Ukukhiqizwa kwe-HIC Resistant Steels
I-Hydrogen induced cracking (HIC) imele inselele evamile, ikakhulukazi embonini ye-petroleum neyokuhluzwa lapho ubumsulwa kanye nekhwalithi iyonke yensimbi ibaluleke kakhulu.
Inqubo yokukhiqiza yezinsimbi ezikwazi ukumelana ne-HIC ihlanganisa amasu abalulekile e-desulphurization kuhlanganise nomjovo we-magnesium nokunyakaziswa ngomjovo we-argon ophansi.
Ukukhiqizwa kwensimbi ehlanzekile kusekelwe kubuchwepheshe bokulawula kanye/noma ukususa okufakiwe ensimbi. Ngokuvamile, izinhlobo nezici ze-non-metallic inclusions ensimbi zinethonya elibalulekile ezintweni zemishini yensimbi futhi ziphinde zinqume ukuhlanzeka kwensimbi. Ngakho-ke ukuhlaziya okunembile kwalezi zici kuyadingeka ukuze kuthuthukiswe inqubo yokwenza insimbi ukuze kukhiqizwe izinsimbi zekhwalithi.
I-Hydrogen induced cracking (HIC) kanye ne-sulphide stress cracking (SSC) kumele izinhlobo ezimbili zomonakalo othile obangelwa i-hydrogen ovame ukuhlangatshezwana nawo embonini ye-petroleum neyokuhluza. Esimweni sokuqala (HIC), ngokuvamile kuqashelwa ukuthi ukumelana kwezinsimbi kuncike ikakhulukazi ezicini zabo ze-microstructural - ukufakwa okungezona ezensimbi kanye namabhande okuhlukanisa.
Ama-manganese sulfide emide athathwa njengezindawo zokuqalwa eziyingozi kakhulu. Esimweni sesibili (SSC), kukholakala ukuthi ukumelana kwezinsimbi kungahlotshaniswa ngokukhethekile nezinga lawo lamandla kuyilapho izici ze-microstructure zingabalulekile kangako. Iphepha elethulwe linikezelwe ocwaningweni lwe-HIC ne-SSC ezinsimbi ze-carbon-manganese, ezihlukile ekwelapheni kwazo ukushisa (i-microstructure, izinga lezakhiwo zemishini) kanye nokuhlanzeka kwazo.
Ukufakwa kwe-MnS kuyisiqalo esiyingozi kakhulu se-HIC, ngakho-ke, njengesilinganiso esiyisisekelo, okuqukethwe kwesibabule kufanele kwehliswe ezinsimbi ezisetshenziswa ezindaweni ezine-asidi. Ngenxa yenqubekelaphambili enqubweni yokwenza insimbi, okuqukethwe kwesibabule kungancishiswa kuze kufike ezingeni eliphansi kakhulu; ngaphansi kwe-0.0008 wt. % (8ppm).
Ukwelashwa kwe-Ca kuvame ukusetshenziswa ukuze kuvinjelwe ukwakheka kwe-MnS emide futhi kulawulwe ukufakwa kwe-sulfide esimweni esiyindilinga, futhi uma kukhona okuqukethwe kwe-Ca okufanele kwesakhiwo sokumelana nokuqhekeka. Uma okuqukethwe kwe-Ca kuphezulu uma kuqhathaniswa nokuqukethwe kuka-S, i-Ca eningi ingenza ama-oxide asebenze njengesiqalisi se-HIC. Amapharamitha amaningana amelela okuqukethwe kwe-Ca okuphumelelayo kwethulwa, futhi okuqukethwe kwe-Ca kudinga ukulawulwa ngokucophelela ebangeni elincane; isibonelo, 3
Ithebula 1: Izidingo zokwakheka kwamakhemikhali zensimbi yamapayipi aqinile, [ppm]
Umfanekiso 1 ubonisa umzila wokukhiqiza insimbi engazweli ku-HIC. Ngaphambi kwenqubo ye-BOF, insimbi eshisayo isuswa yi-sulphurization esiteshini sensimbi eshisayo ye-desulphurization ngomjovo we-magnesium ne-CaO. E-BOF, kufanele kushaje izicucu ezinesulfure ephansi kuphela. I-aluminium ye-deoxidation kanye nama-slag forming agents ayengezwa ngesikhathi sokuthepha. I-alloying eyinhloko nayo iyacutshungulwa ngaleso sikhathi.
Iladi libe selithuthwa liyiswe esiteshini esibhubhuzayo lapho i-argon ishaywa khona ngomkhonto ongaphezulu ukuze kuxutshwe insimbi ne-slag ngenjongo yokukhipha i-desulphurization. Khona-ke, i-ladle idluliswa ukuze iphathwe nge-vacuum. Insimbi ishukunyiswa umjovo we-argon ongezansi ukuze kuqinisekiswe i-desulphurization ejulile kanye ne-degassing.