Conquering Hard Pob Zeb Excavation: Kev Tshawb Fawb Kev Tshawb Fawb Txog Kev Tsim Kho Tshiab Brazing Technology rau Siab -Longevity PDC Cutters Picks

Nyob rau hauv ib puag ncig kev khiav hauj lwm hnyav xws li mining, tunneling, thiab sib sib zog nqus -zoo drilling, "cov hniav" ntawm qhov tho txawv tshuab (TBMs)- cutters- ua haujlwm ua ntej ntawm pob zeb tawg. Txawm li cas los xij, ib txwm muaj WC-Co cemented carbide cutters feem ntau raug kev txom nyem los ntawm kev hnav tsis ua haujlwm thaum ntsib siab - hardness pob zeb formations. Kev hloov cutter nquag tsis yog tsuas yog txo tus nqi nkag tab sis kuj ua rau cov nqi poob qis heev.

Txhawm rau kov yeej qhov kev tsis sib haum no, polycrystalline pob zeb diamond compact (PDC) txiav tawm. Txawm li cas los xij, yuav ua li cas kom ruaj khov rau ultra- txheej PDC nyuaj rau cov hlau tawv tawv tsis muaj kev cuam tshuam pob zeb diamond lub thermal stability? Tsab ntawv xov xwm no muab ib qho hauv - tsom xam qhov tob ntawm PDC lub tshuab txiav tshiab (PCD PICK) txoj kev brazing, qhia seb nws ua tiav li cas "kev sib koom ua ke."

I. Cov Kev Sib Tw ntawm Cov Kev Cai Lij Choj: Kev Nyuaj Siab & Thermal Damage

PDC cutter lub taub hau (PCD PICK) muaj xws li sintered polycrystalline pob zeb diamond txheej sib txuas rau cemented carbide substrate. Conventional brazing feem ntau ntiav tag nrho cov cua sov induction, uas nthuav tawm ob qhov kev sib tw tsis tu ncua:

Residual Thermal Stress:Qhov sib txawv tseem ceeb hauv thermal expansion coefficients thiab elastic moduli muaj nyob ntawm cov hlau substrate, cemented carbide, thiab PDC txheej. Tom qab- cua txias, sib sau ua ke ntawm kev ntxhov siab ua rau nkig tawg lossis chipping nyob rau hauv kev cuam tshuam.

PDC Thermal Degradation:Pob zeb diamond (PCD txheej) yog rhiab heev; brazing kub tshaj 700℃drastically txo nws cov hnav tsis kam thiab tuaj yeem ua rau graphitization, ua rau ua tsis tiav ntxov.

II. Kev daws teeb meem tshiab: Zn-Ni Pre-Plating & Gradient Composite Braze Joint

Cov txheej txheem tshiab - tiam brazing qhia txog ob lub tshuab: kev hloov kho interface thiab kev tswj kev ntxhov siab.

Zn-Ni Plating: Lub Art ntawm Interface Alloying
Tsis zoo li cov brazing ncaj qha, txoj kev no ntxiv ib qho kev kho ua ntej - cov kauj ruam kho: immersing qhov sib txuas ntawm cov cemented carbide substrate rau hauv zinc molten -nickel (Zn{2}}Ni) alloy.
Muaj nuj nqi: Tsim Zn-Ni alloy txheej, ua tiav "pre-braze alloying." Qhov no ua rau muaj txiaj ntsig zoo rau braze filler wetting ntawm lub substrate, ua kom tiav cov kev pab cuam thiab tshem tawm tsis muaj - ntawm - fusion defects. Ib txhij, Ni synergizes nrog cov hlau muab tub lim, elevating shear zog tshaj 300 MPa.

