Lub hardness ntawm cov ntaub ntawv hlau yog hais txog cov khoom muaj peev xwm tiv thaiv lub zos deformation, tshwj xeeb yog yas deformation, indentation, los yog khawb. Nws yog ib qho kev qhia ntawm cov khoom softness los yog hardness.
Hardness tau muab faib ua peb hom raws li txoj kev kuaj.
Scratch Hardness: Qhov no feem ntau yog siv los sib piv cov hardness ntawm cov minerals sib txawv. Txoj kev siv tus pas nrig nrog ib qho kawg nyuaj thiab lwm qhov muag, thiab tom qab ntawd rub tus pas nrig hla cov khoom raug kuaj. Qhov chaw uas khawb qhov tshwm sim txiav txim siab hardness ntawm cov khoom. Qhov zoo, ib qho khoom nyuaj tawm qhov khawb ntev dua, thaum cov khoom softer tawm ib qho luv luv.
Indentation Hardness: Qhov no tsuas yog siv rau cov khoom siv hlau. Cov txheej txheem suav nrog kev siv cov khoom tshwj xeeb los nias lub indenter uas tau xaiv rau hauv cov khoom raug kuaj. Lub hardness ntawm cov khoom yog txiav txim los ntawm qhov luaj li cas ntawm lub zos yas deformation ntawm qhov chaw. Vim muaj qhov sib txawv ntawm qhov indenter, load, thiab lub sij hawm ntawm lub load, muaj ntau ntau hom indentation hardness tests, xws li Brinell hardness, Rockwell hardness, Vickers hardness, thiab microhardness, thiab lwm yam.
Rebound Hardness: Qhov no tsuas yog siv rau cov khoom siv hlau. Cov txheej txheem suav nrog kev tso cai rau lub rauj tshwj xeeb kom poob los ntawm qhov siab thiab cuam tshuam cov qauv ntawm cov khoom raug kuaj. Lub hardness ntawm cov khoom yog txiav txim los ntawm tus nqi ntawm lub zog strain tus qauv absorbs (thiab tom qab ntawd tawm) thaum lub sij hawm muaj kev cuam tshuam, uas yog ntsuas los ntawm qhov siab uas lub rauj rebounds.
Kev ntsuam xyuas qhov nyuaj tshaj plaws rau cov khoom siv hlau-Brinell hardness, Rockwell hardness, thiab Vickers hardness-poob nyob rau hauv qeb ntawm indentation hardness. Tus nqi hardness sawv cev rau cov khoom muaj peev xwm tiv thaiv cov yas deformation thaum lwm yam khoom raug nias rau hauv nws qhov chaw. Rebound hardness tests (Shore, Leeb) ntsuas hardness raws li qhov ntev ntawm elastic deformation ntawm cov hlau, nrog cov nqi hardness qhia txog cov khoom muaj peev xwm rau elastic deformation.
Brinell Hardness
Ib tug indenter nrog ib txoj kab uas hlaDua los ntawm hardened steel los yog carbide pob yog nias rau hauv qhov chaw ntawm cov qauv nrog rau cov coj mus kuaj quab yuamF. Tom qab lub sijhawm tuav tau teev tseg, qhov kev sim quab yuam raug tshem tawm, tawm hauv ib qho indentation nrog ib txoj kab uas hlad. Tus nqi Brinell hardness yog xam los ntawm kev faib lub zog xeem los ntawm thaj tsam ntawm qhov indentation. Qhov tshwm sim tus nqi yog Brinell hardness, denoted liHBSlos yogHBW.
HQhov txawv ntawmHBSthiabHBWnyob rau hauv hom indenter siv.HBSyog hais txog kev sim siv lub pob hlau uas tawv tawv ua lub indenter, feem ntau yog ua haujlwm rau kev ntsuas Brinell hardness qhov tseem ceeb hauv cov ntaub ntawv uas muaj zog qis dua 450, xws li cov hlau mos, grey cam khwb cia hlau, thiab cov hlau tsis muaj hlau.HBW, ntawm qhov tod tes, siv lub pob carbide ua lub indenter thiab yog siv los ntsuas Brinell hardness qhov tseem ceeb hauv cov ntaub ntawv nrog hardness qis dua 650.
