Cov hauv paus ntsiab lus ntawm kev vuam txheej txheem
Vuam yog kev txuas hlau uas muaj tib yam lossis zoo ib yam pes tsawg leeg los ntawm kev ua ntawm tshav kub, nrog lossis tsis muaj kev ntxiv hlau tib yam lossis zoo ib yam. Los ntawm kev vuam, cov seem raug txuas ua ke tsis sib cais kom tsim tau ib qho tag nrho. Kev vuam zoo xav tau kev sib txuas ze heev, uas tsuas ua tau thaum cov khoom tseem ceeb kuj yaj ntawm qhov chaw vuam (cheeb tsam vuam).
Vuam hluav taws xob
Rau cov qauv hlau, ua ntej tshaj plaws yog kev vuam hluav taws xob, uas tau txais qhov kub tsim nyog los ntawm lub arc hluav taws xob. Lub arc hluav taws xob tsim nruab nrab ntawm daim khoom hauv paus thiab tus hu ua electrode, uas thaum ntawd yaj thiab muab cov khoom ntxiv. Kev xaiv kom raug ntawm cov khoom ntxiv (electrode) muaj kev cuam tshuam loj tshaj plaws rau cov yam ntxwv ntawm kev txuas vuam. Cov electrodes raug xaiv raws li cov zog yam ntxwv ntawm cov khoom hauv paus uas yuav vuam. Kev xaiv electrodes, kev txiav txim siab cov xwm txheej vuam, xav tau kev paub tshwj xeeb, yog vim li ntawd thiaj tsim muaj lub koom haum ntawm cov “kws ua haujlwm tshwj xeeb rau kev siv vuam”, uas txoj haujlwm yog, ntawm lwm yam, saib xyuas cov haujlwm vuam thiab rov ua kom zoo ib yam cov ntawv pov thawj ntawm cov neeg vuam.
Vuam thiab txiav nrog roj
Hauv gas welding, cov cua sov tsim nyog raug tsim los ntawm kev hlawv roj, yog li cov khoom siv tseem ceeb thiab cov khoom ntxiv tuaj rau kev yaj. Qhov tseem ceeb dua yog txiav. Lub taub hau txiav muaj, ntxiv rau raj cua sov uas ua haujlwm zoo ib yam li thaum vuam, tseem muaj lwm raj txiav rau oxygen. Cov hlau uas tau sov los ntawm nplaim kub raug hlawv dhau thiab tshuab tawm los ntawm cov kwj oxygen. Kev txiav muab cov nplaim du thiab meej, uas txaus rau ntau lub hom phiaj ntawm steel structures yam tsis tas ua tiav ntxiv.
Kev weld tau
Rau kev ntsuam xyuas cov pob qij txha vuam, yuav tsum nco ntsoov tias thaum txheej txheem vuam, cov qauv ntawm cov khoom ntxiv thiab cov khoom thawj tuaj yeem hloov pauv heev. Qhov kev hloov ntawm tus qauv kuj tseem ceeb heev – nruab nrab ntawm txoj hlua vuam yaj thiab cov khoom thawj uas tsis hloov, raws li qib ntawm kev cuam tshuam los ntawm tshav kub, muaj ib thaj tsam uas muaj ntau yam qauv thiab yog li ntawd muaj ntau yam yam ntxwv. Ze ntawm txoj hlua vuam muaj thaj chaw uas cov khoom thawj yaj lawm (thaj tsam ua fusion) thiab qhov chaw uas muaj kev txuas ntawm thaj tsam vuam thiab cov khoom thawj. Thaj tsam ib puag ncig kuj tseem raug rhuab heev, txawm tias qhov ntawd tsis tau txog qhov chaw yaj lawm. Hauv thaj tsam no ntawm kev kub dhau, muaj kev hloov loj hauv tus qauv, yog li nws feem ntau yog qhov txiav txim siab rau cov yam ntxwv ntawm tag nrho cov pob qij txha vuam.
