ISO VG (Viscosity Grade) is a classification system for industrial lubricants defined by ISO 3448. Each grade corresponds to a kinematic viscosity midpoint at 40°C in centistokes (cSt). For example, VG 46 means the oil has a midpoint viscosity of 46 cSt at 40°C, with an allowed range of 41.4–50.6 cSt (±10%).

Jinsi ya kuchagua daraja sahihi la kina?

Chaguo linategemea matumizi: VG 32–46 kwa sistemu za hydraulic, VG 68–150 kwa sanduku la piga la viwanda, VG 220–460 kwa mbuzi iliyofungwa ya uzani, VG 10–22 kwa spindle zenye kasi ya juu. Daima shauri tafsiri za mtengenezaji wa vifaa.

Kwa nini ISO VG inatofautiana na SAE?

ISO VG grades are based on kinematic viscosity at 40°C and are used for industrial lubricants. SAE grades are used for automotive oils: SAE crankcase grades (e.g. 10W-30) are measured at 100°C, while SAE gear grades (e.g. 75W-90) use a different viscosity range. The two systems do not directly correspond.

Joto linaathiri vipi kina cha mafuta?

Kina cha mafuta hupungua kwa kuongezeka kwa joto. Mfumo wa ISO VG unabainisha kina kwa 40°C. Kiwango cha mabadiliko na joto kinafafanuliwa na Viscosity Index (VI). VI juu zaidi inamaanisha mabadiliko ya kina machache na joto. Mafuta ya kawaida yamana VI 80–100; mafuta ya synthetic yanaweza kufikia VI 150+.

cSt stands for centistokes (mm²/s), the unit of kinematic viscosity. It measures how fast a fluid flows under gravity. 1 cSt = 1 mm²/s. Dynamic viscosity in cP (centipoise) = kinematic viscosity in cSt × density in g/cm³.

Zana ya Uhandisi Isiyolipisha

Darajia za Kina cha Mafuta — ISO VG

Utafutaji wa daraja la kina cha ISO VG kulingana na ISO 3448. Ingiza kinematic viscosity kwa 40 °C kupata daraja unalolingana, au chagua daraja la VG kupata safu ya kina na matumizi ya kawaida.

ISO 3448 VG 2 – VG 1500 cSt @ 40 °C

Kina kwa 40 °C (cSt = mm²/s)

Au Chagua Daraja la ISO VG

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Results

ISO VG Class

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Anuwai ya Mnato (min – max)

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Mnato wa Katikati

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Matumizi ya Kawaida

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Uainishaji wa Mnato wa ISO 3448

ISO 3448 defines 18 viscosity grades for industrial lubricants. Each grade is identified by a number equal to the nominal kinematic viscosity midpoint at 40 °C in centistokes (cSt). The allowed range is ±10% of the midpoint.

Range = Midpoint × 0.9 to Midpoint × 1.1 [cSt at 40 °C]

Jedwali Kamili la ISO VG

ISO VG	Min (cSt)	Midpoint (cSt)	Max (cSt)	Matumizi ya Kawaida

Mwongozo wa Matumizi

Application	ISO VG Inayopendekezwa
Spindles za kasi ya juu	VG 10 – VG 22
Mifumo ya majimaji	VG 32 – VG 46
Lainisha jumla ya mashine	VG 46 – VG 68
Sanduku la gurudumu la viwanda	VG 68 – VG 150
Geari iliyofungwa kwa kazi nzito	VG 220 – VG 460
Geari nzito sana / polepole	VG 680 – VG 1500

Kumbuka: Daraja la ISO VG linabainisha mnato kwa 40 °C tu. Mnato halisi wa uendeshaji unategemea joto la mafuta katika huduma. Tumia Kielelezo cha Mnato (VI) kukadiria mnato kwa joto lingine.