Yadda za a yi Braze Tungsten Carbide?

    Ana amfani da samfuran Tungsten Carbide a aikace-aikace da yawa, gami da kayan aikin yanke, hakowa, naushi, da sauran aikace-aikace masu yawa. Cemented Carbide yana ba da juriya mafi inganci kuma yana tsawaita rayuwar waɗannan kayan aikin iri daban-daban. Saboda babban bangarensa shine tungsten, wanda ba kasafai ba ne kuma ba a sabunta shi ba, farashin simintin carbide yana da inganci. Bugu da kari, carbide da aka yi da siminti yana da taurin gaske, kuma karfin lankwasawa ya yi kasa da na sauran karafa, kamar karfe. Don waɗannan dalilai guda biyu, dole ne a haɗa carbide da aka yi da siminti zuwa wasu karafa ta hanyoyi daban-daban, kamar ta hanyar haɗin zaren, clamping, da walda. Wannan labarin yana magana ne game da yadda ake yin braze tungsten carbide akan wasu karafa.

1. Menene tungsten carbide?

    Tungsten carbide (WC), wanda kuma ake magana da shi da siminti carbide, wani abu ne mai haɗe-haɗe da aka ƙera ta hanyar tsari da ake kira ƙarfe ƙarfe. Ana haxa foda na WC da ƙarfe mai ɗaure, yawanci cobalt ko nickel, an haɗa shi a cikin kayan aikin preform, sannan a juye shi a cikin tanderu. Kalmar "cemented" tana nufin barbashi na tungsten carbide da ake kamawa a cikin kayan haɗin ƙarfe na ƙarfe da kuma "cimented" tare, suna samar da haɗin gwiwar ƙarfe tsakanin ɓangarorin carbide na tungsten da mai ɗaure (WC-Co), a cikin tsarin sintiri. Masana'antar simintin carbide galibi tana nufin wannan abu azaman “carbide” kawai, kodayake ana amfani da kalmomin tungsten carbide da simintin carbide tare da musanyawa.  Carbide yana nuna ƙarfin matsawa mai girma, yana tsayayya da jujjuyawar, kuma yana riƙe ƙimar taurinsa a yanayin zafi mai girma, kayan jiki musamman mai amfani a aikace-aikacen yanke ƙarfe. 

2 . Maki biyu don tabbatar da nasara a brazing da tungsten carbide

A. Sarrafa matsalolin da ke haifar da fadada bambancin

B.Contraction rates na iyaye kayan da wetting na carbide ta braze gami

    A lokacin dumama da sanyaya, ƙarfen mahaifa na tushe yawanci zai faɗaɗa da kwangila a mafi girma fiye da carbide.  Tungsten carbide yana da ƙimar haɓakar zafi na kusan 1/3 zuwa 1/2 na ƙarfe.  Lokacin da taron brazed yayi sanyi, ragowar damuwa na iya haɓakawa a cikin carbide.  Ana ba da shawarar sanyaya santsin kayan aiki na carbide koyaushe don guje wa damuwa da yiwuwar fatattaka. Ba a ba da shawarar quenching ba saboda yana iya haifar da tsagewa a cikin carbides saboda saurin raguwa na mahaifa tushe karfe.

3. Yadda ake zabar gami da braze

    Tungsten carbide yana da wuya a jika. Al'adar braze na azurfa tare da ƙananan abubuwan tara na nickel (Ni) galibi ana amfani da su don ƙera carbides zuwa ƙarfe. Tabbas, duka biyun carbide da karfe dole ne su kasance masu tsabta don haka narkakken gariyar tagulla zai iya jika saman mating ɗin gaba ɗaya. Nika saman carbide don ƙirƙirar ƙasa mai tsabta don brazing yana da mahimmanci. Nika kuma yana da fa'ida na flattening surface topography na carbide , wanda zai iya taimaka tare da braze gami wetting da mannewa. Abubuwan da aka gyara na ƙarfe, haka ma, za su buƙaci tsaftacewa don cire duk wani abu mai saura, mai, datti, ko wasu gurɓataccen ƙasa.  

