Kev kho cua sov ntawm cov fasteners zoo yuav tsum muaj plaub lub ntsiab lus tseem ceeb

Kev kho cua sov ntawm cov fasteners zoo yuav tsum muaj plaub lub ntsiab lus tseem ceeb
Ntxiv rau qhov kev tshuaj xyuas thiab kev tswj xyuas zoo, kuj tseem muaj qee qhov kev tshuaj xyuas tshwj xeeb thiab kev tswj xyuas kev kho cua sov ntawm fasteners. Plaub cov ntsiab lus hauv qab no yuav tsum tau ua kom tiav cov kev kho cua sov ntawm cov fasteners zoo.
1. Decarburization thiab carburization
Nyob rau hauv cov txheej txheem ntawm kev kho cua sov hauv batch ntau lawm, metallographic txoj kev kuj zoo, thiab microhardness txoj kev kuj zoo, thiab tsuas yog ib txwm coj mus kuaj. Vim nws lub sijhawm tshuaj xyuas ntev thiab tus nqi siab.
Txhawm rau txiav txim siab cov pa roj carbon tswj ntawm lub qhov cub hauv lub sijhawm, kev tshawb nrhiav pom thiab Rockwell hardness test tuaj yeem siv rau kev txiav txim siab ua ntej ntawm decarburization thiab carburization. Kev kuaj pom qhov hluav taws kub yog txhawm rau tua cov khoom hluav taws thiab maj mam txhuam cov nplaim taws ntawm lub tshuab ua haujlwm los txiav txim siab seb cov pa roj carbon monoxide ntawm qhov chaw thiab lub siab puas yog tib yam. Tau kawg, qhov no xav kom cov neeg ua haujlwm muaj kev txawj ntse thiab muaj peev xwm lees paub lub peev xwm.
Rockwell hardness test yog ua nyob rau ntawm ib sab ntawm lub hexagon ntsia liaj qhov rooj. Ua ntej, maj mam txhuam lub dav hlau hexagon ntawm qhov quenched nrog daim ntawv abrasive los ntsuas thawj Rockwell hardness. Tom qab ntawd, zom qhov saum npoo li ntawm 0.5 hli ntawm lub grinder thiab ntsuas Rockwell hardness. Yog hais tias ob lub hardness qhov tseem ceeb yog qhov qub, nws txhais tau tias tsis yog decarburization lossis carburization. Yog tias yav dhau los hardness qis dua qhov hardness dhau los, nws qhia tias decarburization nto. Thaum yav dhau los hardness siab dua yav dhau los, nws qhia tau hais tias deg carburization. Feem ntau, thaum qhov sib txawv hardness tsawg dua 5HRC, qhov decarburization lossis carburization ntawm qhov chaw yog nyob rau hauv qhov kev pom zoo thaum siv txoj kev metallographic lossis microhardness txoj kev siv rau kev tshuaj xyuas.
2. Hardness thiab lub zog
Nyob rau hauv kev tshuaj xyuas ntawm threaded fasteners, nws yog tsis yooj yim sua kom tsuas xyuas cov ntaub ntawv uas cuam tshuam raws li tus nqi hardness thiab hloov lub zog tus nqi. Muaj qhov hardenability yam nyob nruab nrab. Vim hais tias lub teb chaws tus qauv GB3098.1 thiab GB3098.3 teev hais tias qhov kev txiav txim hardness yog ntsuas ntawm 1/2 ntawm tus ntoo khaub lig seem vojvoog ntawm ib feem. Tensile qauv kuj raug coj los ntawm 1/2 vojvoog. Qhov no tsis txwv tsis pub muaj qhov tsis muaj zog thiab tsis muaj zog nyob rau hauv nruab nrab ntawm ib feem.
