Technical Details Engine Valves

Mono-Metallic: valves are made from one material which has high heat resistance and good performance.

Bimetallic: valves are a combination of highly heat resistant material (head) and stem is made from (martenistic steel) so the best usage of both materials is achieved. This is done using special purpose machines called friction welding.

Tip Welded: A small piece of steel is welded on the stem end when the entire valve is manufactured in stainless steel (non-quenchable). This is done to increase the impact and wear resistance of the stem end. Then, this tip is quenched to improve their mechanical properties.

Hard Chromed: Electromechanical process a layer of hard chromium is stored on the stem. The function of the layer is to reduce the friction between the stem and the valve guide, and to store among its micro-cracks, small amounts of lubricating oil.

Nitrided:

The advantages of gas nitriding over the other variants are:

  • Precise control of chemical potential of nitrogen in the nitriding atmosphere by controling gas flow rate of nitrogen and oxygen.
  • All round nitriding effect (can be a disadvantage in some cases, compared with plasma nitriding)
  • Large batch sizes possible - the limiting factor being furnace size and gas flow
  • With modern computer control of the atmosphere the nitriding results can be closely controlled
  • Relatively low equipment cost - especially compared with plasma