Bokhoni ba lisebelisoa tsa tšepe ho hanyetsa ho kenngoa ha bokaholimo ka lintho tse thata ho bitsoa ho thatafala. Ho latela mekhoa e fapaneng ea liteko le boholo ba ts'ebeliso, boima bo ka aroloa ka thata ea Brinell, Rockwell hardness, Vickers hardness, Shore hardness, microhardness le boima bo phahameng ba mocheso. Ho na le hardness tse tharo tse sebelisoang hangata bakeng sa liphaephe: Brinell, Rockwell, le Vickers hardness.
A. Brinell hardness (HB)
Sebelisa bolo ea tšepe kapa bolo ea carbide ea bophara bo itseng ho tobetsa holim'a sampole ka matla a boletsoeng a teko (F). Ka mor'a nako e behiloeng ea ho tšoara, tlosa matla a teko 'me u lekanye bophara ba ho indentation (L) sebakeng sa mohlala. Brinell hardness value ke quotient e fumanoang ka ho arola matla a teko ka bokaholimo ba sphere e indenting. E hlahisoa ka HBS (bolo ea tšepe), yuniti ke N/mm2 (MPa).
Foromo ea lipalo ke:
Ka foromo: F-matla a teko a hatelletse ka holim'a sampole ea tšepe, N;
D-Diameter ea bolo ea tšepe bakeng sa teko, limilimithara;
d-average bophara ba ho indentation, mm.
Tekanyo ea boima ba Brinell e nepahetse haholoanyane ebile e ka tšeptjoa, empa ka kakaretso HBS e loketse feela lisebelisoa tsa tšepe tse ka tlase ho 450N/mm2 (MPa), 'me ha e tšoanelehe bakeng sa tšepe e thata kapa lipoleiti tse tšesaane. Har'a litekanyetso tsa lipeipi tsa tšepe, Brinell hardness ke eona e sebelisoang ka ho fetisisa. The indentation diameter d hangata e sebelisoa ho hlalosa ho thatafala ha thepa, e leng ntho e utloahalang le e bonolo.
Mohlala: 120HBS10/1000130: Ho bolela hore boleng ba boima ba Brinell bo lekantsoeng ka ho sebelisa bolo ea tšepe ea bophara ba 10mm tlas'a matla a teko a 1000Kgf (9.807KN) bakeng sa 30s (metsotsoana) ke 120N/mm2 (MPa).
B. Rockwell hardness (HR)
Teko ea ho thatafala ha Rockwell, joalo ka tlhahlobo ea boima ba Brinell, ke mokhoa oa tlhahlobo ea indentation. Phapang ke hore e lekanya botebo ba ho indentation. Ke hore, tlas'a ketso e latellanang ea matla a pele a teko (Fo) le matla a teko kaofela (F), indenter (cone kapa bolo ea tšepe ea leloala la tšepe) e hatelloa ka holim'a sampuli. Ka mor'a nako e behiloeng ea ho tšoara, matla a maholo a tlosoa. Matla a teko, sebelisa tekanyo e lekantsoeng ea ho indentation ea botebo bo setseng (e) ho bala boleng ba boima. Boleng ba eona ke palo e sa tsejoeng, e emeloang ke letšoao la HR, 'me litekanyo tse sebelisoang li kenyelletsa litekanyo tse 9, ho akarelletsa le A, B, C, D, E, F, G, H, le K. Har'a tsona, litekanyo tse atisang ho sebelisoa bakeng sa tšepe. tlhahlobo ea boima ba 'mele hangata ke A, B, le C, e leng HRA, HRB, le HRC.
The hardness value e baloa ho sebelisa foromo e latelang:
Ha u etsa liteko ka sekala sa A le C, HR=100-e
Ha u etsa liteko ka sekala sa B, HR=130-e
Ka foromo, e - keketseho e setseng ea botebo ba indentation e hlahisoa karolong e boletsoeng ea 0.002mm, ke hore, ha axial displacement ea indenter e le yuniti e le 'ngoe (0.002mm), e lekana le phetoho ea thata ea Rockwell ka e le' ngoe. palo. Ha boleng ba e e kholoanyane, boima ba tšepe bo tlase, 'me ka tsela e fapaneng.
Boemo bo sebetsang ba likala tse tharo tse ka holimo ke tse latelang:
HRA (diamane cone indenter) 20-88
HRC (diamane cone indenter) 20-70
HRB (bophara ba 1.588mm tšepe bolo ea indenter) 20-100
Rockwell hardness test ke mokhoa o sebelisoang haholo hajoale, oo HRC e sebelisoang maemong a lipeipi tsa tšepe ea bobeli feela ho Brinell hardness HB. Rockwell hardness e ka sebelisoa ho lekanya lisebelisoa tsa tšepe ho tloha ho tse bonolo haholo ho isa ho tse thata haholo. E etsa bakeng sa mefokolo ea mokhoa oa Brinell. E bonolo ho feta mokhoa oa Brinell mme boleng ba boima bo ka baloa ka ho toba ho tloha ho daela mochine o thata. Leha ho le joalo, ka lebaka la ho indentation e nyenyane, boleng ba boima ha bo nepahale joaloka mokhoa oa Brinell.
C. Vickers hardness (HV)
Teko ea boima ba Vickers hape ke mokhoa oa tlhahlobo ea indentation. E tobetsa "square pyramidal diamond indenter" e nang le angle e kenyellelitsoeng ea 1360 lipakeng tsa libaka tse fapaneng sebakeng sa tlhahlobo ka matla a khethiloeng a teko (F), ebe e e tlosa kamora nako e behiloeng ea ho e ts'oara. Matla, lekanya bolelele ba li-diagonal tse peli tsa indentation.
The Vickers hardness value ke quotient ea matla a teko a arotsoeng ke sebaka se ka holimo sa indentation. Foromo ea eona ea lipalo ke:
Ka foromo: Letšoao la boima ba HV-Vickers, N/mm2 (MPa);
F–teko matla, N;
d - moelelo oa lipalo oa li-diagonal tse peli tsa indentation, mm.
Matla a teko F a sebelisitsoeng ho Vickers hardness 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 boima bo ka lekanngoa Lebelo ke 5 ~ 1000HV.
Mohlala oa mokhoa oa ho bua: 640HV30/20 e bolela hore boleng ba boima ba Vickers bo lekantsoeng ka matla a teko ea 30Hgf (294.2N) bakeng sa 20S (metsotsoana) ke 640N/mm2 (MPa).
Mokhoa oa ho thatafala oa Vickers o ka sebelisoa ho tseba ho thatafala ha lisebelisoa tsa tšepe tse tšesaane haholo le likarolo tsa bokaholimo. E na le melemo e ka sehloohong ea mekhoa ea Brinell le Rockwell mme e hlōla mefokolo ea bona ea motheo, empa ha e bonolo joaloka mokhoa oa Rockwell. Mokhoa oa Vickers ha o sebelisoe hangata maemong a lipeipi tsa tšepe.
Nako ea poso: Apr-03-2024