Tshooj 2 Kev txiav txim siab ntawm Deg Hardened Layer Depth
Los ntawm kev kho cua sov (carburizing quenching, carbonitriding quenching, nitriding, thiab lwm yam) los yog kev kho cua sov saum npoo (induction quenching, nplaim quenching, electron beam quenching, thiab lwm yam), nrog rau hlau infiltration thiab non-metal infiltration, nto ntawm hlau. qhov chaw tuaj yeem kho rau qhov tob. Hardened txheej kom haum rau cov kev pabcuam. Nyob rau hauv lub premise ntawm kev txiav txim lub ntsiab txhais ntawm hardened txheej, hardness gradient txoj kev yuav siv tau los ntsuas qhov tob ntawm hardened txheej. Thaum muaj qhov pom tseeb ntawm cov txheej txheem hardened thiab cov matrix, cov txheej txheem metallographic kuj tseem siv tau.
Rau kev npaj cov qauv, cov kev cai dav dav rau kev npaj cov qauv metallographic yuav tsum ua raws (saib Tshooj 5, Tshooj 5.1). Cov qauv yuav tsum tau muab mounted los tiv thaiv lub npoo npoo ntawm cov qauv los ntawm kev chamfered; tus qauv yuav tsum tau eroded ib txwm rau kev kuaj metallographic lossis kom nkag siab txog cov txheej txheem hardness faib thaum siv txoj kev hardness. Thaum ntsuas hardness, nws raug nquahu kom ua nws hauv lub xeev polished.
2.1 Cov kev cai dav dav rau kev txiav txim siab ntawm cov tawv tawv txheej txheej tob
Kev txiav txim siab ntawm qhov tob ntawm txheej hardened tau txais nyob rau hauv cov txheej txheem tshwj xeeb yuav tsum tau ua raws li qhov yuav tsum tau muaj ntawm cov qauv ntsuas thiab cov txheej txheem kev ua haujlwm.
2.1.1 Kev xaiv qauv thiab kev npaj ua qauv
Cov qauv ntsuas qhov tob ntawm cov txheej txheej hardened yuav tsum tau muab coj los ntawm cov khoom tom qab ua tiav cov txheej txheem tshwj xeeb. Qhov chaw thiab ntau npaum li cas yuav tsum tau teev nyob rau hauv cov txheej txheem cov ntaub ntawv, thiab cov qauv xa mus rau lub cub tawg kuj raug xaiv raws li cov kev cai.
Qhov tob ntawm txheej txheej hardened yuav tsum tau ntsuas nyob rau ntawm ib tug ntoo khaub lig-section perpendicular mus rau lub hardened txheej. Qhov chaw xeem yuav tsum suav nrog tag nrho cov txheej txheem tawv tawv thiab ib feem ntawm cov qauv tseem ceeb, thiab yuav tsum nyob ze li sai tau rau cov kev taw qhia axial ntawm ib feem lossis thaj chaw uas tau teev tseg hauv daim ntawv cog lus kev cob qhia.
Rau cov qauv txheej tawv tawv nyias, tuaj yeem siv cov qauv zoo li lub ntsej muag, raws li pom hauv daim duab 2-1. Cov kauj ruam cov qauv kuj tuaj yeem siv tau thaum txiav txim siab qhov txwv ntawm cov txheej txheej tawv tawv qhov tob. Qhov siab ntawm txhua kauj ruam ntawm cov qauv kauj ruam yog 0.05mm lossis 0.10mm, thiab nws qhov chaw thiab txhua kauj ruam saum npoo yuav tsum yog hauv av thiab ua tiav, raws li qhia hauv daim duab 2-2.
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2.1.2 Kev txiav txim siab ntawm hardness gradient
Txoj kev hardness yog siv los txiav txim qhov tob ntawm txheej txheej hardened, uas yog raws li qhov hardness gradient nkhaus ntawm qhov chaw mus rau sab hauv.
Lub hardness gradient feem ntau yog ntsuas siv Vickers hardness tester, tab sis Knoop hardness tester kuj tseem siv tau raws li cov kev pom zoo los ntawm ob tog rau qhov kev pom zoo. Qhov siv tau ntawm kev xeem quab yuam tuaj yeem yog {{0}}.9807 ~ 9.807N (0.1 ~ 1kgf).
