304 yog lub hom phiaj dav dav hlau stainless uas tau siv dav los ua cov khoom siv thiab tshuab qhov chaw uas xav tau kev sib xyaw ua ke zoo.
Cov khoom (corrosion resistance and formability) ntawm cov cuab yeej thiab tshuab qhov chaw. Txhawm rau kom muaj kev tiv thaiv corrosion nyob rau hauv stainless hlau, cov hlau yuav tsum muaj ntau tshaj 18% chromium thiab ntau dua 8% cov ntsiab lus nickel. Hnub no koj tham txog nickel thiab chromium hauv304 stainless hlau.
Lub luag haujlwm ntawm nickel hauv stainless hlau
Lub luag haujlwm ntawm npib tsib xee hauv stainless hlau yog ua ke nrog chromium ua si tawm.
Nickel yog ib qho zoo heev corrosion-resistant cov ntaub ntawv thiab ib qho tseem ceeb alloying caij ntawm alloy hlau. Nickel hauv cov hlau yog tsim los ntawm cov ntsiab lus austenitic, tab sis cov pa roj carbon tsawg tsawg kom tau txais lub koom haum austenitic ntshiab, cov ntsiab lus nickel nce mus txog 24%; thiab tsuas yog 27% cov ntsiab lus npib tsib xee los ua cov hlau hauv qee qhov kev tawm tsam corrosion kuj tau hloov pauv. Yog li nickel tsis tuaj yeem ua stainless hlau ib leeg. Tab sis npib tsib xee thiab chromium muaj nyob hauv stainless hlau, nickel-muaj stainless hlau muaj ntau yam khoom muaj txiaj ntsig.
Raws li cov saum toj no, nws yuav pom tau hais tias lub luag hauj lwm ntawm npib tsib xee raws li ib tug alloying caij nyob rau hauv stainless hlau nyob rau hauv lub fact tias nws ua rau lub koom haum ntawm high-chromium hlau hloov, ua rau corrosion kuj ntawm stainless hlau thiab cov txheej txheem kev ua tau zoo kom tau. tej kev txhim kho.
Lub luag haujlwm ntawm chromium hauv stainless hlau
Lub genus ntawm stainless hlau tsuas yog ib lub ntsiab lus, uas yog chromium, txhua stainless hlau muaj ib qho nyiaj ntawm chromium. Txog tam sim no, tsis muaj chromium-dawb stainless hlau. Chromium tau dhau los ua lub hauv paus tseem ceeb uas txiav txim siab qhov kev ua tau zoo ntawm cov hlau tsis muaj steel, qhov laj thawj tseem ceeb yog ntxiv chromium ua cov khoom sib xyaw rau cov hlau, ua rau nws qhov kev sib cav sib ceg rau kev txhim kho corrosion kuj. Qhov kev hloov no tuaj yeem piav qhia los ntawm cov hauv qab no:
① chromium kom cov electrode muaj peev xwm ntawm cov hlau-raws li cov khoom tov
② chromium absorption ntawm hlau electrons kom passivate hlau
PS: passivation yog vim cov tshuaj tiv thaiv anodic raug tiv thaiv thiab tshwm sim los ntawm qhov tshwm sim ntawm cov hlau thiab hlau alloy corrosion kuj tau txhim kho. Muaj ntau txoj kev xav ua rau kev ua haujlwm ntawm cov hlau thiab alloys, feem ntau yog zaj duab xis txoj kev xav, adsorption theory, thiab electron arrangement theory.
Nickel thiab chromium
Chromium thiab npib tsib xee hauv stainless hlau ob leeg ua lub luag haujlwm hauv kev tiv thaiv corrosion.
Chromium yuav tsim ib zaj duab xis chromium trioxide raunto ntawm stainless hlau, thiab ua lub luag haujlwm hauv kev tiv thaiv cov matrix los txuas ntxiv mus rau corrode.
Nickel rau kev nthuav dav ntawm austenitic ntsiab, kom cov khoom nyob rau hauv chav tsev kub tsim ib tug ib-theem austenitic qauv, kom tsis txhob muaj qhov tshwm sim ntawm intergranular corrosion, tab sis nyob rau hauv cov yas deformation, ib co residual austenite yuav tsim nyob rau hauv lub luag hauj lwm ntawm strain-induced martensite. , yog li qhov no yog qhov tsis tuaj yeem, qhov cuam tshuam ntawm intergranularaustenitic stainless hlauyog ib qho teeb meem loj.
