Ubushobozi bw'icyuma bwo kurwanya gupfundika kw'ubuso bw'ibintu bikomeye bwitwa ubukana. Dukurikije uburyo butandukanye bwo gupima n'uburyo bwo kubukoresha, ubukana bushobora kugabanywamo ubukana bwa Brinell, ubukana bwa Rockwell, ubukana bwa Vickers, ubukana bwa Shore, ubukana bwa micro na ubukana bwa high temperature. Hari ubukana butatu bukunze gukoreshwa ku miyoboro: ubukana bwa Brinell, Rockwell, na Vickers.
A. Ubukomere bwa Brinell (HB)
Koresha umupira w'icyuma cyangwa umupira wa karubide ufite umurambararo runaka kugira ngo ukandagire ku buso bw'icyitegererezo ukoresheje imbaraga zagenwe zo gupima (F). Nyuma y'igihe cyagenwe cyo gufata, kura imbaraga za test hanyuma upime umurambararo wa induction (L) ku buso bw'icyitegererezo. Agaciro k'ubukana bwa Brinell ni quotient iboneka mu kugabanya imbaraga za test n'ubuso bw'umubumbe wa induction. Igaragazwa muri HBS (umupira w'icyuma), igice ni N/mm2 (MPa).
Ifishi yo kubara ni iyi:
Muri formula: F – imbaraga zo gupima zashyizwe ku buso bw'icyitegererezo cy'icyuma, N;
D–Umurambararo w'umupira w'icyuma wo gupima, mm;
d – umurambararo mpuzandengo w'umurambararo w'inyuma, mm.
Igipimo cy'ubukomere bwa Brinell ni cyiza kandi cyizewe, ariko muri rusange HBS ikwiriye gusa ibikoresho by'icyuma biri munsi ya 450N/mm2 (MPa), kandi ntikwiriye ibyuma bikomeye cyangwa ibyuma bito. Mu bipimo by'imiyoboro y'icyuma, ubukomere bwa Brinell ni bwo bukoreshwa cyane. Umurambararo w'umurambararo d ukunze gukoreshwa mu kugaragaza ubukomere bw'ibikoresho, bikaba byoroshye kandi bisobanutse.
Urugero: 120HBS10/1000130: Bivuze ko agaciro k'ubukomere bwa Brinell gapimwe hakoreshejwe umupira w'icyuma ufite umurambararo wa mm 10 munsi y'ingufu za 1000Kgf (9.807KN) mu gihe cy'amasegonda 30 (amasegonda) ari 120N/mm2 (MPa).
B. Ubukomere bwa Rockwell (HR)
Ikizamini cyo gukomera cya Rockwell, kimwe n'ikizamini cyo gukomera cya Brinell, ni uburyo bwo gupima uburebure bw'icyuma. Itandukaniro ni uko gipima uburebure bw'icyuma. Ni ukuvuga ko, munsi y'igikorwa gikurikiranye cy'imbaraga z'ikizamini cya mbere (Fo) n'imbaraga zose z'ikizamini (F), uburebure bw'icyuma (agapira k'icyuma cyangwa umupira w'icyuma w'icyuma) bushyirwa hejuru y'icyitegererezo. Nyuma y'igihe cyagenwe cyo gufata, imbaraga nyamukuru zirakurwaho. Imbaraga zo gupima, koresha inyongera y'uburebure bw'icyuma gisigaye (e) kugira ngo ubare agaciro k'ubukomere. Agaciro kayo ni umubare utazwi, ugaragazwa n'ikimenyetso cya HR, kandi ibipimo byakoreshejwe birimo ibipimo 9, birimo A, B, C, D, E, F, G, H, na K. Muri byo, ibipimo bikunze gukoreshwa mu gupima uburebure bw'icyuma muri rusange ni A, B, na C, ari byo HRA, HRB, na HRC.
