Hom hnav: kev faib tawm thiab cov yam ntxwv ntawm hnav

2024 Tus sau: Howard Calhoun | [email protected]. Kawg hloov kho: 2023-12-17 10:28

Hnav yog to taub raws li kev puas tsuaj zuj zus ntawm qhov sib txhuam ntawm ntau yam khub. Muaj ntau hom hnav. Lawv yog vim muaj ntau yam. Tab sis lawv txhua tus muaj ib qho zoo sib xws - cov khoom sib cais los ntawm cov khoom siv hauv paus. Qhov no ua rau muaj kev cuam tshuam hauv kev ua haujlwm ntawm cov txheej txheem, thiab lwm yam tuaj yeem ua rau lawv tawg. Qhov sib txawv ntawm cov pob qij txha nce, qhov tsaws pib tuav raws li qhov tshwm sim ntawm kev tsim ntawm ib qho tseem ceeb backlash. Kab lus no tham txog yam tseem ceeb ntawm hnav, muab lawv cov yam ntxwv thiab kev faib tawm dav dav.

Txoj kev hnav khaub ncaws hnav

Ib qho abrasive yog cov khoom tawg yooj yim ntawm lub hauv paus los yog cov khoom siv dag zog, nrog lub zog tseem ceeb txaus los khawb lwm cov ntaub ntawv nyuaj.

Hom kev hnav khaub ncaws, uas muaj kev puas tsuaj ntawm cov qauv thiab kev ncaj ncees ntawm txheej txheej thaumkev cuam tshuam nrog cov khoom microparticles hu ua abrasive. Nws yuav tsum raug muab tso tseg tias rau qhov kev puas tsuaj zoo li no, kev sib txhuam nrawm yuav tsum yog qhov tseem ceeb (ntau meters ib ob). Txawm hais tias nrog kev ua haujlwm ntev, kev puas tsuaj tshwm sim txawm tias qis dua thiab clamping quab yuam.

Lub luag haujlwm ntawm cov tshuaj abrasive tuaj yeem yog ob qho tib si ruaj khov (cov theem khoom ntawm cov hlau thiab cov hlau) thiab txav cov khoom txawv teb chaws uas tau poob rau hauv thaj chaw tiv tauj ntawm qhov chaw rub tawm (xuab zeb, plua plav thiab lwm yam).

Cov yam hauv qab no cuam tshuam rau tus nqi ntawm abrasive hnav thiab nws qhov kev siv:

• nature ntawm keeb kwm ntawm abrasive hais;
• mechanism ua haujlwm ib puag ncig (degree of aggressiveness);
• khoom khoom ntawm kev sib txhuam khub;
• cuam tshuam loads;
• ntsuas kub thiab ntau lwm yam.

Abrasion with hard particles (grains)

Hom kev siv tshuab no tshwm sim thaum cov nplej abrasive nkag mus rau hauv cov hlau lossis lwm yam khoom siv. Lub hardness Performance index ntawm cov khoom no ho ntau tshaj qhov hardness index ntawm cov hlau nws tus kheej. Qhov no ua rau deformation ntawm cov ntaub ntawv ntawm kev sib txhuam khub, tshwm sim ntawm qaug zog stresses, thiab nto abrasion.

Yog tias lub tshuab ua haujlwm nyob rau hauv cov xwm txheej ntawm kev hloov pauv ntau zaus, tom qab ntawd cov txiaj ntsig ntawm kev phom sij ntawm cov abrasive yog txhim kho. Nyob rau hauv cov ntaub ntawv no, cov abrasive particle tawm tsis tsuas yog cov cim, tab sis kuj dents ntawm cov hlau nto.

Nrog qhov nce ntawm feem ntawm cov tshuaj abrasive, lubabrasive hnav. Abrasive hais yog heev nyuaj, tab sis tib lub sij hawm nkig. Yog li ntawd, lub cev loj tuaj yeem ua rau me me.

Ntawm oxidative hnav

hom kev hnav no tshwm sim thaum cov yeeb yaj kiab oxide xoob tshwm rau ntawm qhov chaw ntawm cov khoom txhuam, uas tau tshem tawm sai sai vim yog kev sib txhuam. Feem ntau cov khoom siv engineering zoo li oxidize hauv huab cua ntawm qhov kub siab. Yog li ntawd, cov txheej txheem uas ua haujlwm yam tsis muaj lubrication thiab tsis muaj lub tshuab ua kom txias yog raug rau hom hnav ntawm qhov chaw.

Qhov ntau dua qhov kev puas tsuaj ntawm cov yeeb yaj kiab oxide thiab qhov ntau dua ntawm nws qhov tsim, qhov hnyav dua qhov hnav ntawm qhov chaw.

Hom kev hnav no yog qhov zoo rau cov pob qij txha thiab bolted, ntau yam kev ncua kev kawm, thiab qhov tseeb rau txhua chav ua haujlwm yam tsis muaj lubrication.