Kev tawg ntawm qhov weld seam txhais tau tias muaj kab nrib pleb tshwm sim hauv seam, uas tshwm sim tam sim tom qab vuam thaum tseem kub siab heev lossis tej zaum tsuas yog thaum txias hauv thaj tsam xiav liab kub (kwv yees li 300oC). Kev tawg yog ib yam uas nyob ntawm electrode ntau heev; nws tshwm sim yuav luag tsuas yog rau cov electrode muaj txheej npog xwb, hom uas yog yam tseem ceeb rau cov qauv hlau. Kom kab nrib pleb tshwm sim, yuav tsum muaj ob qho xwm txheej, xws li cov kev ntxhov siab siab vim txheej txheem vuam lossis lwm yam kev cuam tshuam sab nraud, thiab nrog rau qhov nce ntawm kev tawv/khav theeb ntawm cov khoom.
Ib sab ntawm cov kev hloov metallurgical hauv cov qauv thiab qauv ntawm cov khoom siv, cov txheej txheem cev nqaij daim tawv kuj tseem ceeb, uas muaj feem nrog cov nqi kub loj uas thaum vuam raug xa mus rau cov khoom siv thiab cov kub siab uas tau mus txog. Kev sov tsis yog tshwm sim sib npaug, tabsis tsuas yog hauv tej thaj tsam me. Kev nthuav kub uas txuas nrog kev sov raug txwv los ntawm kev nyem sab hauv ntawm thaj tsam sov los ntawm cov khoom uas tsis sov. Ntxiv rau ntawd tseem muaj kev nyem sab nraud, vim tias cov ntu thaum vuam yuav tsum raug nias kom ruaj, yog li ntawd thaum sov muaj kev nias yas tshwm. Thaum txias, txoj hlua vuam thiab nws ib puag ncig khaws ua ke tshaj plaws (kev txo loj). Thaum txias, vim kev nthuav tsis tau, yuav tsum muaj cov kev ntxhov siab yuam (kev ntxhov siab los ntawm kev txo loj). Los ntawm kev ua kom cov ntu uas yuav vuam sov ua ntej txog 200 oC txog 300 oC, kev txias tuaj yeem qeeb tau ntau. Vim txo qhov cuam tshuam ntawm kev tawv, tau txais kev tsim qauv zoo dua, kev tawv ntxiv tseem tsawg dua.
Kev tshuaj xyuas cov ntaub ntawv thiab cov haujlwm vuam
Dav dav: Vim tias qhov zoo ntawm cov hauj lwm vuam nyob ntawm ntau yam xwm txheej, thiab kawg kiag los kuj nyob ntawm kev txawj thiab kev ntseeg tau ntawm tus neeg ua haujlwm txawj, nws yuav tsum muaj kev saib xyuas thiab kuaj xyuas txhua yam hauj lwm vuam kom meej. Ntawm cov kev kuaj tau hais txog cov uas txheeb xyuas qhov peev xwm vuam ntawm cov ntaub ntawv thiab cov electrodes, kev sib piv ntawm cov xwm txheej vuam thiab cov txheej txheem vuam rau ib rooj plaub twg, kev kuaj qauv, thiab lwm yam.
Daim duab 1 - Kev sim khoov ntawm lub vuam seam
Kuaj kev khoov ntawm cov vuam seam: Qhov no yog kev kuaj khoov ntawm ib lub nqaj yooj yim muaj ntu plaub fab (sl. 1), uas muaj ib txoj kab nqes ntev nyob rau hauv sab uas raug rub, uas tau muab vuam dua ib txheej rau ntawm chav sov. Lub seam ua rau kev muaj peev xwm deformed poob heev, yog li cov kuaj feem ntau tawg kiag li tawv thiab cia li sai. Lub kaum khoov ntawm cov phaj nyias loj dua; nws nqis thaum phaj tuab dua.