Lub hardness gradient yog ntsuas ntawm ob lossis ntau qhov chaw raws li kev pom zoo ntawm ob tog rau qhov kev pom zoo. Kev ntsuas qhov tshwm sim ntawm txhua qhov chaw yuav tsum tau kos raws li qhov sib txawv ntawm qhov hardness hloov nkhaus piv rau qhov deb ntawm qhov chaw.
Txoj hauj lwm ntawm hardness ntsuas yog qhia nyob rau hauv lub rooj txoj kev nyob rau hauv daim duab {{0}}. Nyob rau hauv qhov dav W ntawm 1.5 hli, Vickers hardness yog ntsuas ntawm ib los yog ntau dua cov kab sib txuas perpendicular rau saum npoo. Qhov kev ncua deb ntawm cov kab sib txuas no yuav tsum ua raws li Vickers hardness test standard cov cai. Qhov kev ncua deb (Δd) ntawm txhua ob qhov chaw nyob ib sab yuav tsum tsis txhob tsawg tshaj li lub sij hawm ib txwm ntawm kab pheeb ces kaum ntawm indentation. Qhov sib txawv ntawm qhov sib txawv (d2-d1) nruab nrab ntawm qhov nruab nrab ntawm qhov sib txuas ntawm qhov sib txuas thiab qhov chaw yuav tsum tsis pub tshaj 0.1mm. Qhov tseeb ntawm kev ntsuas qhov kev ncua deb ntawm qhov chaw ntawm qhov indentation mus rau saum npoo yuav tsum tsis pub dhau ± 25 μm.
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Qhov nruab nrab-rau-nto deb ntawm thawj indentation (d1) ntawm qhov chaw yuav tsum yog tsawg kawg yog 2.5 npaug ntawm kab pheeb ces kaum ntawm Vickers hardness indentation.
Raws li cov ntaub ntawv ntsuas, qhov nkhaus qhia hauv daim duab 2-4 tuaj yeem kos tau, thiab cov txheej txheem hardened sib sib zog nqus tuaj yeem tau txais raws li cov ntsiab lus ntawm ntau yam hardened txheej tob.
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2.2 Kev txiav txim siab ntawm qhov tob ntawm carburized lossis carbonitrided quenched hardened txheej ntawm steel qhov chaw
Qhov tob ntawm carburized los yog carbonitrided quenching hardened txheej ntawm steel qhov chaw (ntau tshaj 0.3mm) yog feem ntau ntsuas siv cov txheej txheem teev nyob rau hauv GB/T 9450-2005 "Kev txiav txim thiab xyuas qhov tob ntawm lub Carburized thiab quenched Hardened Txheej ntawm Steel Parts". Txoj kev no Nws kuj yog tib txoj kev txiav txim.
2.2.1 Txhais qhov tob ntawm carburizing thiab quenching hardened txheej
GB/T 9450-2005 qhia tias qhov ntsug nrug deb ntawm qhov chaw mus rau qhov chaw uas Vickers hardness tus nqi yog 550HV1 yog qhov tob ntawm carburizing thiab quenching hardened txheej. Qhov 550HV1 no hu ua qhov txwv hardness tus nqi. Cov ntsiab lus no siv rau cov khoom ua haujlwm uas tau raug carburized lossis carbonitrided thiab quenched, thiab tus nqi hardness ntawm qhov tob ntawm quenching hardened txheej los ntawm qhov chaw (txhais tau tias yog qhov chaw) tsawg dua 450HV. Thaum qhov taw tes siab dua 450HV, tus nqi tshwj xeeb siab dua 550HV (nrog 25HV raws li thawj theem) yuav tsum raug xaiv raws li qhov txwv hardness. Yog hais tias tus nqi hardness tseem ceeb ntawm qhov chaw no yog 470HV, qhov txwv hardness tus nqi yuav tsum tau teem li 575HV. Yog tias muaj lwm qhov kev pom zoo, cov kev cai ntawm daim ntawv cog lus yuav raug siv.