Nrog qhov nce ntawm kev sib txhuam ceev, qhov kub ntawm qhov sib tsoo ntawm qhov chaw nce. Qhov no ua rau kev siv zog ntawm kev puas tsuaj. Kev nce hauv kev poob siab muaj qhov zoo sib xws.

Hnav vim yas deformation

Hom kev hnav ntawm lub tshuab no yog qhov zoo rau cov khoom thauj khoom hnyav. Nws lub ntsiab lus yog nyob rau hauv kev hloov cov duab geometric ntawm cov khoom nyob rau hauv lub zog ntawm cov khoom tseem ceeb.

Nws yog qhov zoo tshaj plaws rau kev sib txuas keyed thiab splined, nrog rau cov xov, pins, thiab lwm yam.

Zoodeformations kuj tuaj yeem tshwm sim hauv cov pob qij txha. Thiab lawv tsis tas yuav nrawm. Load yog qhov tseem ceeb ntawm no.

Feem ntau cov deformations tshwm sim ntawm cov ntsia hlau thiab cov log ntawm cov khoom dov. Txhawm rau tiv thaiv, nws yog ib qho tsim nyog los npaj kev tiv thaiv raws sij hawm thiab tshuaj xyuas cov txheej txheem.

Nyob vim chipping

Qhov kev faib tawm ntawm hom kev hnav yuav tsis ua tiav yog tias peb pom qhov kev hnav khaub ncaws vim yog chipping. Nws essence yog raws li nram no. Nyob rau hauv qhov hnyav (tej zaum txawm tias huab) kev ua haujlwm, cov txheej txheej ntawm cov khoom siv rub tawm tau dhau los ntawm cov qauv thiab theem hloov pauv. Cov laj thawj ntawm qhov sib txawv yog qhov kub siab, cua sov thiab txias txias, siab siab, thiab lwm yam. Cov khoom ntawm cov txheej txheej tshwm sim txawv heev ntawm cov khoom qub. Raws li txoj cai, cov theem no yog nkig thiab tawg nyob rau hauv load.

Yog li, tus yam ntxwv dawb kab txaij tsim rau ntawm cov hlau thiab cam khwb cia hlau thaum sib txhuam yam tsis muaj lubrication. Cov cheeb tsam no tsis tuaj yeem etched txawm tias muaj cov tshuaj nitric lossis hydrofluoric acids hauv cawv. Cov kws tshaj lij hauv kev tshawb fawb hlau hu ua qhov tsim no ib txheej dawb. Nws muaj ib tug ncaj siab Rockwell hardness thiab yog nkig heev. Ib lub chaw kuaj mob tau ua cov theem thiab kev soj ntsuam ntawm cov txheej txheem dawb. Nws muab tawm hais tias nws yog ib tug neeg kho tshuab sib tov ntawm martensite thiab cementite. Nws kuj muaj me me ntawm ferrite. Qhov kawg ntawm nws txhuame me thiab nws tsis tuaj yeem txo qhov hardness.

Kev tsim (synthesis) ntawm cov khoom no yog nrog los ntawm cov tsos ntawm cov teeb meem sab hauv tensile thiab compressive rog. Thaum cov vectors ntawm kev ntxhov siab nyob rau hauv coincide nrog rau sab nraud loads ntawm ib feem, me me kab nrib pleb tsim rau nws nto nyob rau hauv lub cheeb tsam ntawm lub dawb txheej. Cov microcracks no yog cov kev ntxhov siab concentrators thiab accumulators, uas ua rau nkig tawg ntawm cov khoom tag nrho.

Hnav los ntawm Fetting Corrosion

txheej txheem no tshwm sim ntawm qhov chaw uas nyob ze rau ib leeg. Qhov laj thawj yog kev hloov pauv. Nws yuav tsum raug sau tseg tias cov ntaub ntawv ntawm lub cev ntawm kev sib txhuam khub tuaj yeem sib txawv heev (hlau-hlau lossis tsis-hlau-hlau).

qhov tshwm sim no tau tshwm sim nyob rau ntawm qhov chaw me me ntawm lub cev (kwv yees li 0.025 micrometers).

Raws li qhov kev hloov pauv, cov chaw corrosion tshwm rau ntawm qhov chaw, uas loj hlob thiab ua rau kev puas tsuaj ntawm txheej txheej saum npoo.

Hnav los ntawm vibratory cavitation

hom hnav no tshwm sim thaum cov khoom lag luam ua haujlwm hauv cov kua nruab nrab. Txawm hais tias nws tuaj yeem tshwm sim thaum lub dav hlau ua kua ntaus ib feem ntawm lub tshuab lossis lub tshuab. Lub physics ntawm cov txheej txheem yog raws li nram no. Cov kua siab ntawm theem ciam teb (nruab nrab ntawm cov kua thiab cov khoom) tee, uas ua rau cov tsos ntawm qhov hu ua cavitation npuas. Qhov kev siv ntawm qhov hnav no nyob ntawm cov huab cua hauv cov kua thiab nyob rau ntawm lub siab sab nraud.

