Matanho matatu ekuoma kwesimbi

Kugona kwesimbi kudzivirira kupinda kwechinhu chakaoma pamusoro pemvura kunonzi kuomarara. Zvichienderana nenzira dzakasiyana dzekuyedza uye kushandiswa kwayo, kuomarara kunogona kukamurwa kuita kuomarara kweBrinell, kuomarara kweRockwell, kuomarara kweVickers, kuomarara kweShore, kuomarara kudiki uye kuomarara kwekupisa kwakanyanya. Kune kuomarara kutatu kunowanzo shandiswa pamapaipi: Brinell, Rockwell, uye Vickers.

A. Kuomarara kweBrinell (HB)

Shandisa bhora resimbi kana bhora rekabhoridhi rine dhayamita yakati kuti upinde pamusoro pemuenzaniso uchishandisa simba rekuyedza (F). Mushure menguva yakatarwa yekubata, bvisa simba rekuyedza uye yera dhayamita yekupinda (L) pamusoro pemuenzaniso. Kukosha kwehukoshi hweBrinell ndiyo quotient inowanikwa nekukamura simba rekuyedza nenzvimbo yepamusoro yesphere yakapindirwa. Inoratidzwa muHBS (bhora resimbi), unit yacho iN/mm2 (MPa).

Fomura yekuverenga ndeiyi:
Mufomura: F–simba rekuyedza rakamanikidzwa pamusoro pemuenzaniso wesimbi, N;
D–Dhayamita yebhora resimbi rekuyedza, mm;
d–avhareji yedhayamita yekudzika kwemukati, mm.
Kuyerwa kwekuomarara kweBrinell kwakarurama uye kwakavimbika, asi kazhinji HBS yakakodzera chete zvinhu zvesimbi zviri pasi pe450N/mm2 (MPa), uye haina kukodzera simbi yakaoma kana mapurati matete. Pakati pemitemo yemapaipi esimbi, kuomarara kweBrinell ndiko kunonyanya kushandiswa. Dhiyamita d yekudzika inowanzoshandiswa kuratidza kuomarara kwechinhu chacho, izvo zviri nyore uye zvinonzwisisika.
Muenzaniso: 120HBS10/1000130: Zvinoreva kuti kukosha kwekuomarara kweBrinell kwakayerwa nekushandisa bhora resimbi rine dhayamita ye10mm pasi pesimba rekuyedza re1000Kgf (9.807KN) kwemasekonzi makumi matatu (masekondi) i120N/mm2 (MPa).

B. Kuomarara kweRockwell (HR)

Kuedza kuomarara kweRockwell, sekuyedza kuomarara kweBrinell, inzira yekuedza kumira. Musiyano ndewekuti inoyera kudzika kwekupinda. Kureva kuti, pasi pekuita kwakatevedzana kwesimba rekutanga rekuyedza (Fo) uye simba rese rekuyedza (F), indenter (cone kana simbi bhora remuchina wesimbi) inodzvanywa pamusoro pemuenzaniso. Mushure menguva yakatarwa yekubata, simba guru rinobviswa. Simba rekuyedza, shandisa kuwedzera kwehudzamu hwakasara hwekumira (e) kuti uverenge kukosha kwekuomarara. Kukosha kwayo inhamba isingazivikanwe, inomiririrwa nechiratidzo cheHR, uye zviyero zvinoshandiswa zvinosanganisira zviyero 9, zvinosanganisira A, B, C, D, E, F, G, H, naK. Pakati pavo, zviyero zvinowanzoshandiswa pakuyedza kuomarara kwesimbi zvinowanzova A, B, naC, zvinoti HRA, HRB, naHRC.

Kukosha kwekuoma kunoverengerwa uchishandisa fomura inotevera:
Pakuyedza uchishandisa zviyero zveA neC, HR=100-e
Pakuyedza neB scale, HR=130-e
Mufomura, e – kuwedzera kwehudzamu hwekudzika kwemukati kunoratidzwa muyuniti yakatarwa ye0.002mm, ndiko kuti, kana axial displacement yemukati iri yuniti imwe (0.002mm), zvakaenzana nekuchinja kwehudzamu hweRockwell nenhamba imwe. Kana kukosha kwe e kwakakura, hudzamu hwesimbi hunowedzera kudzikira, uye zvinopesana.
Chiyero chinoshanda chezviyero zvitatu zviri pamusoro apa ndeichi:
HRA (dhaimani yekoni inopinza) 20-88
HRC (dhaimani yekoni inopinza) 20-70
HRB (dhayamita 1.588mm simbi bhora indenter) 20-100
Kuedza kuomarara kweRockwell inzira inoshandiswa zvakanyanya pari zvino, iyo HRC inoshandiswa mumatanho esimbi emapaipi esimbi inotevera Brinell hardness HB. Kuomarara kweRockwell kunogona kushandiswa kuyera zvinhu zvesimbi kubva pazvinyoro zvakanyanya kusvika pazvinyoro zvakanyanya. Inogadzirisa zvikanganiso zveBrinell method. Iri nyore pane Brinell method uye kukosha kwekuomarara kunogona kuverengwa zvakananga kubva padial yemuchina wekuomarara. Zvisinei, nekuda kwekudzika kwayo kudiki, kukosha kwekuomarara hakuna kunyatsojeka seBrinell method.

C. Kuomarara kweVickers (HV)

Vickers hardness test inzira yekuedza kupinza dentation. Inodzvanya square pyramidal diamond indenter ine angle ye1360 pakati penzvimbo dzakatarisana mu test surface pane test force yakasarudzwa (F), uye inoibvisa mushure menguva yakatarwa yekubata. Shandisa simba, yera kureba kwema diagonal maviri e indentation.

Kukosha kweVickers kuomarara ndiko quotient yesimba rekuyedza rakakamurwa nenzvimbo yepamusoro inobuda. Fomura yayo yekuverenga ndeiyi:
Mufomura: HV–Vickers hardness symbol, N/mm2 (MPa);
Simba rekuyedza F–N;
d–avhareji yemasvomhu emadhayagiramu maviri ekudzika kwemukati, mm.
Simba rekuyedza F rinoshandiswa pakuomarara kweVickers i5 (49.03), 10 (98.07), 20 (196.1), 30 (294.2), 50 (490.3), 100 (980.7) Kgf (N) uye mamwe mazinga matanhatu. Kukosha kwekuomarara kunogona kuyerwa. Range yacho i5~1000HV.
Muenzaniso wenzira yekutaura: 640HV30/20 zvinoreva kuti kukosha kwekuomarara kweVickers kwakayerwa nesimba rekuyedza re30Hgf (294.2N) kwe20S (masekondi) i640N/mm2 (MPa).
Nzira yekuomesa yeVickers inogona kushandiswa kuona kuomarara kwezvinhu zvakatetepa zvesimbi uye pamusoro pezvinhu. Ine mabhenefiti makuru enzira dzeBrinell neRockwell uye inokunda zvikanganiso zvavo zvikuru, asi haisi nyore senzira yeRockwell. Nzira yeVickers haiwanzo shandiswa mumatanho esimbi.