NBR vs Hydraulic Oil (ISO VG 46) Compatibility

Volume swell, hardness shift and temperature range for Nitrile (Buna-N) (NBR) in Hydraulic Oil (ISO VG 46).

NBR in Hydraulic Oil (ISO VG 46)

NBR in Hydraulic Oil (ISO VG 46) is computed deterministically from the parameters encoded in this page's address, so the same inputs always produce the same result and the same OAS-XXXX verification hash.

Volume swell and hardness change

Volume swell and hardness change is computed deterministically from the parameters encoded in this page's address, so the same inputs always produce the same result and the same OAS-XXXX verification hash.

Service temperature and extrusion limit

Service temperature and extrusion limit is computed deterministically from the parameters encoded in this page's address, so the same inputs always produce the same result and the same OAS-XXXX verification hash.

Engineering summary

Governing parameters and computed results for NBR vs Hydraulic Oil (ISO VG 46) Compatibility.

Governing parameters and computed results for this calculation
Parameter Value
Compound NBR
Fluid Hydraulic Oil (ISO VG 46)

Frequently asked questions

What volume swell is acceptable for an elastomer seal?
Keep combined volume swell at or below 20%. Swell from 10% to 20% is workable with a wider gland, but above 20% the compound is considered incompatible and the seal will extrude or take a permanent set.
How does temperature change elastomer swell?
Thermal volumetric expansion adds to fluid swell: ΔV/V = 3·α·ΔT, where α is the linear expansion coefficient. A compound at 250 °F above a 70 °F reference gains several percent of thermal swell on top of its fluid swell.
Which elastomer resists Skydrol and phosphate-ester fluids?
EPDM and PTFE resist Skydrol and phosphate esters, while nitrile and fluorocarbon swell heavily. For aviation hydraulic service, EPDM is the standard choice; PTFE is used where near-zero swell is required.