Rau tib daim ntawv xeem thiab nyob rau hauv qhov kev xeem zoo tib yam, cov txiaj ntsig los ntawm ob txoj kev yuav txawv, nrog rauHBWtus nqi feem ntau yog siab duaHBStus nqi. Txawm li cas los xij, tsis muaj kev sib raug zoo ntawm ob qho tib si.
Txij li thaum xyoo 2003, Tuam Tshoj tau txais cov txheej txheem thoob ntiaj teb thiab hloov kev siv cov khoom siv tawv tawv nrog cov pob carbide rau Brinell hardness kuaj. Vim li ntawd,HBStsis siv lawm, thiabHBWtau dhau los ua tus qauv sau rau Brinell hardness. Feem ntau,HByog siv ib leeg los sawv cev Brinell hardness, uas feem ntau yog hais txogHBW. Txawm li cas los xij,HBStseem tuaj yeem pom hauv qee cov ntaub ntawv thiab cov ntaub ntawv kawm.
Brinell hardness test yog haum rau cov ntaub ntawv xws li cam khwb cia hlau, non-ferrous alloys, thiab ntau yam annealed los yog tempered steels. Nws tsis tsim nyog rau kev sim cov ntaub ntawv uas nyuaj dhau, me me dhau, nyias dhau, lossis cov qauv uas tsis tuaj yeem zam qhov loj me ntawm lawv qhov chaw.
Rockwell Hardness
Cov txheej txheem siv lub pob zeb diamond cone indenter nrog 120 degree apex lub kaum sab xis lossis lub pob zeb tawv tawv ua lub indenter, nrog rau kev teeb tsa tshwj xeeb. Qhov kev sim pib nrog qhov pib load ntawm 10 kgf, ua raws li daim ntawv thov ntawm tag nrho cov load (uas yog cov sum ntawm thawj load thiab lub ntsiab load) ntawm 60, 100, los yog 150 kgf. Lub indenter yog nias rau hauv cov qauv hauv qab no loads sequentially. Tom qab tag nrho cov load yog siv, lub hardness yog txiav txim los ntawm qhov sib txawv nyob rau hauv indentation qhov tob ntawm qhov tob nyob rau hauv thawj load thiab qhov tob nyob rau hauv lub load tag nrho ib zaug lub ntsiab load raug tshem tawm, thaum lub sij hawm thawj load tseem.
Txoj kev no feem ntau yog siv rau hauvRockwell hardnesskuaj. Qhov tob indentation nyob rau hauv thawj load thiab tag nrho cov load yog siv los xam cov hardness tus nqi, uas qhia txog cov khoom tsis kam mus indentation nyob rau hauv ob qho tib si loads.
Rockwell hardness test siv peb lub zog sib txawv thiab peb hom indenters, uas ua rau cuaj qhov sib xyaw ua ke, txhua qhov sib xws rau ib qho ntawm cuaj Rockwell hardness nplai. Cov cuaj nplai no npog yuav luag txhua yam khoom siv hlau siv. Cov nplais siv feem ntau yogHRA, HRB, thiabHRC, nrogHRCyog qhov siv dav tshaj plaws.
Hom Rockwell Hardness Testing Standard Table
|
Hardness cim |
Hom Indenters |
F / N (kgf) |
Hardness Scope |
Daim ntawv thov |
|
HRA |
120 degree pob zeb diamond cone |
588.4(60) |
20~88 |
Carbide, cermet, thiab nto-hardened steels |
|
HRB |
Ø 1.588 mm Hardened steel pob |
980.7(100) |
20~100 |
Annealed thiab normalized steels, aluminium alloys, tooj liab alloys, cam khwb cia hlau |
|
HRC |
120 degree pob zeb diamond cone |
1471(150) |
20~70 |
Quenched steel, tempered steel, thiab sib sib zog nqus nto-hardened steel |
CovHRC nplaifeem ntau yog siv rau hardness qhov tseem ceeb ntawm 20 txog 70 HRC. Thaum tus nqi hardness qis dua 20 HRC, qhov rhiab heev ntawm qhov kev sim txo qis vim hais tias lub conical taub ntawm lub indenter nkag mus tob rau hauv cov khoom. Hauv qhov no, lubHRB scaleyuav tsum tau siv xwb, vim nws yog ntau haum rau cov ntaub ntawv softer.
