Hauv lojforging, thaum qhov zoo ntawm raw cov ntaub ntawv tsis zoo los yog forging txheej txheem tsis nyob rau hauv lub sij hawm, forging tawg yog feem ntau yooj yim tshwm sim.
Cov hauv qab no qhia txog ntau qhov xwm txheej ntawm forging tawg los ntawm cov khoom siv tsis zoo.
(1)Forgingkab nrib pleb tshwm sim los ntawm ingot defects

Feem ntau ntawm cov ingot tsis xws luag yuav ua rau tawg thaum lub sij hawm forging, raws li qhia nyob rau hauv daim duab, uas yog lub hauv paus tawg ntawm 2Cr13 spindle forging.
Qhov no yog vim hais tias qhov kub ntawm crystallization yog nqaim thiab cov linear shrinkage coefficient loj thaum lub 6T ingot solidifies.
Vim tsis txaus condensation thiab shrinkage, kub sib txawv ntawm sab hauv thiab sab nraud, loj axial tensile kev nyuaj siab, lub dendrite tawg, tsim ib tug inter-axial tawg nyob rau hauv lub ingot, uas yog ntxiv nthuav thaum lub sij hawm forging los ua ib tug tawg nyob rau hauv spindle forging.

Qhov tsis xws luag tuaj yeem tshem tawm los ntawm:
(1) Txhim kho qhov purity ntawm molten steel smelting;
(2) Ingot txias maj mam, txo thermal stress;
(3) Siv cov khoom cua kub zoo thiab rwb thaiv tsev, ua kom muaj peev xwm ua kom lub ntsws;
(4) Siv lub hauv paus compaction forging txheej txheem.

(2)Forgingkab nrib pleb tshwm sim los ntawm nag lossis daus ntawm teeb meem impurities nyob rau hauv steel raws li grain ciam teb.

Cov leej faj nyob rau hauv cov hlau feem ntau precipitated nyob rau hauv lub grain ciam teb nyob rau hauv daim ntawv ntawm FeS, nws melting point tsuas yog 982 ℃.Thaum lub forging kub ntawm 1200 ℃, LUB FeS nyob rau hauv ciam teb ntawm grain yuav yaj thiab nyob ib ncig ntawm cov nplej nyob rau hauv daim ntawv ntawm cov kua zaj duab xis, uas yuav ua kom puas lub bonds ntawm cov nplej thiab ua thermal fragility, thiab lub cracking yuav tshwm sim tom qab me ntsis forging.

Thaum tooj liab muaj nyob rau hauv cov hlau yog rhuab nyob rau hauv ib tug peroxidation cua ntawm 1100 ~ 1200 ℃, vim xaiv oxidation, tooj liab nplua nuj nyob rau hauv txheej txheej.Thaum lub solubility ntawm tooj liab nyob rau hauv austenite ntau tshaj ntawm tooj liab, tooj liab yog faib nyob rau hauv daim ntawv ntawm cov kua zaj duab xis nyob rau hauv grain ciam teb, tsim tooj liab brittleness thiab tsis tuaj yeem forged.
Yog hais tias muaj tin thiab antimony nyob rau hauv steel, solubility ntawm tooj liab nyob rau hauv austenite yuav raug txo kom loj, thiab embrittlement tendency yuav intensified.
Vim yog cov ntsiab lus tooj liab siab, qhov saum npoo ntawm cov hlau forgings yog xaiv oxidized thaum lub sij hawm forging cua sov, yog li ntawd cov tooj liab yog enriched nyob rau hauv grain ciam teb, thiab forging tawg yog tsim los ntawm nucleating thiab expanding raws tooj liab-nplua nuj theem ntawm grain ciam teb.

(3)Forging tawgtshwm sim los ntawm heterogeneous theem (thib ob)

Cov khoom siv hluav taws xob ntawm theem ob hauv cov hlau feem ntau sib txawv ntawm cov hlau matrix, yog li qhov kev ntxhov siab ntxiv yuav ua rau tag nrho cov txheej txheem plasticity txo qis thaum lub deformation ntws.Thaum cov kev ntxhov siab hauv zos tshaj qhov kev sib khi ntawm cov theem heterogeneous thiab matrix, kev sib cais yuav tshwm sim thiab cov qhov yuav raug tsim.
Piv txwv li, oxides, nitrides, carbides, borides, sulfides, silicates thiab lwm yam hlau.
Cia peb hais cov theem no tuab.
Kev faib cov saw hlau, tshwj xeeb tshaj yog nyob rau thaj tsam ntawm cov qoob loo uas tsis muaj zog binding muaj zog, kub forging yuav tawg.
Lub macroscopic morphology ntawm forging cracking tshwm sim los ntawm nplua AlN nag lossis daus raws lis ciam teb ntawm 20SiMn steel 87t ingots tau oxidized thiab nthuav tawm raws li polyhedral columnar crystals.
Kev tsom xam ntawm microscopic qhia tau hais tias forging cracking muaj feem xyuam rau qhov loj ntawm cov nplua nplej AlN nag lossis daus nyob rau hauv thawj ciam teb.

Cov countermeasures rautiv thaiv forging crackingtshwm sim los ntawm nag lossis daus ntawm aluminium nitride raws crystal yog raws li nram no:
1. Txwv tsis pub cov txhuas ntxiv rau cov hlau, tshem tawm nitrogen los ntawm cov hlau los yog inhibit AlN nag lossis daus los ntawm kev ntxiv titanium;
2. Txais kev xa khoom kub ingot thiab supercooled theem hloov txheej txheem kev kho mob;
3. Ua kom cov cua sov kom sov (> 900 ℃) thiab ncaj qha tshav kub forging;
4. Ua ntej forging, txaus homogenization annealing yog nqa tawm los ua grain ciam teb nag lossis daus theem diffusion.