xov xwm

Vim li cas stomata tshwm?

1.1 Sab hauv ntawm lub laser welded qhov yog nyob rau hauv ib qho tsis ruaj tsis khov kev co lub xeev, thiab ntws ntawm lub qhov thiab lub pas dej molten yog khaus heev.Cov hlau vapor nyob rau hauv lub qhov erupts outwards thiab coj mus raulub zog vortextsim ntawm qhov qhib ntawm lub qhov, uas yob cov roj tiv thaiv (Ar) rau hauv qab ntawm lub qhov, thiab nroglub qhov txav mus rau pem hauv ntej, cov roj tiv thaiv no yuav nkag mus rau hauv lub pas dej molten nyob rau hauv daim ntawv ntawm npuas.Vim yog qhov tsis tshua muaj solubility ntawm Ar thiab ceev ceev ceev ntawm laser welding, cov npuas nyob rau hauv lub weld seam ua ntej lawv yuav khiav.tsim stomata.Dab tsi ntxiv, nws yogtshwm sim los ntawmkev tiv thaiv tsis zoo thaum lub sij hawm vuam txheej txheem uas nitrogen invades lub molten pas dej ua ke los ntawm sab nraud, thiab solubility ntawm nitrogen nyob rau hauv cov kua hlau yog txawv heev los ntawm solubility ntawm nitrogen nyob rau hauv cov khoom hlau.Yog li ntawd nyob rau hauvqhov txias thiab solidification ntawm cov hlau, lub solubility ntawm nitrogen txo nrog qhov txo ntawm qhov kub thiab txias thaum lub pas dej ua ke hlau yog txias rau thaum pib ntawm crystallization yuav ua rau ib tug loj dheev poob nyob rau hauv solubility.Lub sij hawm no ib tug loj npaum li cas ntawm cov roj precipitatesua npuas ncauj.Yog hais tias tus nqi ntab ntawm cov npuas yog tsawg dua cov hlau crystallization tus nqi, cov pores yog generated.

Txoj kev ntawm laser fusion vuam suppresses porosity

1. Tshem tawm vuam qhov pores los ntawm kev kho qhov chaw ua ntej vuam

Pre-welding nto kev kho mob yog ib txoj kev zoo los tswj cov metallurgical pores ntawm aluminium alloy laser welds.Txoj kev kho saum npoo tuaj yeem muab faib ualub cev kho tshuab ntxuav thiab tshuaj ntxuavfeem ntau.

Tom qab kev sib piv, kev siv cov txheej txheem tshuaj los daws qhov chaw ntawm lub rooj tsavxwm kuaj (hlau ntxuav - ntxuav - alkali ntxuav - ntxuav - ntxuav - ntxuav - ziab) yog qhov zoo tshaj plaws.Ntawm lawv, alkali ntxuav yog tshem tawm los ntawm lub thickness ntawm cov khoom nrog ib tug aqueous tov ntawm 25% NaOH (sodium hydroxide), thiab cov pickling yog nqa tawm nrog ib tug 20% ​​HNO3 (nitric acid) + 2% HF (hydrogen fluoride. ) aqueous tov rau neutralize cov residual lye.Tom qab kev kho saum npoo ntawm daim ntawv xeem, qhov vuam yog nqa tawm hauv 24 teev, thiab lub rooj sib txoos ua ntej vuam yog sib sau ua ke nrog cov dej cawv tsis muaj dej thaum lub phaj ntsuas tau teeb tsa ntev ntev tom qab kev sim phaj kho.

2. Inhibit vuam pores los ntawm vuam txheej txheem tsis

Qhov tsim ntawm weld porosity tsis yog tsuas yog cuam tshuam rau qhov zoo ntawm weldment nto kho, tab sis kuj muaj feem xyuam rau vuam txheej txheem tsis.Cov kev cuam tshuam ntawm vuam tsis nyob rau hauv lub qhov hws ntawm lub weld yog feem ntau xav txog nyob rau hauv lub nkag mus rau ntawm lub weld, uas yog, lub zog ntawm lub rov qab dav piv ntawm lub weld nyob rau hauv lub pores.

Los ntawmkuajpeb tuaj yeem paub qhov ntawdNws tuaj yeem pom tau tias thaum lub vuam rov qab dav piv R yog> 0.6, qhov sib xyaw ua ke ntawm cov saw pores hauv vuam tuaj yeem txhim kho zoo..Thiab thaum lub dav rov qab piv R yog> 0.8, lub hav zoov ntawm atmospheric pores nyob rau hauv lub weld tuaj yeem txhim kho zoo.Dab tsi ntxiv, qhov seem ntawm qhov pores hauv qhov vuam tuaj yeem raug tshem tawm mus rau qhov loj.

3. Inhibit vuam pores los ntawm kev xaiv cov roj shielding thiab txaus tus nqi

Kev xaiv cov roj tiv thaiv cuam tshuam rau qhov zoo, kev ua tau zoo thiab tus nqi ntawm vuam ncaj qha.Nyob rau hauv tus txheej txheem ntawm laser welding, qhov tseeb tshuab ntawm kev tiv thaiv roj yuav txo tau cov weld pores zoo.

Raws li pom hauv daim duab saum toj no, Ar (argon) thiab Nws (helium) yog siv los tiv thaiv qhov chaw ntawm qhov vuam.Nyob rau hauv cov txheej txheem ntawm aluminium alloy laser vuam, Ar thiab Nws muaj ntau qib ntawm ionization ntawm lub laser uas ua rau sib txawv weld forming.Nws tuaj yeem pom tau tias qhov porosity ntawm cov weld tau los ntawm kev siv Ar raws li cov roj shielding tsawg dua li ntawm cov weld thaum Nws raug xaiv los ua cov roj tiv thaiv.

Nyob rau tib lub sijhawm, peb kuj yuav tsum tau them sai sai rau qhov tseeb tias cov pa roj ntws tsawg dhau (<10L / min) thiab ntau cov plasmas.tsim los ntawm welding tsis tuaj yeem raug tshuab,uas yuav ualub vuam pas dej tsis ruaj tsis khov thiab qhov tshwm sim ntawm porosity tsim nce.Yog tias cov pa nruab nrab ntawm cov pa ntws (kwv yees li 15L / min) plasma tswj tau zoo thiab cov roj tiv thaiv ua rau muaj txiaj ntsig zoo los tiv thaiv oxidation ntawm cov molten.pas dej ua ke,nws yuav tsim qhov tsawg tshaj plaws porosity.Cov pa roj ntau dhau yog nrog cov roj ntau dhau, yog li ntawd ib feem ntawm cov roj tiv thaiv tau sib xyaw rau hauv lub tank sab hauv, uas ua rau cov porosity nce.

Muaj kev cuam tshuam los ntawm kev ua haujlwm ntawm cov khoom siv nws tus kheej, nwsua tsis tauyuav tsum zam kom tsis txhob muaj qhov vuam tsis tsimporositynyob rau hauv cov txheej txheem vuam.Dab tsi nws tuaj yeem ua tiav yogtxo cov porositytus nqi.