Kev tawv ntawm qhov txiav: Thaum ua qhov kev sim khoov ntawm seam, kab nrib pleb feem ntau tshwm sim thawj zaug hauv seam, ua rau muaj kev puas tsuaj khaus. Cov khoom hauv paus yuav tsum muaj peev xwm txais lub load uas tshwm sim sai heev thaum seam tawg khaus. Yuav tsum xav kom kab nrib pleb hauv cheeb tsam weld tsis nthuav ceev thiab mus rau hauv cov khoom hauv paus, tab sis kom kab nrib pleb tsuas pub nce qeeb xwb. Cov khoom hauv paus yuav tsum muaj kev tawv txaus kom txais tau lub load ntais no, thiab peev xwm no yuav tsum khaws tau kom txaus txawm nyob rau qhov kub qis. Kev tawv ntawm qhov txiav, nrog rau lwm yam khoom siv tshuab, nyob ntau heev ntawm qhov kub uas ua qhov kev sim. Nyob rau qhov kub qis, piv txwv li qis dua 0 oC, nws yuav nqis mus rau ib feem ntawm tus nqi ntawm 20 oC. Qhov chaw uas kev poob qis no tshwm ceev yog tseem ceeb rau kev ntsuas ib yam khoom. Rau cov qauv hlau vuam niaj hnub no, yuav tsum muaj cov khoom uas muaj kev ruaj khov zoo thaum laus, piv txwv li muaj zog siab nrog qhov txiav-tawv zoo hauv cov kev sim rub txias.
Daim duab 2 - Kev hloov cev hauv cov xwm txheej kev nyuaj siab ntawm qhov txiav ncej
Hardness: Cov xwm txheej ntawm hardness nyob rau thaj tsam vuam muaj qhov tseem ceeb heev. Nws tseem ceeb kom paub txog qhov nce ntawm hardness, vim kev ncua ntev thaum tawg poob sai thaum hardness nce ntxiv (sl. 3), hos lub zog rub σB nce yuav luag raws li Brinell hardness HB. Rau cov hlau siv hauv kev tsim kho, kwv yees li σB = 0,36*HB. Ib qho piv txwv ntawm hardness ntawm lub ntsiab kaum weld ntawm I-beam tau qhia hauv sl. 4. Hauv thaj tsam hloov pauv, muaj qhov sib txawv loj ntawm hardness ntawm qhov deb me heev. Txoj kev hloov ntawm hardness nyob ntawm tus qauv uas tsim. Kab σ-ε-l kuj hloov raws hardness zoo ib yam li lub xeev kev ntxhov siab ntawm qhov ntxhib txiav (sl. 2).
Duab 3 - Brinell qhov tawv thiab qhov ncua ntev
Sl. 4 - Qhov tawv hauv cheeb tsam ntawm cov vuam hauv caj dab ntawm ib tug I-kab mob vuam
Kev kuaj tsis ua kom puas ntawm cov txuas vuam tiav
Kev tshuaj xyuas radiography – Thaum tshuaj xyuas cov tuab me me, daim duab xoo hluav taws xob yuav ua kom pom ntawm ib lub vijtsam xwb. Hloov xoo hluav taws xob, kuj siv tau cov hluav taws xob gamma los ntawm cov khoom radioactive. Daim duab xoo hluav taws xob tso cai kom txiav txim txog qhov zoo ntawm txoj hlua vuam. Cov slag lossis qhov pores uas nkag rau hauv, nrog rau cov kev ua yuam kev hauv kev sib txuas thiab cov kab tawg, kuj yuav raug txheeb tau li no thiab, yog tsim nyog, tshem tawm.
Kev xyuam xim magnetically – Tsim ib daim teb sib nqus rau ntu ntawm hlau uas tab tom raug kuaj, ces cov hlau me me uas muab nphoo yuav teem raws li daim teb ntawd. Los ntawm tej yam txawv txav hauv daim teb sib nqus, tej kab nrib pleb tuaj yeem pom tau. Txoj kev no muaj txiaj ntsig tshwj xeeb rau kev nrhiav kab nrib pleb saum npoo, tabsis nws tsis tshua nkag siab txog cov kev sib xyaw slag thiab qhov pores, thiab kuj tsis tshua pom tau cov kab nrib pleb uas nyob hauv sab hauv ntawm cov phaj tuab.
Kev xeem nrog ultrasound – Cov nthwv suab luv heev rov qab tsis yog tsuas yog ntawm cov nplaim ciam, tab sis kuj ntawm cov nplaim faib hauv sab hauv xws li piv txwv ntawm cov kab tawg los sis cov chaw sib cais.