Cov ntaub ntawv zoo raw khoom yog lub hauv paus rau kev tsim cov fasteners zoo. Txawm li cas los xij, ntau cov khoom lag luam fastener yuav muaj cov kab nrib pleb. Vim li cas qhov no tshwm sim?

Tam sim no, cov kev qhia tshwj xeeb ntawm cov qauv steel hlau rods muab los ntawm domestic steel mills yog φ 5.5- φ 45, qhov ntau mature ntau yog φ 6.5- φ 30. Muaj ntau yam xwm txheej zoo tshwm sim los ntawm kev sib cais ntawm phosphorus, xws li phosphorus segregation. me me hlau pas nrig thiab bar. Kev cuam tshuam ntawm phosphorus cais thiab kev tsom xam ntawm kev sib tsoo yog qhia hauv qab no rau kev siv. Qhov sib ntxiv ntawm phosphorus nyob rau hauv cov hlau carbon theem daim duab kos yuav sib raug kaw lub austenite theem cheeb tsam thiab inevitably nce qhov kev ncua deb ntawm lub solidus thiab liquidus. Thaum phosphorus uas muaj hlau yog txias los ntawm cov kua rau cov khoom, nws yuav tsum tau mus txog qhov kub thiab txias.

Lub diffusion tus nqi ntawm phosphorus nyob rau hauv steel yog qeeb, thiab molten hlau nrog siab phosphorus concentration (tsawg melting point) yog tag nrho ntawm cov thawj solidified dendrites, uas ua rau phosphorus segregation. Rau cov khoom uas feem ntau muaj cov kab nrib pleb thaum lub sij hawm txias forging los yog txias extrusion, kev ntsuam xyuas metallographic thiab tsom xam pom tias cov ferrite thiab pearlite raug faib rau hauv strips, thiab muaj dawb banded ferrite hauv matrix. Muaj qhov sib cuam tshuam lub teeb grey sulfide suav nrog thaj chaw ntawm banded ferrite matrix. Lub banded qauv ntawm sulfide yog hu ua "dab kab" vim hais tias ntawm sulfide segregation.
Yog vim li cas yog tias thaj chaw uas muaj phosphorus loj segregation nthuav tawm thaj tsam dawb nyob rau hauv thaj chaw phosphorus enrichment. Nyob rau hauv qhov nruam casting slab, vim muaj cov ntsiab lus phosphorus siab nyob rau hauv thaj chaw dawb, cov columnar crystals nplua nuj nyob rau hauv phosphorus concentrate, txo cov ntsiab lus phosphorus. Thaum lub billet solidifies, lub austenite dendrites yog thawj zaug sib cais los ntawm cov hlau molten. Cov phosphorus thiab sulfur nyob rau hauv cov dendrites yog txo, tab sis thaum kawg solidified molten hlau muaj phosphorus thiab sulfur ntsiab. Nws solidifies ntawm dendrite axes vim hais tias cov phosphorus thiab sulfur ntsiab yog siab. Lub sijhawm no, sulfide yog tsim, thiab phosphorus yog yaj hauv matrix. Vim hais tias phosphorus thiab sulfur ntsiab yog siab, sulfide yog tsim ntawm no, thiab phosphorus yog yaj nyob rau hauv lub matrix. Yog li ntawd, Vim yog cov ntsiab lus siab ntawm phosphorus thiab sulfur ntsiab lus, cov ntsiab lus carbon hauv phosphorus cov kua dej yog siab. Ntawm ob sab ntawm txoj siv carbonaceous, uas yog, ntawm ob sab ntawm phosphorus enrichment cheeb tsam, ib tug ntev thiab nqaim pearlite txoj siv nyob rau tib lub sij hawm mus rau lub ferrite dawb siv yog tsim, thiab nyob ib sab cov ntaub so ntswg yog sib cais. Nyob rau hauv cov cua kub siab, lub billet yuav txuas mus rau cov kev taw qhia ntawm lub shafts, vim hais tias cov ferrite siv muaj phosphorus siab, uas yog, phosphorus segregation yuav ua rau tsim ib tug hnyav dav ci ferrite siv qauv nrog ib tug dav ci ferrite siv qauv. . Nws tuaj yeem pom tau tias tseem muaj cov kab grey sulphide strips nyob rau hauv dav ci ferrite siv, uas yog faib nrog ib tug ntev strip ntawm sulfide nplua nuj phosphorus ferrite siv, uas peb feem ntau hu ua "dab kab". (Saib daim duab 1-2)