Lub suab vibration tuaj yeem ua tus catalyst. Tshwj xeeb yog teeb meem nyob rau hauv cov ntaub ntawv no yog vibrations ntawm lub ultrasonic spectrum. Heev feem ntau, xws li ib tug teeb meem tshwm sim tshwm sim nyob rau hauv lub rubbing qhov chaw ntawm internal combustion engines. Kev tshawb fawb qhia tau hais tias sonic cavitation hnav tawm peb mus rau plaub zaug sai dua li kev sib txhuam.

Hnav vim thermal tawg

Qhov teeb meem no yog ib yam rau lub log ntawm cov tsheb ciav hlau thiab cov tsheb ciav hlau. Thaum lub sij hawm txav ntawm lub tsheb ciav hlau, tus neeg tsav tsheb feem ntau yuav tsum tau qeeb. Qhov no ua rau lub log yuav plam thiab cua sov. Thaum khaws ceev, qhov txhuam qhov chaw txias dua sai sai. Xws li thermal cycling ua rau tsim ntau cov kab nrib pleb ntawm qhov chaw ntawm lub log. Qhov no tseem ceeb accelerates hnav ntawm cov khoom. Tam sim no, tshwj xeeb alloy steels yog siv rau zus tau tej cov railway log. Tab sis ua ntej steel ntawm qhov zoo tib yam tau siv. Cov log qub tseem siv ntau lub tsheb ciav hlau niaj hnub no, yog li qhov teeb meem no tseem cuam tshuam.

Txoj kev cuam tshuam nrog thermal tawg

Qhov kev ntsuas tau zoo tshaj plaws los tiv thaiv cov kab nrib pleb yuav yog los ua kom txias txias. Cov roj tshwj xeeb thiab roj tuaj yeem siv rau qhov no. Nyob rau hauv cov ntaub ntawv ntawm lub tsheb ciav hlau log, qhov kev ntsuas no, rau pom tseeb yog vim li cas, yog tsis haum. Hauv qhov no, koj tuaj yeem ua si ntawm cov tshuaj muaj pes tsawg leeg ntawm cov khoom siv thiab xaiv cov qib steel zoo dua los ntawm qhov kev pom no. Qee qib ntawm alloy steels muaj qhov sib npaug qis ntawm kev nthuav dav. Thiab cov cuab yeej no tuaj yeem siv tau kom zoo dua.

Qeeerosion hnav nta

Xav txog hom kev sib txhuam thiab hnav, peb tsis tuaj yeem pom qhov hu ua yaig hnav. Hauv cov ntsiab lus yooj yim, qhov no yog kev puas tsuaj ntawm qhov chaw nyob rau hauv kev cuam tshuam ntawm ib puag ncig.

Hauv engineering, lub tswv yim no yog hais txog kev puas tsuaj ntawm qhov chaw ntawm lub tshuab thiab cov txheej txheem sib dhos raws li kev cuam tshuam ntawm ib puag ncig. Cov kev cuam tshuam zoo li no suav nrog huab cua thiab kua ntws, chav lossis ntau yam roj. Qhov ua rau hnav yog, zoo li ua ntej, kev sib txhuam. Tsuas yog nyob rau hauv rooj plaub no, tsis yog abrasive hais, tab sis roj los yog kua molecules ua rau saum npoo.

Microcracks tshwm sim thaum tus txheej txheem no. Cov molecules ntawm cov kua thiab chav nyob rau hauv lub siab siab nkag mus rau hauv lawv thiab ua rau kev puas tsuaj ntawm tag nrho cov saum npoo ntawm cov khoom.

Kua lossis chav kuj tseem muaj cov khoom abrasive hauv kev ncua. Nyob rau hauv cov ntaub ntawv no, xws li ib tug sib tov yuav ua rau abrasive-erosive puas thiab hnav.

qaug zog hnav thiab nws cov yam ntxwv

Hom kev hnav thiab kev ua txhaum geometry muaj ntau haiv neeg. Ntau yam teeb meem rau tus tsim engineers thiab mechanical engineers yog tshwm sim los ntawm qaug zog spalling ntawm qhov chaw ntawm qhov chaw. Qhov "mob" no yog insidious heev. Qhov tshwm sim ntawm qaug zog spalling tshwm sim nyob rau hauv qhov chaw uas ua hauj lwm rau lub sij hawm ntev nyob rau hauv tej yam kev mob ntawm alternating loads. Nov yog tus yam ntxwv "mob" ntawm cov iav pob qij txha.

hom hnav no yog nrog los ntawm kev pib ntawm cov kab nrib pleb ntawm qhov chaw thiab lawv nkag mustob rau hauv cov khoom. Tag nrho cov network ntawm microcracks zoo li no tshwm sim ntawm thaj chaw tsis tseem ceeb. Nyob rau hauv kev cuam tshuam ntawm kev kub ntxhov thiab kub, me me sib txawv ntawm cov hlau flake tawm ntawm lub cev tseem ceeb thiab poob tawm. Lub luag haujlwm tseem ceeb hauv cov txheej txheem no yog ua los ntawm roj nplua nyeem (roj), uas nkag mus rau hauv microcracks thiab txhawb kev puas tsuaj.