An yi amfani da ƙananan microscope na lantarki don lura da raunin gajiya da kuma nazarin tsarin karaya; A lokaci guda kuma, an gudanar da gwajin gajiya mai jujjuyawa akan samfuran da aka lalatar da su a yanayin zafi daban-daban don kwatanta rayuwar gajiyawar karfen gwajin tare da kuma ba tare da decarburization ba, da kuma nazarin tasirin decarburization akan aikin gajiyawar karfen gwajin. Sakamakon ya nuna cewa, saboda wanzuwar hadawan abu da iskar shaka da decarburization a cikin tsarin dumama, hulɗar da ke tsakanin su biyu, wanda ya haifar da kauri na cikakken decarburized Layer tare da ci gaban zafin jiki yana nuna yanayin karuwa sannan kuma raguwa, da kauri daga cikin cikakken decarburized Layer ya kai matsakaicin darajar 120 μm a 750 ℃, da kuma kauri daga cikin cikakken decarburized Layer ya kai m darajar 20 μm a 850 ℃, da gajiya iyaka na gwajin karfe ne game da 760 MPa, da kuma tushen gajiya fashe a cikin gwajin karfe ne yafi Al2O3 wadanda ba karfe inclusions; Decarburization hali ƙwarai rage gajiya rayuwa na gwajin karfe, shafi gajiya yi na gwajin karfe, da thicker da decarburization Layer, da ƙananan gajiya rayuwa. Domin rage tasirin decarburization Layer a kan gajiya yi na gwajin karfe, da mafi kyau duka zafi magani zafin jiki na gwajin karfe ya kamata a saita a 850 ℃.
Gear wani muhimmin bangaren mota ne,saboda aiki a babban gudun, meshing part na gear surface dole ne ya sami babban ƙarfi da abrasion juriya, da hakori tushen dole ne da kyau lankwasawa gajiya yi saboda akai maimaita load, domin kauce wa fasa da cewa kai ga abu. karaya. Bincike ya nuna cewa decarburization wani muhimmin al'amari ne da ke shafar jujjuya lankwasa gajiya aiki na karfe, da kuma juyi lankwasawa gajiya aiki ne mai muhimmanci mai nuni da ingancin samfurin, don haka wajibi ne a yi nazarin decarburization hali da juyi lankwasawa gajiya yi na gwajin kayan.
A cikin wannan takarda, tanderun jiyya na zafi a kan 20CrMnTi gear karfe saman decarburization gwajin, bincikar yanayin zafi daban-daban akan gwajin ƙarar decarburization Layer zurfin canjin doka; ta yin amfani da QBWP-6000J mai sauƙi na katako mai gwadawa na gwaji a kan gwajin gwaji na jujjuya lankwasa gajiya, ƙayyadaddun ƙayyadaddun ƙarfin ƙarfin ƙarfin ƙarfin ƙarfe, kuma a lokaci guda don nazarin tasirin decarburization akan gajiyar ƙarfin ƙarfin gwajin don ainihin samarwa don haɓakawa. tsarin samarwa, haɓaka ingancin samfuran kuma samar da madaidaicin tunani. Gwajin aikin gajiyar karfe yana ƙaddara ta injin gwada gajiya mai jujjuyawa.