2.2.2 Kev txiav txim siab ntawm hardened txheej tob los ntawm txoj kev hardness
Siv lub nra ntawm {{0}}.9807 ~ 9.807N (feem ntau siv: 0.9807 ~ 2.942N) los ntsuas qhov hardness gradient nkhaus ntawm qhov chaw mus rau sab hauv raws li txoj kev qhia hauv Tshooj 2.1. Feem ntau, ob lossis ntau dua hardness nkhaus yuav tsum tau ntsuas ntawm txoj haujlwm pom zoo los ntawm ob tog. Txiav txim siab qhov kev ncua deb ntawm qhov chaw ua hauj lwm qhov chaw uas tus nqi hardness yog tus nqi txhais tau tias (xws li 550HV lossis tus nqi Knoop hardness sib thooj) raws li txhua qhov nkhaus, raws li qhia hauv cov lus hauv daim duab 2-4. Thaum qhov sib txawv ntawm txhua tus nqi tsawg dua los yog sib npaug rau 0.1 hli, qhov nruab nrab tus nqi raug coj mus rau qhov tob ntawm txheej hardened. Yog tias qhov sib txawv ntau dua 0.1 hli, qhov ntsuas yuav tsum tau rov ua dua.
Nyob rau hauv cov xwm txheej uas qhov tob ntawm carburizing thiab quenching hardened txheej tau raug txiav txim siab, cov txheej txheem interpolation tuaj yeem siv rau kev txheeb xyuas. Nyob rau ntawm txoj hauj lwm qhov kev ncua deb ntawm qhov saum npoo yog tsawg tshaj li qhov kwv yees hardened txheej tob d1 thiab ntau dua li qhov kwv yees hardened txheej tob d2
(Qhov "ntawm d{{0}} d1 yuav tsum tsis pub tshaj 0.3mm"). Ntsuas yam tsawg kawg yog 5 hardness qhov tseem ceeb (nruab nrab tus nqi) ntawm lawv txhua tus. Cov duab yog raws. Lub hardened txheej tob (CHD) tuaj yeem tau txais raws li cov qauv kev sib tshuam (2-1):
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Nyob rau hauv cov mis, d1 - qhov deb ntawm qhov chaw uas yog tsawg tshaj li qhov tob ntawm hardened txheej;
d2 ——— Qhov kev ncua deb ntawm qhov chaw uas ntau dua qhov tob ntawm txheej hardened;
Daim duab - tus lej lej ntawm qhov hardness ntsuas qhov tseem ceeb ntawm d1 thiab d2, raws li pom hauv daim duab 2-5;
Daim duab - qhov txwv hardness tus nqi (feem ntau yog 550HVI).
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2.2.3 Txoj kev qhia cov txiaj ntsig ntawm carburizing thiab quenching hardened txheej qhov tob ntsuas
Raws li lub hardness xeem tej yam kev mob, qhov tob ntawm carburizing thiab quenching hardened txheej yog qhia raws li nram no:
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2.2.4 Metallographic txoj kev los txiav txim qhov tob ntawm carburizing thiab quenching hardened txheej
Thaum ntsuas qhov tob ntawm txheej tawv tawv siv cov txheej txheem metallographic, nws raug nquahu kom siv lub tshuab ntsuas metallographic uas qhov tob ntawm txheej tawv tawv yog 1/3 ~ 2/3 ntawm qhov pom.
Cov txheej txheem metallographic feem ntau ntsuas ntawm qhov ntsuas metallographic ntawm qhov qub ntu ntawm cov qauv carburized nyob rau hauv qeeb txias (lub xeev sib npaug). Tsis muaj cov qauv kev lag luam nruj thiab sib koom ua ke rau cov txheej txheem kev suav tshwj xeeb ntawm qhov tob ntawm carburized thiab quenched hardened txheej. Nws feem ntau yog raws li cov khoom siv raw. (Carbon steel, alloy steel) thiab thev naus laus zis tuaj yeem muab faib ua 3 txoj hauv kev, saib Table 2-1.
