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)--塑性為異向(xiang)性的材料深拉(la)深成形特性評價的重要指標(biao)。鐵素體(ti)系列不銹鋼中,其平(ping)均r值(zhi)越大,其極限拉(la)深比就(jiu)越高。
c. 拉深皺折-鐵(tie)素(su)體系列(lie)不銹(xiu)鋼(gang)在(zai)沖床上進(jin)行深拉深加工時,在(zai)其(qi)表(biao)面上容(rong)易產生凹凸不平的皺折。可(ke)認為是組合結構不同而引起的塑性(xing)異向(xiang)性(xing)。
d. 時效(xiao)性斷裂(lie)-奧(ao)氏(shi)體系(xi)列不銹鋼SUS304等準穩定型奧(ao)氏(shi)體系(xi)列不銹鋼,在加工(gong)后(hou)有發生時效(xiao)性裂(lie)紋(wen)的(de)現象(xiang)。它與(yu)晶界晶粒無關。一(yi)般(ban)認為是(shi)由于(yu)加工(gong)感應而引(yin)起的(de)馬氏(shi)體、氫和殘(can)余應力(li)所致。
1. 沖壓加工(gong)
沖壓(ya)(ya)加(jia)工(gong)(gong)(gong)行(xing)(xing)業是(shi)家庭式作坊(fang)工(gong)(gong)(gong)業的(de)(de)(de)代表性產(chan)(chan)業,多是(shi)從單獨一(yi)個一(yi)個地(di)加(jia)工(gong)(gong)(gong)西(xi)餐具、器皿等(deng)所(suo)謂的(de)(de)(de)“洋(yang)人筷子”等(deng)開始,發(fa)展到餐飲業的(de)(de)(de)廚(chu)房(fang)用具以及(ji)廚(chu)房(fang)中(zhong)所(suo)使用的(de)(de)(de)水槽、洗(xi)滌(di)盆(pen)、深(shen)拉(la)深(shen)加(jia)工(gong)(gong)(gong)的(de)(de)(de)澡盆(pen)以及(ji)汽(qi)車(che)、電機領域中(zhong)的(de)(de)(de)零(ling)部件等(deng)。主要工(gong)(gong)(gong)藝方法是(shi)采(cai)用剪切、沖孔、拉(la)深(shen)等(deng)進行(xing)(xing)連續加(jia)工(gong)(gong)(gong)。洋(yang)餐具、器皿和鍋的(de)(de)(de)沖壓(ya)(ya)加(jia)工(gong)(gong)(gong),基本上是(shi)屬于圓筒拉(la)深(shen)制成。原材(cai)料(liao)板直徑(jing)D對容器(產(chan)(chan)品)直徑(jing)d之比,D/d稱為(wei)拉(la)深(shen)比。以可(ke)能拉(la)深(shen)的(de)(de)(de)最大(da)原材(cai)料(liao)板直徑(jing)為(wei)Dmax時,則(ze)Dmax/d稱為(wei)極限拉(la)深(shen)比(LDR: Limiting Drawing Ratio)作為(wei)衡量加(jia)工(gong)(gong)(gong)性的(de)(de)(de)指標。不(bu)(bu)銹(xiu)鋼(gang)產(chan)(chan)品得(de)以大(da)幅度的(de)(de)(de)增加(jia)需求與沖壓(ya)(ya)加(jia)工(gong)(gong)(gong)技術(shu)的(de)(de)(de)發(fa)展有(you)很大(da)關(guan)系(xi)。不(bu)(bu)銹(xiu)鋼(gang)產(chan)(chan)品生產(chan)(chan)廠家在(zai)深(shen)拉(la)深(shen)加(jia)工(gong)(gong)(gong)等(deng)方面,由(you)于塑性加(jia)工(gong)(gong)(gong)技術(shu)和材(cai)料(liao)技術(shu)的(de)(de)(de)進展。使得(de)鐵素體系(xi)列不(bu)(bu)銹(xiu)鋼(gang)高加(jia)工(gong)(gong)(gong)性鋼(gang)種,已經(jing)產(chan)(chan)品化了。可(ke)以選定平均(jun)r值(zhi)在(zai)1.2~1.8,LDR為(wei)2.2~2.5的(de)(de)(de)鋼(gang)種。