1. Gwajin kayan aiki da hanyoyin
Gwajin gwaji don naúrar don samar da 20CrMnTi gear karfe, babban abun da ke tattare da sinadaran kamar yadda aka nuna a cikin Table 1. Decarburization Test: Ana sarrafa kayan gwajin a cikin Ф8 mm × 12 mm cylindrical cylindrical, surface ya kamata ya kasance mai haske ba tare da tabo ba. Heat jiyya tanderu aka mai tsanani zuwa 675 ℃, 700 ℃, 725 ℃, 750 ℃, 800 ℃, 850 ℃, 900 ℃, 950 ℃, 1,000 ℃, 1,000 ℃, maza da kuma rike da dakin da zazzabi - 1,000 ℃, a cikin dakin da zazzabi. Bayan maganin zafi na samfurin ta hanyar saitin, niƙa da gogewa, tare da 4% na ɓarkewar maganin barasa na nitric acid, yin amfani da microscopy na ƙarfe don lura da ƙirar ƙarfe na decarburization na gwaji, auna zurfin decarburization Layer a yanayin zafi daban-daban. Juya lankwasawa gajiya gwajin: gwajin abu bisa ga bukatun na aiki na biyu kungiyoyin na spin lankwasawa gajiya samfurori, rukuni na farko ba ya gudanar da decarburization gwajin, na biyu rukuni na decarburization gwajin a yanayin zafi daban-daban. Yin amfani da na'urar gwajin gajiya, ƙungiyoyin biyu na ƙarfe na gwaji don jujjuya gwajin gajiya, ƙayyadaddun iyakar gajiyar ƙungiyoyin gwaji guda biyu, kwatankwacin rayuwar gajiyar ƙungiyoyin gwaji guda biyu, amfani da na'urar daukar hoto. Electron microscope gajiya karaya lura, nazarin dalilan da karaya daga cikin samfurin, gano sakamakon decarburization na gajiya Properties na gwajin karfe.
Tebur 1 Abubuwan sinadaran (jari mai yawa) na gwajin karfe wt%
Sakamakon dumama zafin jiki akan decarburization
A ilimin halittar jiki na decarburization kungiyar karkashin daban-daban dumama yanayin zafi da aka nuna a cikin siffa 1. Kamar yadda za a iya gani daga adadi, lokacin da yawan zafin jiki ne 675 ℃, da samfurin surface ba ya bayyana decarburization Layer; lokacin da zafin jiki ya tashi zuwa 700 ℃, samfurin saman decarburization Layer ya fara bayyana, don bakin ciki ferrite decarburization Layer; tare da zafin jiki yakan zuwa 725 ℃, samfurin surface decarburization Layer kauri ya karu sosai; 750 ℃ decarburization Layer kauri ya kai ga iyakar darajar, a wannan lokaci, da ferrite hatsi ne mafi bayyananne, m; lokacin da zafin jiki ya tashi zuwa 800 ℃, decarburization Layer kauri ya fara raguwa sosai, kauri ya fadi zuwa rabin 750 ℃; lokacin da yawan zafin jiki ya ci gaba da tashi zuwa 850 ℃ da kauri na decarburization aka nuna a cikin siffa 1. 800 ℃, da cikakken decarburization Layer kauri ya fara rage muhimmanci, ta kauri fadi zuwa 750 ℃ lokacin da rabi; lokacin da yawan zafin jiki ya ci gaba da tashi zuwa 850 ℃ da sama, gwajin karfe cikakken decarburization Layer kauri ya ci gaba da raguwa, rabin decarburization Layer kauri ya fara karuwa a hankali har sai da cikakken decarburization Layer ilimin halittar jiki duk bace, rabin decarburization Layer ilimin halittar jiki a hankali share. Ana iya ganin cewa kauri daga cikin cikakken decarburized Layer tare da karuwa a cikin zafin jiki da aka farko ya karu sa'an nan kuma rage, dalilin wannan sabon abu ne saboda da samfurin a cikin dumama tsari a lokaci guda da hadawan abu da iskar shaka da decarburization hali, kawai a lokacin da. da decarburization kudi ne sauri fiye da gudun hadawan abu da iskar shaka zai bayyana decarburization sabon abu. A farkon dumama, kauri daga cikin cikakken decarburized Layer yana ƙaruwa sannu a hankali tare da karuwa a cikin zafin jiki har sai kauri na cikakken decarburized Layer ya kai matsakaicin darajar, a wannan lokacin don ci gaba da haɓaka yawan zafin jiki, samfurin oxidation na samfurin ya fi sauri fiye. Ƙididdigar ƙaddamarwa, wanda ke hana haɓakar haɓakar daɗaɗɗen Layer cikakke, yana haifar da yanayin ƙasa. Ana iya ganin cewa, a cikin kewayon 675 ℃ 950 ℃, darajar da kauri na cikakken decarburized Layer a 750 ℃ ne mafi girma, da kuma darajar da kauri na cikakken decarburized Layer a 850 ℃ ne mafi karami. saboda haka, dumama zafin jiki na gwajin karfe bada shawarar zama 850 ℃.
