Uburyo butandukanye bwo gupima (Brinell, Rockwell, Vickers) bufite uburyo bwihariye ku mushinga uri kugeragezwa. Ikizamini cya Rockwell T kirakwiriye mu gusuzuma imiyoboro yoroheje yo ku nkuta binyuze mu gukata umuyoboro mu burebure no gupima urukuta uhereye ku murambararo w'imbere aho kuva ku murambararo w'inyuma.
Gutumiza imodoka yo mu bwoko bwa "tubing" bisa nko kujya mu iduka ry’imodoka no gutumiza imodoka cyangwa ikamyo. Muri iki gihe, amahitamo menshi ahari yemerera abaguzi guhindura imodoka mu buryo butandukanye - amabara y’imbere n’inyuma, imitako y’imbere, amahitamo yo gutunganya inyuma, amahitamo ya "powertrain", na sisitemu y’amajwi ihangana cyane na sisitemu yo kwidagadurira mu rugo. Ukurikije aya mahitamo yose, ushobora kutanyurwa n’imodoka isanzwe kandi idakoresha ibikoresho byinshi.
Imiyoboro y'icyuma ni yo yonyine. Ifite amahitamo menshi cyangwa ibipimo. Uretse ingano, ibipimo bigaragaza imiterere ya shimi n'ibindi byinshi bya mekanike nka minimum yield strength (MYS), ultimate tensile strength (UTS), na minimum elongation mbere yo gutsindwa. Ariko, benshi mu nganda—injeniyeri, abashinzwe kugura, n'inganda—bakoresha amagambo make yemewe mu nganda asaba gukoresha umuyoboro “usanzwe” wometseho kandi agaragaza ikintu kimwe gusa: ubukana.
Gerageza gutumiza imodoka ukoresheje ikintu kimwe (“Nkeneye imodoka ifite moteri yikora”) kandi ntuzagera kure ukoresheje umucuruzi. Agomba kuzuza ifishi yo gutumiza irimo amahitamo menshi. Umuyoboro ni uwo gusa - kugira ngo abone umuyoboro ukwiye wo gukoreshwa, uruganda rukora imiyoboro rukeneye amakuru menshi atari ubukana gusa.
Ni gute gukomera bihinduka ikintu kizwi nk'igisimbura ibindi bintu by'ikoranabuhanga? Birashoboka ko byatangiye n'umutezi ukora imiyoboro. Kubera ko gupima gukomera byihuse, byoroshye, kandi bigasaba ibikoresho bihendutse, abacuruza imiyoboro bakunze gukoresha isuzuma ry'ubukomere kugira ngo bagereranye imiyoboro ibiri. Kugira ngo bakore isuzuma ry'ubukomere, icyo bakeneye gusa ni umuyoboro w'uburebure bworoshye n'aho bahagarara.
Ubukomere bw'imiyoboro y'amazi bufitanye isano ryiza na UTS, kandi nk'uko bisanzwe, ijanisha cyangwa ijanisha ry'imiyoboro ni ingirakamaro mu gupima MYS, bityo biroroshye kubona uburyo gupima ubukomere bishobora kuba igikoresho gikwiriye ku zindi miterere.
Nanone, ibindi bizamini biragoye cyane. Nubwo isuzuma ry’ubukomere rifata umunota umwe gusa ku mashini imwe, isuzuma rya MYS, UTS n’isuzuma ry’uburebure bisaba gutegura icyitegererezo no gushora imari mu bikoresho binini bya laboratwari. Mu kugereranya, bifata amasegonda kugira ngo umukozi utunganya uruganda rw’imiyoboro akore isuzuma ry’ubukomere n’amasaha kugira ngo umutekinisiye w’umwuga w’ibyuma akore isuzuma ry’ubukomere. Ntabwo bigoye gukora isuzuma ry’ubukomere.
Ibi ntibivuze ko abakora imiyoboro yakozwe mu buryo bwa tekiniki badakoresha isuzuma ry’ubukana. Birumvikana ko abantu benshi babikora, ariko kubera ko bakora isuzuma ry’ubushobozi bwo gusubiramo no kongera gukoresha ibikoresho byabo byose byo gupima, bazi neza imbogamizi z’isuzuma. Abenshi bakoresha isuzuma ry’ubukana bw’imiyoboro nk’igice cy’igikorwa cyo kuyikora, ariko ntibayikoresha mu gupima imiterere y’imiyoboro. Iki ni ikizamini cyo gutsinda cyangwa gutsindwa gusa.
