冷彎成(cheng)(cheng)型(xing)產(chan)品在生產(chan)加工時一定要注(zhu)意產(chan)品的彈性變(bian)形和在成(cheng)(cheng)型(xing)過(guo)程中形成(cheng)(cheng)的張力，主要特點如下：
1. 產品的彈性變(bian)形(xing)
冷彎(wan)產品(pin)質量很大程度上取決(jue)于冷彎(wan)成型機(ji)(ji)的(de)(de)精度。欲正(zheng)確調整冷彎(wan)成型機(ji)(ji)，必須(xu)要預(yu)先確定金屬對(dui)輥(gun)的(de)(de)壓(ya)力與輥(gun)縫(feng)之間(jian)(jian)的(de)(de)變(bian)(bian)(bian)化關系，即彈(dan)(dan)(dan)性(xing)(xing)(xing)變(bian)(bian)(bian)形(xing)(xing)(xing)(xing)(xing)情況(kuang)。成型機(ji)(ji)的(de)(de)彈(dan)(dan)(dan)性(xing)(xing)(xing)變(bian)(bian)(bian)形(xing)(xing)(xing)(xing)(xing)由(you)工作(zuo)輥(gun)、軸承及軸承座(zuo)、機(ji)(ji)架牌坊、壓(ya)下(xia)裝置等的(de)(de)彈(dan)(dan)(dan)性(xing)(xing)(xing)變(bian)(bian)(bian)形(xing)(xing)(xing)(xing)(xing)和安裝間(jian)(jian)隙組(zu)成。研究表明，當總負載(zai)不大時(shi)，軋輥(gun)彈(dan)(dan)(dan)性(xing)(xing)(xing)變(bian)(bian)(bian)形(xing)(xing)(xing)(xing)(xing)僅占(zhan)(zhan)總彈(dan)(dan)(dan)性(xing)(xing)(xing)變(bian)(bian)(bian)形(xing)(xing)(xing)(xing)(xing)的(de)(de)25%;而當載(zai)荷大時(shi)（達200kN),成型輥(gun)彈(dan)(dan)(dan)性(xing)(xing)(xing)變(bian)(bian)(bian)形(xing)(xing)(xing)(xing)(xing)占(zhan)(zhan)總彈(dan)(dan)(dan)性(xing)(xing)(xing)變(bian)(bian)(bian)形(xing)(xing)(xing)(xing)(xing)的(de)(de)70%。可見成型輥(gun)的(de)(de)彈(dan)(dan)(dan)性(xing)(xing)(xing)變(bian)(bian)(bian)形(xing)(xing)(xing)(xing)(xing)是成型機(ji)(ji)彈(dan)(dan)(dan)性(xing)(xing)(xing)變(bian)(bian)(bian)形(xing)(xing)(xing)(xing)(xing)中(zhong)的(de)(de)主要部分。
生產實際(ji)及理論計(ji)算表明，對于（1~4)mm×(400~1500)mm冷(leng)彎成型機(ji)，當(dang)冷(leng)彎集中載荷為200kN時，成型輥(gun)彈性變形達1.49mm.
成型機彈(dan)性(xing)(xing)(xing)變(bian)(bian)形對產品質(zhi)量的影(ying)響可在(zai)成型輥孔型設(she)計(ji)(ji)中(zhong)設(she)置輥縫(feng)時加以補償。它(ta)應等于金屬料(liao)厚度(du)與彈(dan)跳(tiao)間距差值。另(ling)外(wai)，冷彎(wan)(wan)生(sheng)產實踐(jian)及理論研究(jiu)表(biao)明(ming)(ming)，冷彎(wan)(wan)過(guo)程(cheng)中(zhong)除塑性(xing)(xing)(xing)變(bian)(bian)形外(wai)，還存(cun)在(zai)彈(dan)性(xing)(xing)(xing)變(bian)(bian)形和彈(dan)塑性(xing)(xing)(xing)變(bian)(bian)形共存(cun)的狀況，當金屬移出孔型后，彎(wan)(wan)曲角(jiao)要發(fa)生(sheng)變(bian)(bian)化。如(ru)圖5-16(a)所示，設(she)計(ji)(ji)彎(wan)(wan)曲角(jiao)為β,移出孔型后會回(hui)彈(dan)γ角(jiao)度(du)，因此欲得精(jing)確形狀產品，成品道次應考(kao)慮過(guo)量彎(wan)(wan)角(jiao)度(du)，以彌補回(hui)彈(dan)，見圖5-16(b).實踐(jian)證明(ming)(ming)，材(cai)料(liao)彈(dan)性(xing)(xing)(xing)極限越(yue)大，回(hui)彈(dan)就越(yue)大，材(cai)料(liao)越(yue)厚回(hui)彈(dan)越(yue)大，彎(wan)(wan)曲臂越(yue)長回(hui)彈(dan)越(yue)大，彎(wan)(wan)曲角(jiao)越(yue)多(duo)回(hui)彈(dan)也(ye)會越(yue)大。
此(ci)外工(gong)藝過程(cheng)的不(bu)同(tong)，材(cai)料彎(wan)曲時應(ying)力、應(ying)變狀(zhuang)態不(bu)同(tong)，回彈量(liang)亦不(bu)同(tong)。一般認(ren)為，對于簡單斷面(mian)冷(leng)彎(wan)型鋼，由于彎(wan)折處及邊(bian)部存在拉應(ying)力，回彈較小，所以(yi)一般可不(bu)取(qu)過量(liang)彎(wan)角度(du)，或(huo)者僅考(kao)慮30'~1°即可。而對于波(bo)紋型鋼，中心波(bo)要考(kao)慮向(xiang)內過彎(wan)1°,邊(bian)波(bo)要大(da)30'。
2. 機組(zu)張(zhang)力
在冷彎成(cheng)(cheng)型(xing)機組(zu)上(shang)，帶鋼前(qian)進(jin)的(de)(de)驅(qu)動(dong)力是通過驅(qu)動(dong)輥(gun)和帶鋼之(zhi)間的(de)(de)摩擦力傳遞(di)的(de)(de)。為(wei)了(le)(le)在成(cheng)(cheng)型(xing)過程中形成(cheng)(cheng)張力、不產(chan)生堆鋼、使成(cheng)(cheng)型(xing)后(hou)型(xing)鋼平(ping)直，成(cheng)(cheng)型(xing)輥(gun)的(de)(de)平(ping)均輥(gun)徑(jing)要加(jia)工(gong)成(cheng)(cheng)從第(di)一(yi)架(jia)開始逐漸增(zeng)大的(de)(de)趨勢，即(ji)Dn+1稍大于Dn,使后(hou)一(yi)架(jia)對(dui)前(qian)一(yi)架(jia)有一(yi)個拉(la)伸作用。由于直徑(jing)增(zeng)加(jia)其線(xian)速度(du)就會增(zeng)加(jia)，因此(ci)在架(jia)次之(zhi)間就形成(cheng)(cheng)了(le)(le)張力，從而帶鋼能平(ping)直地運(yun)行。
Dn+1=(1.005~1.010)Dn
式中 Dn 第n架(jia)成型輥(gun)平均(jun)直徑；
Dn+1 第n+1架成型輥平均直徑。
