Choosing rubber for high temperatures
Rubber used in engines, industrial furnaces, steam lines or hot oil systems must retain its elasticity and sealing ability at high temperatures. The wrong material choice leads to seal hardening, cracking and premature failure.
Why is temperature important?
Every elastomer material has a maximum temperature limit for continuous service. When this limit is exceeded, the material oxidizes, hardens and loses its elastic properties. The application's continuous operating temperature and short-term peak temperature should therefore be assessed separately.
Temperature comparison of materials
- NBR — up to about +100 °C; oil-resistant but limited at high temperature. See: oil-resistant NBR rubber.
- EPDM — about +130 °C–150 °C; good for steam and hot water. See: what is EPDM rubber.
- Silicone — up to +200 °C (higher for short periods); wide range. See: silicone rubber applications.
- Viton (FKM) — +200 °C–250 °C; both high temperature and chemical resistance. See: Viton FKM for high temperatures.
Temperature alone is not enough
For the right choice, in addition to temperature you must consider the contact medium:
- Oil and fuel → NBR or Viton (FKM)
- Steam, hot water, air → EPDM
- Aggressive chemicals → Viton (FKM)
- Food and wide temperature range → silicone
Shore hardness and shape
Temperature also affects the material's Shore hardness; at high heat the material softens, while in the cold it hardens. Thermal expansion and compression allowance should therefore be considered in seal design.
Practical steps for selection
First determine the continuous and peak temperature, then the contact medium, then the pressure and mechanical load. At the intersection of these three factors, the suitable elastomer and compound formulation can be selected.
NUR KAUÇUK support
NUR KAUÇUK offers silicone-, EPDM- and Viton-based solutions for high-temperature applications. Our production and quality processes ensure the material suits the operating conditions.
To choose the most suitable material for your high-temperature project, see the products section and contact us for engineering support.