Intergranular corrosion, tseem hu ua intergranular nres (IGA) yog ib qho kev txhim kho corrosion hauv zos uas tshwm sim thiab tsim los ntawm los yog ze rau ntawm ib thaj tsam ntawm cov hlau nyob rau hauv ib qho chaw zoo corrosion. Intergranular corrosion pib los ntawm qhov chaw ntawm cov khoom siv hlau, txhim kho raws li cov ciam teb rau sab hauv, kom cov adhesion ntawm cov nplej ploj, thiab lub zog ntawm cov khoom yuav luag tag. Cov kev ntsuam xyuas ntawm intergranular corrosion ntawm cov ntaub ntawv thiab cov khoom feem ntau muaj xws li immersion test thiab electrochemical ntsuas.
Cov kev sim immersion ntawm intergranular corrosion feem ntau muaj xws li: boiling nitric acid test, acid ferric sulfate test, acid copper sulfate test thiab nitric acid-hydrofluoric acid test.
Boiling nitric acid test yuav tsum muaj tsib lub voj voog (48h / voj voog) ntawm kev sim hauv 65% ntawm boiling HNO3, thiab cov tshuaj ntsuam xyuas yuav tsum tau hloov kho tom qab txhua lub voj voog sim. Thaum kawg, cov txiaj ntsig kev xeem raug ntsuas raws li qhov poob ntawm cov qauv. Qee qhov xwm txheej, cov qoob loo tau pom los ntawm qhov muag liab qab lossis lub tshuab tsom.
Acid ferric sulfate test yog ob txoj kev kuaj reagent nrog Fe2 (SO4) 3 ua tus neeg sawv cev passivating thiab H2SO4 ua tus neeg sawv cev depassivating. Nws tuaj yeem siv los ntsuas cov qoob loo ciam teb corrosion tshwm sim los ntawm chromium carbide nag lossis daus nyob rau hauv tsis ruaj tsis khov austenitic stainless hlau thiab intergranular corrosion tshwm sim los ntawm chromium carbide thiab σ theem hauv stabilized stainless hlau. Cov txheej txheem kuj tuaj yeem siv los ntsuas qhov sib txawv ntawm kev sib txhuam ntawm cov kua qaub-resistant steels thiab corrosion-resistant alloys tshwm sim los ntawm grain ciam teb chromium thiab molybdenum deficiency los yog σ nag lossis daus.
Acid tooj liab sulfate tov test yog thawj daim ntawv thov ntawm intergranular corrosion test method, tseem hu ua Hatfield method, Krupp method or Strauss method. CuSO4 yog tus neeg sawv cev passivating nyob rau hauv cov tshuaj ntsuam xyuas, thiab H2SO4 accelerates corrosion.
Xyoo 1958, Warren thawj zaug tau thov kom siv 10%HNO3+3% HF cov tshuaj raws li kev ntsuas kom muaj nuj nqis rau kev ntsuas qhov sib txawv ntawm qhov sib txawv ntawm molybdenum-muaj austenitic stainless hlau. Txoj kev no tsim nyog rau kev ntsuam xyuas qhov sib txawv ntawm qhov sib txawv ntawm cov molybdenum-muaj austenitic stainless hlau vim yog grain ciam chromium deficiency. Qhov ntsuas kub yuav tsum tau ua thaum lub sijhawm ntsuas yog 70 degree ± 0.5 degree, 2h raws li lub voj voog, tag nrho ob lub voj voog, cov txiaj ntsig kev xeem raug ntsuas raws li qhov tsis zoo.