Kuki ukeneye kumenya ibya MYS, UTS na minimum lengation? Bigaragaza uko umuyoboro uzitwara mu guteranya.
MYS ni imbaraga nkeya zitera guhinduka burundu kw'ibikoresho. Iyo ugerageje gupfunyika insinga igororotse (nk'aho ipakira ikoti) gato ukayirekura, kimwe mu bintu bibiri kizabaho: izasubira uko yari imeze mbere (igororotse) cyangwa igakomeza gupfunyika. Niba ikiri igororotse, ntabwo warenze MYS. Niba ikiri ipfunyika, warayirenze.
Noneho, koresha imashini kugira ngo ufatanye impande zombi z'insinga. Niba ushobora guca insinga mo ibice bibiri, uba urenze UTS yayo. Uyishyiramo imbaraga nyinshi kandi ufite insinga ebyiri zo kwerekana imbaraga zawe zidasanzwe. Niba uburebure bw'insinga bwa mbere ari santimetero 5, kandi uburebure bubiri nyuma yo gutsindwa bugera kuri santimetero 6, insinga irarengerwa na santimetero 1, cyangwa 20%. Ikizamini nyacyo cyo kurekura gipimwa muri santimetero 2 uvuye aho gutsindwa kwabayeho, ariko uko byagenda kose - igitekerezo cy'insinga yo gukurura kigaragaza UTS.
Ingero z'icyuma zigomba gucibwa, gusya, no gusya hakoreshejwe umuti urimo aside nkeya (ubusanzwe aside nitrike na alcool (nitroethanol)) kugira ngo ibinyampeke bigaragare. Ubunini bwa 100x bukunze gukoreshwa mu gusuzuma ibinyampeke by'icyuma no kumenya ingano y'ibinyampeke.
Ubukomere ni ikizamini cy'uko ibikoresho bihangana n'ingaruka. Tekereza gushyira umuyoboro mugufi mu cyuma gifite imyasa ishongeshejwe hanyuma ugafunga cyuma. Uretse gufunga cyuma, imyasa y'icyuma inasiga uduce tw'imyasa ku buso bw'icyuma.
Uko ni ko ikizamini cy'ubukomere gikora, ariko ntabwo ari ikibazo gikomeye cyane. Iki kizamini gifite ingano y'ingaruka igenzurwa n'umuvuduko ugenzurwa. Izi mbaraga zihindura ubuso, zigatuma habaho guhagarara cyangwa guhagarara. Ingano cyangwa ubujyakuzimu bw'aho guhagarara bigena ubukomere bw'icyuma.
Mu gusuzuma icyuma, ibipimo bisanzwe byo gukomerera ni Brinell, Vickers, na Rockwell. Buri kimwe gifite igipimo cyacyo, kandi bimwe bifite uburyo bwinshi bwo gupima, nka Rockwell A, B, na C. Ku miyoboro y'icyuma, ASTM Specification A513 ivuga ikizamini cya Rockwell B (kigufi nka HRB cyangwa RB). Ikizamini cya Rockwell B gipima itandukaniro mu kwinjira kw'icyuma n'umupira w'icyuma wa santimetero 1⁄16 hagati y'umutwaro muto mbere yo gupimwa n'umutwaro w'ibanze wa 100 kgf. Umusaruro usanzwe ku cyuma gisanzwe cyoroshye ni HRB 60.
Abahanga mu by'ibikoresho bazi ko ubukomere bufitanye isano na UTS. Kubwibyo, ubukomere runaka bushobora guhanura UTS. Mu buryo nk'ubwo, abakora imiyoboro bazi ko MYS na UTS bifitanye isano. Ku muyoboro wasutswe, MYS ubusanzwe iba iri hagati ya 70% na 85% bya UTS. Ingano nyayo iterwa n'uburyo umuyoboro ukora. Ubukomere bwa HRB 60 bufitanye isano na UTS ya 60.000 pounds kuri santimetero kare (PSI) na MYS ya 80%, cyangwa 48.000 PSI.
Uburyo busanzwe bwo gushyiraho imiyoboro muri rusange ni ubukana ntarengwa. Uretse ingano, injeniyeri yari ashishikajwe no gushyiraho umuyoboro wa ERW ukoreshwa mu bukana bw'amashanyarazi (ERW) mu rwego rwo gukora neza, bishobora gutuma ubukana ntarengwa bwa HRB 60 bushobora kugaragara ku gishushanyo cy'ibice. Iki cyemezo cyonyine kijyana ku miterere itandukanye ya nyuma ya mekanike, harimo n'ubukana ubwabwo.
