20# bututun ƙarfe mara ƙarfi shine ƙimar kayan da aka ƙayyade a cikin GB3087-2008 "Bututun ƙarfe marasa ƙarfi don ƙananan matsa lamba da matsakaicin tukunyar jirgi". Yana da wani high quality-carbon tsarin karfe bututu dace da masana'antu daban-daban low-matsa lamba da matsakaici-matsi tukunyar jirgi. Abu ne na gama-gari kuma mai girma na bututun ƙarfe. Lokacin da mai kera kayan aikin tukunyar jirgi ke kera kan mai mai zafi mai ƙarancin zafin jiki, an gano cewa akwai munanan lahani a saman ciki na dumbin gidajen haɗin bututu. Abun haɗin gwiwar bututu shine karfe 20 tare da ƙayyadaddun Φ57mm × 5mm. Mun duba bututun karfe da ya fashe kuma mun gudanar da gwaje-gwaje don sake haifar da lahani da gano musabbabin tsagewar.

1. Crack siffa bincike
Crack ilimin halittar jiki: Ana iya ganin cewa akwai fashe-fashe da yawa da aka rarraba tare da madaidaiciyar shugabanci na bututun ƙarfe. An shirya tsagewar da kyau. Kowane tsaga yana da siffa mai kaɗawa, tare da ɗan jujjuyawa a cikin tafarki mai tsayi kuma ba shi da tsatsauran ra'ayi. Akwai wani kusurwar karkatarwa tsakanin tsagewar da saman bututun ƙarfe da wani faɗin. Akwai oxides da decarburization a gefen fashe. Kasan a fili babu alamar fadada. Tsarin matrix shine al'ada ferrite + pearlite, wanda aka rarraba a cikin band kuma yana da girman hatsi na 8. Dalilin fashewa yana da alaƙa da rikici tsakanin bangon ciki na bututun ƙarfe da ƙwayar ciki a lokacin samar da karfe bututu.

Bisa ga macroscopic da microscopic morphological halaye na fasa, za a iya gane cewa fashewa da aka haifar kafin karshen zafi magani na karfe bututu. Bututun ƙarfe yana amfani da bututu mai zagaye na Φ90mm. Babban tsarin da ake aiwatar da shi shine huɗa mai zafi, zafi mai zafi da rage diamita, da zane biyu masu sanyi. Ƙayyadaddun tsari shine cewa Φ90mm zagaye tube billet an yi birgima a cikin Φ93mm × 5.8mm tube mai laushi, sa'an nan kuma zafi mai birgima kuma an rage zuwa Φ72mm × 6.2mm. Bayan pickling da lubrication, ana aiwatar da zanen sanyi na farko. Bayanin ƙayyadaddun bayanan sanyi shine Φ65mm × 5.5mm. Bayan tsaka-tsaki annealing, pickling, da man shafawa, ana aiwatar da zanen sanyi na biyu. Bayanin ƙayyadaddun bayanan sanyi shine Φ57mm × 5mm.

Dangane da binciken tsarin samar da kayayyaki, abubuwan da suka shafi rikice-rikicen da ke tsakanin bangon ciki na bututun karfe da mutun na ciki sune galibi ingancin lubrication kuma suna da alaƙa da filastik na bututun ƙarfe. Idan filastik na bututun ƙarfe ba shi da kyau, yuwuwar zana fashe za ta ƙaru sosai, kuma ƙarancin filastik yana da alaƙa da matsakaicin matsakaicin matsakaicin matsananciyar damuwa mai hana zafi magani. Bisa ga wannan, an yi la'akari da cewa za a iya haifar da raguwa a cikin tsarin zane mai sanyi. Bugu da kari, saboda tsagewar ba a bude su da yawa ba kuma babu wata alama ta fadadawa, hakan yana nufin tsagewar ba su fuskanci tasirin nakasar zane na biyu ba bayan an yi su, don haka an kara da cewa mafi kusantar su. lokaci don tsagewar da za a haifar ya kamata ya zama tsarin zane na sanyi na biyu. Abubuwan da suka fi dacewa da tasiri sune rashin lubrication mara kyau da/ko rashin kulawa da damuwa.

