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(zi)由鍛(duan)(duan)(duan)(duan)造(zao)所(suo)用設備(bei)和工(gong)(gong)具通用性較(jiao)大(da)，鍛(duan)(duan)(duan)(duan)件(jian)(jian)的質量大(da)小(xiao)不等。但是，自(zi)由鍛(duan)(duan)(duan)(duan)件(jian)(jian)的形(xing)狀(zhuang)和尺(chi)寸主要依靠鍛(duan)(duan)(duan)(duan)工(gong)(gong)的操作(zuo)技術(shu)(shu)來保(bao)證，對鍛(duan)(duan)(duan)(duan)工(gong)(gong)的技術(shu)(shu)水平要求高，勞動強(qiang)度大(da)，生產(chan)(chan)率低，鍛(duan)(duan)(duan)(duan)件(jian)(jian)的精度低，加工(gong)(gong)余量大(da)，且不能獲得較(jiao)復雜的形(xing)狀(zhuang)。所(suo)以主要用于(yu)單件(jian)(jian)、小(xiao)批生產(chan)(chan)以及(ji)修配工(gong)(gong)作(zuo)。對于(yu)大(da)型鍛(duan)(duan)(duan)(duan)件(jian)(jian)，自(zi)由鍛(duan)(duan)(duan)(duan)造(zao)是唯一的生產(chan)(chan)方(fang)法。自(zi)由鍛(duan)(duan)(duan)(duan)造(zao)有手(shou)工(gong)(gong)鍛(duan)(duan)(duan)(duan)和機(ji)器鍛(duan)(duan)(duan)(duan)兩種。


 手(shou)工(gong)鍛是(shi)靠人力利用(yong)砧鐵(tie)、大錘(chui)、小(xiao)錘(chui)、手(shou)鉗、沖子(zi)、鑿子(zi)和型錘(chui)等工(gong)具(ju)，使(shi)坯料變形(xing)制成鍛件(jian)的(de)加工(gong)方法(fa)。手(shou)工(gong)鍛所用(yong)的(de)設備和工(gong)具(ju)簡單、投資(zi)少，但勞動強度大、生產率(lv)低，適用(yong)于修(xiu)理工(gong)作以及機器鍛的(de)輔助工(gong)作。


 手(shou)工(gong)(gong)鍛是由掌鉗(qian)工(gong)(gong)和打(da)錘(chui)(chui)工(gong)(gong)配合進(jin)行操作的。掌鉗(qian)工(gong)(gong)左(zuo)手(shou)握鉗(qian)，用以夾持、移(yi)動和翻(fan)轉工(gong)(gong)件(jian)；右(you)手(shou)握小(xiao)錘(chui)(chui)，用于變(bian)形量很小(xiao)的鍛打(da)和指(zhi)揮錘(chui)(chui)工(gong)(gong)的操作。打(da)錘(chui)(chui)工(gong)(gong)雙手(shou)握大錘(chui)(chui)，站在砧鐵的外(wai)側進(jin)行錘(chui)(chui)擊。


 機(ji)(ji)器鍛(duan)是(shi)利用機(ji)(ji)器產生(sheng)的沖擊(ji)力或壓力使坯料變形的加工方(fang)法(fa)。它的生(sheng)產率較高(gao)，但仍是(shi)自由鍛(duan)造的基(ji)本(ben)方(fang)法(fa)。


 機(ji)器(qi)鍛造所用的(de)(de)設備有(you)空氣(qi)錘(chui)、蒸(zheng)汽(qi)錘(chui)和水壓(ya)機(ji)等，其中以空氣(qi)錘(chui)應用最為廣泛(fan)。它有(you)壓(ya)縮(suo)汽(qi)缸和工(gong)(gong)(gong)作汽(qi)缸，壓(ya)縮(suo)汽(qi)缸內有(you)壓(ya)縮(suo)活(huo)(huo)塞，由(you)電動機(ji)經減(jian)速機(ji)構再借曲柄－連桿(gan)機(ji)構帶動而作上(shang)下運(yun)動。當(dang)壓(ya)縮(suo)活(huo)(huo)塞上(shang)升(sheng)時(shi)(shi)，將(jiang)空氣(qi)壓(ya)人工(gong)(gong)(gong)作汽(qi)缸的(de)(de)上(shang)部(bu)，使(shi)工(gong)(gong)(gong)作活(huo)(huo)塞連同錘(chui)頭(tou)和上(shang)砧(zhen)鐵下擊。當(dang)壓(ya)縮(suo)活(huo)(huo)塞下降時(shi)(shi)，將(jiang)空氣(qi)壓(ya)人工(gong)(gong)(gong)作汽(qi)缸的(de)(de)下部(bu)，使(shi)工(gong)(gong)(gong)作活(huo)(huo)塞連同錘(chui)頭(tou)上(shang)升(sheng)。