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Thaum ua kom ntseeg tau tias cov khoom ua haujlwm muaj qhov sib sib zog nqus siab-carbon cheeb tsam, nws kuj yog feem ntau yuav tsum tau hais tias cov pa roj carbon concentration gradient nyob rau hauv qhov chaw hloov ntawm carburized txheej yuav tsum tsis txhob loj dhau los ua kom qeeb qhov kev ntxhov siab ntawm cov txheej txheem carburized thiab matrix. . Yog li ntawd, feem ntau nws yuav tsum tau hais tias cov sum ntawm cov hypereutectoid txheej thiab eutectoid txheej account rau kwv yees li 50% mus rau 75% ntawm tag nrho cov permeability txheej.
2.2.5 Kev txiav txim siab ntawm ntiav carburized hardened txheej tob
Rau workpieces nrog ib tug carburized (carbonitriding) hardened txheej tob hauv qab no 0.3mm, cov saum toj no txoj kev yog tsis muaj feem xyuam, tab sis GB/T 9451-2005 "Kev txiav txim siab ntawm tag nrho hardened txheej tob los yog zoo hardened txheej tob ntawm nyias. cov txheej txheej ntawm steel qhov chaw" yuav tsum tau siv. txoj kev qhia. Cov txheej txheem no tau teev tseg tias qhov kev ncua deb ntawm txheej hardened ntsuas nyob rau hauv ntsug kev taw qhia ntawm lub workpiece nto mus rau qhov teev microhardness tus nqi yog hu ua zoo hardened txheej qhov tob, thiab qhov kev ncua deb ntsuas los ntawm hardened txheej yam tsis muaj kev hloov tseem ceeb nyob rau hauv lub microhardness tus nqi yog hu ua. tag nrho hardened txheej tob.
Txoj kev ntsuas tshwj xeeb thiab cov qauv qhia yog tib yam li GB / T {{0}}}, tab sis cov khoom siv rau Vickers hardness test feem ntau yuav yog 1.97N (0.2kgf) thiab 2.94N ( 0.3 kgf).
2.3 Kev txiav txim siab ntawm nitrided txheej tob ntawm steel qhov chaw
Qhov kev txiav txim siab tob ntawm nitriding (nitrocarburizing) txheej steel feem feem ntau ua raws li GB / T 11354-2005 "Steel Parts - Nitriding Layer Depth Determination and Metallographic Structure Inspection". Cov kev ntsuas tshwj xeeb suav nrog txoj kev hardness, metallographic method thiab txoj kev tawg. Ntawm lawv, txoj kev hardness yog txoj kev txiav txim siab.
2.3.1 Kev txhais ntawm nitriding txheej tob
Qhov tob ntawm nitriding (nitrocarburizing) txheej yog qhov sib npaug ntawm cov txheej txheej txheej txheej thiab txheej txheej diffusion.
Txhais los ntawm hardness: Qhov ntsug nrug ntsuas los ntawm qhov saum npoo ntawm cov qauv mus rau qhov taw tes 50HV siab dua Vickers hardness tus nqi ntawm lub substrate yog qhov tob ntawm txheej nitriding.
Rau qhov chaw uas lub hardness ntawm nitrided txheej ntawm carbon steel los yog tsawg-carbon low-alloy steel hloov maj mam, qhov tob ntawm nitrided txheej yuav raug txhais raws li qhov deb ntawm qhov chaw raws li ntsug nto kev taw qhia qhov twg Vickers hardness yog 30HV. siab dua Vickers hardness ntawm matrix. Yog tias muaj lwm qhov kev pom zoo, cov kev cai ntawm daim ntawv cog lus yuav raug siv.
2.3.2 Kev txiav txim siab ntawm nitriding txheej tob los ntawm txoj kev hardness
Txoj kev hardness yog siv los ntsuas qhov tob ntawm txheej nitriding. Vickers hardness yog siv raws li tus qauv (Knoop hardness kuj siv tau). Kev xeem quab yuam yog {{0}}.9807 ~ 9.807N, thiab 0.9807 ~ 2.942N feem ntau yog siv.
Qhov tob ntawm txheej nitriding yog nyob ntawm lub hauv paus hardness ntawm ib feem. Nws yuav tsum tau hais tias qhov nruab nrab tus nqi (qhov tseeb rau 10 tus lej) ntawm 3- taw tes hardness qhov tseem ceeb ntsuas ntawm 3 npaug ntawm qhov tob ntawm nitriding txheej los ntawm qhov chaw yog qhov ntsuas lub hauv paus hardness.
