I. Thermal lalacewa da cobalt cire PDC
A cikin babban matsa lamba sintering tsari na PDC, cobalt abubuwa a matsayin mai kara kuzari don inganta kai tsaye hade da lu'u-lu'u da lu'u-lu'u, da kuma yin lu'u-lu'u Layer da tungsten carbide matrix zama gaba daya, sakamakon PDC yankan hakora dace da oilfield geological hakowa tare da high tauri da kyau kwarai lalacewa juriya.
Juriyar zafi na lu'u-lu'u yana da iyaka. A ƙarƙashin matsin yanayi, saman lu'u-lu'u na iya canzawa a yanayin zafi a kusa da 900 ℃ ko sama. A lokacin amfani, PDC na gargajiya suna ƙasƙantar da kai a kusan 750 ℃. A lokacin da ake hakowa ta cikin yadudduka na dutse mai wuya da abrasive, PDCs na iya samun sauƙin isa ga wannan zafin jiki saboda tsananin zafi, kuma yanayin zafin jiki na nan take (watau yanayin da ba a sani ba) na iya zama mafi girma, wanda ya zarce wurin narkewar cobalt (1495°C).
Idan aka kwatanta da tsantsar lu'u-lu'u, saboda kasancewar cobalt, lu'u-lu'u yana canzawa zuwa graphite a ƙananan yanayin zafi. Sakamakon haka, sawa a kan lu'u-lu'u yana faruwa ne ta hanyar graphitization sakamakon yanayin zafi na cikin gida. Bugu da ƙari, ƙimar haɓakar zafin jiki na cobalt ya fi na lu'u-lu'u girma, don haka yayin dumama, haɗin kai tsakanin hatsin lu'u-lu'u na iya rushewa ta hanyar faɗaɗa cobalt.
A cikin 1983, masu bincike biyu sun yi maganin cire lu'u-lu'u a saman daidaitattun yadudduka na lu'u-lu'u na PDC, suna haɓaka aikin haƙoran PDC. Duk da haka, wannan ƙirƙira ba ta sami kulawar da ta dace ba. Sai bayan shekara ta 2000, tare da zurfin fahimtar yaduddukan lu'u-lu'u na PDC, dillalan dillalai sun fara amfani da wannan fasaha ga haƙoran PDC da aka yi amfani da su wajen hako dutse. Haƙoran da aka yi wa wannan hanyar sun dace da ɓangarorin ƙwanƙwasa sosai tare da manyan lalacewa na inji kuma ana kiran su da haƙoran “de-cobalted”.
Ana yin abin da ake kira "de-cobalt" ta hanyar gargajiya don yin PDC, sa'an nan kuma an nutsar da saman Layer na lu'u-lu'u a cikin acid mai karfi don cire lokaci na cobalt ta hanyar tsarin etching acid. Zurfin cirewar cobalt zai iya kaiwa kusan 200 microns.
An gudanar da gwajin lalacewa mai nauyi akan haƙoran PDC guda biyu iri ɗaya (ɗayan wanda aka yi masa maganin cire cobalt akan saman lu'u-lu'u). Bayan yanke 5000m na granite, an gano cewa yawan lalacewa na PDC da ba a cire cobalt ba ya fara karuwa sosai. Sabanin haka, PDC da aka cire cobalt ya kiyaye ingantaccen saurin yankewa yayin da yake yanke kusan 15000m na dutse.
2. Hanyar ganowa na PDC
Akwai nau'ikan hanyoyi guda biyu don gano haƙoran PDC, wato gwaji mai lalacewa da gwaji mara lalacewa.
1. Gwajin lalata
Waɗannan gwaje-gwajen an yi niyya ne don daidaita yanayin ƙasa kamar yadda ya kamata don kimanta aikin yanke haƙora a ƙarƙashin irin waɗannan yanayi. Manyan nau'ikan gwaji guda biyu na lalata sune gwaje-gwajen juriya da gwajin juriya.
