Ua rau tawg ntawm cov hlau

Cracking ntawm hlau yog ib txoj kev nyuaj uas muaj ntau yam. Cov hauv qab no yog qee qhov laj thawj tseem ceeb:

- Cov yam ntxwv ntawm cov khoom nws tus kheej: cov tshuaj lom neeg muaj pes tsawg leeg thiab cov koom haum metallographic ncaj qha cuam tshuam qhov cuam tshuam ntawm cov hlau, xws li carbon, phosphorus, sulfur thiab lwm cov ntsiab lus nce yuav txo qhov cuam tshuam toughness.

- Cov txheej txheem kev kho cua sov: txheej txheem kev kho cua sov tsis raug, xws li quenching, tempering, thiab lwm yam, tuaj yeem ua rau muaj kev hloov pauv hauv microstructure thiab cov khoom ntawm cov khoom, yog li cuam tshuam rau nws cov toughness.

- Internal defects: inclusions, segregation, npuas, sab hauv cov kab nrib pleb thiab lwm yam tsis xws luag nyob rau hauv cov khoom yuav txo nws cov kev cuam tshuam toughness thiab ua ib tug stress concentration point.

- Kev npaj cov qauv thiab kuaj cov qauv: cov qauv coj mus kuaj kev taw qhia, ntsuas geometry thiab kev ua haujlwm zoo, ntsuas kub, thiab lwm yam.

Hlau tawg yog ib qho ntawm cov laj thawj tseem ceeb ntawm kev ua tsis tiav nyob rau hauv ntau cov qauv, tshwj xeeb tshaj yog nyob rau hauv cov khoom uas raug kev nyuaj siab los yog siab loads. Los ntawm kev soj ntsuam kev tawg, cov teeb meem tawg tuaj yeem tshawb pom nyob rau lub sijhawm, yog li zam kev nyab xeeb kev sib tsoo los ntawm kev ua haujlwm tsis zoo, xws li tawg, tawg, tawg, thiab lwm yam.

Kev soj ntsuam kev sib tsoo pab kom nkag siab qhov ua rau, tus nqi ntawm kev nthuav dav thiab qhov seem ntawm lub neej ntawm cov kab nrib pleb. Los ntawm kev kho kom tsim nyog lossis kev ntsuas kev saib xyuas, kev nthuav dav ntawm cov kab nrib pleb tuaj yeem ua rau qeeb, yog li txuas ntxiv kev pab cuam lub neej ntawm cov hlau thiab txo cov nqi hloov thiab kho.

Kev faib tawm thiab qhov sib txawv ntawm cov hlau tawg

Kev kho cua sov ua kom tawg

Yam ntxwv:

Morphology: Thaum tshav kub kub kho cov kab nrib pleb feem ntau tsim nyob rau hauv martensitic transformation cheeb tsam, yog li lawv cov kab nrib pleb yuav tawg raws cov siv lead ua los yog tawg los ntawm cov siv lead ua. Cov kab nrib pleb tuaj yeem yog radial, cais kab lossis net.

Qhov chaw: Cov kab nrib pleb feem ntau yuav tshwm sim ntawm cov ces kaum ntse ntawm qhov chaw ua haujlwm, ntawm kev hloov pauv tam sim ntawm ntu ntu.

Seem: Cov seem ntawm qhov quenching tawg yog feem ntau tsis oxidized thiab tej zaum yuav dawb, npub dawb los yog lub teeb liab (dej xeb los ntawm quenching).

Ua rau:

Kev sib tsoo tshwm sim thaum qhov kev ntxhov siab loj uas tau tsim thaum lub sij hawm quenching yog ntau dua li cov khoom siv lub zog thiab tshaj cov yas deformation txwv.

Tej zaum nws yuav cuam tshuam rau yam xws li kub kub quenching kub thiab txias ceev heev.

Yog vim li cas rau kev kho cua sov tawg

ib. Khoom siv metallurgical zoo:

Metallurgical teeb meem xws li shrinkage thiab loj dov tsis xws luag yuav ua rau cov khoom inhomogeneities uas ua rau muaj kev pheej hmoo ntawm quenching tawg.

b. Cov ntsiab lus carbon cov ntsiab lus thiab cov ntsiab lus alloying: kev nce hauv cov ntsiab lus ntawm cov pa roj carbon monoxide txo qis lub zog tawg ntawm martensite, yog li ua kom muaj kev nyiam rau quenching tawg.

c. Cov txheej txheem quenching:

quenching cua sov txoj kev thiab kev tswj tsis raug ntawm cua kub ceev, cua sov tsis sib xws, quenching kub siab dhau heev lawm yuav ua rau quenching tawg.

