工字(zi)(zi)型(xing)(xing)鋼(gang)不(bu)論是普通(tong)型(xing)(xing)還是輕型(xing)(xing)的，由于截面(mian)尺寸均相對(dui)較高、較窄(zhai)，故對(dui)截面(mian)兩個主軸(zhou)的慣(guan)性矩(ju)相差較大(da)，故僅能直接用于在(zai)其(qi)腹(fu)(fu)板(ban)平面(mian)內受彎(wan)的構(gou)(gou)件(jian)(jian)或將其(qi)組成格構(gou)(gou)式受力構(gou)(gou)件(jian)(jian)。對(dui)軸(zhou)心受壓構(gou)(gou)件(jian)(jian)或在(zai)垂直于腹(fu)(fu)板(ban)平面(mian)還有彎(wan)曲(qu)的構(gou)(gou)件(jian)(jian)均不(bu)宜采用，這就使(shi)其(qi)在(zai)應用范圍上有著很大(da)的局限。工字(zi)(zi)鋼(gang)廣泛地應用于建筑或 其(qi)他金(jin)屬結構(gou)(gou)。

普(pu)通工(gong)字鋼，輕型(xing)工(gong)字鋼，由于截面尺寸均相對較高、較窄，故(gu)對截面兩(liang)個主軸(zhou)的(de)慣性(xing)矩相差較大，這就使(shi)其在(zai)應用(yong)(yong)范圍上有著很大的(de)局限。工(gong)字鋼的(de)使(shi)用(yong)(yong)應依據設計圖紙(zhi)的(de)要求進行選用(yong)(yong)。

在結構設計中選用工字鋼應依據其力學性能，化學性能，可焊性能，結構尺寸等選擇合理的工字鋼進行使用。

其(qi)規(gui)格以高(gao)×腿(tui)厚×腰厚表(biao)示(shi)，也可用號數 表(biao)示(shi)規(gui)格的主要尺寸(cun)。如18號工字(zi)鋼，表(biao)示(shi)高(gao)為18 cm的工字(zi)鋼。

若高度相同 的工字(zi)鋼，則(ze)可在(zai)號數后面加注角碼(ma)a或(huo)b或(huo)c予以(yi)表示(shi)，如36a、36b、 36c等。

它分為普通工(gong)字鋼(gang)(gang)、輕型(xing)工(gong)字鋼(gang)(gang)和(he)寬翼(yi)緣(yuan)(yuan)工(gong)字鋼(gang)(gang)。按翼(yi)緣(yuan)(yuan)與腹板高(gao)度(du) 比又分為寬幅(fu)、中(zhong)幅(fu)、窄幅(fu)寬翼(yi)緣(yuan)(yuan)工(gong)字鋼(gang)(gang)。

前二者生產的規格為10—60號(hao)，即 相應的高度為10 cm—60 cm。

工(gong)(gong)字(zi)(zi)鋼(gang)(gang)的規格是用腰(yao)寬(kuan)(kuan)的厘米值來(lai)表示的，如(ru)10號工(gong)(gong)字(zi)(zi)鋼(gang)(gang)，其腰(yao)寬(kuan)(kuan)為10cm。工(gong)(gong)字(zi)(zi)鋼(gang)(gang)的種類有熱軋(ya)普(pu)通工(gong)(gong)字(zi)(zi)鋼(gang)(gang)、輕型工(gong)(gong)字(zi)(zi)鋼(gang)(gang)和寬(kuan)(kuan)平行腿(tui)工(gong)(gong)字(zi)(zi)鋼(gang)(gang)（H型鋼(gang)(gang)）。我國熱軋(ya)普(pu)通工(gong)(gong)字(zi)(zi)鋼(gang)(gang)的腰(yao)寬(kuan)(kuan)為100～630mm，表示為No.10～No.63，腿(tui)內(nei)側(ce)壁斜(xie)度為1：6。軋(ya)制(zhi)工(gong)(gong)字(zi)(zi)鋼(gang)(gang)的孔型系(xi)統有直軋(ya)孔型系(xi)統、斜(xie)軋(ya)孔型系(xi)統和混合孔型系(xi)統。此外，工(gong)(gong)字(zi)(zi)鋼(gang)(gang)還(huan)可以采用特(te)殊軋(ya)法(fa)。

