1. Metallographic thiab hardness kuaj
(1) Thaum lub sij hawm niaj hnub soj ntsuam, lub hardness ntawm lub saum npoo tej zaum yuav raug ntsuas nyob rau hauv lub kawg, shank los yog lub taub hau ntawm cov ntsia hlau (ntev li ntev raws li qhov tob ntawm zoo hardened txheej ntawm rooj plaub carburization thiab geometry ntawm cov ntsia hlau tso cai). Rau cov ntsia hlau uas muaj cov kab nominal tsis tsawg dua M4, qhov tawv tawv yuav tsum tau ntsuas los ntawm micro-Vickers hardness tester (kuaj quab yuam 0.3HV). Nyob rau ntawm tus hniav profile ntawm qhov ntev ntawm cov qauv, qhov kev ncua deb ntawm ntug ntawm cov qauv yog tsawg kawg yog 0.05mm. Rau cov ntsia hlau nrog lub npe nominal txoj kab uas hla me dua M4, nws yuav tsum nyob ntawm lub dav hlau, thiab nyiam dua ntawm lub taub hau. Cov tub ntxhais hardness yuav tsum tau nqa tawm ntawm 1/2 lub vojvoog ntawm lub dav hlau transverse nrog txaus nyob deb ntawm qhov kawg ntawm cov ntsia hlau (yuav tsum muaj ib tug tiav xov me txoj kab uas hla).
(2) Saib xyuas lub microstructure nyob rau hauv ib lub tshuab ntsuas metallographic, thiab yuav tsum tsis muaj banded hypoeutecoid ferrite ntawm cov txheej txheem carburizing hardened zoo thiab cov tub ntxhais. Qhov kev ntsuam xyuas qhov tob ntawm cov txheej txheem hardened carburizing yuav tsum tau ua nyob rau ntawm lub flank ntawm cov xov, thiab ntsuas qhov taw tes yuav tsum yog ib nrab ntawm qhov kev ncua deb ntawm tus hniav crest thiab cov hniav hauv qab. Txawm li cas los xij, rau cov ntsia hlau tsis loj dua M4, qhov kev sim yuav tsum tau ua nyob rau hauv qab ntawm cov hniav. Thaum ntsuas nrog micro-Vickers hardness tester nrog lub zog ntsuas ntawm 3N, qhov tob ntawm cov txheej txheem hardened carburization yuav tsum raug xam los ntawm qhov ntsuas qhov siab tshaj qhov tseem ceeb ntawm hardness los ntawm 30HV0..3.
2. Mechanical properties test
(1) Kev ntsuas kev ua tau zoo ntawm cov ntsia hlau yog txhawm rau ntsia hlau tus qauv rau hauv daim ntawv xeem kom txog rau thaum ib txoj xov tiav dhau qhov kev xeem yam tsis muaj kev tawg.
(2) Kev ntsuas kev puas tsuaj rau lub cev yog txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau nws nws , qhov tawg yuav tsum tsis txhob tshwm sim nyob rau hauv lub clamped threaded ib feem.
(3) Ua ib qho kev sim tensile ntawm tus qauv ntsia hlau los xyuas qhov tsawg kawg nkaus tensile load rau qhov tsis ua hauj lwm. Qhov tawg yuav tsum nyob rau hauv qhov ntev ntawm tus pas nrig lossis cov xov tsis muaj xov, thiab yuav tsum tsis txhob tshwm sim ntawm qhov sib txuas ntawm tus ntsia thawv taub hau thiab tus pas nrig. Ua ntej tus qauv tawg, nws yuav tsum yog Nws tuaj yeem ncav cuag qhov tsawg kawg nkaus tensile load teev los ntawm cov chav kawm ua tau zoo.
(4) Hydrogen embrittlement yog ib qho teeb meem uas yuav tsum tau them sai sai rau hauv cov txheej txheem kev kho deg ntawm tus kheej tapping ntsia hlau. Nyob rau hauv cov txheej txheem pickling, cov ntsia hlau yog nplawm nyob rau hauv dilute hydrochloric acid, thiab tus nqi ntawm hydrogen absorbed los ntawm pickling steel nce linearly nrog lub square cag ntawm lub sij hawm thiab ncav cuag tus nqi saturation. Tsawg dua 100%, ntau cov hydrogen atoms yuav raug tsim, uas yuav txuas rau saum npoo ntawm cov ntsia hlau, uas ua rau hydrogen infiltration, thiab cov hlau yuav nkig vim qhov nqus ntawm hydrogen.
Tus kheej tapping ntsia hlau muaj lub sijhawm tsav tsheb hydrogen ntawm 6 ~ 8h, thiab qhov kub ntawm 160 ~ 200 ℃ (phosphating) thiab 200 ~ 240 ℃ (electroplating). Txawm li cas los xij, nyob rau hauv cov txheej txheem tsim khoom, lub sijhawm tsav hydrogen yuav tsum tau txiav txim siab raws li ntau yam kev tsim khoom xws li core hardness, nto roughness, electroplating lub sij hawm, txheej thickness, pickling lub sij hawm, thiab acid concentration. Nws yog qhov zoo tshaj los ua nws ua ntej passivation thiab tsuas yog tom qab electroplating.
Kev ntsuas hydrogen embrittlement resistance test yuav tsum nruj me ntsis, thiab thaum hydrogen embrittlement tshwm sim, cov txheej txheem hydrogen dej nyab yuav tsum tau txhim kho.
