Nws nyuaj dua, granite lossis marble, npib tsib xee lossis txhuas? Thiab yog dab tsi yog hardness lawm? Peb yuav sim teb cov lus nug no hauv peb tsab xov xwm. Ntau tus kws tshawb fawb txawv teb chaws tau daws qhov teeb meem ntawm kev txiav txim siab hardness ntawm cov ntxhia thiab cov khoom. Ntawm lawv yog Albert Schor, Friedrich Moos, Johan August Brinell, William Vickers thiab lwm tus. Txawm li cas los xij, tib txoj kev lees paub rau kev suav hardness hauv kev tshawb fawb tseem tsis muaj nyob.
YDab tsi yog qhov nyuaj?
Txhua yam khoom uas paub txog kev tshawb fawb muaj ntau yam ntawm lub cev thiab cov khoom zoo. Kab lus no yuav tham txog qhov hardness yog dab tsi. Qhov no yog lub peev xwm ntawm cov khoom siv los tiv thaiv kev nkag mus ntawm lwm tus, lub cev ruaj khov rau hauv nws (piv txwv li, cov cuab yeej txiav los yog tho).
Lub hardness ntawm cov tshuaj feem ntau yog ntsuas nyob rau hauv tshwj xeeb units - kgf/mm 2 (kilogram-force per square millimeter of area). Nws raug xaiv los ua cov ntawv Latin HB, HRC lossis HRB, nyob ntawm qhov ntsuas tau xaiv.
Cov ntxhia nyuaj tshaj plaws hauv ntiaj teb yog pob zeb diamond. Yog tias peb tham txog cov ntaub ntawv ntawm cov khoom siv dag zog, ces qhov ruaj khov tshaj plaws yog fullerite. Nws yog cov khoom siv lead ua molecular uas ua rau kub siab (kwv yees li 300 degrees Celsius) thiab kub siab heev (tshaj 90,000 cua). Raws li cov kws tshawb fawb, fullerite yog ib thiab ib nrab zaug nyuaj dua pob zeb diamond.
YDab tsi yog qhov nyuaj?
Muaj peb lub ntsiab hardness xaiv:
- Ntog (txiav txim siab los ntawm qhov piv ntawm cov khoom thauj mus rau qhov chaw ntawm qhov luam tawm).
- Projection (tus piv ntawm lub load rau qhov projection cheeb tsam ntawm lub imprint).
- Volume (load to print volume ratio).
Dhau li ntawm qhov no, qhov nyuaj ntawm lub cev yog ntsuas nyob rau hauv plaub yam:
- Nanohardness (Load tsawg dua 1 gf).
- Microhardness (1 - 200 gf).
- Hardness ntawm qis loads (200 gf - 5 kgf).
- Macrohardness (ntau dua 5 kgf).
Hardness of metals
Tawm ntawm 104 lub ntsiab lus ntawm Mendeleev lub sijhawm ua haujlwm, 82 yog hlau. Thiab tag nrho cov alloys paub rau txiv neej mus txog tsib txhiab! Lub Scope ntawm hlau nyob rau hauv lub ntiaj teb no niaj hnub no yog incredibly dav. Cov no yog cov tub rog thiab tshuaj industries, metallurgy, hluav taws xob engineering, chaw lag luam, hniav nyiaj hniav kub, nkoj tsim, tshuaj, thiab lwm yam.
Ntawm tag nrho cov yam ntxwv ntawm lub cev thiab tshuaj lom neeg ntawm cov hlau, hardness yog deb ntawm qhov kawgluag hauj lwm. Tom qab tag nrho, nws qhia meej meej:
- degree ntawm hnav tsis kam ntawm cov hlau;
- siab tsis kam;
- nws muaj peev xwm txiav lwm yam khoom.
Ntawm lwm yam, qhov nyuaj ntawm cov hlau qhia seb nws puas tuaj yeem ua tiav ntawm qee lub tshuab, txawm tias nws tuaj yeem polished thiab lwm yam. Los ntawm txoj kev, cov kws tshawb fawb tau ua pov thawj ntev ntev tias qhov hardness ntawm cov hlau feem ntau txiav txim siab nws cov khoom siv kho tshuab.
Dab tsi yog qhov nyuaj ntawm hlau, tooj liab thiab txhuas? Thiab cov hlau twg yog qhov nyuaj tshaj plaws thiab ruaj khov tshaj?