Feem ntau, lub hardenability ntawm cov khoom yog zoo, thiab hardness ntawm cov ntsia hlau seem yuav muab sib npaug zos rau ntawm tus ntoo khaub lig seem. Ntev npaum li qhov hardness tsim nyog, lub zog thiab lav kev ntxhov siab tuaj yeem ua tau raws li qhov yuav tsum tau ua. Txawm li cas los xij, thaum lub hardenability ntawm cov khoom tsis zoo, txawm hais tias nws tuaj yeem kuaj xyuas qhov hardness raws li txoj haujlwm tau teev tseg, lub zog thiab lav kev ntxhov siab feem ntau tsis tuaj yeem ua tau raws li qhov yuav tsum tau ua. Tshwj xeeb tshaj yog thaum lub deg hardness nyhav rau qis qis.
Txhawm rau tswj lub zog thiab lav kev ntxhov siab nyob rau hauv qhov kev lees paub, qhov qis qis ntawm hardness feem ntau yog nce. Piv txwv li, 8.8 hardness tswj ntau yam: M16 nrog rau cov nram qab no specifications yog 26 ~ 31HRC, thiab M16 nrog ntau tshaj 28 ~ 34HRC yog tsim nyog; 10.9 Nws yuav tsum tau tswj ntawm 36 ~ 39HRC. 10.9 lossis siab dua yog lwm qhov teeb meem.
3. Kev sim rov qab
Bolts, screws thiab studs ntawm qib 8.8 txog 12.9 yuav tsum tau tempered yam tsawg 10 degree C rau 30 feeb kom ncav cuag qhov kub siab tshaj plaws tempering nyob rau hauv tiag tiag ntau lawm. Ntawm tib tus qauv, qhov sib txawv ntawm qhov nruab nrab hardness ntawm peb lub ntsiab lus ua ntej thiab tom qab kev xeem yuav tsum tsis pub tshaj 20HV.
Kev ntsuas rov ua kom sov tuaj yeem tshawb xyuas qhov kev ua haujlwm tsis raug uas nyuam qhuav tau mus txog qhov tshwj xeeb hardness ntau yam vim tsis txaus quenching hardness, siv lub over-low kub tempering, thiab xyuas kom meej tag nrho cov khoom ntawm cov khoom. Tshwj xeeb, ntsia hlau fasteners ua los ntawm cov pa roj carbon tsawg martensitic steel yog tempered ntawm qhov kub thiab txias. Txawm hais tias lwm yam khoom siv tshuab tuaj yeem ua tau raws li qhov yuav tsum tau ua, qhov seem elongation hloov pauv tau zoo heev thaum ntsuas qhov kev lees paub kev ntxhov siab, uas yog ntau dua 12.5 μ m. Tsis tas li ntawd, nws yuav raug cuam tshuam tam sim ntawd nyob rau hauv tej yam kev mob ntawm kev siv. Hauv qee lub tsheb thiab kev tsim kho bolts, lawv mam li tawg. Thaum tempering nrog qhov kub siab tshaj plaws yog siv, qhov tshwm sim saum toj no tuaj yeem txo qis. Txawm li cas los xij, yuav tsum tau saib xyuas thaum tsim qib 10.9 bolts nrog qis carbon martensitic steel.
4. Hydrogen embrittlement tshuaj xyuas
Hydrogen embrittlement rhiab heev rhiab heev nrog qhov nce ntawm lub zog fastener. Dehydrogenation yuav tsum tau nqa tawm rau sab nraud xov fasteners ntawm 10.9 thiab siab dua, nto hardened self-tapping screws thiab ua ke screws nrog hardened steel washers.
Kev kho dehydrogenation feem ntau yog ua nyob rau hauv qhov cub lossis tempering rauv ntawm qhov kub ntawm 190 txog 230 ° C rau ntau tshaj 4 teev kom diffuse hydrogen.
Threaded fasteners tuaj yeem nruj rau ntawm cov clamps tshwj xeeb thiab nruj kom cov ntsia hlau tuaj yeem ua rau muaj kev ntxhov siab ntau rau 48 teev. Tom qab loosening, threaded fastener yuav tsis tawg. Txoj kev no yog siv los ua ib txoj hauv kev tshawb xyuas hydrogen embrittlement.