Ubwa mbere, ubukana bwa HRB 60 ntabwo butubwira byinshi. Isomwa rya HRB 60 ni umubare utagira ingano. Ibikoresho byapimwe na HRB 59 byoroshye kurusha ibikoresho byapimwe na HRB 60, naho HRB 61 irakomeye kurusha HRB 60, ariko ni angahe? Ntabwo bishobora gupimwa nk'ingano (ipimwa muri decibel), torque (ipimwa muri pound-feet), umuvuduko (ipimwa mu ntera ugereranyije n'igihe), cyangwa UTS (ipimwa muri pound kuri santimetero kare). Gusoma HRB 60 ntabwo bitubwira ikintu cyihariye. Iyi ni imiterere y'ibikoresho, ariko si imiterere ifatika. Icya kabiri, isuzuma ry'ubukana ntirikwiriye kugira ngo risubirwemo cyangwa risubirwemo. Gusuzuma ahantu habiri ku gipimo cy'igerageza, nubwo aho ikizamini cyapimwe haba hegeranye, akenshi bivamo itandukaniro rikomeye mu bipimo by'ubukana. Gutera iki kibazo ni imiterere y'ikizamini. Nyuma yo gupimwa ahantu, ntibishobora gupimwa ku nshuro ya kabiri kugira ngo harebwe ibisubizo. Gusubiramo ikizamini ntibishoboka.
Ibi ntibivuze ko gupima ubukana bw'ibikoresho bigoranye. Mu by'ukuri, bitanga ubuyobozi bwiza ku buryo ibikoresho bipima, kandi ni ikizamini cyoroshye kandi cyihuse. Ariko, buri wese mu bijyanye no kugena, kugura no gukora imiyoboro agomba kumenya aho idashobora gukoreshwa nk'ibipimo by'ikizamini.
Kubera ko imiyoboro "isanzwe" idasobanutse neza, iyo bikenewe, abakora imiyoboro bakunze kuyigabanya bakayishyira mu bwoko bubiri bw'imiyoboro y'icyuma ikoreshwa cyane n'imiyoboro ivugwa muri ASTM A513: 1008 na 1010. Ndetse na nyuma yo gukuraho ubundi bwoko bwose bw'imiyoboro, amahirwe yo kugaragaza imiterere y'imiyoboro y'ubwo bwoko bubiri bw'imiyoboro arafunguye cyane. Mu by'ukuri, ubwo bwoko bw'imiyoboro bufite imiterere myinshi cyane y'imiyoboro y'ubwoko ubwo aribwo bwose.
Urugero, umuyoboro uvugwa ko woroshye iyo MYS iri hasi kandi uburebure bwayo buri hejuru, bivuze ko ukora neza mu gukurura, guhindagurika no gushyiraho kurusha umuyoboro uvugwa ko ukomeye, ufite MYS iri hejuru kandi uburebure bwayo buri hasi. Ibi bisa n'itandukaniro riri hagati y'insinga zoroshye n'izikomeye, nk'udupira two guhambira n'udupira two gutobora.
Uburebure ubwabwo ni ikindi kintu gifite ingaruka zikomeye ku miyoboro y'ingenzi. Imiyoboro ifite uburebure bwinshi ishobora kwihanganira imbaraga zo gukurura; ibikoresho bifite uburebure buke birakomera cyane bityo bikaba byagorwa no kunanirwa gukabije nk'umunaniro. Ariko, uburebure ntibufitanye isano itaziguye na UTS, ari nayo yonyine imiterere ya mekanike ifitanye isano itaziguye n'ubukomere.
Kuki imiterere y’imiyoboro itandukanye cyane? Ubwa mbere, imiterere y’imiti iratandukanye. Icyuma ni igisubizo gikomeye cy’icyuma na karuboni n’izindi alloys z’ingenzi. Kugira ngo byoroshye, tuzareba gusa ijanisha rya karuboni hano. Atome za karuboni zisimbura zimwe muri atome z’icyuma, zigakora imiterere ya kristu y’icyuma. ASTM 1008 ni urwego rw’ibanze rufite ingano ya karuboni kuva kuri 0% kugeza kuri 0.10%. Zeru ni umubare wihariye cyane utanga imiterere yihariye iyo ingano ya karuboni mu cyuma iri hasi cyane. ASTM 1010 igaragaza ingano ya karuboni iri hagati ya 0.08% na 0.13%. Izi tandukaniro risa nkaho ari rinini cyane, ariko ni rinini bihagije kugira ngo rigire itandukaniro rikomeye ahandi.
