冷彎成型產(chan)品在生產(chan)加工時一定要注意產(chan)品的(de)彈性(xing)變形(xing)和在成型過程中形(xing)成的(de)張力，主(zhu)要特點(dian)如下：
1. 產品的彈(dan)性變(bian)形(xing)
冷彎(wan)產(chan)品質量很大(da)程度上取決于冷彎(wan)成(cheng)型(xing)(xing)機的(de)精度。欲(yu)正確(que)調整冷彎(wan)成(cheng)型(xing)(xing)機，必須要預先確(que)定金屬對(dui)輥(gun)的(de)壓(ya)(ya)力與輥(gun)縫之間的(de)變(bian)(bian)化關系(xi)，即彈(dan)(dan)(dan)性(xing)變(bian)(bian)形(xing)(xing)情況。成(cheng)型(xing)(xing)機的(de)彈(dan)(dan)(dan)性(xing)變(bian)(bian)形(xing)(xing)由工作輥(gun)、軸承及軸承座、機架牌坊、壓(ya)(ya)下裝置(zhi)等(deng)的(de)彈(dan)(dan)(dan)性(xing)變(bian)(bian)形(xing)(xing)和安裝間隙組(zu)成(cheng)。研究表明，當總負載不大(da)時，軋輥(gun)彈(dan)(dan)(dan)性(xing)變(bian)(bian)形(xing)(xing)僅占總彈(dan)(dan)(dan)性(xing)變(bian)(bian)形(xing)(xing)的(de)25%;而當載荷大(da)時（達200kN),成(cheng)型(xing)(xing)輥(gun)彈(dan)(dan)(dan)性(xing)變(bian)(bian)形(xing)(xing)占總彈(dan)(dan)(dan)性(xing)變(bian)(bian)形(xing)(xing)的(de)70%。可見(jian)成(cheng)型(xing)(xing)輥(gun)的(de)彈(dan)(dan)(dan)性(xing)變(bian)(bian)形(xing)(xing)是(shi)成(cheng)型(xing)(xing)機彈(dan)(dan)(dan)性(xing)變(bian)(bian)形(xing)(xing)中的(de)主要部分。
生產實際及(ji)理論計算表明，對于（1~4)mm×(400~1500)mm冷彎成(cheng)型(xing)機，當冷彎集中(zhong)載(zai)荷為200kN時，成(cheng)型(xing)輥彈性變(bian)形達(da)1.49mm.
成(cheng)型機彈(dan)(dan)(dan)(dan)(dan)(dan)性(xing)(xing)變(bian)(bian)形(xing)對(dui)產(chan)品質量(liang)的影響可在成(cheng)型輥(gun)孔(kong)型設(she)計中設(she)置輥(gun)縫時加以(yi)補(bu)償(chang)。它應(ying)等于金屬料(liao)厚(hou)度與彈(dan)(dan)(dan)(dan)(dan)(dan)跳間距差值。另外，冷(leng)彎(wan)(wan)生產(chan)實(shi)踐(jian)及理(li)論研究表明，冷(leng)彎(wan)(wan)過程中除塑性(xing)(xing)變(bian)(bian)形(xing)外，還存在彈(dan)(dan)(dan)(dan)(dan)(dan)性(xing)(xing)變(bian)(bian)形(xing)和彈(dan)(dan)(dan)(dan)(dan)(dan)塑性(xing)(xing)變(bian)(bian)形(xing)共存的狀(zhuang)(zhuang)況(kuang)，當金屬移出孔(kong)型后，彎(wan)(wan)曲(qu)角(jiao)要發(fa)生變(bian)(bian)化。如圖5-16(a)所示，設(she)計彎(wan)(wan)曲(qu)角(jiao)為β,移出孔(kong)型后會(hui)回(hui)(hui)(hui)彈(dan)(dan)(dan)(dan)(dan)(dan)γ角(jiao)度，因此欲得精(jing)確(que)形(xing)狀(zhuang)(zhuang)產(chan)品，成(cheng)品道次應(ying)考(kao)慮過量(liang)彎(wan)(wan)角(jiao)度，以(yi)彌(mi)補(bu)回(hui)(hui)(hui)彈(dan)(dan)(dan)(dan)(dan)(dan)，見圖5-16(b).實(shi)踐(jian)證明，材(cai)(cai)料(liao)彈(dan)(dan)(dan)(dan)(dan)(dan)性(xing)(xing)極限越(yue)大(da)(da)，回(hui)(hui)(hui)彈(dan)(dan)(dan)(dan)(dan)(dan)就越(yue)大(da)(da)，材(cai)(cai)料(liao)越(yue)厚(hou)回(hui)(hui)(hui)彈(dan)(dan)(dan)(dan)(dan)(dan)越(yue)大(da)(da)，彎(wan)(wan)曲(qu)臂(bei)越(yue)長回(hui)(hui)(hui)彈(dan)(dan)(dan)(dan)(dan)(dan)越(yue)大(da)(da)，彎(wan)(wan)曲(qu)角(jiao)越(yue)多回(hui)(hui)(hui)彈(dan)(dan)(dan)(dan)(dan)(dan)也會(hui)越(yue)大(da)(da)。
此外工藝過(guo)程的不(bu)(bu)同，材料彎(wan)曲時應(ying)力、應(ying)變狀(zhuang)態不(bu)(bu)同，回彈量亦不(bu)(bu)同。一般認為，對(dui)于簡單斷面冷(leng)彎(wan)型鋼，由(you)于彎(wan)折處及邊部存(cun)在拉應(ying)力，回彈較(jiao)小(xiao)，所以一般可不(bu)(bu)取過(guo)量彎(wan)角度，或者僅考慮30'~1°即(ji)可。而對(dui)于波紋型鋼，中心波要考慮向內過(guo)彎(wan)1°,邊波要大(da)30'。
2. 機組張力
在冷彎成(cheng)(cheng)型機(ji)組上(shang)，帶鋼(gang)前進的(de)(de)(de)驅(qu)動(dong)力(li)(li)是通過(guo)驅(qu)動(dong)輥(gun)和(he)帶鋼(gang)之間的(de)(de)(de)摩擦(ca)力(li)(li)傳遞(di)的(de)(de)(de)。為了在成(cheng)(cheng)型過(guo)程(cheng)中形成(cheng)(cheng)張力(li)(li)、不產生堆(dui)鋼(gang)、使成(cheng)(cheng)型后(hou)型鋼(gang)平(ping)(ping)直，成(cheng)(cheng)型輥(gun)的(de)(de)(de)平(ping)(ping)均輥(gun)徑要加工成(cheng)(cheng)從第一架(jia)(jia)開始逐漸增(zeng)大的(de)(de)(de)趨勢，即Dn+1稍大于Dn,使后(hou)一架(jia)(jia)對(dui)前一架(jia)(jia)有一個拉伸(shen)作用。由于直徑增(zeng)加其線速度就(jiu)會增(zeng)加，因(yin)此在架(jia)(jia)次之間就(jiu)形成(cheng)(cheng)了張力(li)(li)，從而帶鋼(gang)能平(ping)(ping)直地運行。
Dn+1=(1.005~1.010)Dn
式(shi)中 Dn 第n架成型輥平均直徑；
Dn+1 第n+1架成型輥平均直徑。
