Amandla ezinto zensimbi okumelana nokugoba kobuso ngezinto eziqinile abizwa ngokuthi ubulukhuni. Ngokwezindlela ezahlukene zokuhlola kanye nobubanzi bokusetshenziswa, ubulukhuni bungahlukaniswa bube ubulukhuni beBrinell, ubulukhuni beRockwell, ubulukhuni beVickers, ubulukhuni beShore, ubulukhuni obuncane kanye nobulukhuni bokushisa okuphezulu. Kunezinhlobo ezintathu zobulukhuni ezivame ukusetshenziswa kumapayipi: ubulukhuni beBrinell, Rockwell, kanye neVickers.
A. Ukuqina kukaBrinell (HB)
Sebenzisa ibhola lensimbi noma ibhola le-carbide elinobubanzi obuthile ukuze ucindezele endaweni yesampula ngamandla okuhlola acacisiwe (F). Ngemva kwesikhathi esibekiwe sokubamba, susa amandla okuhlola bese ulinganisa ububanzi bokugoba (L) ebusweni besampula. Inani lobunzima be-Brinell yi-quotient etholakala ngokuhlukanisa amandla okuhlola ngendawo engaphezulu kwe-indented sphere. Ivezwa ku-HBS (ibhola lensimbi), iyunithi yi-N/mm2 (MPa).
Ifomula yokubala ithi:
Kufomula: F–amandla okuhlola acindezelwe ebusweni besampula yensimbi, N;
Ububanzi bebhola lensimbi D lokuhlola, mm;
d – ububanzi obumaphakathi bokugoba, mm.
Ukulinganiswa kobulukhuni beBrinell kunembe kakhulu futhi kunokwethenjelwa, kodwa ngokuvamile i-HBS ifaneleka kuphela ezintweni zensimbi ezingaphansi kuka-450N/mm2 (MPa), futhi ayifaneleki ensimbini eqinile noma amapuleti amancane. Phakathi kwezindinganiso zamapayipi ensimbi, ubulukhuni beBrinell yibona obusetshenziswa kakhulu. Ububanzi bokugoba u-d buvame ukusetshenziselwa ukuveza ubulukhuni bezinto, okubili okunembile futhi okulula.
Isibonelo: 120HBS10/1000130: Kusho ukuthi inani lobulukhuni beBrinell elilinganiswa ngokusebenzisa ibhola lensimbi elingu-10mm ububanzi ngaphansi kwamandla okuhlola angu-1000Kgf (9.807KN) amasekhondi angu-30 (imizuzwana) lingu-120N/mm2 (MPa).
B. Ubulukhuni beRockwell (HR)
Ukuhlolwa kobulukhuni kweRockwell, njengokuhlolwa kobulukhuni kweBrinell, kuyindlela yokuhlola ukugxila. Umehluko ukuthi ilinganisa ukujula kokugxila. Okusho ukuthi, ngaphansi kwesenzo esilandelanayo samandla okuqala okuhlola (Fo) kanye namandla okuhlola aphelele (F), i-indenter (ibhola lekhoni noma lensimbi lomshini wensimbi) icindezelwa ebusweni besampula. Ngemva kwesikhathi esibekiwe sokubamba, amandla amakhulu ayasuswa. Amandla okuhlola, sebenzisa ukwanda kokujula kokugxila okusele okulinganisiwe (e) ukuze ubale inani lobulukhuni. Inani layo liyinombolo engaziwa, emelelwa uphawu lwe-HR, futhi izikali ezisetshenziswayo zifaka izikali ezingu-9, kufaka phakathi u-A, B, C, D, E, F, G, H, no-K. Phakathi kwazo, izikali ezivame ukusetshenziswa ekuhlolweni kobulukhuni bensimbi ngokuvamile u-A, B, no-C, okungukuthi i-HRA, i-HRB, kanye ne-HRC.
