Overheated kub khiav nplej tsis tuaj yeem kho thiab yuav tsum tau muab pov tseg. Overheating yog ib qho teeb meem loj uas tshwm sim los ntawm qhov kub thiab txias heev los yog lub sij hawm tuav ntev, ua rau oxidation los yog hauv zos melting ntawm cov ciam teb, uas ua rau muaj kev puas tsuaj rau cov khoom siv microstructure.
1. Yog vim li cas overheating irreparable?
Kev puas tsuaj tas mus li ntawm cov ciam teb: Thaum lub sij hawm overheating, oxidation, voids, thiab txawm tias qis -melting- taw tes eutectic remelting tshwm sim ntawm cov ciam teb, cuam tshuam qhov txuas ntxiv thiab kev sib txuas ntawm cov hlau;
Kev poob qis hauv cov khoom siv kho tshuab: Cov khoom siv plasticity, toughness, thiab lub zog yog txo qis, ua rau nws tsis tuaj yeem tiv taus thermal cycling kev ntxhov siab;
Unrecoverable los ntawm kev kho cua sov: Cov txheej txheem xws li normalizing thiab annealing tsuas tuaj yeem kho cov nplej, tab sis tsis tuaj yeem kho cov oxidation lossis melting puas ntawm cov ciam teb.
Ntau cov ntaub ntawv pov thawj qhia tau hais tias kev kub dhau yog qhov "tsis tuaj yeem rov qab tau," uas yuav tsum tau muab pov tseg thiab tsis tuaj yeem tshem tawm los ntawm ib qho txheej txheem.
2. Yuav ua li cas txiav txim siab yog tias muaj cua sov dhau lawm? Kev txiav txim siab thiab cov yam ntxwv zoo
Metallographic Observation: Widened grain ciam teb, zoo li remelting spheres, daim duab peb sab molten zones, los yog intergranular faib ntawm dub oxides.
Macroscopic Fracture: Pom ib qho greyish-dawb, tsis yog-hlau "pob zeb{2}}zoo li pob zeb tawg."
Kev ntsuas kev ua tau zoo: txo qhov cuam tshuam hnyav; tensile fracture nthuav tawm cov yam ntxwv ntawm cov pob txha tawg.
Yog tias pom ib qho ntawm cov yam ntxwv saum toj no, kev siv yuav tsum tau nres tam sim ntawd thiab hloov cov khoom siv.
3. Cov lus pom zoo teb
Local Overheating: Yog tias tsuas yog thaj tsam ntawm ntug yog me ntsis overheated, qhov puas tuaj yeem raug tshem tawm thiab rov ua dua.
Overheating: Tag nrho cov khoom yuav tsum tau muab pov tseg; Kev pabcuam txuas ntxiv raug txwv nruj heev los tiv thaiv kev tawg sai sai thaum lub sijhawm tsim khoom thiab muaj peev xwm ua rau muaj kev nyab xeeb.
Kev Tiv Thaiv Kev Ntsuas: nruj me ntsis tswj cov cua kub kom tsis txhob siab tshaj qhov kub ntawm cov khoom (piv txwv li, H13 steel feem ntau yuav tsum tsis txhob siab tshaj 1150 degree), thiab zam kom tsis txhob raug kub kub ntev.
Cov ntaub ntawv txhim khu kev qha zoo qhia tau hais tias aluminium alloys thiab pwm steels yog qhov ua rau overheating thaum lawv qhov qis melting point eutectic kub tshaj; tshwj xeeb yuav tsum tau them rau qhov kub thiab txias.