(1) Saka gwajin juriya
Ana amfani da nau'ikan kayan aiki iri uku don yin gwajin juriya na PDC:
A. Lathe a tsaye (VTL)
Yayin gwajin, fara gyara bit ɗin PDC zuwa lathe VTL kuma sanya samfurin dutse (yawanci granite) kusa da bit PDC. Sa'an nan kuma juya samfurin dutsen a kusa da axis na lathe a wani takamaiman gudun. PDC bit yana yanke cikin samfurin dutse tare da takamaiman zurfin. Lokacin amfani da granite don gwaji, wannan zurfin yankan gabaɗaya bai wuce 1 mm ba. Wannan gwajin na iya zama bushe ko jika. A cikin "bushe gwajin VTL," lokacin da PDC bit ya yanke ta cikin dutsen, ba a sanya sanyaya; duk zafi mai zafi da aka haifar yana shiga cikin PDC, yana haɓaka aikin graphitization na lu'u-lu'u. Wannan hanyar gwaji tana ba da kyakkyawan sakamako yayin kimanta raƙuman ruwa na PDC a ƙarƙashin yanayin da ke buƙatar babban matsin hakowa ko saurin juyawa.
"Gwajin VTL rigar" yana gano rayuwar PDC a ƙarƙashin matsakaicin yanayin zafi ta hanyar sanyaya haƙoran PDC da ruwa ko iska yayin gwaji. Sabili da haka, babban tushen lalacewa na wannan gwajin shine nika samfurin dutse maimakon yanayin dumama.
B, lathe a kwance
Hakanan ana yin wannan gwajin tare da granite, kuma ka'idodin gwajin daidai yake da VTL. Lokacin gwajin ƴan mintuna ne kawai, kuma girgizar zafi tsakanin granite da haƙoran PDC yana da iyaka.
Ma'aunin gwajin granite da masu samar da kayan aikin PDC ke amfani da su zasu bambanta. Misali, ma'aunin gwajin da Kamfanin Synthetic Corporation da Kamfanin DI a Amurka ke amfani da shi ba daidai ba ne, amma suna amfani da kayan granite iri ɗaya don gwaje-gwajen su, dutsen polycrystalline mai ƙaƙƙarfan matsakaici zuwa matsakaici mai ƙarancin porosity da ƙarfi na 190MPa.
C. Abrasion rabo auna kayan
A ƙarƙashin ƙayyadaddun sharuɗɗan, ana amfani da Layer lu'u-lu'u na PDC don datsa dabaran niƙa na silicon carbide, kuma ana ɗaukar ƙimar yawan lalacewa na dabaran niƙa da ƙimar lalacewa na PDC azaman ma'aunin lalacewa na PDC, wanda ake kira rabo rabo.
(2) Gwajin juriya na tasiri
Hanyar gwajin tasiri ta haɗa da shigar da haƙoran PDC a kusurwar digiri 15-25 sannan a zubar da wani abu daga wani tsayin tsayi don buga layin lu'u-lu'u akan haƙoran PDC a tsaye. Nauyi da tsayin abin da ke fadowa suna nuna tasirin ƙarfin ƙarfin da haƙorin gwajin ya fuskanta, wanda a hankali zai iya ƙaruwa har zuwa joules 100. Ana iya shafar kowane haƙori sau 3-7 har sai ba za a iya ƙara gwada shi ba. Gabaɗaya, aƙalla samfurori 10 na kowane nau'in hakori ana gwada su a kowane matakin makamashi. Tun da akwai kewayon juriya na hakora don tasiri, sakamakon gwajin a kowane matakin makamashi shine matsakaicin yanki na spalling lu'u-lu'u bayan tasiri ga kowane hakori.
2. Gwajin mara lalacewa
Dabarar gwajin da ba ta lalata da aka fi amfani da ita ba (ban da duba na gani da na gani) shine binciken ultrasonic (Cscan).
Fasahar sikanin C na iya gano ƙananan lahani da ƙayyade wuri da girman lahani. Lokacin yin wannan gwajin, da farko sanya haƙoran PDC a cikin tankin ruwa, sannan bincika tare da binciken ultrasonic;
An sake buga wannan labarin daga "International Metalworking Network"
Lokacin aikawa: Maris 21-2025
