Cov khoom siv raw zoo yog lub hauv paus rau kev tsim cov khoom siv txuas zoo. Txawm li cas los xij, ntau lub tuam txhab tsim cov khoom siv txuas yuav muaj qhov tawg. Vim li cas qhov no thiaj tshwm sim?

Tam sim no, cov lus qhia dav dav ntawm cov hlau carbon hlau uas muab los ntawm cov chaw tsim hlau hauv tsev yog φ 5.5- φ 45, qhov ntau dua yog φ 6.5- φ 30. Muaj ntau qhov xwm txheej zoo los ntawm kev sib cais phosphorus, xws li kev sib cais phosphorus ntawm cov hlau me me thiab cov hlau. Kev cuam tshuam ntawm kev sib cais phosphorus thiab kev tshuaj xyuas ntawm kev tsim tawg tau qhia hauv qab no rau kev siv. Kev ntxiv phosphorus hauv daim duab hlau carbon theem yuav kaw thaj tsam austenite theem thiab ua rau qhov deb ntawm solidus thiab liquidus nce ntxiv. Thaum phosphorus muaj hlau txias los ntawm kua mus rau khoom, nws yuav tsum mus dhau qhov kub thiab txias loj.

Tus nqi ntawm phosphorus diffusion hauv hlau yog qeeb, thiab cov hlau molten nrog cov phosphorus concentration siab (qis melting point) yog puv nrog thawj cov dendrites khov kho, uas ua rau phosphorus sib cais. Rau cov khoom uas feem ntau muaj cov kab nrib pleb thaum lub sijhawm txias forging lossis txias extrusion, kev tshuaj xyuas metallographic thiab kev tshuaj xyuas qhia tias ferrite thiab pearlite tau faib ua strips, thiab muaj ferrite dawb banded hauv matrix. Muaj cov cheeb tsam sib xyaw ua ke ntawm lub teeb grey sulfide ntawm cov banded ferrite matrix. Cov qauv banded ntawm sulfide hu ua "ghost line" vim yog sulfide sib cais.
Qhov laj thawj yog tias thaj chaw uas muaj kev sib cais phosphorus loj heev nthuav tawm thaj chaw dawb kaj hauv thaj chaw phosphorus nplua nuj. Hauv cov slab casting tas mus li, vim muaj cov phosphorus ntau hauv thaj chaw dawb, cov siv lead ua ke nplua nuj hauv phosphorus concentrate, txo cov phosphorus. Thaum lub billet khov, cov austenite dendrites raug cais tawm ntawm cov hlau molten thawj zaug. Cov phosphorus thiab sulfur hauv cov dendrites no raug txo qis, tab sis cov hlau molten khov thaum kawg muaj phosphorus thiab sulfur ntsiab lus. Nws khov ntawm cov dendrite axes vim tias cov phosphorus thiab sulfur ntsiab lus siab. Lub sijhawm no, sulfide tsim, thiab phosphorus yaj hauv matrix. Vim tias cov phosphorus thiab sulfur ntsiab lus siab, sulfide tsim ntawm no, thiab phosphorus yaj hauv matrix. Yog li ntawd, Vim muaj cov phosphorus thiab sulfur ntsiab lus siab, cov carbon ntsiab lus hauv phosphorus cov kua khov siab. Ntawm ob sab ntawm txoj siv carbonaceous, uas yog, ntawm ob sab ntawm thaj chaw phosphorus nplua nuj, txoj siv pearlite ntev thiab nqaim sib nrug sib luag rau txoj siv ferrite dawb yog tsim, thiab cov ntaub so ntswg ib txwm nyob ib sab raug cais tawm. Nyob rau hauv lub siab cua sov, lub billet yuav nthuav mus rau qhov kev coj ua ntawm cov shafts, vim tias txoj siv ferrite muaj phosphorus siab, uas yog, phosphorus sib cais yuav ua rau muaj cov qauv ferrite dav dav nrog cov qauv ferrite dav dav. Nws tuaj yeem pom tias tseem muaj cov kab sulphide grey hauv txoj siv ferrite dav dav, uas tau faib nrog cov kab ntev ntawm sulfide nplua nuj phosphorus ferrite, uas peb feem ntau hu ua "kab dab". (Saib Daim Duab 1-2)