在不(bu)銹鋼(gang)制品(pin)的(de)沖壓加工(gong)中(zhong),如果使用奧(ao)氏(shi)(shi)體系(xi)列不(bu)銹鋼(gang)或鐵(tie)素體系(xi)列不(bu)銹鋼(gang)的(de)高加工(gong)性能鋼(gang)種時(shi),可以(yi)進(jin)行一(yi)定程度的(de)深拉深加工(gong)。奧(ao)氏(shi)(shi)體系(xi)列不(bu)銹鋼(gang)的(de)代表型鋼(gang)種 SUS 304(18Cr -18Ni),因為(wei)它的(de)LDR為(wei)2.5,可以(yi)進(jin)行相(xiang)對較(jiao)大的(de)深拉深加工(gong)。
但由(you)于(yu)加(jia)(jia)(jia)工(gong)硬化傾向大而急劇地增(zeng)加(jia)(jia)(jia)了加(jia)(jia)(jia)工(gong)難度(du)(du),有時(shi)竟發(fa)生裂紋或斷裂。為(wei)此,沖壓廠(chang)家就(jiu)在中(zhong)間加(jia)(jia)(jia)上一道(dao)熱處理工(gong)序之后再進行深(shen)拉(la)深(shen)加(jia)(jia)(jia)工(gong)。還必須(xu)注意,奧氏(shi)體系列不銹鋼的奧氏(shi)體穩(wen)定(ding)度(du)(du)低的鋼種經過拉(la)深(shen)后,有可(ke)能發(fa)生時(shi)效斷裂現象。

近年來(lai),新(xin)潟縣(xian)燕(yan)市(shi)的沖壓(ya)加工廠和新(xin)鴻(hong)縣(xian)工業技(ji)術中心共同開發不(bu)銹鋼(gang)熱(re)(re)沖壓(ya)技(ji)術,實現了超深(shen)拉(la)(la)深(shen)加工。熱(re)(re)沖壓(ya)技(ji)術就是將凹模或者(zhe)凸模其中之一進行加熱(re)(re),這(zhe)樣不(bu)銹鋼(gang)原來(lai)的拉(la)(la)深(shen)程度就可以(yi)提高1.5~2.0倍。熱(re)(re)沖壓(ya)加工設(she)備的工作(zuo)原理(li)如圖6-9所示。其加工特性如圖6-10所示。
2. 彎(wan)曲與連續沖裁
奧氏體(ti)系(xi)列(lie)(lie)不銹(xiu)(xiu)鋼進(jin)行彎(wan)曲加(jia)(jia)(jia)工(gong)(gong)(gong)(gong)是件簡單之(zhi)事,可以(yi)制(zhi)(zhi)(zhi)作角鋼、槽鋼等(deng)型(xing)材使(shi)用。鐵素體(ti)系(xi)列(lie)(lie),馬氏體(ti)系(xi)列(lie)(lie)不銹(xiu)(xiu)鋼作為(wei)(wei)型(xing)材加(jia)(jia)(jia)工(gong)(gong)(gong)(gong),一般(ban)情況下沒有(you)問題,但當彎(wan)曲半徑(jing)R小的(de)(de)時(shi)候,在折彎(wan)處(chu)有(you)時(shi)會發生斷(duan)裂。在JIS標(biao)準中(zhong),對鐵素體(ti)、馬氏體(ti)系(xi)列(lie)(lie)的(de)(de)不銹(xiu)(xiu)鋼彎(wan)曲試(shi)驗標(biao)準規定,彎(wan)曲半徑(jing)R為(wei)(wei)1.0t(t為(wei)(wei)板(ban)材厚(hou)度)不應發生彎(wan)曲斷(duan)裂。還有(you),必須注意不銹(xiu)(xiu)鋼彎(wan)曲加(jia)(jia)(jia)工(gong)(gong)(gong)(gong)回彈量大的(de)(de)特點。