Fig.1 Histomorphology na decarburized Layer na gwajin karfe gudanar a daban-daban dumama yanayin zafi na 1h
Idan aka kwatanta da rabin-decarburized Layer, kauri na cikakken decarburized Layer yana da mummunan tasiri a kan kayan kayan aiki, zai rage girman kayan aikin injiniya na kayan aiki, kamar rage ƙarfin, taurin, juriya da iyakacin gajiya. , da dai sauransu, da kuma ƙara da hankali ga tsagewa, yana shafar ingancin walda da sauransu. Sabili da haka, sarrafa kauri na cikakken decarburized Layer yana da mahimmanci don inganta aikin samfur. Hoto na 2 yana nuna bambance-bambancen lanƙwasa na kauri na cikakken daftarin da aka yanke tare da zafin jiki, wanda ke nuna bambancin kauri na cikakken ƙaƙƙarfan Layer. Ana iya gani daga adadi cewa kauri na cikakken decarburized Layer ne kawai game da 34μm a 700 ℃; tare da zafin jiki yana tasowa zuwa 725 ℃, kauri na cikakken decarburized Layer yana ƙaruwa sosai zuwa 86 μm, wanda shine fiye da sau biyu na kauri na cikakken decarburized Layer a 700 ℃; lokacin da zafin jiki ya tashi zuwa 750 ℃, kauri na cikakken decarburized Layer Lokacin da zafin jiki ya tashi zuwa 750 ℃, kauri na cikakken decarburized Layer ya kai matsakaicin darajar 120 μm; yayin da zafin jiki ke ci gaba da hauhawa, kauri na cikakken decarburized Layer fara raguwa sosai, zuwa 70 μm a 800 ℃, sannan zuwa mafi ƙarancin ƙimar kusan 20μm a 850 ℃.
Fig.2 Kauri na cikakken decarburized Layer a yanayi daban-daban
Tasirin decarburization akan aikin gajiya a cikin lankwasawa
Domin nazarin tasirin decarburization a kan gajiyar Properties na spring karfe, an gudanar da kungiyoyi biyu na lankwasawa gajiya gwaje-gwaje, na farko rukuni na gajiya gwajin kai tsaye ba tare da decarburization, da kuma na biyu rukuni na gajiya gwaji bayan decarburization a cikin wannan damuwa. matakin (810 MPa), da kuma decarburization tsari da aka gudanar a 700-850 ℃ ga 1 h. An nuna rukunin farko na samfurori a cikin Tebura 2, wanda shine rayuwar gajiyar baƙin ƙarfe na bazara.
Rayuwar gajiyar rukuni na farko na samfurori an nuna a cikin Table 2. Kamar yadda za a iya gani daga Table 2, ba tare da decarburization ba, gwajin gwajin gwajin ya kasance kawai a cikin hawan 107 a 810 MPa, kuma babu wani fashewa da ya faru; lokacin da matakin damuwa ya wuce 830 MPa, wasu samfurori sun fara raguwa; lokacin da matakin damuwa ya wuce 850 MPa, samfuran gajiyar duk sun karye.
Tebur 2 Rayuwar gajiya a ƙarƙashin matakan damuwa daban-daban (ba tare da lalatawa ba)
Don ƙayyade iyakar gajiya, ana amfani da hanyar rukuni don ƙayyade iyakar ƙarfin ƙarfin gwajin, kuma bayan ƙididdigar ƙididdiga na bayanai, iyakar gajiyar ƙarfin gwajin ya kai kimanin 760 MPa; don kwatanta rayuwar gajiyawar ƙarfe na gwaji a ƙarƙashin matsaloli daban-daban, an tsara madaidaicin SN, kamar yadda aka nuna a cikin Hoto 3. Kamar yadda ake iya gani daga Hoto 3, matakan damuwa daban-daban sun dace da rayuwar gajiya daban-daban, lokacin da rayuwar gajiya ta 7. , daidai da adadin hawan keke don 107, wanda ke nufin cewa samfurin a ƙarƙashin waɗannan yanayi yana cikin jihar, ana iya ƙaddamar da ƙimar ƙarfin damuwa kamar ƙimar ƙarfin gajiya, wato, 760 MPa. Ana iya ganin cewa S - N mai mahimmanci yana da mahimmanci don ƙayyade rayuwar gajiyar kayan aiki yana da mahimmancin ƙima.
