1. Uvavanyo kunye noHlalutyo lwethiyori
Kwezi-3iivalvu zamatayaraiisampulu ezibonelelwe yinkampani, ezi-2 ziivalvu, kwaye enye yivalvu engekasetyenziswa. Kwi-A kunye ne-B, ivalvu engasetyenziswanga iphawulwe njengengwevu. Umfanekiso opheleleyo 1. Umphezulu wangaphandle wevalvu A awunzulu, umphezulu wangaphandle wevalvu B ngumphezulu, umphezulu wangaphandle wevalvu C ngumphezulu, kwaye umphezulu wangaphandle wevalvu C ngumphezulu. Iivalvu A kunye ne-B zigqunywe ziimveliso zokugqwala. Ivalvu A kunye ne-B ziqhekekile kwiindawo ezigobileyo, inxalenye engaphandle yegophe ikwivalvu, umlomo weringi yevalvu B uqhekekile ekupheleni, kwaye utolo olumhlophe phakathi kweendawo eziqhekekileyo kumphezulu wevalvu A luphawulwe. Ukusuka apha ngasentla, iintanda zikho kuyo yonke indawo, iintanda zezona zikhulu, kwaye iintanda zikho kuyo yonke indawo.
Icandelo leivalvu yetayaraIisampulu ze-A, B, kunye ne-C zisikwe ukusuka kwindawo egobileyo, kwaye imo yomphezulu yabonwa nge-microscope ye-electron ye-scan ye-ZEISS-SUPRA55, kwaye ukwakheka kwendawo encinci kwahlalutywa nge-EDS. Umfanekiso 2 (a) ubonisa isakhiwo se-microsurface yevalvu B. Kuyabonakala ukuba kukho amasuntswana amaninzi amhlophe nakhanyayo kumphezulu (okuboniswe ziintolo ezimhlophe kumfanekiso), kwaye uhlalutyo lwe-EDS lwamasuntswana amhlophe lunomxholo ophezulu we-S. Iziphumo zohlalutyo lwamandla amasuntswana amhlophe ziboniswe kuMfanekiso 2 (b).
Imifanekiso 2 (c) kunye (e) zii-microstructures zomphezulu we-valve B. Kunokubonwa kuMfanekiso 2 (c) ukuba umphezulu uphantse ugutyungelwe ziimveliso zokugqwala, kwaye izinto ezigqwala zeemveliso zokugqwala ngohlalutyo lwe-energy spectrum ziquka ikakhulu i-S, i-Cl kunye ne-O, umxholo we-S kwiindawo ezahlukeneyo uphezulu, kwaye iziphumo zohlalutyo lwe-energy spectrum ziboniswe kuMfanekiso 2(d). Kunokubonwa kuMfanekiso 2(e) ukuba kukho ii-micro-cracks ecaleni kweringi ye-valve kumphezulu we-valve A. Imifanekiso 2(f) kunye ne-(g) zii-micro-morphologies zomphezulu we-valve C, umphezulu nawo ugutyungelwe ziimveliso zokugqwala, kwaye izinto ezigqwala ziquka i-S, i-Cl kunye ne-O, efana noMfanekiso 2(e). Isizathu sokugqwala sisenokuba yi-stress corrosion cracking (SCC) evela kuhlalutyo lwemveliso yokugqwala kumphezulu we-valve. Umzobo 2(h) ukwangumfanekiso womphezulu wevalvu C. Kuyabonakala ukuba umphezulu ucocekile, kwaye ukwakheka kweekhemikhali kumphezulu ohlalutyiweyo yi-EDS kufana nokwe-alloy yobhedu, nto leyo ebonisa ukuba ivalvu ayigqwalanga. Ngokuthelekisa imo yemicroscopic kunye nokwakheka kweekhemikhali kumphezulu weevalvu ezintathu, kuboniswa ukuba kukho imidiya egqwalisayo efana ne-S, O kunye ne-Cl kwindawo engqongileyo.