落(luo)料(liao)(俗稱下料(liao))或(huo)稱為(wei)(wei)沖(chong)裁加(jia)(jia)(jia)工(gong)(gong)(gong)(gong),大多(duo)數是采用沖(chong)床連續(xu)加(jia)(jia)(jia)工(gong)(gong)(gong)(gong)的(de)(de)方式(shi),有(you)時(shi)在沖(chong)切斷(duan)面上(shang),發生塌(ta)邊(bian)現象(即沖(chong)切面與基準平(ping)面不垂直)。精(jing)(jing)(jing)密落(luo)料(liao)是從變壓(ya)器(qi)等(deng)使(shi)用疊層的(de)(de)電(dian)磁鋼板(ban)的(de)(de)加(jia)(jia)(jia)工(gong)(gong)(gong)(gong)技(ji)術(shu)開展起來的(de)(de)技(ji)術(shu),對粒子(zi)加(jia)(jia)(jia)速(su)器(qi)的(de)(de)套環(collar)或(huo)電(dian)子(zi)零部件中(zhong)的(de)(de)引(yin)線(xian)框(lead frame)等(deng)等(deng),從較厚(hou)的(de)(de)板(ban)材到超(chao)薄材,精(jing)(jing)(jing)密落(luo)料(liao)得(de)到廣泛應用。沖(chong)壓(ya)加(jia)(jia)(jia)工(gong)(gong)(gong)(gong)機械(xie)亦(yi)可以(yi)進(jin)行精(jing)(jing)(jing)密沖(chong)壓(ya)(落(luo)料(liao))加(jia)(jia)(jia)工(gong)(gong)(gong)(gong),但由于(yu)沖(chong)壓(ya)塌(ta)邊(bian)的(de)(de)問題,一般(ban)不能作為(wei)(wei)成品(pin)(pin)直接使(shi)用。在精(jing)(jing)(jing)密沖(chong)壓(ya)中(zhong),為(wei)(wei)控制(zhi)(zhi)(zhi)塌(ta)邊(bian),就需加(jia)(jia)(jia)一道機械(xie)控制(zhi)(zhi)(zhi)的(de)(de)工(gong)(gong)(gong)(gong)藝措施(shi),這需要按(an)產品(pin)(pin)用途以(yi)及成本兩方面來權衡。在加(jia)(jia)(jia)工(gong)(gong)(gong)(gong)方法(fa)競爭上(shang),還有(you)一種(zhong)“蝕刻”方法(fa),在電(dian)子(zi)產品(pin)(pin)的(de)(de)接線(xian)框等(deng)超(chao)薄產品(pin)(pin)中(zhong),在加(jia)(jia)(jia)工(gong)(gong)(gong)(gong)廠家的(de)(de)技(ji)術(shu)競爭中(zhong),兩者幾乎各占(zhan)一半。
3. 加工油、表面保護薄膜和其他潤滑
a. 表(biao)(biao)面保護薄膜(mo)(mo)-為了保持不(bu)銹鋼的匠(jiang)藝性(xing)、防止產生瑕疵以及作為潤滑(hua)而敷于材(cai)料表(biao)(biao)面的聚氯乙烯(xi)或(huo)聚乙烯(xi)等(deng)薄膜(mo)(mo)。
b. 揮(hui)發(fa)性加工(gong)(gong)油--加工(gong)(gong)時(shi)有潤滑效(xiao)果而后又能揮(hui)發(fa)掉(diao)(diao)的(de)加工(gong)(gong)油。使用完全(quan)揮(hui)發(fa)型的(de),可以省(sheng)掉(diao)(diao)清洗(xi)工(gong)(gong)序。
c. 潤滑不(bu)銹鋼(gang)板-具(ju)有透(tou)明石蠟涂裝的不(bu)銹鋼(gang),它比(bi)加(jia)(jia)工油或表面保護膜有更好的加(jia)(jia)工性。