Don sanin dalilin tsagewar, an gudanar da gwaje-gwajen haifuwa tare da haɗin gwiwar masana'antun bututun ƙarfe. Dangane da binciken da aka yi a sama, an gudanar da gwaje-gwaje masu zuwa: A ƙarƙashin yanayin cewa matakan raguwa da diamita masu zafi sun kasance ba su canzawa, ana canza lubrication da / ko danniya taimako annealing yanayin kula da zafi, kuma ana bincika bututun ƙarfe da aka zana. yi ƙoƙarin haifar da lahani iri ɗaya.

2. Tsarin gwaji
An gabatar da tsare-tsaren gwaji guda tara ta hanyar canza tsarin man shafawa da ma'auni na tsari. Daga cikin su, al'ada phosphating da lubrication lokacin da ake bukata shine 40min, matsakaicin matsakaicin matsakaicin matsakaicin matsakaicin damuwa annealing da ake buƙata shine 830 ℃, kuma buƙatun lokacin rufewa na yau da kullun shine 20min. Tsarin gwajin yana amfani da rukunin zane mai sanyi 30t da tanderun maganin zafin ƙasa.

3. Sakamakon gwaji
Ta hanyar duba bututun karfen da tsare-tsare guda 9 na sama suka samar, an gano cewa, sai dai tsarin na 3, 4, 5, da 6, sauran tsare-tsare duk sun yi girgiza ko jujjuya tsaga zuwa nau'i daban-daban. Daga cikin su, makirci na 1 yana da mataki na shekara; tsare-tsare na 2 da na 8 suna da tsage-tsage masu juyawa, kuma ƙwaƙƙwaran ƙwayoyin halitta sun yi kama da wanda aka samu a samarwa; makirci na 7 da 9 sun girgiza, amma ba a sami fashe-fashe ba.

4. Nazari da tattaunawa
Ta hanyar jerin gwaje-gwajen, an tabbatar da cikakken cewa man shafawa da matsananciyar damuwa na damuwa a lokacin aikin zane mai sanyi na bututun ƙarfe yana da tasiri mai mahimmanci akan ingancin bututun ƙarfe da aka gama. Musamman ma, tsare-tsare na 2 da 8 sun sake haifar da lahani iri ɗaya akan bangon ciki na bututun ƙarfe da aka samu a cikin samarwa na sama.

Tsarin 1 shine a yi zanen sanyi na farko akan bututun uwa mai rahusa mai zafi ba tare da aiwatar da aikin phosphating da lubrication ba. Saboda rashin lubrication, nauyin da ake buƙata yayin aikin zane mai sanyi ya kai matsakaicin nauyin injin zane mai sanyi. Tsarin zane mai sanyi yana da wahala sosai. Girgizawar bututun ƙarfe da gogayya tare da ƙirar yana haifar da matakai na bayyane akan bangon ciki na bututu, yana nuna cewa lokacin da filastik na bututun uwar yana da kyau, kodayake zanen da ba a shafa ba yana da mummunan sakamako, ba shi da sauƙi a haifar da shi. m fasa. A cikin tsari na 2, bututun ƙarfe tare da ƙarancin phosphating da lubrication yana ci gaba da zana sanyi ba tare da annashuwa na matsakaita ba, yana haifar da fashe-fashe iri ɗaya. Koyaya, a cikin Tsarin 3, ba a sami lahani ba a cikin ci gaba da zane mai sanyi na bututun ƙarfe tare da ingantaccen fosfat da lubrication ba tare da annealing na matsakaici na danniya ba, wanda da farko yana nuna cewa rashin lubrication shine babban dalilin fashe fashe. Tsare-tsare na 4 zuwa 6 shine canza tsarin kula da zafi yayin tabbatar da lubrication mai kyau, kuma babu wani lahani na zane da ya faru a sakamakon haka, yana nuna cewa matsananciyar damuwa na damuwa ba shine babban abin da ke haifar da faɗuwar ɓarna ba. Tsare-tsare na 7 zuwa 9 suna canza tsarin kula da zafi yayin rage lokacin phosphating da lubrication da rabi. Sakamakon haka, bututun ƙarfe na tsare-tsare na 7 da 9 suna da layukan girgiza, kuma Tsarin 8 yana haifar da fashe-fashe iri ɗaya.

