自由鍛造時，被加工金屬在上、下砧鐵之間受壓產生變形，在水平面的各個方向金屬能自由流動，故稱自由鍛造。


 自由(you)鍛(duan)造所(suo)用設備和工(gong)(gong)具通用性較大，鍛(duan)件(jian)的(de)質量(liang)大小(xiao)不(bu)(bu)等。但是，自由(you)鍛(duan)件(jian)的(de)形(xing)狀(zhuang)和尺(chi)寸(cun)主要依靠鍛(duan)工(gong)(gong)的(de)操作(zuo)技(ji)(ji)術(shu)來保證(zheng)，對(dui)鍛(duan)工(gong)(gong)的(de)技(ji)(ji)術(shu)水平要求高(gao)，勞(lao)動強(qiang)度大，生產率低(di)，鍛(duan)件(jian)的(de)精度低(di)，加(jia)工(gong)(gong)余量(liang)大，且不(bu)(bu)能獲得較復雜(za)的(de)形(xing)狀(zhuang)。所(suo)以(yi)主要用于(yu)(yu)單(dan)件(jian)、小(xiao)批生產以(yi)及修(xiu)配工(gong)(gong)作(zuo)。對(dui)于(yu)(yu)大型鍛(duan)件(jian)，自由(you)鍛(duan)造是唯(wei)一的(de)生產方法。自由(you)鍛(duan)造有手工(gong)(gong)鍛(duan)和機(ji)器(qi)鍛(duan)兩種。


 手工(gong)鍛是靠人力(li)利用砧鐵(tie)、大錘、小錘、手鉗(qian)、沖(chong)子、鑿子和型錘等工(gong)具，使坯料變形制(zhi)成鍛件的加工(gong)方法(fa)。手工(gong)鍛所用的設(she)備和工(gong)具簡單、投資少，但勞動強度(du)大、生產率(lv)低，適用于修理工(gong)作(zuo)以及機器鍛的輔(fu)助工(gong)作(zuo)。


 手(shou)工(gong)(gong)(gong)(gong)鍛是由掌鉗(qian)工(gong)(gong)(gong)(gong)和打錘(chui)工(gong)(gong)(gong)(gong)配合(he)進(jin)行操作的(de)。掌鉗(qian)工(gong)(gong)(gong)(gong)左手(shou)握鉗(qian)，用(yong)(yong)以夾持、移動(dong)和翻轉(zhuan)工(gong)(gong)(gong)(gong)件；右手(shou)握小錘(chui)，用(yong)(yong)于變形量很(hen)小的(de)鍛打和指揮錘(chui)工(gong)(gong)(gong)(gong)的(de)操作。打錘(chui)工(gong)(gong)(gong)(gong)雙(shuang)手(shou)握大(da)錘(chui)，站在砧(zhen)鐵的(de)外(wai)側進(jin)行錘(chui)擊。


 機器鍛(duan)是利用機器產(chan)生的(de)(de)沖擊力或壓力使坯料變(bian)形的(de)(de)加工方(fang)法(fa)。它(ta)的(de)(de)生產(chan)率較(jiao)高(gao)，但(dan)仍是自由鍛(duan)造的(de)(de)基本方(fang)法(fa)。


 機(ji)(ji)器鍛造所用的(de)設(she)備(bei)有(you)(you)空(kong)氣(qi)錘(chui)、蒸汽(qi)錘(chui)和水壓(ya)(ya)(ya)機(ji)(ji)等(deng)，其中以空(kong)氣(qi)錘(chui)應(ying)用最為(wei)廣泛(fan)。它有(you)(you)壓(ya)(ya)(ya)縮汽(qi)缸(gang)(gang)(gang)和工(gong)作汽(qi)缸(gang)(gang)(gang)，壓(ya)(ya)(ya)縮汽(qi)缸(gang)(gang)(gang)內有(you)(you)壓(ya)(ya)(ya)縮活(huo)塞(sai)，由電動機(ji)(ji)經(jing)減速機(ji)(ji)構再借曲柄(bing)－連(lian)桿機(ji)(ji)構帶動而作上(shang)下運動。當(dang)壓(ya)(ya)(ya)縮活(huo)塞(sai)上(shang)升時(shi)，將空(kong)氣(qi)壓(ya)(ya)(ya)人(ren)工(gong)作汽(qi)缸(gang)(gang)(gang)的(de)上(shang)部(bu)，使(shi)工(gong)作活(huo)塞(sai)連(lian)同錘(chui)頭(tou)和上(shang)砧鐵下擊。當(dang)壓(ya)(ya)(ya)縮活(huo)塞(sai)下降時(shi)，將空(kong)氣(qi)壓(ya)(ya)(ya)人(ren)工(gong)作汽(qi)缸(gang)(gang)(gang)的(de)下部(bu)，使(shi)工(gong)作活(huo)塞(sai)連(lian)同錘(chui)頭(tou)上(shang)升。