    · Abubuwan da ake samu na siminti na siminti na siminti tare da ƙarami na nickel (Ni) da Manganese (Mn) za su jika saman siminti. Wadannan gami da braze yawanci suna nuna jika mai kyau na tungsten carbides.  Ana ba da shawarar a zaɓi ƙarfe mai jujjuyawar brazing tare da mafi ƙanƙancin yuwuwar zafin brazing don rage ragowar damuwa a cikin haɗin gwiwa.  

Domin applications da suka haɗa da brazing na manyan carbides, ana yawan amfani da gawa na sandwich braze gami.  Idan ƙananan carbides (1/2 inch2) ba za a iya amfani da su ba, sandwich gami yana da fa'ida wajen hana fashewa da warpage na carbide. Waɗannan nau'ikan trimetal ɗin an lulluɓe su tare da filler braze da aka ɗaure zuwa bangarorin biyu na ainihin jan ƙarfe.  

    Ko da yake yawancin tattaunawar sun kasance game da brazing na tungsten carbide (WC), za mu yi asara idan ba mu ambaci lu'u-lu'u na polycrystalline ko PCD ba. Zazzaɓin brazing na PCD gabaɗaya ana kiyaye shi ƙasa da 1382°F (750°C) don gujewa lalatar lu'u-lu'u.  Sau da yawa, masana'antun PCD na tukwici ga jikin karfe za su yi amfani da ƙaramin zafin jiki, ƙarfe mai cike da baƙin ƙarfe mai girman azurfa, kamar gami da baƙar fata na BAg-24.  Wasu masana'antun suna amfani da gawa na braze ba tare da nickel ko manganese ba, irin su BAg-5 ko BAg-7 alloy braze, tare da ƙananan yanayin zafi da ƙarancin jika na carbide da karfe.

    Ana amfani da juzu'in brazing don hana oxidation na saman da za a haɗa yayin dumama taron.  Ana amfani da Flux foda tare da kayan haɗin gwal na azurfa na gama gari.  Black flux foda yawanci ana ba da shawarar ta hanyar braze da masana'anta saboda yana da ƙari na boron kuma yana da tasiri a yanayin zafi mafi girma.

    Akwai da yawa brazing gami da ake amfani da su don carbide. Classic shine BAG-3, 50% azurfa tare da Cadmium.  Wannan samfurin yana da kyau, amma yana da Cadmium. Mafi yawan amfani shine BAG-7, 56% azurfa tare da Tin, saboda yana jika da sauri; duk da haka, yana da rauni mai rauni mai ƙarfi, kuma gazawar haɗin gwiwa ya zama ruwan dare tare da wannan gami. Mafi ƙarfi wanda ba na Cadmium ba shine BAG-22, 49% azurfa tare da manganese, amma ɗan ɗanɗano ne a cikin kwarara. BAG-24, 50% Azurfa, ba shi da cadmium kuma sulhu ne.  Yana gudana da kyau amma yana da kusan 40% rauni fiye da BAG-3 da BAG-22.

    Mun fi son Black Flux mai ƙarfi, kodayake yawancin brazine cikin nasara tare da Farin Flux. A cikin duka biyun, suna a fili yanayin zafi mai zafi. Bugu da ƙari, mun gano cewa tsaftataccen Black Flux yana ba da mafi kyawun kwarara da ƙarfi fiye da na Black Flux na yau da kullun.  

    Yankin ƙarshe inda kurakurai suka zama ruwan dare shine a cikin ƙirar haɗin gwiwa. Horarwan welder yawanci suna son haɗa sassan sannan su gudanar da dunƙulewa. Lokacin da suka yi brazing, suna so su haɗa sassan sannan su shafa gami da brazing a cikin haɗin gwiwa.   

    Lokacin brazing carbide, sau da yawa yana da tasiri sosai don jujjuya tarnaƙi da ƙasan daraja, sa'an nan kuma sanya guntu na waya mai walƙiya a ƙarƙashin carbide.  Duk abin da kuke yi shine zafi har sai carbide ya daidaita a wurin.   

    Ma'auni ya kamata ya zama cewa carbide ruptures ko karfe ya rushe kafin haɗin gwiwa ya kasa.