Agaciro k'ubukomere kabarwa hakoreshejwe formula ikurikira:
Mu gihe upima ukoresheje ibipimo bya A na C, HR=100-e
Mu gihe ugerageza ukoresheje igipimo cya B, HR=130-e
Muri formula, e – kwiyongera k’ubujyakuzimu bw’inyongera bigaragazwa mu gice cyagenwe cya 0.002mm, ni ukuvuga ko iyo intera y’umurongo w’inyongera ari igice kimwe (0.002mm), bingana n’impinduka mu bukomere bwa Rockwell ku mubare umwe. Uko agaciro ka e kaba kanini, niko ubukomere bw’icyuma bugabanuka, n’ibindi.
Ingano ikoreshwa muri ibi bipimo bitatu byavuzwe haruguru ni iyi ikurikira:
HRA (indenter ya diyama) 20-88
HRC (indenter ya diyama) 20-70
HRB (umurambararo wa 1.588mm icyuma cya indenter y'umupira) 20-100
Ikizamini cy'ubukana bwa Rockwell ni uburyo bukoreshwa cyane muri iki gihe, muri bwo HRC ikoreshwa mu bipimo by'imiyoboro y'icyuma nyuma ya Brinell HB. Ubukana bwa Rockwell bushobora gukoreshwa mu gupima ibikoresho by'icyuma kuva ku byoroshye cyane kugeza ku bikomeye cyane. Bikemura ibibazo by'uburyo bwa Brinell. Byoroshye kurusha uburyo bwa Brinell kandi agaciro k'ubukana gashobora gusomwa neza uhereye ku gasanduku k'imashini y'ubukana. Ariko, bitewe n'uko ifite akantu gato, agaciro k'ubukana ntabwo gakwiye nk'uburyo bwa Brinell.
C. Ubukomere bwa Vickers (HV)
Ikizamini cyo gukomera cya Vickers nacyo ni uburyo bwo gupima ubwiherero. Gikanda diyama kare ifite inguni ya 1360 hagati y’ubuso buhanganye mu buso bw’ikizamini ku ngufu yatoranijwe (F), hanyuma kikayikuraho nyuma y’igihe cyagenwe cyo gufata. Ingufu, pima uburebure bw’impande ebyiri z’ubwiherero.
Agaciro k'ubukana bwa Vickers ni igipimo cy'imbaraga z'igerageza kigabanyijwe n'ubuso bw'aho amazi anyura. Ifishi yayo yo kubara ni iyi:
Muri formula: Ikimenyetso cy'ubukana bwa HV–Vickers, N/mm2 (MPa);
Ingufu zo gupima F–, N;
d – impuzandengo y'imibare y'impande ebyiri z'umurongo ugororotse, mm.
Imbaraga zo gupima F zikoreshwa mu gukomera kwa Vickers ni 5 (49.03), 10 (98.07), 20 (196.1), 30 (294.2), 50 (490.3), 100 (980.7) Kgf (N) n'izindi nzego esheshatu. Agaciro k'ubukomere gashobora gupimwa. Intera ni 5 ~ 1000HV.
Urugero rw'uburyo bwo kugaragaza: 640HV30/20 bivuze ko agaciro k'ubukana bwa Vickers gapimwe hakoreshejwe imbaraga z'igerageza za 30Hgf (294.2N) kuri 20S (amasegonda) ari 640N/mm2 (MPa).
Uburyo bwo gukomeretsa bwa Vickers bushobora gukoreshwa mu kumenya ubukomere bw'ibikoresho by'icyuma bito cyane n'ibice by'ubuso. Bufite ibyiza by'ingenzi by'uburyo bwa Brinell na Rockwell kandi butsinda intege nke zabwo, ariko ntabwo bworoshye nk'uburyo bwa Rockwell. Uburyo bwa Vickers ntibukunze gukoreshwa mu bipimo by'imiyoboro y'icyuma.
Igihe cyo kohereza: Mata-03-2024
