Sulfur muaj tsawg heev solubility nyob rau hauv cov nickel matrix thiab nyhav rau react nrog alloying ntsiab (xws li Ni, Fe, Cr) tsim.qis- melting-point sulfides(eg, Ni₃S₂, CrS, FeS). Lub melting point ntawm cov sulfides feem ntau yog nyob nruab nrab ntawm 600-900 degree, uas yog qis dua qhov kub ua hauj lwm kub ntawm npib tsib xee -raws li alloys (1000-1200℃).
Thaum lub sijhawm ua haujlwm kub (piv txwv li, forging, dov, extrusion), cov sulfides yuav yaj ua ntej, tsim cov yeeb yaj kiab ua kua raws cov ciam teb. Cov yeeb yaj kiab no ua rau lub zog sib txuas ntawm cov nplej, ua rauintergranular tawgthaum lub alloy raug kev nyuaj siab sab nraud. Qhov tshwm sim no hu uakub brittleness, uas ua rau txo cov kub ua hauj lwm plasticity ntawm cov hlau thiab ua rau kev ua tsis xws luag xws li tawg thiab tawg.
Thaum cov sulfur ntsiab lus tshaj qhov txwv, nplua sulfide hais yuav precipitate nyob rau hauv lub grain ciam teb los yog nyob rau hauv lub matrix. Cov khoom no ua raws li kev ntxhov siab concentration. Thaum cov hlau raug cuam tshuam los yog qis- qhov kub thiab txias, microcracks nquag pib thiab nthuav tawm nyob ib ncig ntawm cov khoom sulfide, uas ua rau muaj kev poob qis hauv cov hlau.Charpy cuam tshuam toughnessthiabtawg toughness.
Rau npib tsib xee-raws li alloys siv nyob rau hauv qis- qhov kub thiab txias ib puag ncig (xws li, liquefied natural gas khoom), qhov nce hauv cov ntsiab lus sulfur yuav ua rau muaj kev pheej hmoo ntawm kev puas tsuaj.
Sulfides yog electrochemically heterogeneous nrog cov nickel matrix. Hauv cov xov xwm corrosive (xws li chloride- muaj cov kev daws teeb meem, ib puag ncig acidic), galvanic cell yog tsim los ntawm sulfide particles thiab matrix. Cov sulfides ua raws li cov anode thiab corrode preferentially, ua rau tsim pitting corrosion.
Tsis tas li ntawd, sulfide nag lossis daus ntawm cov ciam teb yuav rhuav tshem qhov txuas ntxiv ntawm cov zaj duab xis passive (Cr₂O₃) ntawm cov hlau nplaum, txo cov hlau tsis kam rau intergranular corrosion thiab kev nyuaj siab corrosion cracking (SCC). Cov nyhuv no yog qhov tshwj xeeb tshaj yog nyob rau hauv siab -kub thiab siab - qhov chaw nyob hauv dej siab (piv txwv li, nuclear reactor coolant systems).
Phosphorus yog ib txwm muajgrain ciam cais cais. Txawm tias nyob rau theem kab, nws nyiam sib cais ntawm cov ciam teb ntawm npib tsib xee-raws li alloys thaum lub sij hawm solidification los yog kev kho cua sov, es tsis dissolving uniformly nyob rau hauv lub matrix.
Kev sib cais ntawm phosphorus ntawm cov ciaj ciam ntawm cov qoob loo txo cov kev sib koom ua ke ntawm cov nplej ciam teb atoms, ua rau cov ciam teb ua qhov tsis muaj zog ntawm cov hlau. Nyob rau hauv chav tsev kub los yog kub tsis tshua muaj, thaum lub alloy raug rau tensile los yog dabtsi yog khoov kev nyuaj siab, tawg yog nquag pib thiab propagate raws phosphorus -segregated grain ciam teb, ua rauintergranular brittle puas. Qhov tshwm sim no hu uatxias brittleness, uas ua rau muaj qhov txo qis hauv cov alloy qhov elongation thiab txo qhov chaw.
Thaum lub sij hawm welding txheej txheem ntawm npib tsib xee-raws li alloys, phosphorus yuav cais nyob rau hauv lub grain ciam teb ntawm weld hlau thiab tshav kub- cuam tshuam cheeb tsam (HAZ) vim ceev ceev. Cov phosphorus segregated txo cov qoob loo ciam teb lub zog ntawm qhov sib koom ua ke thiab ua kom muaj kev nkag siab zoo rauweld solidification tawgthiabliquation cracks.
Rau npib tsib xee-raws li alloy welds siv nyob rau hauv cov cuab yeej tseem ceeb (xws li, tshuaj reactors, nuclear steam generators), phosphorus -induced weld tawg tuaj yeem txo qhov kev pab cuam lub neej thiab kev nyab xeeb ntawm cov cuab yeej, txawm tias ua rau muaj kev puas tsuaj loj.
Rau npib tsib xee-raws li alloys siv nyob rau hauv siab- qhov kub thiab txias ib puag ncig (xws li, aero- cav turbine blades, industrial furnace Cheebtsam), phosphorus segregation ntawm grain ciam teb yuav ua rau kom lubgrain ciam swbnyob rau hauv ntev - lub sij hawm siab - qhov kub thiab txias. Qhov no accelerates lub creep deformation ntawm lub alloy thiab shortens lub creep rupture lub neej.
Tsis tas li ntawd, phosphorus tuaj yeem txhawb kev loj hlob ntawm cov qoob loo ciam teb carbides, rhuav tshem cov nyhuv pinning ntawm carbides ntawm cov ciam teb nplej thiab ntxiv txo qhov siab - qhov kub ntawm cov qauv kev ruaj ntseg ntawm cov hlau.
Hauv kev tsim khoom lag luam, cov ntsiab lus ntawm sulfur thiab phosphorus hauv npib tsib xee-raws li alloys yog tswj nruj me ntsis raws li daim ntawv thov scenarios:
Rau kev xeb dav dav -resistant nickel-raws li alloys (piv txwv li, Hastelloy C276, Inconel 625), S thiab P cov ntsiab lus feem ntau yog txwv rauTsawg dua lossis sib npaug li 0.01%.
Rau siab -kev ua tau zoo nickel-raws li alloys siv nyob rau hauv aerospace, nuclear zog, thiab lwm yam teb (xws li, Inconel 718, Waspaloy), S thiab P cov ntsiab lus yuav tsum tau.Tsawg dua lossis sib npaug li 0.005%los xyuas kom meej cov khoom siv kho tshuab tsis zoo thiab kev pabcuam kev nyab xeeb.
Kev tswj xyuas nruj ntawm cov sulfur thiab phosphorus impurities yog qhov txuas tseem ceeb hauv kev smelting thiab ua cov nickel-raws li alloys, uas ncaj qha txiav txim siab seb cov hlau puas tuaj yeem ua tau raws li qhov yuav tsum tau ua ntawm kev siv engineering tseem ceeb.
