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。


 自由鍛(duan)(duan)造所用(yong)設備和工(gong)具通(tong)用(yong)性較大(da)(da)，鍛(duan)(duan)件(jian)(jian)的(de)(de)(de)質量大(da)(da)小(xiao)不等。但是(shi)，自由鍛(duan)(duan)件(jian)(jian)的(de)(de)(de)形狀和尺寸主要依靠鍛(duan)(duan)工(gong)的(de)(de)(de)操作技術來保證(zheng)，對鍛(duan)(duan)工(gong)的(de)(de)(de)技術水平(ping)要求高，勞動強度(du)大(da)(da)，生(sheng)產率低(di)，鍛(duan)(duan)件(jian)(jian)的(de)(de)(de)精度(du)低(di)，加工(gong)余(yu)量大(da)(da)，且不能獲得較復雜的(de)(de)(de)形狀。所以(yi)主要用(yong)于單件(jian)(jian)、小(xiao)批生(sheng)產以(yi)及修配工(gong)作。對于大(da)(da)型鍛(duan)(duan)件(jian)(jian)，自由鍛(duan)(duan)造是(shi)唯一的(de)(de)(de)生(sheng)產方法(fa)。自由鍛(duan)(duan)造有(you)手工(gong)鍛(duan)(duan)和機器鍛(duan)(duan)兩種(zhong)。


 手工(gong)(gong)鍛(duan)(duan)是靠人(ren)力利用砧鐵(tie)、大(da)錘(chui)(chui)、小錘(chui)(chui)、手鉗、沖子、鑿子和型錘(chui)(chui)等工(gong)(gong)具，使坯料變形制成鍛(duan)(duan)件的加工(gong)(gong)方法。手工(gong)(gong)鍛(duan)(duan)所用的設備和工(gong)(gong)具簡(jian)單(dan)、投(tou)資(zi)少，但(dan)勞動強度大(da)、生產率(lv)低，適用于修理(li)工(gong)(gong)作以及機器鍛(duan)(duan)的輔助工(gong)(gong)作。


 手工(gong)鍛是由掌(zhang)鉗工(gong)和(he)(he)打錘工(gong)配(pei)合進行操作的(de)。掌(zhang)鉗工(gong)左手握(wo)鉗，用(yong)以(yi)夾(jia)持、移動(dong)和(he)(he)翻轉工(gong)件；右(you)手握(wo)小錘，用(yong)于變形量很(hen)小的(de)鍛打和(he)(he)指揮(hui)錘工(gong)的(de)操作。打錘工(gong)雙(shuang)手握(wo)大錘，站在砧鐵的(de)外側(ce)進行錘擊(ji)。


 機器鍛(duan)(duan)是利用(yong)機器產(chan)生(sheng)的沖(chong)擊力或壓力使(shi)坯料(liao)變形(xing)的加工方(fang)法。它的生(sheng)產(chan)率較高，但仍(reng)是自由鍛(duan)(duan)造(zao)的基本方(fang)法。


 機(ji)(ji)器(qi)鍛造(zao)所用的設備有(you)空氣(qi)錘(chui)(chui)、蒸汽(qi)(qi)錘(chui)(chui)和(he)水壓(ya)機(ji)(ji)等，其中(zhong)以空氣(qi)錘(chui)(chui)應用最為廣泛(fan)。它(ta)有(you)壓(ya)縮汽(qi)(qi)缸(gang)和(he)工(gong)(gong)作汽(qi)(qi)缸(gang)，壓(ya)縮汽(qi)(qi)缸(gang)內(nei)有(you)壓(ya)縮活塞，由電動機(ji)(ji)經減速機(ji)(ji)構再借曲(qu)柄－連(lian)桿機(ji)(ji)構帶動而(er)作上(shang)(shang)(shang)(shang)下(xia)運(yun)動。當壓(ya)縮活塞上(shang)(shang)(shang)(shang)升時(shi)，將空氣(qi)壓(ya)人(ren)工(gong)(gong)作汽(qi)(qi)缸(gang)的上(shang)(shang)(shang)(shang)部，使(shi)工(gong)(gong)作活塞連(lian)同(tong)錘(chui)(chui)頭和(he)上(shang)(shang)(shang)(shang)砧鐵下(xia)擊(ji)。當壓(ya)縮活塞下(xia)降時(shi)，將空氣(qi)壓(ya)人(ren)工(gong)(gong)作汽(qi)(qi)缸(gang)的下(xia)部，使(shi)工(gong)(gong)作活塞連(lian)同(tong)錘(chui)(chui)頭上(shang)(shang)(shang)(shang)升。