)Dmax時,則Dmax/d稱為(wei)(wei)極限拉深(shen)(shen)比(LDR: Limiting Drawing Ratio)作(zuo)為(wei)(wei)衡(heng)量加(jia)(jia)(jia)(jia)工性的(de)(de)(de)(de)(de)(de)指標。不(bu)銹(xiu)(xiu)鋼產品(pin)得(de)(de)以(yi)(yi)(yi)大幅度的(de)(de)(de)(de)(de)(de)增加(jia)(jia)(jia)(jia)需求與沖(chong)壓(ya)加(jia)(jia)(jia)(jia)工技術的(de)(de)(de)(de)(de)(de)發展有(you)很大關系。不(bu)銹(xiu)(xiu)鋼產品(pin)生產廠家在深(shen)(shen)拉深(shen)(shen)加(jia)(jia)(jia)(jia)工等方(fang)面,由于塑性加(jia)(jia)(jia)(jia)工技術和(he)材料技術的(de)(de)(de)(de)(de)(de)進(jin)展。使得(de)(de)鐵素體(ti)系列(lie)不(bu)銹(xiu)(xiu)鋼高加(jia)(jia)(jia)(jia)工性鋼種,已(yi)經(jing)產品(pin)化了。可(ke)以(yi)(yi)(yi)選定平均r值在1.2~1.8,LDR為(wei)(wei)2.2~2.5的(de)(de)(de)(de)(de)(de)鋼種。
在(zai)不銹(xiu)(xiu)鋼(gang)制品的(de)沖壓加工(gong)中,如果使用奧氏體(ti)系列(lie)不銹(xiu)(xiu)鋼(gang)或鐵素體(ti)系列(lie)不銹(xiu)(xiu)鋼(gang)的(de)高加工(gong)性能鋼(gang)種時(shi),可以進行一定程度的(de)深拉深加工(gong)。奧氏體(ti)系列(lie)不銹(xiu)(xiu)鋼(gang)的(de)代表型(xing)鋼(gang)種 SUS 304(18Cr -18Ni),因(yin)為它的(de)LDR為2.5,可以進行相對(dui)較(jiao)大的(de)深拉深加工(gong)。
但(dan)由(you)于加(jia)工(gong)硬化傾向大而急劇地增加(jia)了加(jia)工(gong)難度(du),有時竟發生裂(lie)紋或(huo)斷裂(lie)。為此,沖(chong)壓廠家就(jiu)在中間加(jia)上一道熱處理工(gong)序之后(hou)再進行深(shen)拉深(shen)加(jia)工(gong)。還必須注意,奧(ao)氏體系(xi)列不銹(xiu)鋼的(de)奧(ao)氏體穩定度(du)低的(de)鋼種經過(guo)拉深(shen)后(hou),有可(ke)能發生時效(xiao)斷裂(lie)現象。

近年來(lai),新(xin)潟縣燕市(shi)的(de)沖(chong)(chong)壓(ya)(ya)加(jia)工(gong)(gong)廠(chang)和新(xin)鴻縣工(gong)(gong)業技(ji)術中(zhong)心共同開發不(bu)銹(xiu)鋼(gang)熱(re)(re)沖(chong)(chong)壓(ya)(ya)技(ji)術,實現了超深(shen)拉深(shen)加(jia)工(gong)(gong)。熱(re)(re)沖(chong)(chong)壓(ya)(ya)技(ji)術就(jiu)是(shi)將(jiang)凹模或者凸模其中(zhong)之一進行加(jia)熱(re)(re),這樣不(bu)銹(xiu)鋼(gang)原來(lai)的(de)拉深(shen)程度就(jiu)可以提高1.5~2.0倍。熱(re)(re)沖(chong)(chong)壓(ya)(ya)加(jia)工(gong)(gong)設(she)備(bei)的(de)工(gong)(gong)作原理如圖(tu)6-9所示(shi)。其加(jia)工(gong)(gong)特(te)性如圖(tu)6-10所示(shi)。
2. 彎曲與連續沖裁(cai)