在(zai)沖床上進行不(bu)(bu)(bu)銹鋼(gang)板彎曲、沖裁(落(luo)料)等加(jia)工(gong)(gong)時,可(ke)使(shi)用(yong)加(jia)工(gong)(gong)油(you)、表(biao)(biao)面保(bao)(bao)護(hu)(hu)薄(bo)膜(mo)或(huo)直接使(shi)用(yong)潤滑鋼(gang)板。在(zai)表(biao)(biao)6-1中,對(dui)加(jia)工(gong)(gong)油(you)、表(biao)(biao)面保(bao)(bao)護(hu)(hu)薄(bo)膜(mo)和潤滑鋼(gang)板進行比較(jiao)。表(biao)(biao)面保(bao)(bao)護(hu)(hu)薄(bo)膜(mo)是(shi)不(bu)(bu)(bu)銹鋼(gang)保(bao)(bao)持(chi)匠藝性的(de)一(yi)項(xiang)重要措施。所用(yong)樹脂(zhi)為聚(ju)氯乙烯系列或(huo)聚(ju)乙烯系列。材(cai)料運轉自始至終都是(shi)用(yong)表(biao)(biao)面保(bao)(bao)護(hu)(hu)薄(bo)膜(mo)對(dui)材(cai)料表(biao)(biao)面施行保(bao)(bao)護(hu)(hu)。使(shi)用(yong)表(biao)(biao)面保(bao)(bao)護(hu)(hu)薄(bo)膜(mo),最(zui)容(rong)易(yi)發(fa)生(sheng)(sheng)(sheng)的(de)問題就是(shi)殘(can)留糊狀物,貼附(fu)后長期保(bao)(bao)存(cun)在(zai)倉庫(ku)內的(de)或(huo)者(zhe)是(shi)不(bu)(bu)(bu)具備(bei)耐候性能的(de)薄(bo)膜(mo)放(fang)置在(zai)室外的(de),則(ze)容(rong)易(yi)發(fa)生(sheng)(sheng)(sheng)損壞。表(biao)(biao)面保(bao)(bao)護(hu)(hu)薄(bo)膜(mo)要根據用(yong)途和加(jia)工(gong)(gong)方法選(xuan)定。主要廠家生(sheng)(sheng)(sheng)產的(de)表(biao)(biao)面保(bao)(bao)護(hu)(hu)薄(bo)膜(mo)性能及其有關事項(xiang)如表(biao)(biao)6-2所示。不(bu)(bu)(bu)使(shi)用(yong)表(biao)(biao)面保(bao)(bao)護(hu)(hu)薄(bo)膜(mo)時,一(yi)般情況下要使(shi)用(yong)加(jia)工(gong)(gong)油(you)。當使(shi)用(yong)加(jia)工(gong)(gong)油(you)加(jia)工(gong)(gong)后,需進行洗(xi)凈(jing)。洗(xi)凈(jing)的(de)方法有多種(zhong),最(zui)近在(zai)保(bao)(bao)護(hu)(hu)地(di)球環(huan)境問題當中,規定了(le)保(bao)(bao)護(hu)(hu)環(huan)境條(tiao)例,對(dui)于破壞臭氧層(ceng)的(de)清洗(xi)劑做出了(le)限制。


因此,當使用(yong)加(jia)(jia)(jia)(jia)工(gong)(gong)(gong)油(you)時,要(yao)考慮到洗(xi)凈和存(cun)放問題。在(zai)加(jia)(jia)(jia)(jia)工(gong)(gong)(gong)油(you)選定方面(mian),從前認(ren)為(wei)由于不(bu)銹鋼硬度比(bi)普(pu)通(tong)鋼要(yao)高,加(jia)(jia)(jia)(jia)工(gong)(gong)(gong)不(bu)銹鋼比(bi)普(pu)通(tong)鋼困(kun)難,所以要(yao)選用(yong)有黏性(xing)的(de)(de)(de)加(jia)(jia)(jia)(jia)工(gong)(gong)(gong)油(you)。