Magnesium thiab txhuas yog cov hlau softest. Lawv hardness qhov tseem ceeb sib txawv li ntawm 5 kgf / mm2. Txog ob zaug nyuaj - npib tsib xee thiab tooj liab (li 10 kgf / mm 2). Lub hardness ntawm hlau yog kwv yees li ntawm 30 kgf / mm2. Zoo, cov hlau hnyav tshaj plaws ntawm lub hauv paus chiv keeb muaj xws li titanium, osmium thiab iridium.
Kev txiav txim siab ntawm hardness: txoj kev, txoj hauv kev thiab txoj hauv kev
Lub hardness ntawm lub cev ntsuas li cas? Txhawm rau ua qhov no, lub npe hu ua indenter yog nkag rau hauv cov qauv. Nws lub luag haujlwm tuaj yeem ua si los ntawm lub pob hlau hnyav, pyramid lossis pob zeb diamond cone. Tom qab qhov cuam tshuam ncaj qha ntawm lub indenter, ib qho imprint tseem nyob rau hauv cov qauv kuaj, qhov loj ntawm qhov uas txiav txim siab hardness ntawm cov khoom.
Hauv kev xyaum, ob pawg ntawm txoj hauv kev los ntsuas qhov nyuaj yog siv:
- Dynamic.
- Kinetic.
Nyob rau hauv cov ntaub ntawv no, cov ntaub ntawv thov thaum lub sij hawm kev taw qhia ntawm indenter rau hauv lub cev yuav nqa tawmlos ntawm khawb, indenting (feem ntau), txiav los yog rebounding.
Hnub no muaj ntau txoj hauv kev los txiav txim siab tawv:
- Rockwell;
- Brinell;
- raws li Vickers;
- by Shore;
- raws li Mohs.
Raws li, muaj ntau qhov sib txawv ntawm cov khoom siv tawv tawv, tsis muaj kev sib raug zoo ntawm lawv. Ib los yog lwm txoj kev ntsuas yog xaiv los ntawm ntau yam (piv txwv li, cov khoom ntawm ib yam khoom, cov xwm txheej ntawm kev sim, cov cuab yeej siv, thiab lwm yam). Cov khoom siv uas txiav txim siab qhov nyuaj ntawm cov hlau lossis cov ntxhia pob zeb feem ntau hu ua hardness testers.
Rockwell method
Tus nqi Rockwell hardness yog txiav txim siab los ntawm qhov tob ntawm qhov indentation ntawm pob zeb diamond cone los yog hlau pob nyob rau saum npoo ntawm daim ntawv xeem. Ntxiv mus, nws yog dimensionless thiab yog denoted los ntawm cov tsiaj ntawv HR. Cov khoom uas muag muag heev yuav muaj qhov tsis zoo hardness qhov tseem ceeb.
Lub npe hu ua Rockwell hardness tester tau tsim nyob rau thaum pib ntawm lub xyoo pua xeem los ntawm cov neeg Asmeskas Hugh Rockwell thiab Stanley Rockwell. Koj tuaj yeem pom nws ua haujlwm li cas hauv video hauv qab no. Ib qho tseem ceeb rau txoj kev no yog lub thickness ntawm cov qauv kuaj. Nws yuav tsum tsis txhob tsawg dua kaum npaug ntawm qhov tob tob ntawm qhov indenter rau hauv lub cev kuaj.
Nyob ntawm hom indenter thiab thov load, muaj peb ntsuas ntsuas. Lawv raug xaiv los ntawm peb tsab ntawv Latin: A, B thiab C. Tus nqi ntawm Rockwell hardness muaj cov lej. Piv txwv li: 25.5 HRC (kawgtsab ntawv qhia txog qhov ntsuas uas tau siv hauv qhov kev xeem).
Brinell method
Tus nqi Brinell hardness yog txiav txim siab los ntawm txoj kab uas hla ntawm qhov kev xav tau sab laug los ntawm cov pob hlau tawv tawv ntawm cov hlau uas tau sim. Chav ntsuas yog kgf/mm2.
Txoj kev tau npaj rau xyoo 1900 los ntawm Swedish engineer Johan August Brinell. Kev ntsuam xyuas yog ua raws li hauv qab no: ua ntej, lub preload ntawm lub indenter ntawm tus qauv yog teem, thiab tsuas yog tom qab ntawd - lub ntsiab. Ntxiv mus, cov khoom nyob rau hauv no load yuav tiv taus mus txog 30 vib nas this, tom qab uas qhov tob ntawm indentation yog ntsuas. Brinell hardness (hu ua HB) yog xam raws li qhov piv ntawm cov ntaub ntawv thov load rau qhov chaw ntawm lub resulting print.