奧氏體(ti)(ti)(ti)(ti)系列不(bu)銹鋼進行(xing)彎(wan)曲加(jia)(jia)(jia)(jia)(jia)工(gong)(gong)(gong)是件(jian)簡單之事,可以制作角(jiao)鋼、槽(cao)鋼等(deng)型材使(shi)(shi)用(yong)。鐵(tie)素體(ti)(ti)(ti)(ti)系列,馬(ma)氏體(ti)(ti)(ti)(ti)系列不(bu)銹鋼作為(wei)(wei)型材加(jia)(jia)(jia)(jia)(jia)工(gong)(gong)(gong),一(yi)般情況下沒有問題(ti),但(dan)(dan)當彎(wan)曲半徑(jing)R小的(de)(de)(de)(de)時(shi)(shi)候,在(zai)(zai)折彎(wan)處(chu)有時(shi)(shi)會發生斷(duan)裂。在(zai)(zai)JIS標準中(zhong),對鐵(tie)素體(ti)(ti)(ti)(ti)、馬(ma)氏體(ti)(ti)(ti)(ti)系列的(de)(de)(de)(de)不(bu)銹鋼彎(wan)曲試(shi)驗(yan)標準規定,彎(wan)曲半徑(jing)R為(wei)(wei)1.0t(t為(wei)(wei)板材厚度)不(bu)應(ying)發生彎(wan)曲斷(duan)裂。還(huan)有,必須注意不(bu)銹鋼彎(wan)曲加(jia)(jia)(jia)(jia)(jia)工(gong)(gong)(gong)回彈量大的(de)(de)(de)(de)特點。落(luo)(luo)料(liao)(俗稱(cheng)下料(liao))或稱(cheng)為(wei)(wei)沖(chong)裁加(jia)(jia)(jia)(jia)(jia)工(gong)(gong)(gong),大多數是采用(yong)沖(chong)床連續加(jia)(jia)(jia)(jia)(jia)工(gong)(gong)(gong)的(de)(de)(de)(de)方式,有時(shi)(shi)在(zai)(zai)沖(chong)切斷(duan)面上,發生塌邊(bian)現象(即沖(chong)切面與基準平面不(bu)垂直)。精密(mi)(mi)落(luo)(luo)料(liao)是從變壓器等(deng)使(shi)(shi)用(yong)疊(die)層的(de)(de)(de)(de)電(dian)磁鋼板的(de)(de)(de)(de)加(jia)(jia)(jia)(jia)(jia)工(gong)(gong)(gong)技術開展(zhan)起來的(de)(de)(de)(de)技術,對粒子加(jia)(jia)(jia)(jia)(jia)速器的(de)(de)(de)(de)套(tao)環(collar)或電(dian)子零(ling)部(bu)件(jian)中(zhong)的(de)(de)(de)(de)引線框(lead frame)等(deng)等(deng),從較(jiao)厚的(de)(de)(de)(de)板材到(dao)超(chao)薄材,精密(mi)(mi)落(luo)(luo)料(liao)得到(dao)廣泛應(ying)用(yong)。沖(chong)壓加(jia)(jia)(jia)(jia)(jia)工(gong)(gong)(gong)機(ji)械(xie)亦(yi)可以進行(xing)精密(mi)(mi)沖(chong)壓(落(luo)(luo)料(liao))加(jia)(jia)(jia)(jia)(jia)工(gong)(gong)(gong),但(dan)(dan)由于沖(chong)壓塌邊(bian)的(de)(de)(de)(de)問題(ti),一(yi)般不(bu)能作為(wei)(wei)成品(pin)直接使(shi)(shi)用(yong)。在(zai)(zai)精密(mi)(mi)沖(chong)壓中(zhong),為(wei)(wei)控制塌邊(bian),就需加(jia)(jia)(jia)(jia)(jia)一(yi)道(dao)機(ji)械(xie)控制的(de)(de)(de)(de)工(gong)(gong)(gong)藝措施,這需要按產(chan)(chan)品(pin)用(yong)途以及(ji)成本兩(liang)方面來權衡。在(zai)(zai)加(jia)(jia)(jia)(jia)(jia)工(gong)(gong)(gong)方法(fa)競爭上,還(huan)有一(yi)種“蝕刻”方法(fa),在(zai)(zai)電(dian)子產(chan)(chan)品(pin)的(de)(de)(de)(de)接線框等(deng)超(chao)薄產(chan)(chan)品(pin)中(zhong),在(zai)(zai)加(jia)(jia)(jia)(jia)(jia)工(gong)(gong)(gong)廠家的(de)(de)(de)(de)技術競爭中(zhong),兩(liang)者幾乎各占一(yi)半。