（1）直軋孔(kong)型(xing)系統(tong)。直軋孔(kong)型(xing)系統(tong)是指工(gong)字鋼孔(kong)型(xing)的兩個開口腿同時處(chu)于軋輥(gun)軸線的同一側(ce)，腰與(yu)軋輥(gun)軸線平行的孔(kong)型(xing)系統(tong)。

其優點(dian)是軋輥(gun)軸向力小(xiao)，軸向竄動(dong)小(xiao)，不需(xu)工作斜面，孔(kong)型占用輥(gun)身長度小(xiao)，在輥(gun)身長度一定的條(tiao)件下可多配孔(kong)型。

（2）斜軋孔(kong)型(xing)系統。這種孔(kong)型(xing)系統是指工字鋼(gang)孔(kong)型(xing)的(de)兩個開(kai)口腿不同時(shi)處于腰部的(de)同一側(ce)，腰與(yu)水平軸(zhou)線有一夾(jia)角(jiao)。

（3）混(hun)合孔(kong)(kong)型系(xi)(xi)統(tong)(tong)(tong)(tong)。根據軋(ya)機和產(chan)品的(de)特點，為充分發揮各自系(xi)(xi)統(tong)(tong)(tong)(tong)的(de)優點，克服缺點，往往采(cai)(cai)用(yong)(yong)混(hun)合孔(kong)(kong)型系(xi)(xi)統(tong)(tong)(tong)(tong)，即兩(liang)種以上系(xi)(xi)統(tong)(tong)(tong)(tong)的(de)組合。如成品孔(kong)(kong)和成品前孔(kong)(kong)采(cai)(cai)用(yong)(yong)直腿斜軋(ya)孔(kong)(kong)型系(xi)(xi)統(tong)(tong)(tong)(tong)，其(qi)他孔(kong)(kong)型采(cai)(cai)用(yong)(yong)彎腿斜軋(ya)系(xi)(xi)統(tong)(tong)(tong)(tong)；或(huo)者粗軋(ya)孔(kong)(kong)采(cai)(cai)用(yong)(yong)直軋(ya)系(xi)(xi)統(tong)(tong)(tong)(tong)，最(zui)后(hou)3～4個精軋(ya)孔(kong)(kong)采(cai)(cai)用(yong)(yong)直腿斜扎孔(kong)(kong)等。

（4）特殊軋(ya)(ya)(ya)(ya)法(fa)(fa)。由于某種原(yuan)因采(cai)用(yong)通常的(de)軋(ya)(ya)(ya)(ya)制(zhi)方法(fa)(fa)難以軋(ya)(ya)(ya)(ya)出要求的(de)工(gong)(gong)字鋼(gang)(gang)(gang)時，可(ke)采(cai)用(yong)特殊軋(ya)(ya)(ya)(ya)法(fa)(fa)，充(chong)分(fen)利用(yong)不均勻(yun)變形和孔型設計的(de)技巧。例如(ru)，當(dang)鋼(gang)(gang)(gang)坯斷(duan)面較窄而(er)(er)要求軋(ya)(ya)(ya)(ya)制(zhi)較寬的(de)工(gong)(gong)字鋼(gang)(gang)(gang)時，可(ke)采(cai)用(yong)波(bo)浪式(shi)軋(ya)(ya)(ya)(ya)法(fa)(fa)；又如(ru)當(dang)坯料較寬而(er)(er)要求軋(ya)(ya)(ya)(ya)制(zhi)較小號工(gong)(gong)字鋼(gang)(gang)(gang)時，可(ke)采(cai)用(yong)負寬展軋(ya)(ya)(ya)(ya)制(zhi)等(deng)。