Uqhekeko lwevalvu B luvulwe ngovavanyo lokugoba, kwaye kwafunyaniswa ukuba uqhekeko alungenanga kulo lonke icala levalvu, luqhekekile kwicala le-backbend, kwaye aluqhekekanga kwicala elichasene ne-backbend yevalvu. Ukuhlolwa okubonakalayo koqhekeko kubonisa ukuba umbala woqhekeko umnyama, okubonisa ukuba uqhekeko ludliwe, kwaye ezinye iindawo zoqhekeko zimnyama ngombala, okubonisa ukuba uqhekeko lubi kakhulu kwezi ndawo. Uqhekeko lwevalvu B lubonwe phantsi kwe-scanning electron microscope, njengoko kubonisiwe kuMfanekiso 3. Umfanekiso 3 (a) ubonisa imbonakalo enkulu yoqhekeko lwevalvu B. Kunokubonwa ukuba uqhekeko lwangaphandle kufutshane nevalvu lugqunywe ziimveliso zoqhekeko, kwakhona okubonisa ukuba kukho imidiya ebolileyo kwindawo engqongileyo. Ngokohlalutyo lwamandla, iinxalenye zeekhemikhali zemveliso yokonakala ikakhulu yi-S, Cl kunye ne-O, kwaye umxholo we-S kunye ne-O uphezulu, njengoko kubonisiwe kuMfanekiso 3(b). Ukujonga umphezulu woqhekeko, kufunyaniswe ukuba ipateni yokukhula koqhekeko ikwimo yekristale. Inani elikhulu leentanda zesibini lingabonwa ngokujonga ukwaphuka kubukhulu obuphezulu, njengoko kubonisiwe kuMfanekiso 3(c). Iintanda zesibini ziphawulwe ngeentolo ezimhlophe kumfanekiso. Iimveliso zokubola kunye neepateni zokukhula kweentanda kumphezulu wokuqhekeka kwakhona zibonisa iimpawu zokuqhekeka kokubola okuxineneyo.
Ukuqhekeka kwevalvu A akukavulwa, susa icandelo levalvu (kuquka indawo eqhekekileyo), gquba kwaye upolish icandelo le-axial levalvu, kwaye usebenzise isisombululo se-Fe Cl3 (5 g) +HCl (50 mL) + C2H5OH (100 mL) sikroliwe, kwaye isakhiwo se-metallographic kunye ne-crack growth morphology zibonwe nge-microscope ye-optical ye-Zeiss Axio Observer A1m. Umfanekiso 4 (a) ubonisa isakhiwo se-metallographic sevalvu, esiyi-α+β isakhiwo se-dual-phase, kwaye i-β ilungile kwaye i-granular kwaye isasazwe kwi-α-phase matrix. Iipateni zokusasazeka kwe-crack kwii-circumferential cracks ziboniswe kuMfanekiso 4 (a), (b). Ekubeni iindawo zokuqhekeka zizaliswe ziimveliso zokubola, umsantsa phakathi kweendawo ezimbini zokuqhekeka ubanzi, kwaye kunzima ukwahlula iipateni zokusasazeka kwe-crack. Isiganeko se-bifurcation. Ii-crack ezininzi zesibini (eziphawulwe ngeentolo ezimhlophe kumfanekiso) nazo zibonwe kule crack yokuqala, jonga uMfanekiso 4 (c), kwaye ezi crack zesibini zisasazeka ecaleni kwengqolowa. Isampulu yevalvu ekroliweyo yabonwa yi-SEM, kwaye kwafunyaniswa ukuba kukho ii-micro-cracks ezininzi kwezinye iindawo ezihambelana ne-main crack. Ezi micro-cracks zivela kumphezulu zaza zanda zaya ngaphakathi kwi-valve. Ii-cracks zazine-bifurcation kwaye zanda ecaleni kwe-grain, jonga uMfanekiso 4 (c), (d). Imeko-bume kunye nemeko yoxinzelelo lwale microcracks ifana kakhulu neye-main crack, ngoko ke kunokuqikelelwa ukuba imo yokusasazeka kwe-main crack nayo iphakathi kwe-granular, nto leyo eqinisekiswa kukubonwa kokuqhekeka kwe-valve B. Imeko ye-bifurcation ye-crack kwakhona ibonisa iimpawu ze-stress corrosion cracking ye-valve.
2. Uhlalutyo kunye nengxoxo
Ukushwankathela, kunokuqikelelwa ukuba umonakalo wevalvu ubangelwa kukuqhekeka koxinzelelo lokubola okubangelwa yi-SO2. Ukuqhekeka koxinzelelo lokubola ngokubanzi kufuneka kuhlangabezane neemeko ezintathu: (1) izixhobo ezibuthathaka kukuqhekeka koxinzelelo; (2) ukuqhekeka okuphakathi okubuthathaka kwii-alloys zobhedu; (3) iimeko ezithile zoxinzelelo.