Inani lobulukhuni libalwa kusetshenziswa ifomula elandelayo:
Uma kuhlolwa ngezikali ze-A kanye ne-C, i-HR=100-e
Uma kuhlolwa ngesikali se-B, i-HR=130-e
Kufomula, u-e – ukwanda kokujula kokuncishiswa okusele kuvezwa kuyunithi ecacisiwe engu-0.002mm, okungukuthi, lapho ukufuduka kwe-axial kwe-indenter kuyiyunithi eyodwa (0.002mm), kufana nokushintsha kobulukhuni beRockwell ngenombolo eyodwa. Uma inani le-e likhulu, ubulukhuni bensimbi buyancipha, futhi okuphambene nalokho.
Ububanzi obusebenzayo bezikali ezintathu ezingenhla bungokulandelayo:
I-HRA (i-indenter yekhoni yedayimane) 20-88
I-HRC (i-indenter yekhoni yedayimane) 20-70
I-HRB (ububanzi obungu-1.588mm i-indenter yebhola lensimbi) 20-100
Ukuhlolwa kobulukhuni beRockwell kuyindlela esetshenziswa kabanzi njengamanje, phakathi kwayo i-HRC isetshenziswa ezindinganisweni zamapayipi ensimbi, eyesibili kuphela emva kobulukhuni beBrinell HB. Ubulukhuni beRockwell bungasetshenziswa ukukala izinto zensimbi kusukela kokuthambile kakhulu kuya kokulukhuni kakhulu. Kulungisa amaphutha endlela yeBrinell. Ilula kunendlela yeBrinell futhi inani lobulukhuni lingafundwa ngqo kusuka ku-dial yomshini wobulukhuni. Kodwa-ke, ngenxa yokugoba kwayo okuncane, inani lobulukhuni alinembile njengendlela yeBrinell.
C. Ubulukhuni be-Vickers (HV)
Ukuhlolwa kobulukhuni be-Vickers nakho kuyindlela yokuhlola ukugoba. Kucindezela i-indenter yesikwele yedayimane eyi-pyramidal ene-engeli engu-1360 phakathi kwezindawo eziphambene endaweni yokuhlola kumandla okuhlola akhethiwe (F), bese kuyisusa ngemva kwesikhathi esibekiwe sokubamba. Phoqa, kala ubude be-diagonal ezimbili zokugoba.
Inani lobulukhuni be-Vickers liyisilinganiso samandla okuhlola ahlukaniswe yindawo yobuso be-indentation. Ifomula yalo yokubala ithi:
Kule fomula: Uphawu lokuqina kwe-HV–Vickers, N/mm2 (MPa);
Amandla okuhlola u-F, N;
d–isilinganiso sezibalo sama-diagonal amabili e-indentation, mm.
Amandla okuhlola u-F asetshenziswa ku-Vickers hardness angu-5 (49.03), 10 (98.07), 20 (196.1), 30 (294.2), 50 (490.3), 100 (980.7) Kgf (N) kanye namanye amazinga ayisithupha. Inani lobunzima lingalinganiswa. Ububanzi bungu-5~1000HV.
Isibonelo sendlela yokuveza: 640HV30/20 kusho ukuthi inani lobulukhuni be-Vickers elilinganiswe ngamandla okuhlola angu-30Hgf (294.2N) kwama-20S (amasekhondi) lingu-640N/mm2 (MPa).
Indlela yobulukhuni be-Vickers ingasetshenziswa ukunquma ubulukhuni bezinto zensimbi ezincane kakhulu kanye nezendlalelo ezingaphezulu. Inezinzuzo eziyinhloko zezindlela ze-Brinell ne-Rockwell futhi inqoba amaphutha azo ayisisekelo, kodwa ayilula njengendlela ye-Rockwell. Indlela ye-Vickers ayisetshenziswa kakhulu ezindinganisweni zamapayipi ensimbi.
Isikhathi sokuthunyelwe: Ephreli-03-2024
