Hoʻopā welaʻo ia ka hana ʻana o ka metala ma luna o ka mahana o ka hoʻohāinu hou ʻana.
ʻO ka hoʻonui ʻana i ka mahana hiki ke hoʻomaikaʻi i ka plasticity o ka metala, hiki ke hoʻomaikaʻi i ka maikaʻi o loko o ka mea hana, no laila ʻaʻole maʻalahi ka haki. Hiki i ka wela kiʻekiʻe ke hōʻemi i ke kūpaʻa deformation metala, e hōʻemi i ka tonnage i koi ʻia o ka mīkini forging. Akā ʻo ke kaʻina hana forging wela, ʻilihune ka pololei o ka mea hana, ʻaʻole maʻalahi ka ʻili, maʻalahi ka hana ʻana i ka oxidation, decarburization a me ke ahi. Ke nui a mānoanoa ka mea hana, kiʻekiʻe ka ikaika o ka waiwai a haʻahaʻa ka plasticity (e like me ka ʻōwili ʻana o ka pā mānoanoa keu, ka lōʻihi kaha kiʻi o ke koʻokoʻo kila kalapona kiʻekiʻe, etc.),hoʻopaʻa welahoʻohana ʻia. Ke lawa ka plasticity o ka metala (e like me ke kēpau, tin, zinc, copper, aluminika, etc.) a ʻaʻole nui ka nui o ka deformation (e like me ka nui o ka hana stamping), a i ʻole ka nui o ka deformation a me ka hana forging i hoʻohana ʻia ( e like me ka extrusion, radial forging, etc.) he mea kūpono ia i ka deformation plastic o ka metala, ʻaʻole pinepine e hoʻohana i ka forging wela, akā hoʻohana i ka forging anu. Ka wela wela ma waena o ka wela forging mua a me kahoʻopaʻa hopeʻO ka mahana o ka hoʻoheheʻe wela e like me ka nui e hiki ai ke hoʻokō i ka hana forging e like me ka hiki e hoʻokahi wela. Eia naʻe, kiʻekiʻekalai muaʻO ka mahana e alakaʻi i ka ulu nui ʻana o nā hua metala a me ka hoʻokumu ʻana o ka overheating, kahi e hōʻemi ai i ka maikaʻi o nā ʻāpana forging. Ke kokoke ka mahana i ka helu heheʻe o ka metala, ʻo ka heheʻe haʻahaʻa haʻahaʻa e hoʻoheheʻe ʻia a me ka intergranular oxidation e hiki mai, e hopena i ka overburning. Haʻi pinepine ʻia nā billet i puhi ʻia i ka wā e hana ai. ʻO ka generalhoʻopaʻa welaʻO ka mahana: ke kila kalapona 800 ~ 1250 ℃; Alloy structural steel 850 ~ 1150 ℃; Ke kila māmā holo kiʻekiʻe 900 ~ 1100 ℃; Hoʻohana maʻamau ka alumini alumini 380 ~ 500 ℃; ʻO ka hui Titanium 850 ~ 1000 ℃; Ke keleawe 700 ~ 900 ℃.

ʻO ke anu anuanuʻoi aku ka haʻahaʻa ma mua o ka metala recrystallization wela o ka forging, maʻamau i kapa ʻia ʻo ke anuanu forging ma ka lumi wela, a ʻoi aku ka kiʻekiʻe ma mua o ka mahana o ka lumi, akā ʻaʻole i ʻoi aku ma mua o ka recrystallization wela o ka forging i kapa ʻia ʻo warm forging. ʻOi aku ka kiʻekiʻe o ka pololei o ka forging mahana, ʻoi aku ka maʻalahi o ka ʻili a ʻaʻole nui ka pale deformation.
ʻO ka mea hana i hana ʻia e ka hoʻoheheʻe ʻana ma lalo o ka mahana maʻamau he kikoʻī kiʻekiʻe i ke ʻano a me ka nui, ka ʻili maʻemaʻe, ka liʻiliʻi o nā kaʻina hana a me ka maʻalahi o ka hana ʻana. Hiki ke hoʻohana pololei ʻia nā ʻāpana a i ʻole nā ​​​​huahana me ka ʻole o ka ʻoki ʻana. Akā i lokohana anu anu, Ma muli o ka haʻahaʻa haʻahaʻa o ka metala, ua maʻalahi ka haki ʻana i ka wā deformation, a nui ka pale deformation, no lailanui tonage forginga me nā mīkini paʻi e pono ai.