Ngokwesiqhelo kukholelwa ukuba iintsimbi ezicocekileyo azinawo umhlwa woxinzelelo, kwaye zonke ii-alloys zisengozini yokubola koxinzelelo ukuya kumanqanaba ahlukeneyo. Kwizinto zobhedu, ngokubanzi kukholelwa ukuba isakhiwo sesigaba esiphindwe kabini sinomngcipheko ophezulu wokubola koxinzelelo kunesakhiwo sesigaba esinye. Kuye kwaxelwa kwiincwadi ukuba xa umxholo we-Zn kwizinto zobhedu udlula i-20%, unomngcipheko ophezulu wokubola koxinzelelo, kwaye okukhona umxholo we-Zn uphezulu, kokukhona umngcipheko ophezulu wokubola koxinzelelo. Isakhiwo se-metallographic somlomo wegesi kweli tyala yi-α+β dual-phase alloy, kwaye umxholo we-Zn umalunga ne-35%, udlula kakhulu i-20%, ngoko ke sinomngcipheko ophezulu wokubola koxinzelelo kwaye sihlangabezana neemeko zezinto ezifunekayo zokuqhekeka koxinzelelo lokubola.
Kwizinto zobhedu, ukuba ukuncitshiswa koxinzelelo akwenziwa emva kokuguquka kokusebenza okubandayo, ukubola koxinzelelo kuya kwenzeka phantsi kweemeko ezifanelekileyo zoxinzelelo kunye neendawo ezirhabaxa. Uxinzelelo olubangela ukuqhekeka koxinzelelo ludla ngokuba luxinzelelo lokutsalwa kwegesi lwasekuhlaleni, olunokusetyenziswa uxinzelelo okanye uxinzelelo olushiyekileyo. Emva kokuba itayara yelori ivuthelwe, uxinzelelo lokutsalwa luya kwenziwa kwicala le-axial ye-nozzle yomoya ngenxa yoxinzelelo oluphezulu kwitayara, oluya kubangela ukuqhekeka okujikelezayo kwi-nozzle yomoya. Uxinzelelo lokutsalwa olubangelwa luxinzelelo lwangaphakathi lwetayara lunokubalwa ngokulula ngokwe-σ=p R/2t (apho u-p luxinzelelo lwangaphakathi lwetayara, u-R bububanzi bangaphakathi bevalvu, kwaye u-t bubukhulu bodonga lwevalvu). Nangona kunjalo, ngokubanzi, uxinzelelo lokutsalwa oluveliswa luxinzelelo lwangaphakathi lwetayara alukho mkhulu kakhulu, kwaye isiphumo soxinzelelo olushiyekileyo kufuneka siqwalaselwe. Iindawo zokuqhekeka kwe-nozzle zegesi zonke zikwi-backbend, kwaye kuyacaca ukuba ukuguquguquka okushiyekileyo kwi-backbend kukhulu, kwaye kukho uxinzelelo lokutsalwa olushiyekileyo apho. Enyanisweni, kwiindawo ezininzi ze-copper alloy ezisebenzayo, ukuqhekeka koxinzelelo lokubola akubangelwa kakhulu ziingcinezelo zoyilo, kwaye uninzi lwazo lubangelwa ziingcinezelo ezishiyekileyo ezingabonwayo nezingananzwa. Kwimeko enjalo, kwigophe elingasemva levalvu, indlela yoxinzelelo lokutsalwa oluveliswa luxinzelelo lwangaphakathi lwetayara ihambelana nendlela yoxinzelelo olushiyekileyo, kwaye indawo ebekwe ngayo ezi ngcinezelo zimbini inika imeko yoxinzelelo kwi-SCC.
3. Isiphelo kunye neengcebiso
Isiphelo:
Ukuqhekeka kweivalvu yetayaraikakhulu kubangelwa kukuqhekeka koxinzelelo lokugqwala okubangelwa yi-SO2.
Ingcebiso
(1) Landela umthombo wento ebangela ukubola kwindawo ejikelezeivalvu yetayara, kwaye uzame ukuphepha ukudibana ngqo nendawo erhabaxa ejikelezileyo. Umzekelo, umaleko wengubo yokulwa nokugqwala ungafakwa kumphezulu wevalvu.
(2) Uxinzelelo oluseleyo lokuxinana oluvela ekusebenzeni ngokubandayo lunokususwa ngeenkqubo ezifanelekileyo, ezinje ngokuncamathisela uxinzelelo emva kokugoba.
Ixesha lokuthumela: Sep-23-2022