Hoto na 3 SN na gwajin gajiya na jujjuya karfen gwaji
An nuna rayuwar gajiyar rukuni na biyu na samfurori a cikin Table 3. Kamar yadda za a iya gani daga Table 3, bayan da aka yanke gwajin karfe a yanayin zafi daban-daban, an rage yawan hawan keke, kuma sun fi 107, kuma duka. samfuran gajiya sun karye, kuma rayuwar gajiyar ta ragu sosai. Haɗe tare da kauri mai kauri na sama tare da yanayin canjin zafin jiki ana iya gani, 750 ℃ decarburized Layer kauri shine mafi girma, daidai da mafi ƙarancin ƙimar rayuwar gajiya. 850 ℃ decarburized Layer kauri ne mafi karami, m da gajiya rayuwa darajar ne in mun gwada da high. Ana iya ganin cewa halayen decarburization suna rage yawan gajiyar kayan aiki, da kuma lokacin da aka yi amfani da shi a cikin kullun da aka lalata, ƙananan rayuwar gajiya.
Tebur 3 Rayuwar gajiya a yanayin zafi daban-daban (560 MPa)
An lura da yanayin faɗuwar gajiya na samfurin ta hanyar duba microscope na lantarki, kamar yadda aka nuna a cikin siffa 4. Hoto na 4 (a) don yankin tushen fashewa, ana iya ganin adadi a bayyane arc gajiya, bisa ga arc gajiya don gano tushen. na gajiya, ana iya gani, tushen fashewa don "ido-kifi" ba tare da ƙarfe ba, haɗawa a cikin sauƙi don haifar da damuwa, yana haifar da fashewar gajiya; Hoto na 4 (b) don yanayin yanayin yanayin tsaga, ana iya ganin ratsin gajiya a fili, ya kasance kamar rabe-raben kogi, yana da faɗuwar faɗuwa, tare da faɗuwa, a ƙarshe yana haifar da karaya. Hoto na 4 (b) yana nuna yanayin yanayin fadada fashe, ana iya ganin ɗigon gajiya a bayyane, a cikin nau'in rarraba-kamar kogi, wanda ke cikin ɓarna mai ƙima, kuma tare da ci gaba da haɓaka faɗuwar, a ƙarshe yana haifar da karaya. .
Fatigue fracture analysis
Fig.4 SEM ilimin halittar jiki na gajiya karaya surface na gwaji karfe
Don ƙayyade nau'in abubuwan da aka haɗa a cikin hoto na 4, an gudanar da nazarin abubuwan da ke tattare da makamashi, kuma an nuna sakamakon a cikin siffa 5. Ana iya ganin cewa abubuwan da ba na ƙarfe ba suna da yawa Al2O3, wanda ke nuna cewa abubuwan da aka haɗa. su ne babban tushen tsagewar da ke haifar da fashewar inclusions.
Hoto 5 Ƙwararren Ƙarfe na Ƙarfe na Ƙarfe
Kammala
(1) Sanya zafin zafi a 850 ℃ zai rage girman kauri na decarburized Layer don rage tasirin gajiyar aiki.
(2) Iyakar gajiya na gwajin karfen jujjuyawar lankwasawa shine 760 MPa.
(3) Ƙarfe na gwaji a cikin abubuwan da ba na ƙarfe ba, yawanci Al2O3 cakuda.
(4) decarburization tsanani rage gajiya rayuwa na gwajin karfe, da kauri da decarburization Layer, da runtse da gajiya rayuwa.
Lokacin aikawa: Juni-21-2024