Icya kabiri, umuyoboro w'icyuma ushobora gukorwa cyangwa gukorwa hanyuma ugatunganywa mu buryo birindwi butandukanye bwo kuwukora. ASTM A513 ijyanye no gukora imiyoboro ya ERW igaragaza ubwoko burindwi:
Niba imiterere y'ibinyabutabire mu byuma n'intambwe zo gukora umuyoboro nta ngaruka bigira ku bukomere bw'icyuma, ni iki? Gusubiza iki kibazo bivuze gusuzuma ibisobanuro birambuye. Iki kibazo gitera ibindi bibazo bibiri: Ni ibihe bisobanuro birambuye, kandi ni hafi he?
Ibisobanuro birambuye ku binyampeke bigize icyuma ni igisubizo cya mbere. Iyo icyuma gikozwe mu ruganda rw'icyuma rusanzwe, ntigikonja kikagera mu gice kinini gifite ikintu kimwe. Uko icyuma gikonja, molekile z'icyuma zitondeka mu buryo busubiramo (amabara y'urubura), nk'uko shelegi zikora. Nyuma y'uko kristu zikozwe, zihurira mu matsinda yitwa ibinyampeke. Uko gukonja bigenda birushaho kwiyongera, ibinyampeke birakura kandi bigatera imbere mu rupapuro cyangwa ku isahani. Ibinyampeke birahagarara gukura uko molekile za nyuma z'icyuma zinjira mu binyampeke. Ibi byose biba ku rwego rwa mikorosikopi kuko ingano y'icyuma isanzwe ifite ubugari bwa santimetero 64 cyangwa santimetero 0.0025. Nubwo buri ngano isa n'iyindi, ntabwo ari imwe. Ziratandukanye gato mu bunini, icyerekezo n'ingano ya karuboni. Imiterere y'ibinyampeke yitwa imipaka y'ibinyampeke. Iyo icyuma kinaniwe, urugero bitewe n'umunaniro, gikunda kunanirwa ku mipaka y'ibinyampeke.
Ni ku rugero rungana iki ugomba kureba kugira ngo ubone uduce duto twagaragara? Kurushaho gukurura, cyangwa kureba inshuro 100, birahagije. Ariko, kureba icyuma kitavuwe inshuro 100 gusa, imbaraga ntizigaragaza byinshi. Icyitegererezo gitegurwa hakoreshejwe gusiga icyitegererezo no gusiga hejuru ukoresheje aside (ubusanzwe aside nitrike na alcool) yitwa nitroethanol etchant.
Ibinyampeke n'urukuta rwabyo rw'imbere ni byo bigena imbaraga z'ingaruka, MYS, UTS n'uburebure icyuma gishobora kwihanganira mbere yuko gicika.
Intambwe zo gukora ibyuma, nko kuzunguruka kw'imirongo ishyushye n'ikonje, zishyira imbaraga mu miterere y'ingano; iyo zihinduye imiterere burundu, bivuze ko imbaraga zihindura imiterere y'ingano. Izindi ntambwe zo gutunganya, nko gupfunyika icyuma mu miyoboro, kukibohora, no guhindura imiterere y'ingano y'icyuma binyuze mu ruganda rukora imiyoboro (kugira ngo hakorwe kandi hagatorwe umuyoboro). Gukurura umuyoboro ukonje kuri mandrel nabyo bishyira imbaraga ku bikoresho, kimwe n'intambwe zo gukora nko gushushanya no kugorora. Impinduka mu miterere y'ingano zitwa dislocations.
Intambwe zavuzwe haruguru zigabanya ubushobozi bwo gukurura icyuma, ari nabwo bubasha bwacyo bwo kwihanganira imbaraga zo gukurura (gukurura-gufungura). Icyuma kiracika intege, bivuze ko gishobora kuvunika cyane niba ukomeje kugikoraho. Kurekura ni kimwe mu bigize ubushobozi bwo gukurura icyuma (gukurura ni ikindi). Ni ngombwa kumva ko gutsindwa akenshi bibaho mu gihe cyo gukurura icyuma, atari ugukurura icyuma. Icyuma kirwanya cyane imbaraga zo gukurura icyuma kubera ubushobozi bwacyo bwo gukurura icyuma. Ariko, icyuma kirushaho kwangirika mu gihe cyo gukurura icyuma - ni icyuma gikurura icyuma - bikaba ari inyungu.