d. Workpiece loj thiab puab:

Quenching cov kab nrib pleb yog yooj yim tsim nyob rau hauv lub ntse ces kaum ntawm lub workpiece thiab sai li sai tau hloov nyob rau hauv tus ntoo khaub lig-section, vim hais tias cov chaw no yog nquag muaj kev nyuaj siab concentration. Cov ncej loj loj hauv Quenching yog tias tsis quenched, ua rau thermal stress-induced tawg.

e. Internal defects:

Cov teeb meem uas twb muaj lawm nyob rau hauv cov khoom, xws li vapor npuas, inclusions, hairline, dawb me ntsis, thiab lwm yam, tej zaum yuav dhau los ua ib qho ntawm cov kab nrib pleb nyob rau hauv qhov kev txiav txim ntawm kev kho cua sov kev nyuaj siab thiab maj mam nthuav.

f. Martensite intrinsic brittleness:

Lub intrinsic brittleness ntawm martensite yog qhov ua rau quenching tawg, thiab nws cov qauv siv lead ua, tshuaj muaj pes tsawg leeg, metallurgical tsis xws luag, thiab lwm yam.

Forging tawg

Yam ntxwv:

Morphology: forging cov kab nrib pleb yog tsim los ntawm qhov kub thiab txias, cov kab nrib pleb yog tuab thiab feem ntau muaj nyob rau hauv daim ntawv ntawm ntau lub strips, tsis muaj qhov zoo, tsis muaj kev coj zoo. Qee lub sij hawm nyob ib ncig ntawm qhov tawg tsis yog tag nrho decarburized tab sis semi-decarburized.

Qhov chaw: Feem ntau ua nyob rau hauv lub coarse lub koom haum, kev nyuaj siab concentration los yog alloying ntsiab ntawm lub segregation.

Ntu ntu: ntu tawg tuaj yeem yog xim av tsaus, thiab txawm tias muaj cov tawv nqaij oxygen tshwm sim, qhov no yog vim qhov tawg ntawm forging deformation nthuav dav thiab kev sib cuag nrog huab cua.

Ua rau: a, raw khoom tsis xws luag: residual shrinkage: raw khoom nyob rau hauv lub xub ntiag ntawm tsis tiav kaw ntawm lub qhov hws los yog qhov, tej zaum yuav ua rau cov txheej txheem forging kom txo tau lub zog ntawm cov khoom, yooj yim los tsim cov kab nrib pleb.

b, steel inclusions: non-metallic inclusions nyob rau hauv cov khoom raw, carbide segregation, heterogeneous hlau inclusions, thiab lwm yam., tej zaum yuav tsis muaj zog lub continuation ntawm cov khoom, txhawb kev tsim cov kab nrib pleb.

Txoj kev forging tsis raug:

c, cua sov tsis tsim nyog: qhov cua kub kub yog siab dhau los yog qis dhau, uas yuav ua rau tsis sib xws ntawm kev ntxhov siab hauv cov khoom, uas ua rau tawg tawg thaum lub sij hawm forging.

d, deformation tsis zoo: tus nqi deformation loj dhau, cov yas ntawm cov hlau tsis txaus los tiv thaiv cov duab ntawm lub siab, yooj yim ua rau tawg. Qhov kev tawg no feem ntau tshwm sim thaum pib ntawm forging theem, thiab nthuav dav sai.

e, tsis raug cua txias tom qab forging: qhov cua txias yog nrawm dhau los yog qeeb dhau, tuaj yeem ua rau muaj kev ntxhov siab hauv cov khoom siv, ua rau tawg.

f, kev kho cua sov tsis raws sijhawm: tom qab forging tsis raws sijhawm thiab kev kho cua sov tsim nyog, tuaj yeem ua rau cov khoom siv hauv kev ntxhov siab tsis zoo tso tawm, yog li ua rau muaj kev pheej hmoo ntawm kev tawg.

g, tswj qhov kub tsis zoo:

Hauv cov txheej txheem cua sov thiab cua txias, yog tias qhov ntsuas kub tsis raug tswj tau zoo, nws yuav ua rau muaj kev ntxhov siab ntau dhau ntawm cov khoom, yog li ua rau tawg. Piv txwv li, nyob rau hauv cov txheej txheem quenching, yog tias qhov txias yog ceev heev, quenching tawg yuav tshwm sim.

h. Material stress concentration:

Yog hais tias muaj ib qho kev nyuaj siab nyob rau hauv lub forging, xws li cov ces kaum ntse thiab hla-section kev hloov, thaum qhov kev nyuab siab tshaj cov khoom muaj peev xwm tiv taus, nws yuav ua rau tawg.