1. Cov khoom siv sib txhuam
(1) Cov hlau siv rau kev sib txuas thiab cov cemented carbides feem ntau siv cov tooj liab ntshiab, tooj liab zinc thiab nyiaj tooj liab brazing filler hlau. Tooj liab ntshiab muaj qhov zoo wettability rau txhua yam cemented carbides, tab sis qhov zoo tshaj plaws tuaj yeem tau txais los ntawm kev sib txuas hauv huab cua txo qis ntawm hydrogen. Tib lub sijhawm, vim yog qhov kub brazing siab, qhov kev ntxhov siab hauv qhov sib koom ua ke yog loj, uas ua rau muaj kev nce ntxiv ntawm qhov tawg. Lub zog shear ntawm qhov sib koom ua ke brazed nrog tooj liab ntshiab yog li 150MPa, thiab qhov sib koom ua ke plasticity kuj siab, tab sis nws tsis haum rau kev ua haujlwm kub siab.
Cov hlau tooj liab zinc yog cov hlau filler feem ntau siv rau brazing cov cuab yeej hlau thiab cemented carbides. Txhawm rau txhim kho qhov ntub ntawm cov solder thiab lub zog ntawm qhov sib koom ua ke, Mn, Ni, Fe thiab lwm yam khoom sib xyaw feem ntau ntxiv rau hauv cov solder. Piv txwv li, w (MN) 4% yog ntxiv rau b-cu58znmn kom lub zog shear ntawm cemented carbide brazed cov pob qij txha ncav cuag 300 ~ 320MPa ntawm chav tsev kub; Nws tseem tuaj yeem tswj tau 220 ~ 240mpa ntawm 320 ℃. Ntxiv me ntsis CO raws li b-cu58znmn tuaj yeem ua rau lub zog shear ntawm qhov sib koom ua ke ncav cuag 350Mpa, thiab muaj kev cuam tshuam siab thiab lub zog qaug zog, txhim kho lub neej ua haujlwm ntawm cov cuab yeej txiav thiab cov cuab yeej khawb pob zeb.
Qhov qis dua ntawm cov hlau nyiaj tooj liab uas siv rau kev sib txuas ua ke thiab qhov kev ntxhov siab me dua ntawm qhov sib txuas ua ke yog qhov zoo rau kev txo qhov kev tawg ntawm cov cemented carbide thaum lub sijhawm sib txuas. Txhawm rau txhim kho qhov ntub ntawm cov hlau sib txuas thiab txhim kho lub zog thiab qhov kub ua haujlwm ntawm qhov sib txuas, Mn, Ni thiab lwm yam khoom sib xyaw feem ntau ntxiv rau cov hlau sib txuas. Piv txwv li, b-ag50cuzncdni hlau sib txuas muaj qhov ntub zoo heev rau cov cemented carbide, thiab qhov sib txuas ua ke muaj cov yam ntxwv zoo.
Ntxiv rau peb hom hlau brazing filler saum toj no, Mn raws li thiab Ni raws li brazing filler hlau, xws li b-mn50nicucrco thiab b-ni75crsib, tuaj yeem xaiv rau cemented carbide ua haujlwm saum 500 ℃ thiab xav tau lub zog sib koom ua ke siab. Rau kev brazing ntawm cov hlau ceev ceev, yuav tsum xaiv cov hlau brazing filler tshwj xeeb nrog qhov kub brazing phim qhov kub quenching. Cov hlau filler no muab faib ua ob pawg: ib qho yog ferromanganese hom filler hlau, uas feem ntau yog tsim los ntawm ferromanganese thiab borax. Lub zog shear ntawm qhov sib koom ua ke brazed feem ntau yog li 100MPa, tab sis qhov sib koom ua ke yooj yim tawg; Lwm hom tooj liab tshwj xeeb alloy uas muaj Ni, Fe, Mn thiab Si tsis yooj yim los tsim cov kab nrib pleb hauv cov pob qij txha brazed, thiab nws lub zog shear tuaj yeem nce mus txog 300mpa.
(2) Kev xaiv cov brazing flux thiab cov roj shielding brazing flux yuav tsum phim nrog cov hlau puag thiab cov hlau filler uas yuav tsum tau welded. Thaum brazing cov cuab yeej hlau thiab cemented carbide, cov brazing flux siv feem ntau yog borax thiab boric acid, thiab qee cov fluorides (KF, NaF, CaF2, thiab lwm yam) ntxiv rau. Fb301, fb302 thiab fb105 fluxes siv rau tooj liab zinc solder, thiab fb101 ~ fb104 fluxes siv rau nyiaj tooj liab solder. Borax flux feem ntau yog siv thaum cov hlau brazing filler tshwj xeeb siv los braze cov hlau ceev ceev.
