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)造(zao)所用(yong)設(she)備和工具(ju)通(tong)用(yong)性較大(da)(da)，鍛(duan)件(jian)(jian)的質量大(da)(da)小不等。但是(shi)，自(zi)由鍛(duan)件(jian)(jian)的形狀(zhuang)和尺寸(cun)主要依(yi)靠鍛(duan)工的操作技術來保證，對鍛(duan)工的技術水平要求高，勞動強度(du)大(da)(da)，生產(chan)率(lv)低，鍛(duan)件(jian)(jian)的精度(du)低，加工余量大(da)(da)，且不能獲得較復(fu)雜的形狀(zhuang)。所以主要用(yong)于單(dan)件(jian)(jian)、小批生產(chan)以及修配(pei)工作。對于大(da)(da)型鍛(duan)件(jian)(jian)，自(zi)由鍛(duan)造(zao)是(shi)唯一的生產(chan)方法。自(zi)由鍛(duan)造(zao)有手工鍛(duan)和機器鍛(duan)兩種。

 手工(gong)(gong)鍛(duan)是靠(kao)人力利用砧鐵、大(da)錘、小(xiao)錘、手鉗、沖子、鑿(zao)子和(he)型錘等工(gong)(gong)具(ju)，使坯料變形制成鍛(duan)件的加工(gong)(gong)方法。手工(gong)(gong)鍛(duan)所用的設備和(he)工(gong)(gong)具(ju)簡單、投資少，但勞動強度大(da)、生產率(lv)低(di)，適用于修理(li)工(gong)(gong)作以及機器(qi)鍛(duan)的輔助工(gong)(gong)作。

 手(shou)工(gong)(gong)(gong)鍛是由掌鉗(qian)(qian)(qian)工(gong)(gong)(gong)和打(da)錘(chui)工(gong)(gong)(gong)配合進行操(cao)作(zuo)的(de)。掌鉗(qian)(qian)(qian)工(gong)(gong)(gong)左手(shou)握(wo)鉗(qian)(qian)(qian)，用以夾持(chi)、移(yi)動(dong)和翻轉(zhuan)工(gong)(gong)(gong)件(jian)；右(you)手(shou)握(wo)小錘(chui)，用于變形(xing)量很小的(de)鍛打(da)和指揮錘(chui)工(gong)(gong)(gong)的(de)操(cao)作(zuo)。打(da)錘(chui)工(gong)(gong)(gong)雙手(shou)握(wo)大錘(chui)，站在砧鐵(tie)的(de)外側(ce)進行錘(chui)擊。

 機器鍛是(shi)利(li)用機器產生的(de)沖擊力或壓(ya)力使坯料變形的(de)加(jia)工(gong)方法。它(ta)的(de)生產率較高(gao)，但仍是(shi)自(zi)由鍛造的(de)基本方法。

 機(ji)(ji)器鍛造所用的設備有空氣錘(chui)、蒸汽(qi)錘(chui)和(he)水壓(ya)(ya)機(ji)(ji)等(deng)，其中以空氣錘(chui)應用最為廣泛。它有壓(ya)(ya)縮(suo)汽(qi)缸(gang)和(he)工(gong)(gong)作(zuo)(zuo)汽(qi)缸(gang)，壓(ya)(ya)縮(suo)汽(qi)缸(gang)內有壓(ya)(ya)縮(suo)活(huo)塞(sai)，由電動(dong)機(ji)(ji)經減速機(ji)(ji)構(gou)再(zai)借曲柄(bing)－連(lian)桿機(ji)(ji)構(gou)帶動(dong)而作(zuo)(zuo)上(shang)(shang)(shang)下運動(dong)。當(dang)(dang)壓(ya)(ya)縮(suo)活(huo)塞(sai)上(shang)(shang)(shang)升(sheng)時，將空氣壓(ya)(ya)人工(gong)(gong)作(zuo)(zuo)汽(qi)缸(gang)的上(shang)(shang)(shang)部(bu)，使(shi)工(gong)(gong)作(zuo)(zuo)活(huo)塞(sai)連(lian)同(tong)錘(chui)頭和(he)上(shang)(shang)(shang)砧鐵(tie)下擊。當(dang)(dang)壓(ya)(ya)縮(suo)活(huo)塞(sai)下降時，將空氣壓(ya)(ya)人工(gong)(gong)作(zuo)(zuo)汽(qi)缸(gang)的下部(bu)，使(shi)工(gong)(gong)作(zuo)(zuo)活(huo)塞(sai)連(lian)同(tong)錘(chui)頭上(shang)(shang)(shang)升(sheng)。