Hlau phaj delamination thiab txias brittle cracking tom qab steel phaj hluav taws txiav thiab vuam feem ntau muaj tib yam tshwm sim, ob qho tib si ntawm cov kab nrib pleb nyob rau hauv nruab nrab ntawm lub phaj. Los ntawm kev xav ntawm kev siv, delaminated steel phaj yuav tsum tau muab tshem tawm. Tag nrho cov delamination yuav tsum raug tshem tawm tag nrho, thiab cov delamination hauv zos tuaj yeem raug tshem tawm hauv zos. Qhov txias nkig tawg ntawm cov phaj hlau yog tshwm sim raws li kev tawg hauv nruab nrab, uas qee tus neeg kuj hu ua "cracking". Rau qhov yooj yim ntawm kev txheeb xyuas, nws yog qhov tsim nyog los txhais nws li "txias brittle cracking". Qhov kev tsis zoo no tuaj yeem kho nrog kev kho kom zoo thiab siv cov tshuab vuam tsim nyog yam tsis muaj khawb.

1. Hlau phaj delamination
Delamination yog qhov sib txawv hauv zos nyob rau hauv ntu ntu ntawm cov hlau phaj (billet), uas ua rau ntu ntu ntawm steel phaj tsim ib txheej hauv zos. Nws yog qhov ua rau tuag taus ntawm cov hlau. Cov hlau phaj yuav tsum tsis txhob delaminated, saib daim duab 1. Delamination kuj hu ua interlayer thiab delamination, uas yog ib qho kev tsis xws luag ntawm cov hlau. Npuas nyob rau hauv lub ingot (billet), loj non-metallic inclusions, residual shrinkage kab noj hniav uas tsis tag tshem tawm los yog folding, thiab loj segregation yuav tag nrho cov ua rau lub stratification ntawm steel, thiab tsis tsim nyog dov txo cov txheej txheem yuav aggravate lub stratification.

2. Hom steel phaj stratification
Nyob ntawm qhov ua rau, stratification manifests nws tus kheej nyob rau hauv ntau qhov chaw thiab cov ntaub ntawv. Qee qhov tau muab zais rau hauv cov hlau, thiab sab hauv sab hauv yog sib npaug lossis sib npaug rau cov hlau nto; Qee qhov txuas mus rau cov hlau nto thiab tsim cov zawj zoo li qhov chaw tsis xws luag ntawm cov hlau nto. Feem ntau, muaj ob hom:
Thawj yog qhib stratification. Qhov teeb meem stratification no tuaj yeem pom macroscopically ntawm qhov tawg ntawm cov hlau, thiab feem ntau tuaj yeem rov tshuaj xyuas hauv cov nroj tsuag steel thiab cov chaw tsim khoom.
Qhov thib ob yog kaw stratification. Qhov no stratification defect tsis tuaj yeem pom nyob rau hauv qhov tawg ntawm cov hlau, thiab nws yog ib qho nyuaj rau nrhiav tau nws nyob rau hauv lub manufacturing cog yam tsis muaj 100% ultrasonic flaw nrhiav pom ntawm txhua steel phaj. Nws yog kaw stratification hauv steel phaj. Qhov teeb meem stratification no yog coj los ntawm smelter mus rau cov chaw tsim khoom thiab thaum kawg ua tiav rau hauv cov khoom xa tuaj.
Lub hav zoov ntawm delamination tsis xws luag yuav txo tau cov thickness ntawm steel phaj nyob rau hauv lub delamination cheeb tsam kom dais lub load thiab txo lub load-bearing muaj peev xwm nyob rau hauv tib txoj kev raws li lub delamination. Lub ntug zoo ntawm delamination tsis xws luag yog ntse, uas yog rhiab heev rau kev ntxhov siab thiab yuav ua rau muaj kev ntxhov siab loj heev. Yog tias muaj kev rov ua haujlwm, tshem tawm, cua sov, thiab cua txias thaum lub sijhawm ua haujlwm, qhov kev hloov pauv loj yuav raug tsim nyob rau hauv qhov chaw muaj kev ntxhov siab, ua rau muaj kev ntxhov siab.