3. 加工油、表(biao)面保(bao)護薄膜和其他潤滑
a. 表面保(bao)護薄膜-為了保(bao)持(chi)不銹鋼的匠藝性、防止產生瑕疵以及作為潤滑而敷于材料(liao)表面的聚氯乙(yi)烯或聚乙(yi)烯等薄膜。
b. 揮(hui)發性(xing)加(jia)工(gong)油--加(jia)工(gong)時有潤(run)滑效(xiao)果而后(hou)又能揮(hui)發掉的加(jia)工(gong)油。使(shi)用(yong)完(wan)全揮(hui)發型的,可以省(sheng)掉清洗(xi)工(gong)序。
c. 潤(run)滑不銹鋼板(ban)-具(ju)有透(tou)明石(shi)蠟涂裝的(de)不銹鋼,它比(bi)加(jia)工油(you)或表面保護膜有更好的(de)加(jia)工性。
在(zai)沖(chong)床(chuang)上(shang)進(jin)行不銹(xiu)鋼(gang)板彎(wan)曲、沖(chong)裁(cai)(落料)等加工時,可(ke)使(shi)用(yong)(yong)加工油、表(biao)(biao)面保(bao)(bao)(bao)(bao)(bao)護(hu)(hu)薄(bo)(bo)(bo)(bo)(bo)膜(mo)或直接使(shi)用(yong)(yong)潤滑(hua)(hua)鋼(gang)板。在(zai)表(biao)(biao)6-1中,對(dui)加工油、表(biao)(biao)面保(bao)(bao)(bao)(bao)(bao)護(hu)(hu)薄(bo)(bo)(bo)(bo)(bo)膜(mo)和潤滑(hua)(hua)鋼(gang)板進(jin)行比較。表(biao)(biao)面保(bao)(bao)(bao)(bao)(bao)護(hu)(hu)薄(bo)(bo)(bo)(bo)(bo)膜(mo)是不銹(xiu)鋼(gang)保(bao)(bao)(bao)(bao)(bao)持匠(jiang)藝性的(de)(de)一項(xiang)重要(yao)措施。所(suo)(suo)用(yong)(yong)樹脂為聚氯乙(yi)烯(xi)系列或聚乙(yi)烯(xi)系列。材(cai)料運轉自始至終都是用(yong)(yong)表(biao)(biao)面保(bao)(bao)(bao)(bao)(bao)護(hu)(hu)薄(bo)(bo)(bo)(bo)(bo)膜(mo)對(dui)材(cai)料表(biao)(biao)面施行保(bao)(bao)(bao)(bao)(bao)護(hu)(hu)。使(shi)用(yong)(yong)表(biao)(biao)面保(bao)(bao)(bao)(bao)(bao)護(hu)(hu)薄(bo)(bo)(bo)(bo)(bo)膜(mo),最(zui)容易發(fa)生(sheng)的(de)(de)問題(ti)就是殘留糊(hu)狀物,貼附后長(chang)期保(bao)(bao)(bao)(bao)(bao)存在(zai)倉庫內的(de)(de)或者是不具備(bei)耐候性能的(de)(de)薄(bo)(bo)(bo)(bo)(bo)膜(mo)放置在(zai)室外(wai)的(de)(de),則容易發(fa)生(sheng)損壞(huai)。表(biao)(biao)面保(bao)(bao)(bao)(bao)(bao)護(hu)(hu)薄(bo)(bo)(bo)(bo)(bo)膜(mo)要(yao)根據(ju)用(yong)(yong)途和加工方法選定。主要(yao)廠家(jia)生(sheng)產(chan)的(de)(de)表(biao)(biao)面保(bao)(bao)(bao)(bao)(bao)護(hu)(hu)薄(bo)(bo)(bo)(bo)(bo)膜(mo)性能及其(qi)有(you)關事(shi)項(xiang)如表(biao)(biao)6-2所(suo)(suo)示。不使(shi)用(yong)(yong)表(biao)(biao)面保(bao)(bao)(bao)(bao)(bao)護(hu)(hu)薄(bo)(bo)(bo)(bo)(bo)膜(mo)時,一般情況下要(yao)使(shi)用(yong)(yong)加工油。當使(shi)用(yong)(yong)加工油加工后,需進(jin)行洗凈。洗凈的(de)(de)方法有(you)多種,最(zui)近在(zai)保(bao)(bao)(bao)(bao)(bao)護(hu)(hu)地球(qiu)環(huan)境(jing)問題(ti)當中,規定了保(bao)(bao)(bao)(bao)(bao)護(hu)(hu)環(huan)境(jing)條例,對(dui)于破壞(huai)臭氧層的(de)(de)清洗劑做出(chu)了限制(zhi)。


