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(you)鍛(duan)(duan)造所(suo)用設備和(he)工(gong)(gong)(gong)具通用性(xing)較大，鍛(duan)(duan)件(jian)的(de)質量大小不等。但是，自(zi)由(you)鍛(duan)(duan)件(jian)的(de)形狀和(he)尺寸主要(yao)依靠鍛(duan)(duan)工(gong)(gong)(gong)的(de)操作(zuo)技術來(lai)保證，對鍛(duan)(duan)工(gong)(gong)(gong)的(de)技術水平要(yao)求(qiu)高，勞(lao)動強度大，生(sheng)產(chan)率低，鍛(duan)(duan)件(jian)的(de)精度低，加工(gong)(gong)(gong)余量大，且不能獲(huo)得較復雜的(de)形狀。所(suo)以主要(yao)用于單(dan)件(jian)、小批生(sheng)產(chan)以及(ji)修配工(gong)(gong)(gong)作(zuo)。對于大型鍛(duan)(duan)件(jian)，自(zi)由(you)鍛(duan)(duan)造是唯一的(de)生(sheng)產(chan)方法。自(zi)由(you)鍛(duan)(duan)造有(you)手工(gong)(gong)(gong)鍛(duan)(duan)和(he)機器鍛(duan)(duan)兩種。


 手工(gong)(gong)(gong)(gong)鍛(duan)(duan)是靠人力利用(yong)砧鐵、大(da)錘、小錘、手鉗、沖子、鑿子和(he)型錘等工(gong)(gong)(gong)(gong)具(ju)，使坯(pi)料變形制成(cheng)鍛(duan)(duan)件的(de)加工(gong)(gong)(gong)(gong)方法。手工(gong)(gong)(gong)(gong)鍛(duan)(duan)所用(yong)的(de)設備和(he)工(gong)(gong)(gong)(gong)具(ju)簡單(dan)、投資少(shao)，但勞(lao)動強度大(da)、生產率低，適用(yong)于修(xiu)理工(gong)(gong)(gong)(gong)作(zuo)以及機器鍛(duan)(duan)的(de)輔助工(gong)(gong)(gong)(gong)作(zuo)。


 手(shou)工(gong)鍛是由掌鉗(qian)工(gong)和打(da)錘(chui)工(gong)配合進行操作(zuo)的(de)。掌鉗(qian)工(gong)左手(shou)握(wo)(wo)(wo)鉗(qian)，用(yong)(yong)以(yi)夾持、移動和翻轉工(gong)件；右手(shou)握(wo)(wo)(wo)小(xiao)錘(chui)，用(yong)(yong)于變形量很小(xiao)的(de)鍛打(da)和指(zhi)揮錘(chui)工(gong)的(de)操作(zuo)。打(da)錘(chui)工(gong)雙(shuang)手(shou)握(wo)(wo)(wo)大錘(chui)，站(zhan)在砧鐵的(de)外側進行錘(chui)擊(ji)。


 機器鍛(duan)是(shi)利用(yong)機器產(chan)生(sheng)的沖擊力(li)或(huo)壓力(li)使坯料變形的加工方法。它的生(sheng)產(chan)率(lv)較(jiao)高，但(dan)仍是(shi)自由鍛(duan)造的基本方法。


 機(ji)(ji)器鍛造所用的設備有空氣(qi)錘(chui)、蒸(zheng)汽(qi)(qi)錘(chui)和水壓(ya)機(ji)(ji)等，其中以空氣(qi)錘(chui)應用最(zui)為廣泛。它有壓(ya)縮汽(qi)(qi)缸和工作(zuo)(zuo)汽(qi)(qi)缸，壓(ya)縮汽(qi)(qi)缸內有壓(ya)縮活塞，由(you)電動(dong)機(ji)(ji)經減速機(ji)(ji)構(gou)(gou)再借曲柄－連桿機(ji)(ji)構(gou)(gou)帶動(dong)而作(zuo)(zuo)上(shang)下運動(dong)。當壓(ya)縮活塞上(shang)升(sheng)時，將空氣(qi)壓(ya)人(ren)工作(zuo)(zuo)汽(qi)(qi)缸的上(shang)部，使(shi)工作(zuo)(zuo)活塞連同錘(chui)頭和上(shang)砧(zhen)鐵下擊(ji)。當壓(ya)縮活塞下降(jiang)時，將空氣(qi)壓(ya)人(ren)工作(zuo)(zuo)汽(qi)(qi)缸的下部，使(shi)工作(zuo)(zuo)活塞連同錘(chui)頭上(shang)升(sheng)。