3. Kev ntsuam xyuas txoj kev ua kom txias txias
3.1 Carbon sib npaug txoj kev-kev ntsuam xyuas ntawm qhov txias tawg nyiam ntawm cov hlau
Txij li thaum lub hardening thiab txias tawg nyiam ntawm vuam tshav kub-cuam tshuam cheeb tsam muaj feem xyuam rau cov tshuaj muaj pes tsawg leeg ntawm cov hlau, cov tshuaj muaj pes tsawg leeg yog siv rau indirectly ntsuam xyuas qhov rhiab heev ntawm txias tawg nyob rau hauv cov hlau. Cov ntsiab lus ntawm cov ntsiab lus ntawm cov hlau nyob hauv cov hlau yog hloov mus rau hauv cov ntsiab lus sib npaug ntawm cov pa roj carbon monoxide raws li nws txoj haujlwm, uas yog siv los ua qhov ntsuas qhov ntsuas rau kwv yees qhov ntsuas kub ntawm qhov sib npaug ntawm cov hlau, uas yog cov pa roj carbon sib npaug. Rau cov txheej txheem carbon sib npaug ntawm cov hlau tsis tshua muaj hlau, International Institute of Welding (IIW) pom zoo cov qauv: Ceq(IIW) = C + Mn / 6 + (Cr + Mo + V) / 5 + (Ni + Cu) / 15. Raws li cov qauv, qhov loj dua qhov sib npaug ntawm cov pa roj carbon monoxide, qhov ntau dua qhov nyuaj ntawm cov hlau welded, thiab qhov yooj yim dua nws yog los tsim cov kab nrib pleb hauv qhov kub thiab txias. Yog li ntawd, cov pa roj carbon sib npaug tuaj yeem siv los ntsuas qhov weldability ntawm cov hlau, thiab cov txheej txheem zoo tshaj plaws los tiv thaiv cov kab nrib pleb tuaj yeem raug thov raws li qhov weldability. Thaum siv cov mis pom zoo los ntawm Lub Tsev Haujlwm Thoob Ntiaj Teb, yog Ceq (IIW) ＜ 0.4%, qhov kev xav ntawm qhov tawv nqaij tsis zoo, qhov weldability yog qhov zoo, thiab tsis tas yuav tsum tau preheating ua ntej vuam; yog Ceq (IIW) ≥ 0.4% ~ 0.6%, tshwj xeeb tshaj yog thaum nws siab tshaj 0.5%, cov hlau yog yooj yim rau harden. Qhov no txhais tau hais tias lub weldability tau deteriorated, thiab preheating yuav tsum tau thaum lub sij hawm vuam los tiv thaiv vuam tawg. Lub preheating kub yuav tsum tau nce raws li lub phaj thickness nce.
3.2 Welding txias crack rhiab heev index
Ntxiv nrog rau cov tshuaj lom neeg muaj pes tsawg leeg, qhov ua rau mob khaub thuas tawg nyob rau hauv qis-alloy high-strength steel welding muaj xws li cov ntsiab lus ntawm diffusible hydrogen nyob rau hauv cov deposited hlau, txwv kev nyuaj siab ntawm kev sib koom tes, thiab lwm yam. Ito et al. ntawm Nyij Pooj tau ua ntau qhov kev ntsuam xyuas ntawm ntau tshaj 200 hom hlau uas siv qhov kev tshawb fawb ntawm Y-shaped zawj hlau thiab cov qauv tsim xws li cov kab mob khaub thuas tawg rhiab heev tsim los ntawm cov tshuaj muaj pes tsawg leeg, diffusible hydrogen, thiab txwv (los yog phaj thickness) , thiab siv qhov ntsuas qhov sib txawv ntawm qhov kub thiab txias los txiav txim siab qhov kub thiab txias uas yuav tsum tau ua ua ntej vuam los tiv thaiv cov kab mob khaub thuas. Nws feem ntau ntseeg tau tias cov qauv hauv qab no tuaj yeem siv rau cov hlau tsis tshua muaj hlau uas muaj cov ntsiab lus carbon tsis ntau tshaj 0.16% thiab lub zog tensile ntawm 400-900MPa. Pcm=C+Si/30+Mn/20+Cu/20+Ni/60+Cr/20+Mo/15+V/10+5B (%);
Pc = Pcm + [H] / 60 + t / 600 (%)
Rau = 1440PC-392 (℃)
Qhov twg: [H] ——Diffusible hydrogen ntsiab lus ntawm deposited hlau ntsuas los ntawm Japanese JIS 3113 tus qauv (ml / 100g); t — Phaj thickness (mm); Rau - Yam tsawg kawg nkaus preheating kub ua ntej vuam (℃).
