Bokhoni ba thepa ea tšepe ba ho hanela ho kobeha ha bokaholimo ke lintho tse thata bo bitsoa thata. Ho ea ka mekhoa e fapaneng ea liteko le boholo ba ts'ebeliso, thatafalo e ka aroloa ka thatafalo ea Brinell, thatafalo ea Rockwell, thatafalo ea Vickers, thatafalo ea Shore, thatafalo e nyane le thatafalo ea mocheso o phahameng. Ho na le thatafalo tse tharo tse sebelisoang hangata bakeng sa liphaephe: thatafalo ea Brinell, Rockwell, le Vickers.
A. Bothata ba Brinell (HB)
Sebelisa bolo ea tšepe kapa bolo ea khabide ea bophara bo itseng ho hatella bokaholimo ba sampole ka matla a teko a boletsoeng (F). Kamora nako e boletsoeng ea ho tšoara, tlosa matla a teko 'me u lekanye bophara ba indentation (L) bokaholimong ba sampole. Boleng ba Brinell hardness ke quotient e fumanoang ka ho arola matla a teko ka sebaka sa bokaholimo ba lesaka le kentsoeng. E hlalositsoe ka HBS (bolo ea tšepe), yuniti ke N/mm2 (MPa).
Foromo ea lipalo ke:
Ka foromo: F–matla a teko a hatelletsoeng holim'a sampole ea tšepe, N;
D–Bophara ba bolo ea tšepe bakeng sa teko, mm;
d – bophara bo tloaelehileng ba ho kenella ha lesoba, mm.
Tekanyo ea boima ba Brinell e nepahetse ebile e ka tšeptjoa haholoanyane, empa ka kakaretso HBS e loketse feela thepa ea tšepe e ka tlase ho 450N/mm2 (MPa), 'me ha e lokele tšepe e thata kapa lipoleiti tse tšesaane. Har'a litekanyetso tsa liphaephe tsa tšepe, boima ba Brinell ke bona bo sebelisoang haholo. Bophara ba indentation d hangata bo sebelisoa ho hlalosa boima ba thepa, e leng ntho e utloahalang le e bonolo.
Mohlala: 120HBS10/1000130: E bolela hore boleng ba thatafalo ea Brinell bo lekanngoang ka ho sebelisa bolo ea tšepe ea bophara ba 10mm tlas'a matla a teko a 1000Kgf (9.807KN) bakeng sa metsotsoana e 30 (metsotsoana) ke 120N/mm2 (MPa).
B. Bothata ba Rockwell (HR)
Teko ea ho thatafala ha Rockwell, joalo ka teko ea ho thatafala ha Brinell, ke mokhoa oa teko ea ho intša. Phapang ke hore e lekanya botebo ba ho intša. Ke hore, tlas'a ketso e latellanang ea matla a pele a teko (Fo) le matla a kakaretso a teko (F), indenter (khoune kapa bolo ea tšepe ea leloala la tšepe) e hatelloa holim'a sampole. Kamora nako e boletsoeng ea ho tšoara, matla a mantlha aa tlosoa. Matla a teko, sebelisa keketseho ea botebo ba ho intša bo setseng (e) e lekantsoeng ho bala boleng ba ho thatafala. Boleng ba eona ke nomoro e sa tsejoeng, e emeloang ke letšoao la HR, 'me litekanyo tse sebelisitsoeng li kenyelletsa litekanyo tse 9, ho kenyeletsoa A, B, C, D, E, F, G, H, le K. Har'a tsona, litekanyo tse sebelisoang hangata bakeng sa teko ea ho thatafala ha tšepe ke A, B, le C, e leng HRA, HRB, le HRC.
Boleng ba thata bo balwa ho sebelisoa foromo e latelang:
Ha o leka ka sekala sa A le C, HR=100-e
Ha o leka ka sekala sa B, HR=130-e
Ka foromong, e – keketseho ea botebo ba indentation e setseng e hlahisoa yuniting e boletsoeng ea 0.002mm, ke hore, ha ho falla ha axial ea indenter e le yuniti e le 'ngoe (0.002mm), ho lekana le phetoho ea ho thatafala ha Rockwell ka nomoro e le 'ngoe. Ha boleng ba e bo boholo, ho thatafala ha tšepe hoa theoha, 'me ka tsela e fapaneng.
Sekala se sebetsang sa tse tharo tse ka holimo ke se latelang:
HRA (khoune ea daemane e koetsoeng) 20-88
HRC (khoune ea daemane e harelaneng) 20-70
HRB (bophara ba 1.588mm tšepe e bohareng ba bolo) 20-100
Teko ea ho thatafala ha Rockwell ke mokhoa o sebelisoang haholo hajoale, oo har'a oona HRC e sebelisoang litekanyetsong tsa liphaephe tsa tšepe tse latelang Brinell Hardness HB. Ho thatafala ha Rockwell ho ka sebelisoa ho lekanya thepa ea tšepe ho tloha ho bonolo haholo ho isa ho thata haholo. E koahela mefokolo ea mokhoa oa Brinell. E bonolo ho feta mokhoa oa Brinell 'me boleng ba ho thatafala bo ka baloa ka ho toba ho tsoa daeleng ea mochini oa ho thatafala. Leha ho le joalo, ka lebaka la ho kenella ha eona hanyane, boleng ba ho thatafala ha bo nepahale joalo ka mokhoa oa Brinell.
C. Bothata ba Vickers (HV)
Teko ea ho thatafala ha Vickers le eona ke mokhoa oa teko ea ho kenya khutlo. E hatella khutlo ea daemane e sekwere ea pyramidal e nang le sekhutlo se kenyellelitsoeng sa 1360 pakeng tsa libaka tse fapaneng ho ea holim'a teko ka matla a khethiloeng a teko (F), 'me e e tlosa kamora nako e boletsoeng ea ho tšoara. Matlafatsa, lekanya bolelele ba li-diagonal tse peli tsa khutlo.
Boleng ba thata ba Vickers ke quotient ea matla a teko a arotsoeng ke sebaka sa bokaholimo ba indentation. Foromo ea eona ea lipalo ke:
Ka mokhoa o latelang: Letšoao la ho thatafala ha HV–Vickers, N/mm2 (MPa);
Matla a teko ea F, N;
d – karolelano ea lipalo ea li-diagonal tse peli tsa indentation, mm.
Matla a teko F a sebelisitsoeng ho thatafalo ea Vickers ke 5 (49.03), 10 (98.07), 20 (196.1), 30 (294.2), 50 (490.3), 100 (980.7) Kgf (N) le maemo a mang a tšeletseng. Boleng ba thatafalo bo ka lekanngoa. Sebaka ke 5~1000HV.
Mohlala oa mokhoa oa tlhahiso: 640HV30/20 e bolela hore boleng ba thata ba Vickers bo lekantsoeng ka matla a teko a 30Hgf (294.2N) bakeng sa 20S (metsotsoana) ke 640N/mm2 (MPa).
Mokhoa oa ho thatafala ha Vickers o ka sebelisoa ho fumana hore na thepa e tšesaane haholo ea tšepe le likarolo tse ka holimo li thata hakae. O na le melemo e meholo ea mekhoa ea Brinell le Rockwell 'me o hlola mefokolo ea bona ea mantlha, empa ha o bonolo joaloka mokhoa oa Rockwell. Mokhoa oa Vickers ha o sebelisoe hangata litekanyetsong tsa liphaephe tsa tšepe.
Nako ea poso: Mmesa-03-2024