Yuav kom tiv thaiv tau qhov oxidation ntawm cov hlau cuab yeej thaum lub sijhawm brazing cua sov thiab kom tsis txhob ntxuav tom qab brazing, roj shielded brazing siv tau. Cov roj tiv thaiv tuaj yeem yog cov roj inert lossis cov roj txo qis, thiab qhov dew point ntawm cov roj yuav tsum qis dua -40 ℃ Cemented carbide tuaj yeem brazed nyob rau hauv kev tiv thaiv ntawm hydrogen, thiab qhov dew point ntawm hydrogen xav tau yuav tsum qis dua -59 ℃.
2. Kev siv tshuab txhuam
Ua ntej brazing, cov hlau siv yuav tsum tau ntxuav kom huv si, thiab qhov chaw ua haujlwm tsis tas yuav du dhau kom yooj yim rau kev ntub thiab kis cov ntaub ntawv thiab brazing flux. Qhov chaw ntawm cemented carbide yuav tsum tau xuab zeb blasted ua ntej brazing, lossis polished nrog silicon carbide lossis pob zeb diamond sib tsoo log kom tshem tawm cov pa roj carbon ntau dhau ntawm qhov chaw, kom cov hlau filler brazing ntub thaum lub sijhawm brazing. Cemented carbide uas muaj titanium carbide nyuaj rau ntub. Tooj liab oxide lossis nickel oxide paste yog siv rau ntawm nws qhov chaw hauv txoj kev tshiab thiab ci hauv huab cua txo kom tooj liab lossis nickel hloov mus rau qhov chaw, kom ua rau cov solder muaj zog ntub dua.
Yuav tsum tau ua kom cov hlau siv ua cov cuab yeej carbon ua ntej lossis tib lub sijhawm ua kom cov hlau kub. Yog tias ua kom cov hlau kub ua ntej ua kom cov hlau kub, qhov kub ntawm cov hlau siv yuav tsum siab dua qhov kub ntawm cov hlau uas siv yuav tsum siab dua qhov kub ntawm cov hlau uas siv, kom cov hlau uas siv tseem muaj zog txaus thaum rov ua kom sov mus txog qhov kub ntawm cov hlau uas siv yam tsis muaj kev puas tsuaj. Thaum ua kom cov hlau kub thiab cov hlau uas siv ua ke ua ke, yuav tsum xaiv cov hlau uas muaj qhov kub ntawm cov hlau kub ze rau qhov kub ntawm cov hlau uas siv.
Cov hlau ua haujlwm sib xyaw muaj ntau yam khoom sib xyaw. Yuav tsum txiav txim siab seb cov hlau sib xyaw ua ke, cov txheej txheem kho cua sov thiab cov thev naus laus zis ntawm kev sib xyaw ua ke thiab cov txheej txheem kho cua sov yuav tsum tau ua raws li hom hlau tshwj xeeb, kom tau txais kev ua haujlwm zoo ntawm kev sib koom ua ke.
Qhov kub quenching ntawm cov hlau ceev ceev feem ntau siab dua li qhov kub yaj ntawm cov nyiaj tooj liab thiab tooj liab zinc solder, yog li nws yog qhov tsim nyog yuav tsum tau quenched ua ntej brazing thiab braze thaum lossis tom qab tempering thib ob. Yog tias xav tau quenching tom qab brazing, tsuas yog cov hlau tshwj xeeb brazing filler hlau saum toj no tuaj yeem siv rau brazing. Thaum brazing cov cuab yeej txiav hlau ceev ceev, nws yog qhov tsim nyog los siv lub cub tawg coke. Thaum cov hlau brazing filler hlau yaj, tshem tawm cov cuab yeej txiav thiab tam sim ntawd pressurize nws, extrude cov hlau brazing filler ntau dhau, tom qab ntawd nqa roj quenching, thiab tom qab ntawd tempering nws ntawm 550 ~ 570 ℃.
Thaum brazing lub cemented carbide hniav nrog lub cuab yeej hlau, txoj kev ntawm kev nce qhov sib txawv brazing thiab siv cov yas them nyiaj gasket hauv qhov sib txawv brazing yuav tsum tau txais, thiab txias qeeb yuav tsum tau ua tom qab welding kom txo qhov kev ntxhov siab brazing, tiv thaiv kev tawg thiab ntev lub neej kev pabcuam ntawm cov cuab yeej cemented carbide sib dhos.
Tom qab vuam fiber, cov flux residue ntawm qhov vuam yuav tsum tau ntxuav nrog dej kub lossis cov tshuaj sib xyaw tshem tawm slag, thiab tom qab ntawd pickled nrog cov tshuaj pickling tsim nyog kom tshem tawm cov zaj duab xis oxide ntawm lub hauv paus cuab yeej pas nrig. Txawm li cas los xij, ceev faj tsis txhob siv cov tshuaj nitric acid los tiv thaiv kev xeb ntawm cov hlau sib koom ua ke.
Lub sijhawm tshaj tawm: Lub Rau Hli-13-2022