Xam cov welding txias crack rhiab heev Performance index Pc ntawm steel phaj ntawm no thickness, thiab qhov tsawg kawg nkaus preheating kub rau ua ntej cracking. Thaum xam qhov tshwm sim To≥50 ℃, cov hlau phaj muaj qee yam vuam txias tawg rhiab heev thiab yuav tsum tau preheated.

4. Kho qhov txias brittle "cracking" ntawm cov khoom loj
Tom qab cov hlau phaj vuam tiav, ib feem ntawm cov phaj hlau tawg, uas yog hu ua "delamination". Saib daim duab 2 hauv qab no rau qhov morphology ntawm qhov tawg. Cov kws tshaj lij vuam ntseeg tias nws yog qhov tsim nyog los txhais cov txheej txheem kho raws li "cov txheej txheem kho vuam ntawm Z-kev taw qhia cov kab nrib pleb hauv cov hlau phaj". Txij li thaum cov khoom siv loj, nws yog ib qho kev ua haujlwm ntau heev kom tshem tawm cov phaj steel, thiab tom qab ntawd txuas nws dua. Tag nrho cov khoom yuav zoo li deformed, thiab tag nrho cov khoom yuav raug muab pov tseg, uas yuav ua rau poob zoo.
4.1. Ua rau thiab tiv thaiv kev ntsuas ntawm Z-kev taw qhia tawg
Z-kev taw qhia cov kab nrib pleb tshwm sim los ntawm kev txiav thiab vuam yog cov kab nrib pleb txias. Qhov ntau dua qhov hardness thiab thickness ntawm steel phaj, qhov ntau dua qhov tshwm sim ntawm Z-kev taw qhia cov kab nrib pleb. Yuav ua li cas kom tsis txhob muaj nws tshwm sim, txoj kev zoo tshaj plaws yog preheat ua ntej txiav thiab vuam, thiab qhov preheating kub nyob ntawm qib thiab thickness ntawm steel phaj. Preheating tuaj yeem ua tau los ntawm kev txiav phom thiab hluav taws xob crawler cua sov, thiab qhov ntsuas kub yuav tsum tau ntsuas nyob rau sab nraub qaum ntawm qhov cua sov. (Ceeb Toom: Tag nrho cov hlau phaj txiav yuav tsum tau muab rhaub kom sib npaug kom tsis txhob muaj cua sov hauv cheeb tsam hauv cheeb tsam hu rau lub tshav kub) Preheating tuaj yeem txo qhov tshwm sim ntawm Z-kev taw qhia cov kab nrib pleb tshwm sim los ntawm kev txiav thiab vuam.
① Siv lub ntsej muag ib lub ntsej muag kom zom kom txog thaum nws pom thaj chaw uas ib ncig ntawm cov xaim hluav taws xob ib ncig ntawm cov xaim hluav taws xob sib txuas yog qhov zoo tshaj plaws). Tom qab welding thawj txheej, tam sim ntawd coj mus rhaub cov weld nrog lub khob hliav qab rauj, thiab ces welding cov txheej hauv qab no, thiab coj mus rhaub cov weld nrog rauj tom qab txhua txheej. Xyuas kom meej tias qhov kub ntawm interlayer yog ≤200 ℃.
② Yog tias qhov tawg yog qhov sib sib zog nqus, preheat qhov chaw nyob ib puag ncig ntawm kev kho qhov vuam mus txog 100 ℃, tam sim ntawd siv cov pa roj carbon arc cua planer los ntxuav cov hauv paus hniav, thiab tom qab ntawd siv lub kaum sab xis grinder kom grind kom txog thaum cov hlau nplaum raug nthuav tawm (yog tias qhov kub thiab txias. qhov kho vuam yog tsawg dua 100 ℃, preheat dua) thiab tom qab ntawd vuam.
③ Tom qab vuam, siv aluminium silicate wool los yog asbestos insulate lub vuam rau ≥2 teev.
④ Rau kev nyab xeeb vim li cas, ua ultrasonic flaw detection ntawm qhov chaw kho.