Composite Flux: Tsim kom muaj Thermal Expansion Gradient
Cov tshuaj txhuam hniav yog tsim kho tshiab nrog 10% ~ 20% cemented carbide hmoov (xws li, WC-12Co).
Lub hauv paus ntsiab lus: Cemented carbide hmoov muaj cov thermal expansion coefficient tsawg, thaum molten muab tub lim hlau muaj coefficient siab. Lawv cov khoom sib xyaw ua "cov khoom sib xyaw" nrog cov coefficient nruab nrab. Qhov no tsim cov qauv gradient: "Steel substrate (High) → Composite braze joint (Medium) → Cemented carbide (Low).
Cov txiaj ntsig: Ua kom muaj txiaj ntsig zoo txo ​​qhov kev ntxhov siab ntawm lub ntsej muag, tiv thaiv micro- tawg thiab porosity hauv braze sib koom.

III. Core Process Flow Paub meej

Kev ua haujlwm zoo brazing tsis yog tsuas yog siv cov khoom siv xwb tab sis kuj tseem muaj kev tswj xyuas thermal.

Kauj Ruam 1: Substrate Preheating & Flux Daim Ntawv Thov
Uniformly coated lub puab qhov ntawm cov hlau substrate nrog tshwj xeeb flux muab tshuaj txhuam uas muaj WC-Co hmoov (qhuav thickness ~ 0.3-0.4mm). Muab ib daim ntawv nyiaj -raws li cov ntawv hlau (54%-57% Ag) thiab inductively preheat rau 670 ~ 690℃kom txog thaum lub filler tag nrho melts mus rau hauv lub xeev npaj-rau-braze.

Kauj Ruam 2: PDC Lub taub hau Thermal Protection & Plating
Cov kauj ruam no yog qhov tseem ceeb rau kev tiv thaiv pob zeb diamond. Ib qho tshwj xeeb tooj liab raj fixture tag nrho encloses PDC cutter taub hau lub pob zeb diamond txheej.
Kev Tiv Thaiv Thaum Tshav Kub Kub Lub Cev: Siv tooj liab zoo thermal conductivity rau cov cua kub sai sai.
Kev tiv thaiv huab cua: Tshem tawm cov tubular fixture nrog siab -purity argon. Qhov no txo ​​qis cov pa oxygen ib feem ntawm lub pob zeb diamond nto (tiv thaiv oxidation) thiab tshem tawm cov cua sov uas seem ntawm cov roj ntws.
Nyob rau hauv qhov kev tiv thaiv no, raus cov cemented carbide kawg rau hauv 650-680℃plating tov rau ~ 40 vib nas this.

Kauj Ruam 3: Precision Induction Brazing
Ntxig lub taub hau kho PDC rau hauv preheated steel substrate. Vim yog tooj liab fixture thiab argon ntws, qhov tseeb kub ntawm lub pob zeb diamond txheej tseem nyob nyab xeeb hauv qab 700℃pib. Thaum lub braze sib koom ua kom pom qhov ci, ua kua, tig clockwise 2-3 zaug kom tshem tawm impurities. Txias kom tau txais lub tshuab txiav muaj zog.

IV. Kev Ua Haujlwm Leap: Cov ntaub ntawv-Thov tau txais txiaj ntsig

Kev sib piv (piv txwv li, Piv txwv 1 vs. Cov Txheej Txheem Txheej Txheem Sib Piv 1) qhia txog kev txhim kho zoo kawg li thoob plaws cov kev ntsuas tseem ceeb:

Qhov tshiab PDC cutter (PCD PICK) brazing thev naus laus zis tau ua tiav kev sib txuas ntawm microscopic interface alloying nrog macroscopic thermal tiv thaiv. Nws daws qhov kev sib tw tsis tu ncua ntawm pob zeb diamond thermal puas thiab zoo kawg nkaus mitigates thermal expansion mismatch ntawm cov ntaub ntawv los ntawm "gradient hloov txheej" tswvyim.

Rau cov neeg siv khoom hauv kev lag luam mining thiab underground engineering, qhov no txhais tau hais tias tsawg dua cov xwm txheej rau kev hloov pauv, kev khawb nrawm dua, thiab cov nqi qis dua. Raws li kev sib tw pob zeb nyuaj zuj zus, qhov kev txhim kho vuam ruaj khov no- tiag tiag "armoring cov hniav"- sawv cev rau kev txiav- ntug kev lag luam xav tau sai.