Beto ifite imbaraga nyinshi zo gukanda ariko ubushobozi bwo kuyikoresha buragabanuka ugereranije na beto. Iyi miterere itandukanye n'iy'icyuma. Niyo mpamvu beto ikoreshwa mu mihanda, inyubako n'inzira z'abanyamaguru ikunze gushyirwaho imigozi. Umusaruro uba umusaruro ufite imbaraga nk'iz'ibikoresho bibiri: iyo ikoresha imbaraga nyinshi, icyuma kirakomera, naho iyo ikoresha imbaraga nke, sima.
Mu gihe cyo gukora mu bukonje, uko ubushobozi bwo gukora icyuma bugabanuka, niko ubukana bwacyo bwiyongera. Mu yandi magambo, kizakomeza gukomera. Bitewe n'uko ibintu bimeze, ibi bishobora kuba inyungu; icyakora, bishobora kuba ingaruka mbi kuko ubukana bugereranywa no kugorama. Ni ukuvuga ko uko icyuma kirushaho gukomera, kirushaho kugorama; bityo, kiba gifite amahirwe menshi yo kwangirika.
Mu yandi magambo, buri ntambwe ikoreshwa ikoresha uburyo bworoshye bwo gukoresha umuyoboro. Irushaho gukomera uko igice gikora, kandi iyo gikomeye cyane ntacyo kiba kimaze. Gukomera ni ukugoka, kandi umuyoboro ugoka ushobora kwangirika iyo ukoreshejwe.
Ese uwakoze iyi porogaramu afite amahitamo muri uru rubanza? Muri make, yego. Iyo hitamo ni ugukora, kandi nubwo atari amayobera cyane, yegereye cyane amayobera uko ushoboye kose.
Mu magambo asanzwe, gushyushya icyuma bikuraho ingaruka zose z’umuvuduko w’umubiri ku cyuma. Ubu buryo bushyushya icyuma kugeza ku bushyuhe bwo kugabanya umuvuduko cyangwa kongera gushyushya, bityo bigakuraho kwimuka. Bitewe n’ubushyuhe bwihariye n’igihe byakoreshejwe mu gushyushya, bityo uburyo bugarura ubushobozi bwacyo bwose cyangwa bumwe.
Gufunga no gukonjesha bigenzura iterambere ry'ibinyampeke. Ibi ni ingirakamaro niba intego ari ukugabanya ububobere bw'ibikoresho, ariko gukura kw'ibinyampeke mu buryo butagenzuwe bishobora koroshya icyuma cyane, bigatuma kidakoreshwa mu buryo cyagenewe gukoreshwa. Guhagarika inzira yo gufunga ni ikindi kintu gisa n'icy'ubumaji. Kuzimya ku bushyuhe bukwiye ukoresheje igikoresho gikwiye cyo kuzimya mu gihe gikwiye bituma inzira ihagarara vuba kugira ngo icyuma gishobore kuboneka.
Ese tugomba kureka ibipimo by'ubukana? Oya. Ibiranga ubukana bifite agaciro cyane cyane nk'ahantu ho kwibandaho mu kugena imiyoboro y'icyuma. Igipimo cy'ingirakamaro, ubukana ni kimwe mu bintu byinshi bigomba kugaragazwa mu gutumiza ibikoresho by'imiyoboro no kugenzurwa nyuma yo kubihabwa (kandi bigomba kwandikwa hamwe na buri koherezwa). Iyo igenzura ry'ubukana ari ryo tegeko ngenderwaho ryo kugenzura, rigomba kugira agaciro gakwiye k'ibipimo n'urwego rwo kugenzura.
Ariko, si ikizamini nyacyo cyo kwemeza (kwakira cyangwa kwanga) ibikoresho. Uretse ubukana, abakora ibikoresho bagomba rimwe na rimwe kugerageza ibyoherezwa kugira ngo bamenye indi miterere ijyanye nabyo, nka MYS, UTS, cyangwa uburebure buke, bitewe n'uko umuyoboro ukoreshwa.
Wynn H. Kearns is responsible for regional sales for Indiana Tube Corp., 2100 Lexington Road, Evansville, IN 47720, 812-424-9028, wkearns@indianatube.com, www.indianatube.com.
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