Binciken kwatankwacin da ke sama ya nuna cewa tsage-tsatse za su faru a cikin lokuta biyu na rashin lubrication mara kyau + babu tsaka-tsaki mai raɗaɗi da ƙarancin lubrication + ƙarancin zafin jiki na matsakaici. A cikin yanayin rashin lubrication mai kyau + mai kyau na tsaka-tsakin tsaka-tsakin, mai kyau mai kyau + babu tsaka-tsakin tsaka-tsakin, da mai kyau mai kyau + ƙananan zafin jiki na matsakaici, ko da yake girgiza layin layi zai faru, ƙananan fasa ba zai faru a bango na ciki na bututun karfe ba. Lubrication mara kyau shine babban abin da ke haifar da ɓarna mai juyawa, kuma rashin jin daɗin jin daɗi na tsaka-tsaki shine dalilin taimako.

Tun da danniya na zane na bututun ƙarfe ya dace da ƙarfin juzu'i, ƙarancin lubrication zai haifar da haɓakar ƙarfin zane da raguwar ƙimar zane. Gudun yana da ƙasa lokacin da aka fara zana bututun ƙarfe. Idan gudun ya yi ƙasa da ƙayyadaddun ƙima, wato, ya kai ga bifurcation batu, madauki zai haifar da rawar jiki mai jin daɗi, wanda zai haifar da layukan girgiza. A cikin yanayin rashin isasshen lubrication, ƙaddamarwar axial tsakanin farfajiya (musamman na ciki) karfe da kuma mutu yayin zane yana ƙaruwa sosai, yana haifar da taurin aiki. Idan m danniya taimako annealing zafi magani zafin jiki na karfe bututu bai isa ba (kamar game da 630 ℃ saita a cikin gwajin) ko babu annealing, yana da sauki a sa surface fasa.

Bisa ga msar tambayar lissafi (mafi ƙasƙanci recrystallization zazzabi ≈ 0.4×1350 ℃), da recrystallization zafin jiki na 20 # karfe ne game da 610 ℃. Idan annealing zafin jiki yana kusa da recrystallization zafin jiki, karfe bututu kasa cika recrystallize, da kuma aiki hardening ba a kawar da, sakamakon da matalauta abu plasticity, karfe kwarara da aka katange a lokacin gogayya, da ciki da kuma waje yadudduka na karfe ne mai tsanani. nakasassu ba daidai ba, don haka yana haifar da ƙarin damuwa mai girma axial. A sakamakon haka, damuwa axial na karfen saman ciki na bututun karfe ya wuce iyakarsa, ta haka ne ya haifar da fasa.

5. Kammalawa
Ƙirƙirar fashewar ɓarna a bangon ciki na bututun ƙarfe 20 # maras sumul yana faruwa ne ta hanyar haɗaɗɗun sakamako mara kyau na lubrication yayin zane da rashin isassun taimako na matsakaicin matsananciyar damuwa mai hana zafi magani (ko annealing). Daga cikin su, rashin man shafawa shine babban abin da ya haifar, kuma rashin jin daɗin rage damuwa na tsaka-tsaki (ko babu damuwa) shine dalili. Don guje wa lahani iri ɗaya, masana'antun yakamata su buƙaci masu gudanar da bita don bin ƙa'idodin fasaha masu dacewa na aikin mai da zafi a cikin samarwa. Bugu da kari, tun da nadi-kasa ci gaba annealing tanderu ne ci gaba annealing tanderu, ko da yake shi ne dace da kuma sauri load da saukewa, yana da wuya a sarrafa zafin jiki da kuma gudun kayan daban-daban bayani dalla-dalla da kuma girma a cikin tanderun. Idan ba a aiwatar da shi sosai bisa ga ƙa'idodi ba, yana da sauƙi don haifar da rashin daidaituwar zafin jiki ko ɗan gajeren lokaci, yana haifar da ƙarancin recrystallization, yana haifar da lahani a cikin samarwa na gaba. Don haka, masana'antun da ke amfani da tanderun murɗaɗɗen abin nadi-ƙasa don maganin zafi ya kamata su sarrafa buƙatu daban-daban da ainihin ayyukan jiyya na zafi.