Technical Report: Nitretation Hardened Valves


RIC was a pioneer in introducing nitretation hardened valves to the aftermarket in Brazil. The heat treatment process is used in the production of valves for internal combustion engines. It was introduced in Brazil in July 2004 with Marea Valves, which originally used nitride hardened valves.

A Nitretation hardening substantially increases the valves’ thermo-mechanical properties, guaranteeing a tolerance of an additional 750 degrees Celsius and up to 1,200 Vickers of hardness.

Oxidation or post-oxidation is a heat treatment that provides an extremely smoot, lubricated surface, avoiding oxidation and eliminating friction between the guide and the valve stem.

The treatment causes a grayish black coloration that tends to be eliminated with the movement of the valves but that does not result in the loss of the valves’ technical properties.

The nitrate- hardened valves have presented excellent results in engines converted for VNG (Vehicular Natural Gas). Currently, almost all of the valves produced by RIC are nitrate hardened.

All engines, in principal, were projected to operate at sea level. Nitrate hardened valves have adopted as a solution by automobile manufacturers around the world, keeping in mind a variety of climatic characteristics, fuels and the diverging environmental standards presented by different countries.

Currently, the majority of automobile manufacturers in Brazil and overseas have been adopting this technology, keeping in mind the Kyoto Treaty, in Japan, signed in 2002 that prohibited the use of chromium, mercury, cadium and lead in the manufacturing process.

Technical Area