具有黏性(xing)的(de)(de)(de)加(jia)(jia)(jia)(jia)工(gong)(gong)(gong)油(you)往往是黏糊糊的(de)(de)(de),在(zai)加(jia)(jia)(jia)(jia)工(gong)(gong)(gong)過程中不(bu)但變黑(hei)而且難以清洗(xi)。另(ling)外,其中多(duo)數情(qing)況下加(jia)(jia)(jia)(jia)入氯系(xi)列添加(jia)(jia)(jia)(jia)劑。因此,更有必要(yao)進行充分(fen)地清洗(xi)。近年(nian)來(lai),開發(fa)了(le)許多(duo)水溶(rong)性(xing)加(jia)(jia)(jia)(jia)工(gong)(gong)(gong)油(you),在(zai)深(shen)拉深(shen)等(deng)加(jia)(jia)(jia)(jia)工(gong)(gong)(gong)中,其潤(run)滑性(xing)堪比(bi)原用(yong)油(you)性(xing)的(de)(de)(de)加(jia)(jia)(jia)(jia)工(gong)(gong)(gong)油(you)。水溶(rong)性(xing)加(jia)(jia)(jia)(jia)工(gong)(gong)(gong)油(you)比(bi)較容(rong)易清洗(xi),應用(yong)效(xiao)果很好(hao)。作為(wei)新技(ji)術,雖然加(jia)(jia)(jia)(jia)工(gong)(gong)(gong)條(tiao)件受到某種程度的(de)(de)(de)限制,免(mian)清洗(xi)的(de)(de)(de)揮發(fa)型(xing)加(jia)(jia)(jia)(jia)工(gong)(gong)(gong)油(you)仍得到推廣。
在揮(hui)發(fa)性加(jia)工(gong)油(you)(you)中(zhong)(zhong),有完(wan)全揮(hui)發(fa)型(xing)(xing)和部分殘(can)留型(xing)(xing)等(deng)(deng)產(chan)品。需根據加(jia)工(gong)條件選擇,使(shi)用(yong)完(wan)全揮(hui)發(fa)型(xing)(xing)的(de)可(ke)以省掉加(jia)工(gong)后的(de)清洗(xi)(xi)。在家電生產(chan)廠中(zhong)(zhong),沖制(zhi)(zhi)全自動洗(xi)(xi)衣機不銹鋼洗(xi)(xi)衣桶時就是采(cai)用(yong)完(wan)全揮(hui)發(fa)型(xing)(xing)加(jia)工(gong)油(you)(you)。在其他領域中(zhong)(zhong),完(wan)全揮(hui)發(fa)型(xing)(xing)加(jia)工(gong)油(you)(you)已(yi)實際運用(yong)到沖孔(kong)、內緣翻邊(bian)、壓制(zhi)(zhi)筋板、彎曲和卷(juan)邊(bian)等(deng)(deng)沖壓工(gong)藝(yi)中(zhong)(zhong)。

由(you)(you)于(yu)使(shi)(shi)用揮(hui)發性加(jia)(jia)工(gong)油可(ke)(ke)以(yi)省(sheng)掉(diao)清(qing)洗工(gong)序,在流(liu)水加(jia)(jia)工(gong)作(zuo)業線上使(shi)(shi)用,可(ke)(ke)以(yi)降(jiang)低(di)成本(ben)。主(zhu)要生產廠(chang)家的(de)揮(hui)發性加(jia)(jia)工(gong)油產品如(ru)表6-3所(suo)示(shi)。如(ru)將揮(hui)發性加(jia)(jia)工(gong)油的(de)涂(tu)敷(fu)方(fang)式(shi)和(he)加(jia)(jia)工(gong)條件(jian)進(jin)行改進(jin)時(shi)(shi),即可(ke)(ke)以(yi)完全省(sheng)掉(diao)清(qing)洗工(gong)作(zuo)。