因此(ci),當使用加(jia)(jia)工(gong)(gong)(gong)油(you)(you)時(shi),要考(kao)慮到(dao)洗(xi)凈和存放問題。在(zai)(zai)(zai)加(jia)(jia)工(gong)(gong)(gong)油(you)(you)選定(ding)方面,從前認為由于不(bu)銹鋼(gang)(gang)硬度比普通(tong)鋼(gang)(gang)要高,加(jia)(jia)工(gong)(gong)(gong)不(bu)銹鋼(gang)(gang)比普通(tong)鋼(gang)(gang)困(kun)難(nan),所以(yi)要選用有(you)黏性的(de)加(jia)(jia)工(gong)(gong)(gong)油(you)(you)。具有(you)黏性的(de)加(jia)(jia)工(gong)(gong)(gong)油(you)(you)往(wang)往(wang)是(shi)黏糊糊的(de),在(zai)(zai)(zai)加(jia)(jia)工(gong)(gong)(gong)過程中不(bu)但變黑而且難(nan)以(yi)清洗(xi)。另外,其(qi)中多數情況下加(jia)(jia)入氯系列(lie)添加(jia)(jia)劑。因此(ci),更(geng)有(you)必要進行充分地清洗(xi)。近(jin)年來,開發了許多水溶性加(jia)(jia)工(gong)(gong)(gong)油(you)(you),在(zai)(zai)(zai)深(shen)拉深(shen)等(deng)加(jia)(jia)工(gong)(gong)(gong)中,其(qi)潤滑(hua)性堪比原用油(you)(you)性的(de)加(jia)(jia)工(gong)(gong)(gong)油(you)(you)。水溶性加(jia)(jia)工(gong)(gong)(gong)油(you)(you)比較容易清洗(xi),應用效果(guo)很好。作(zuo)為新(xin)技術,雖然(ran)加(jia)(jia)工(gong)(gong)(gong)條件(jian)受到(dao)某種(zhong)程度的(de)限制,免(mian)清洗(xi)的(de)揮發型加(jia)(jia)工(gong)(gong)(gong)油(you)(you)仍得到(dao)推廣。
在(zai)揮(hui)(hui)(hui)發性加(jia)工(gong)油(you)中(zhong),有(you)完(wan)(wan)全揮(hui)(hui)(hui)發型和部分殘留型等(deng)產品。需根(gen)據加(jia)工(gong)條件(jian)選擇,使用(yong)(yong)完(wan)(wan)全揮(hui)(hui)(hui)發型的(de)可以省掉加(jia)工(gong)后的(de)清洗(xi)(xi)(xi)。在(zai)家電生(sheng)產廠中(zhong),沖(chong)制(zhi)(zhi)全自(zi)動洗(xi)(xi)(xi)衣(yi)機不銹鋼洗(xi)(xi)(xi)衣(yi)桶時就是(shi)采用(yong)(yong)完(wan)(wan)全揮(hui)(hui)(hui)發型加(jia)工(gong)油(you)。在(zai)其他領域(yu)中(zhong),完(wan)(wan)全揮(hui)(hui)(hui)發型加(jia)工(gong)油(you)已(yi)實際運用(yong)(yong)到(dao)沖(chong)孔、內(nei)緣(yuan)翻邊、壓(ya)(ya)制(zhi)(zhi)筋板、彎曲和卷邊等(deng)沖(chong)壓(ya)(ya)工(gong)藝中(zhong)。

