Controlled physical relation and source record

Same-Temperature Viscosity Relation and Controlled Classification Record

Calculate dynamic viscosity from kinematic viscosity and density only when both describe the same fluid state at the same declared temperature. A separate record can compare a measured value with limits copied from your controlled source. No ISO VG, SAE J300, SAE J306 or AGMA grade equivalence is built in or assigned.

η = νρSame temperature requiredNo grade cross-referenceNo SUS approximation

A. Same-temperature dynamic/kinematic relation

Required state match: density and kinematic viscosity must refer to the same sample or composition, pressure/state and temperature. The page supplies no density default and performs no temperature correction.

Ідентифікатор випадку / розрахунку *

Fluid, sample and batch ID *

Kinematic viscosity ν *1 mm²/s is numerically 1 cSt.

ν measurement temperature *

ν method, instrument and source record *

Щільність ρ *

ρ measurement temperature *

ρ method and source record *

Reviewer and date *

Eight relation evidence gates

ν and ρ refer to the same fluid composition, sample/batch and physical state.

Both temperatures are measured or controlled and numerically match; neither is a generic catalogue temperature.

The kinematic-viscosity method, unit, result ID and traceability are verified.

The density method, unit, result ID and traceability are verified at the same state.

ν is in mm²/s and ρ is in kg/m³; no silent unit conversion or typical-density assumption remains.

This relation is not being used to predict viscosity at another temperature.

The arithmetic will not be treated as an ISO VG, SAE or AGMA grade assignment or product equivalence.

An accountable reviewer will retain both source measurements with this result.

No current relation result

Complete the traceable record and submit explicitly.

Relation result

Kinematic viscosity—

Щільність—

Matched temperature—

Dynamic viscosity—

Dynamic viscosity (SI)—

Evidence state0 / 8 complete

No relation record

No current numerical result is available.

B. Controlled classification-interval comparison

No embedded classification: enter the exact limits only from a legal controlled copy applicable to the product, property, test method, temperature and purpose. The result checks the entered interval; it does not select a grade or convert between ISO VG, SAE or AGMA.

Comparison record ID *

Classification system *

Designation being checked *

Controlled document *

Edition, year and amendments *

Lifecycle/status source and check date *

Controlled-copy / licence ID *

Clause, table, page and row *

Property and amplitude/quantity basis *

Required test method and revision *

Classification/test temperature *

Controlled unit *

Measured value *

Measurement/report ID and uncertainty *

Lower boundary *

Lower-boundary equality *

Upper boundary *

Upper-boundary equality *

Product, application and source-defined applicability *

Reviewer and date *

Eight classification evidence gates

The exact limits were transcribed from a legal, complete and controlled copy.

Edition, current status, amendments, corrigenda and replacement history were checked.

The product/application is inside the source-defined scope and exclusions.

Property, test method, temperature, unit and reporting convention match the source exactly.

Both boundaries and each equality rule were verified from the exact clause/table/page/row.

The measured value, sample, method, temperature and uncertainty are traceable.

No cross-standard equivalence, nearest grade or lubricant/product selection is being inferred.

An accountable reviewer accepts the applicability record and comparison only.

Not compared

Enter one controlled interval and submit explicitly.

Controlled interval result

Designation entered—

Measured value—

Entered interval—

ПорівнянняNot compared

Boundary state—

Evidence state0 / 8 complete

No controlled comparison

No current interval result is available.

Formula, units and applicability boundary

η = νρ

η [mPa·s] = ν [mm²/s] × ρ [kg/m³] / 1000

Dimensionally, (m²/s)(kg/m³) = kg/(m·s) = Pa·s. Therefore mm²/s contributes 10⁻⁶ and conversion to mPa·s contributes 10³, giving the displayed division by 1000. ASTM D445-26 publicly states the physical relation and the identities 1 mm²/s = 1 cSt and 1 mPa·s = 1 cP. NIST identifies Pa·s and m²/s as SI forms; cP and cSt are legacy CGS names.

Temperature boundary: this is not a viscosity-temperature model. ASTM D341-20(2025) describes estimating a viscosity-temperature relationship over a limited range when kinematic viscosities at two temperatures are known. One value at 40 °C does not establish a value or grade at 100 °C.

Decision boundary: neither section selects a lubricant, assigns a grade, confirms standard compliance, predicts operating viscosity, substitutes for an OEM recommendation or authorizes equipment operation.

Source register and permitted use

Ідентифікатор	Official source and lifecycle	Used for	Not used for
S1	ISO 3448:1992, Edition 2 — published, confirmed 2023; stage 90.93	Industrial-liquid-lubricant classification scope and lifecycle.	Grade table, limits or SAE/AGMA equivalence: NEEDS_LICENSED_SOURCE.
S2	ISO 3448:1992/Cor 1:1993	Official Technical Corrigendum 1 lifecycle.	No numerical effect guessed from its public title.
S3	SAE J300_202405 — revised 9 May 2024	Current engine-oil rheological-classification scope.	Complete criteria or ISO VG equivalence: NEEDS_LICENSED_SOURCE.
S4	SAE J306_202502 — revised 25 February 2025	Current automotive-driveline rheological-classification scope.	Complete criteria or ISO VG equivalence: NEEDS_LICENSED_SOURCE.
S5	ANSI/AGMA 9005-F16 — reaffirmed May 2026	Industrial-gear scope, OEM-precedence warning and Saybolt lifecycle context.	Lubricant-number table or product selection: NEEDS_LICENSED_SOURCE.
S6	ASTM D445-26 — active current record	η = νρ and displayed viscosity-unit identities.	No different-temperature density or default density.
S7	ASTM D2161-20(2025) — active current record	Same-temperature SUS/SFS scope and legacy/obsolete warning.	Exact equations/tables: NEEDS_LICENSED_SOURCE; none embedded.
S8	ASTM D341-20(2025) — active current record	Two known temperature points and limited-range warning.	No one-point temperature extrapolation or grade equivalence.
S9	NIST SP 811, Chapter 8 — official guidance	SI unit framing for dynamic and kinematic viscosity.	No lubricant classification or limits.

Corrections made during review

The cross-standard grade engine was removed

One kinematic-viscosity value at 40 °C does not prove equivalence among ISO industrial, SAE engine, SAE driveline and AGMA industrial-gear classifications.

Nearest-grade assignment was removed

The former code returned the closest midpoint even in gaps and outside its own embedded ranges. The replacement never chooses a designation.

The temperature-mismatched density default was removed

Density and kinematic viscosity now require separate traceable sources and equal declared temperatures. There is no 870 kg/m³ fallback.

SUS arithmetic was removed

ASTM D2161 controls same-temperature official equations and describes the petroleum-industry practice as obsolete. No protected equation or 4.635 shortcut is embedded.

SAE scope is no longer reduced to one 100 °C value

Current J300 and J306 records identify distinct engine-oil and automotive-driveline rheological classifications. Their complete protected criteria are not reconstructed.

Controlled limits remain user-entered

The comparison requires edition, lifecycle, controlled copy, clause/table/page/row, method, temperature, unit, inclusivity and applicability evidence.

Detached state and structured FAQ claims were removed

No defaults, presets, auto-calculate, browser storage, clipboard, dynamic result HTML or FAQPage schema remains.

Unrelated residual-unbalance guidance was removed

The viscosity workflow no longer links its decision path to ISO 1940 or a balancing calculator.