但是(shi),揮(hui)發性加(jia)(jia)工(gong)油涂(tu)敷(fu)方(fang)式(shi)、加(jia)(jia)工(gong)條件(jian)及加(jia)(jia)工(gong)夾(jia)具的(de)質量管理不善時(shi)(shi),由(you)(you)于(yu)加(jia)(jia)工(gong)夾(jia)具的(de)磨損(sun)等可(ke)(ke)能(neng)產生對不銹鋼的(de)鐵(tie)粉銹蝕事故。關于(yu)鐵(tie)粉銹蝕檢查方(fang)法,可(ke)(ke)參(can)照本(ben)書后部章(zhang)節中的(de)“使(shi)(shi)用時(shi)(shi)注(zhu)意重占(zhan)日惠(hui)執處(chu)理”由(you)(you)的(de)說明。
先前在沖壓加工(gong)過(guo)程(cheng)中(zhong)(zhong)(zhong)使(shi)(shi)用加工(gong)油。為(wei)了(le)洗(xi)凈(jing)這些(xie)加工(gong)油而(er)使(shi)(shi)用了(le)破壞臭氧(yang)層(ceng)的(de)(de)三氯乙烷,三氯乙烯等。后來,洗(xi)凈(jing)方法改為(wei)堿性洗(xi)凈(jing)方法。在1995年,考慮到保護地球環境問題,開發了(le)潤滑(hua)(hua)不(bu)(bu)銹(xiu)(xiu)鋼(gang)板(ban)(ban)。在汽(qi)車、電機、燃氣(qi)器具領(ling)域(yu)中(zhong)(zhong)(zhong),積極推廣了(le)省(sheng)掉(diao)清洗(xi)工(gong)序(xu)的(de)(de)潤滑(hua)(hua)不(bu)(bu)銹(xiu)(xiu)鋼(gang)板(ban)(ban)。特別是在汽(qi)車領(ling)域(yu)中(zhong)(zhong)(zhong)的(de)(de)排氣(qi)分支管的(de)(de)不(bu)(bu)銹(xiu)(xiu)鋼(gang)化(hua)過(guo)程(cheng)中(zhong)(zhong)(zhong),實(shi)踐證明,加工(gong)這種形狀復雜的(de)(de)工(gong)件,認為(wei)潤滑(hua)(hua)不(bu)(bu)銹(xiu)(xiu)鋼(gang)板(ban)(ban)比以前使(shi)(shi)用潤滑(hua)(hua)油的(de)(de)加工(gong)性更優越。所以,潤滑(hua)(hua)不(bu)(bu)銹(xiu)(xiu)鋼(gang)板(ban)(ban)的(de)(de)需(xu)要量大幅度增(zeng)加。

潤(run)滑不銹(xiu)(xiu)鋼板,根(gen)據(ju)用(yong)(yong)途亦(yi)有(you)不涂薄膜(mo)的(de)。非脫(tuo)膜(mo)型和脫(tuo)膜(mo)型兩類(lei)已經產品(pin)化(hua)了。潤(run)滑不銹(xiu)(xiu)鋼板種類(lei)和特性如表6-4所示。在建筑材料領(ling)域(yu)中,使用(yong)(yong)潤(run)滑不銹(xiu)(xiu)鋼板做屋(wu)頂時,非脫(tuo)膜(mo)型和脫(tuo)膜(mo)型一樣(yang),其薄膜(mo)經過(guo)1~2年(nian)的(de)紫外(wai)線照射就消失了。作(zuo)為(wei)工程實(shi)例,用(yong)(yong)于西武百貨大(da)(da)樓和福岡(gang)機場候機大(da)(da)廳。實(shi)踐(jian)證明(ming),潤(run)滑不銹(xiu)(xiu)鋼板的(de)加(jia)工性比加(jia)工油(you)還要優越,見表6-5。
不銹(xiu)鋼板生產(chan)(chan)廠(chang)家的(de)潤(run)滑(hua)不銹(xiu)鋼板產(chan)(chan)品,在透(tou)明涂(tu)裝(zhuang)不銹(xiu)鋼項目中有介紹。