Thaum lub hardness ntawm cov qauv ntau tshaj 67 HRC, lub siab ntawm lub taub ntawm lub indenter yuav siab dhau heev lawm, uas yuav ua rau lub pob zeb diamond puas thiab ho shorten lub lifespan ntawm lub indenter. Yog li ntawd, nws yog feem ntau pom zoo kom hloov mus rau lubHRA scalerau cov khoom uas muaj hardness ntau dua 67 HRC.
Rockwell hardness test yog qhov yooj yim rau kev khiav lag luam, ceev, thiab tsim cov indentations me me, ua rau nws tsim nyog rau kev ntsuam xyuas cov khoom tiav tiav nrog rau cov khoom ua haujlwm nyuaj thiab nyias. Vim qhov me me indentation, tus nqi hardness tuaj yeem hloov tau ntau dua rau cov ntaub ntawv uas tsis sib xws microstructures lossis hardness, uas ua rau qis dua qhov tseeb piv rau Brinell hardness test. Rockwell hardness test feem ntau yog siv los ntsuas qhov hardness ntawm steels, non-ferrous hlau, carbide cov ntaub ntawv, thiab lwm yam alloys.
Vickers Hardness
Lub hauv paus ntsiab lus ntawm Vickers hardness ntsuas yog zoo ib yam li Brinell hardness. Lub pob zeb diamond pyramid indenter nrog lub kaum sab xis ntawm 136 degree yog siv, thiab lub zog ntsuas ntsuasFyog siv rau cov khoom nto. Tom qab tuav lub load rau ib lub sij hawm teev, lub xeem quab yuam raug tshem tawm. Tus nqi hardness yog txiav txim los ntawm qhov nruab nrab siab exerted nyob rau hauv lub cheeb tsam cheeb tsam ntawm square-raws li pyramid indentation, thiab hardness tus nqi yog denoted los ntawm lub cim.HV.
Vickers hardness test muaj ntau yam kev ntsuas, muaj peev xwm ntsuas cov ntaub ntawv nrog hardness qhov tseem ceeb xws li10-1000 HV. Lub indentation yog me me, ua rau nws tshwj xeeb tshaj yog haum rau kev ntsuas cov ntaub ntawv thinner thiab deg-hardened txheej, xws li carburized los yog nitrided nto.
Leeb Hardness
Nyob rau hauv kev xeem Leeb hardness, ib qho kev cuam tshuam lub cev nrog ib tug tungsten carbide pob indenter yog siv los ntaus lub nto ntawm cov qauv nyob rau hauv ib tug tshwj xeeb quab yuam, ua rau nws rebound. Vim qhov sib txawv hardness ntawm cov khoom, lub rebound ceev sib txawv. Cov cuab yeej cuam tshuam yog nruab nrog cov hlau nplaum tas mus li, thiab thaum lub cev cuam tshuam nce thiab nqis, cov coil nyob ib puag ncig tsim cov teeb liab electromagnetic uas yog proportional rau lub rebound tshaj tawm. Cov teeb liab no ces hloov mus rau Leeb hardness tus nqi los ntawm ib qho hluav taws xob Circuit Court, thiab tus nqi yog denoted los ntawm lub cimHL.
Lub Leeb hardness tester tsis xav tau lub rooj zaum ua haujlwm; nws hardness sensor yog me me li tus cwj mem thiab tuaj yeem ua haujlwm ncaj qha los ntawm tes. Qhov no ua rau nws yooj yim rau kev sim loj, hnyav workpieces lossis geometrically complex qauv yam tsis muaj teeb meem.
Lwm qhov zoo dua ntawm Leeb hardness tester yog tias nws ua rau muaj kev puas tsuaj tsawg heev rau cov khoom, thiab qee zaum, nws tuaj yeem siv rau.kev kuaj tsis muaj kev puas tsuaj. Nws yog qhov tshwj xeeb tshwj xeeb rau kev sim hardness nyob rau hauv ntau cov lus qhia, qhov chaw nqaim, thiab cov chaw tshwj xeeb, qhov twg lwm txoj kev yuav nyuaj rau kev thov.