Flange ntsia liaj qhov rooj

Hauv cov txheej txheem kub dov, tsuav yog muaj phosphorus sib cais, nws tsis yooj yim sua kom tau txais cov qauv me me. Qhov tseem ceeb tshaj, vim tias phosphorus sib cais tau tsim cov qauv "dab kab", nws yuav txo cov khoom siv kho tshuab ntawm cov khoom. Phosphorus sib cais hauv cov hlau carbon bonded yog qhov tshwm sim, tab sis nws qib sib txawv. phosphorus sib cais hnyav ("dab kab" qauv) yuav ua rau muaj kev cuam tshuam tsis zoo rau cov hlau. Nws yog qhov tseeb, qhov kev sib cais hnyav ntawm phosphorus yog qhov ua rau muaj kev tawg txias. Vim tias cov ntsiab lus phosphorus hauv cov hlau sib txawv sib txawv, cov ntaub ntawv muaj zog thiab tawv sib txawv. Ntawm qhov tod tes, nws ua rau cov khoom tsim kev ntxhov siab sab hauv, uas yuav ua rau cov khoom yooj yim tawg. Hauv cov ntaub ntawv nrog "dab kab" qauv, nws yog vim qhov txo qis ntawm qhov nyuaj, lub zog, elongation tom qab tawg thiab txo qis thaj chaw, tshwj xeeb tshaj yog qhov txo qis ntawm kev cuam tshuam toughness, uas cov ntsiab lus phosphorus hauv cov ntaub ntawv muaj kev sib raug zoo nrog cov qauv thiab cov khoom ntawm hlau.
Hauv cov ntaub so ntswg "dab kab" nyob nruab nrab ntawm thaj chaw pom kev, ntau cov sulfide nyias nyias, lub teeb grey tau pom los ntawm metallography. Cov khoom tsis yog hlau hauv cov hlau qauv feem ntau muaj nyob rau hauv daim ntawv ntawm oxides thiab sulfides. Raws li GB / T10561-2005 Daim Duab Qhia Txog Kev Faib Tawm rau Cov Ntsiab Lus ntawm Cov Khoom Tsis Yog Hlau hauv Hlau, cov ntsiab lus sulfide ntawm Chav Kawm B suav nrog yog 2.5 lossis siab dua. Cov khoom tsis yog hlau yog qhov ua rau tawg. Nws qhov muaj nyob yuav ua rau puas tsuaj rau kev sib txuas thiab kev sib cog lus ntawm cov qauv hlau, yog li txo qis lub zog intergranular.
Nws tau xav tias cov sulfide hauv cov qauv sab hauv "ghost line" ntawm cov hlau yog qhov yooj yim tawg tshaj plaws. Yog li ntawd, ntau cov fasteners tawg hauv kev txias thiab kev kho cua sov quenching ntawm qhov chaw tsim khoom, uas tau tshwm sim los ntawm ntau lub teeb grey ntev sulfides. Cov ntaub nonwoven no rhuav tshem qhov kev sib txuas ntawm cov khoom hlau thiab ua rau muaj kev pheej hmoo ntawm kev kho cua sov. "Ghost line" tsis tuaj yeem tshem tawm los ntawm normalizing thiab lwm txoj kev, thiab cov ntsiab lus impurity yuav tsum tau tswj hwm nruj me ntsis ua ntej smelting lossis cov khoom siv raw nkag mus rau hauv cov nroj tsuag. Raws li cov khoom sib xyaw thiab deformability, cov khoom tsis yog hlau tau muab faib ua alumina (hom A) silicate (hom C) thiab spherical oxide (hom D). Nws qhov tsos yuav txiav tawm qhov kev sib txuas ntawm cov hlau thiab ua qhov lossis tawg tom qab tev tawm, uas yooj yim tsim cov tawg thaum lub sijhawm txias thiab ua rau muaj kev ntxhov siab thaum lub sijhawm kho cua sov, yog li ua rau muaj kev tawg quenching. Yog li ntawd, cov khoom tsis yog hlau yuav tsum tau tswj hwm nruj me ntsis. Cov Hlau Carbon Structural Steels GB/T700-2006 thiab GB T699-2016 Cov Hlau Carbon Zoo Tshaj Plaws uas tam sim no muaj cov kev cai rau cov khoom uas tsis yog hlau. Rau cov khoom tseem ceeb, feem ntau yog A, B, C hom coarse series, cov series zoo tsis pub tshaj 1.5, D, Ds hom coarse system thiab theem 2 tsis pub tshaj theem 2.

Hebei Chengyi Engineering Materials Co., Ltd. yog ib lub tuam txhab uas muaj 21 xyoo ntawm kev tsim khoom thiab muag khoom siv fasteners. Peb cov fasteners siv cov khoom siv raw zoo, kev tsim khoom thiab kev tsim khoom siab heev, thiab kev tswj hwm zoo meej kom ntseeg tau tias cov khoom zoo. Yog tias koj xav yuav cov fasteners, thov hu rau peb.