Qee hardness qhov tseem ceeb rau cov khoom sib txawv (raws li Brinell):
- Ntoo – 2, 6-7, 0 HB.
- Aluminium - 15 HB.
- Copper - 35 HB.
- Mild steel - 120 HB.
- iav - 500 HB.
- Tuam hlau - 650-700 HB.
Vickers method
Hardness raws li Vickers txoj kev yog txiav txim siab los ntawm nias lub pob zeb diamond taub rau hauv cov qauv, muaj cov duab ntawm lub ntsej muag plaub fab. Tom qab tshem tawm cov load, ntsuas ob kab pheeb ces kaum tsim nyob rau saum npoo ntawm cov khoom thiab xam cov zauv xam tus nqi d (hauv millimeters).
Vickers hardness tester yog qhov compact heev (saib daim duab hauv qab). Kev ntsuas yog ua nyob rau hauv chav tsev kub (+ 20 degrees). Tus nqi hardness ntawm lub cev yog qhia los ntawm cov ntawv HV.
Shor method
Txoj kev ntsuas qhov nyuaj no tau thov los ntawm Asmeskas tus tsim khoom Albert Shor. Nws kuj yog feem ntau hu ua "rov qab txoj kev". Thaum ntsuas Shore hardness, tus ntaus nrig ntawm tus qauv loj thiab loj yog poob los ntawm qhov siab mus rau saum npoo ntawm cov khoom raug kuaj. Tus nqi tseem ceeb ntawm qhov kev sim no yog qhov rebound qhov siab ntawm tus neeg ntaus, ntsuas hauv cov pa ua ke.
Shore hardness yog ntsuas nyob rau hauv thaj tsam ntawm 20 txog 140 units. Ib puas units sib haum mus rau rebound qhov siab ntawm 13.6 hli (± 0.5 hli). Raws li tus qauv, tus nqi no yog hardness ntawm hardened carbon steel. Cov cuab yeej niaj hnub no los ntsuas qhov nyuaj ntawm cov ntaub ntawv raws li Shore hu ua scleroscope lossis durometer (nws tuaj yeem pom hauv daim duab hauv qab no).
Mohs scale
Lub Mohs hardness nplai yog txheeb ze thiab siv tshwj xeeb rau cov zaub mov. Kaum cov zaub mov raug xaiv raws li cov khoom siv siv, uas tau teem caij kom nce hardness (hauv daim duab hauv qab no). Raws li qhov teev muaj 10 ntsiab lus (los ntawm 1 txog 10).
Cov nplai ntxhia ntawm qhov tawv tawv tau thov los ntawm German tus kws tshawb fawb Friedrich Moos rov qab rau xyoo 1811. Txawm li cas los xij, nws tseem siv hauv geology.
Yuav ua li cas txiav txim siab qhov nyuaj ntawm ib qho ntxhia ntawm Mohs nplai? Qhov no tuaj yeem ua tau los ntawm kev ua tib zoo tshuaj xyuas qhov kos sab laug los ntawm tus qauv. Nws yog qhov yooj yim los siv tus ntiv tes, ib lub npib tooj, ib daim iav lossis rab riam steel.
Yog licov pob zeb hauv av kuaj tau sau rau ntawm daim ntawv tsis khawb nws, ces nws qhov hardness yog sib npaug rau ib qho. Yog hais tias lub pob zeb yog khawb tau yooj yim nrog ib tug ntiv tes, nws hardness yog 2. Peb cov ntsiab lus muaj cov ntxhia pob zeb uas yooj yim khawb nrog rab riam. Yog tias koj yuav tsum ua qee yam kom tso lub cim rau ntawm lub pob zeb, ces nws qhov hardness yog 4 lossis 5. Minerals nrog hardness ntawm 6 lossis siab dua lawv tus kheej tawm khawb ntawm rab riam.
In xaus…
Yog li ntawd yog dab tsi yog hardness? Qhov no yog lub peev xwm ntawm lub cev lub cev los tiv thaiv kev puas tsuaj thiab deformation nyob rau hauv lub zog ntawm kev sib cuag hauv zos. Cov ntxhia nyuaj tshaj plaws hauv ntiaj teb yog suav tias yog pob zeb diamond, thiab cov hlau ruaj khov tshaj plaws yog iridium. Hauv kev tshawb fawb thiab thev naus laus zis niaj hnub no, siv ntau txoj kev ntsuas hardness (raws li Brinell, Rockwell, Vickers, Shore thiab Mohs).
