Cov qauv siv hlau uas siv feem ntau hauv kev tsim cov iav yog quenched thiab tempered steel, tawv tawv steel, carburized thiab quenched steel thiab nitrided steel. Lub zog ntawm cam khwb cia steel yog me ntsis qis dua li ntawm cov forged steel, thiab nws yog feem ntau siv rau cov iav uas muaj qhov ntau thiab tsawg. Cov cuab yeej ntawm lub zog ntawm grey cam khwb cia hlau tsis zoo, thiab nws tuaj yeem siv rau hauv lub teeb-qhib qhib lub iav kis; ductile hlau tuaj yeem qee cov hloov hlau los ua zog; cov iav yas siv ntau dua. Rau lub teeb ua haujlwm thiab qhov uas yuav tsum muaj suab nrov, cov zog uas txuas nrog lawv feem ntau siv cov iav hlau uas muaj cov zoo thermal conductivity.
Nyob rau hauv lub neej yav tom ntej, zog yuav raug tsim hauv cov kev taw qhia ntawm lub nra hnyav, siab nrawm, siab qhov tseeb thiab siab ceev, thiab siv zog ua haujlwm me me, lub teeb nyob rau hauv qhov hnyav, ntev hauv lub neej thiab kev lag luam thiab txhim khu kev qha.
Kev txhim kho ntawm cov iav kev tshawb xav thiab cov txheej txheem tsim khoom yuav yog cov tshuab txuas ntxiv rau kev kawm txog cov hniav puas. Qhov no yog lub hauv paus rau kev tsim kom muaj txoj kev suav ntsuas lub zog. Nws yog qhov theoretical lub hauv paus rau kev txhim kho cov qav load peev xwm thiab ntev lub neej ntawm cov iav. Txoj kev txhim kho yog sawv cev los ntawm lub voj voos hniav. Tus hniav tshiab profile; tshawb xyuas cov ntaub ntawv iav tshiab thiab cov txheej txheem tshiab rau kev tsim cov iav; kawm cov nyom kev hloov kho ntawm lub zog, kev tsim khoom thiab kev ua haujlwm tsis raug, thiab kev faib tawm ntawm thaj chaw ntsuas kub, thiab ua kom hloov kho cov hniav txhawm rau txhim kho kev sib dhos ntawm cov iav ua haujlwm thiab thaum puv qhov chaw thaum lub chaw sib tsoo ntawm cov hniav nce, qhov kev thauj khoom muaj peev xwm ntawm cov iav tau zoo tuaj.
Kev txhuam, lub hauv paus pib thiab lub tshuab lubrication yog qhov pib ua haujlwm hauv kev tshawb fawb iav. Kawm kev tshawb xav ntawm elastic kua dynamic siab lubrication, txhawb kev siv hluavtaws lubricating roj thiab ua kom zoo ntxiv cov roj ntsha ntxiv rau hauv cov roj tsis tuaj yeem tsuas yog txhim kho qhov kev coj tus kheej ntawm cov hniav saum npoo, tab sis kuj tseem tuaj yeem txhim kho kev xa mus ua haujlwm.
