Hydrogen Embrittlement rhiab heev ntawm Rail Bolts thiab Post-Glazing Hydrogen Tshem Tawm Txheej Txheem rau Siab-Lub Zog Bolts
Vim li cas siab - lub zog khiav bolts muaj kev cuam tshuam rau hydrogen embrittlement dua li cov bolts zoo tib yam?
High- lub zog bolts muaj cov qauv zoo martensitic nrog cov lattice siab distortion, nthuav tawm muaj zog hydrogen atom adsorption. Cathodic cov tshuaj tiv thaiv thaum lub sij hawm electroplating tsim muaj ntau hydrogen atoms, uas yooj yim nkag mus rau hauv lub lattice gaps thiab tsim "hydrogen- induced stress." Ordinary bolts muaj ib tug ferrite-pearlite qauv nrog xoob lattices, tso cai sai hydrogen diffusion thiab tsis muaj tsub zuj zuj. Nyob rau hauv siab - lub zog bolts, hydrogen diffusion yog thaiv, ua rau tsub zuj zuj ntawm kev ntxhov siab concentrations; Tshaj qhov tseem ceeb ntawm cov ntsiab lus hydrogen ua rau cov pob txha tawg.
Dab tsi yog qhov tseem ceeb ntawm pob txha tawg qhov sib txawv ntawm hydrogen embrittlement thiab kev qaug zog zoo tib yam?
Hydrogen embrittlement fractures yogtiaj tus, ci, thiab crystalline, nrog tsis pom kev qaug zog striations. Kev puas tsuaj feem ntau tshwm sim ntawm cov hauv paus xov los yog lub taub hau -shank hloov thiab yog tam sim ntawd brittle tsis ua hauj lwm yam tsis muaj lus ceeb toom ua ntej. Fatigue fractures muaj qhov txawvLub hauv paus pib qaug zog, thaj chaw nthuav dav (nrog rau kev sib tw zoo), thiab qhov kawg ntawm qhov tawg, sib sau maj mam nyob rau hauv alternating loads. Fracture deg tus yam ntxwv pab kom ceev ceev ntawm hydrogen embrittlement raws li qhov ua rau.
Dab tsi yog qhov tseem ceeb ntawm kev tshaj tawm -plating dehydrogenation, thiab lawv txawv li cas ntawm cov khoom siv ntsia liaj qhov rooj?
Core parameters yogdehydrogenation kubthiabtuav lub sij hawm. Suav cov qauv qhia 190℃-230℃tsis pub tsawg tshaj 4 teev. Rau 10.9-qib carbon steel bolts, 200℃× 4 teev txaus; rau 12.9-qib alloy steel bolts (siab dua susceptibility), 220℃× 6 teev yuav tsum tau. Dehydrogenation yuav tsum tshwm simhauv 24 teevntawm plating- ncua sij hawm tso cai rau hydrogen kom sib sib zog nqus mus rau hauv lattices, ua kom tiav tshem tawm tsis tau.
Cov txheej txheem electroplating twg ua rau muaj kev pheej hmoo hydrogen embrittlement, thiab yuav ua li cas zam lawv hauv engineering?
Acid electroplating(piv txwv li, acid zinc plating, acid tooj liab plating) ua rau muaj kev pheej hmoo siab tshaj plaws, vim tias acidic electrolytes ua kom hydrogen tiam thiab nkag mus. Engineering tseem ceebcyanide- dawb alkaline zinc platinglos yogmechanical galvanizingrau siab - lub zog bolts. Mechanical galvanizing siv lub cev deposition, ua tsis muaj hydrogen atoms thiab tshem tawm embrittlement ntawm qhov chaw. Yog hais tias acidic plating yog yuav tsum tau, nruj me ntsis tswj tam sim no ceev thiab ncua lub sij hawm dehydrogenation kom ua tiav hydrogen dim.
Yuav ua li cas ua ntej tshuaj ntsuam bolts nrog hydrogen embrittlement txaus ntshai siv yooj yim ntawm - txoj hauv kev?
Txoj kev uas feem ntau yog covncua kev kuaj pob txha tawg (vaj huam sib luag). Ib qho piv txwv ntawm bolts yog raug rau 70% -80% ntawm lawv cov khoom muaj zog preload thiab tuav rau 24-48 teev. Kev tawg thaum tuav qhia tias muaj hydrogen embrittlement hnyav. Tsis tas li ntawd, akhoov kuaj-bending bolts nyob ib ncig ntawm ib txoj kab uas hla mandrel- nthuav tawm embrittlement yog nkig tawg (tsis muaj yas deformation) nrog lub ntsej muag ci tshwm sim. Tag nrho cov bolts ua tsis tiav yuav tsum tau muab pov tseg thiab tsis siv.