由(you)于使(shi)用(yong)(yong)揮(hui)(hui)發(fa)性加工(gong)(gong)油可(ke)(ke)以省掉清(qing)(qing)洗工(gong)(gong)序,在流水加工(gong)(gong)作業線(xian)上使(shi)用(yong)(yong),可(ke)(ke)以降低成(cheng)本。主要(yao)生產(chan)廠家的揮(hui)(hui)發(fa)性加工(gong)(gong)油產(chan)品如(ru)表6-3所示。如(ru)將揮(hui)(hui)發(fa)性加工(gong)(gong)油的涂敷(fu)方(fang)式和加工(gong)(gong)條件進(jin)行改進(jin)時(shi),即可(ke)(ke)以完全省掉清(qing)(qing)洗工(gong)(gong)作。但(dan)是,揮(hui)(hui)發(fa)性加工(gong)(gong)油涂敷(fu)方(fang)式、加工(gong)(gong)條件及(ji)加工(gong)(gong)夾具的質量管理不善時(shi),由(you)于加工(gong)(gong)夾具的磨損等可(ke)(ke)能產(chan)生對不銹(xiu)鋼的鐵(tie)粉銹(xiu)蝕事故。關于鐵(tie)粉銹(xiu)蝕檢查(cha)方(fang)法,可(ke)(ke)參照本書后部章節中(zhong)的“使(shi)用(yong)(yong)時(shi)注意重占日惠執處理”由(you)的說明。
先前在(zai)沖壓加(jia)(jia)工(gong)過(guo)程中(zhong)(zhong)使(shi)(shi)用加(jia)(jia)工(gong)油(you)。為(wei)(wei)了洗凈這些加(jia)(jia)工(gong)油(you)而使(shi)(shi)用了破壞臭氧層的三(san)氯乙烷,三(san)氯乙烯等。后來(lai),洗凈方法改為(wei)(wei)堿(jian)性洗凈方法。在(zai)1995年,考慮到保護地(di)球環境(jing)問題,開(kai)發了潤(run)(run)滑(hua)不(bu)(bu)銹(xiu)鋼(gang)板(ban)。在(zai)汽(qi)車、電(dian)機、燃氣(qi)器具領(ling)域中(zhong)(zhong),積極推廣了省(sheng)掉清洗工(gong)序的潤(run)(run)滑(hua)不(bu)(bu)銹(xiu)鋼(gang)板(ban)。特別是(shi)在(zai)汽(qi)車領(ling)域中(zhong)(zhong)的排氣(qi)分支(zhi)管的不(bu)(bu)銹(xiu)鋼(gang)化過(guo)程中(zhong)(zhong),實踐證明,加(jia)(jia)工(gong)這種形(xing)狀復雜的工(gong)件(jian),認為(wei)(wei)潤(run)(run)滑(hua)不(bu)(bu)銹(xiu)鋼(gang)板(ban)比以(yi)前使(shi)(shi)用潤(run)(run)滑(hua)油(you)的加(jia)(jia)工(gong)性更優(you)越(yue)。所以(yi),潤(run)(run)滑(hua)不(bu)(bu)銹(xiu)鋼(gang)板(ban)的需要量大(da)幅度增(zeng)加(jia)(jia)。

潤滑(hua)不(bu)(bu)銹鋼(gang)板(ban),根據用途亦有不(bu)(bu)涂薄(bo)膜(mo)(mo)的(de)。非(fei)(fei)脫(tuo)膜(mo)(mo)型(xing)和(he)脫(tuo)膜(mo)(mo)型(xing)兩類(lei)已經產品(pin)化了(le)(le)。潤滑(hua)不(bu)(bu)銹鋼(gang)板(ban)種(zhong)類(lei)和(he)特性如表6-4所(suo)示。在(zai)建筑材(cai)料領域中,使用潤滑(hua)不(bu)(bu)銹鋼(gang)板(ban)做屋頂時,非(fei)(fei)脫(tuo)膜(mo)(mo)型(xing)和(he)脫(tuo)膜(mo)(mo)型(xing)一(yi)樣,其薄(bo)膜(mo)(mo)經過(guo)1~2年的(de)紫外線(xian)照射(she)就消(xiao)失了(le)(le)。作為工程實(shi)例(li),用于(yu)西武百貨(huo)大(da)樓和(he)福岡(gang)機(ji)場候機(ji)大(da)廳。實(shi)踐證明(ming),潤滑(hua)不(bu)(bu)銹鋼(gang)板(ban)的(de)加工性比加工油還要優越,見表6-5。
不銹鋼板(ban)生產廠(chang)家的潤(run)滑不銹鋼板(ban)產品,在透明涂裝不銹鋼項目(mu)中有介紹。