Flange Bolt

Nyob rau hauv cov txheej txheem kub dov, tsuav yog muaj phosphorus cais, nws yog tsis yooj yim sua kom tau ib tug uniform microstructure. Qhov tseem ceeb tshaj, vim tias kev sib cais ntawm phosphorus tau tsim ib qho "dab kab" qauv, nws yuav ua rau txo qis cov khoom siv ntawm cov khoom. Phosphorus segregation nyob rau hauv carbon bonded steel yog ntau, tab sis nws degree txawv. Kev sib cais hnyav phosphorus ("dab kab" qauv) yuav ua rau muaj kev cuam tshuam tsis zoo rau cov hlau. Obviously, qhov sib cais hnyav ntawm phosphorus yog qhov ua txhaum ntawm qhov txias taub hau tawg. Vim tias cov ntsiab lus phosphorus hauv cov nplej sib txawv ntawm cov hlau sib txawv, cov ntaub ntawv muaj qhov sib txawv ntawm qhov sib txawv thiab hardness. Ntawm qhov tod tes, nws ua rau cov khoom tsim kev ntxhov siab sab hauv, uas yuav ua rau cov khoom tawg yooj yim. Nyob rau hauv cov ntaub ntawv nrog "dab kab" qauv, nws yog precisely vim hais tias ntawm qhov txo ntawm hardness, lub zog, elongation tom qab tawg thiab txo ntawm cheeb tsam, tshwj xeeb tshaj yog txo ntawm tej yam toughness, uas cov phosphorus ntsiab lus nyob rau hauv cov ntaub ntawv muaj ib tug zoo kev sib raug zoo nrog cov qauv thiab cov khoom steel.
Nyob rau hauv cov ntaub so ntswg "dab kab" nyob rau hauv nruab nrab ntawm lub teb ntawm lub zeem muag, ib tug loj npaum li cas ntawm nyias, lub teeb grey sulfide tau kuaj pom los ntawm metallography. Cov non-metallic inclusions nyob rau hauv structural steel mas muaj nyob rau hauv daim ntawv ntawm oxides thiab sulfides. Raws li GB / T10561-2005 Standard Classification Diagram rau cov ntsiab lus ntawm Nonmetallic Inclusions nyob rau hauv hlau, sulfide cov ntsiab lus ntawm chav kawm B suav yog 2.5 los yog siab dua. Nonmetallic inclusions yog lub peev xwm tawg qhov chaw. Nws qhov muaj nyob yuav ua rau puas tsuaj rau qhov txuas ntxiv thiab kev cog lus ntawm cov qauv hlau, yog li txo qis lub zog intergranular.
Nws yog speculated tias sulfide nyob rau hauv cov qauv sab hauv "dab kab" ntawm cov hlau yog qhov yooj yim tshaj plaws tawg. Yog li ntawd, ib tug loj tus naj npawb ntawm fasteners tawg nyob rau hauv txias taub hau thiab kho cua sov quenching ntawm qhov chaw tsim khoom, uas yog tshwm sim los ntawm ib tug loj tus naj npawb ntawm lub teeb grey ntev sulfides. Cov ntaub nonwoven no rhuav tshem qhov txuas ntxiv ntawm cov khoom hlau thiab ua rau muaj kev pheej hmoo ntawm kev kho cua sov. "Dab kab" tsis tuaj yeem raug tshem tawm los ntawm normalizing thiab lwm txoj hauv kev, thiab cov khoom tsis huv yuav tsum tau tswj nruj me ntsis ua ntej smelting lossis raw cov ntaub ntawv nkag mus rau hauv cov nroj tsuag. Raws li muaj pes tsawg leeg thiab deformability, non-metallic inclusions muab faib ua alumina (hom A) silicate (hom C) thiab kheej kheej oxide (hom D). Nws cov tsos yuav txiav tawm qhov txuas ntxiv ntawm cov hlau thiab ua pits lossis tawg tom qab tev, uas yog ib qho yooj yim rau cov kab nrib pleb thaum lub caij txias thiab ua rau muaj kev ntxhov siab thaum kho cua sov, yog li ua rau quenching tawg. Yog li ntawd, tsis yog-hlau inclusions yuav tsum nruj me ntsis tswj. Tam sim no Cov Qauv Carbon Steels GB / T700-2006 thiab GB T699-2016 High Quality Carbon Steels muab tso rau cov kev xav tau rau cov khoom tsis yog xim hlau. Rau qhov tseem ceeb, nws yog feem ntau A, B, C hom coarse series, nplua series tsis ntau tshaj 1.5, D, Ds hom ntxhib system thiab qib 2 tsis ntau tshaj qib 2.

Hebei Chengyi Engineering Materials Co., Ltd. yog lub tuam txhab nrog 21 xyoo ntawm kev tsim khoom thiab kev muag khoom. Peb cov fasteners siv cov ntaub ntawv zoo raw khoom, kev tsim khoom siab heev thiab kev tsim khoom siv tshuab, thiab kev tswj xyuas zoo tshaj plaws los xyuas kom meej cov khoom zoo. Yog tias koj txaus siab rau kev yuav khoom fasteners, thov hu rau peb.