Engine valve having improved high-temperature wear resistance

An engine valve having improved high-temperature wear resistance and having a valve face coated with an Fe-based alloy powder, said engine valve being characterized in that the Fe-based alloy forming said coated valve face has a composition consisting essentially of, by weight:

• 0.7 to 1.5% of C,
• 10 to 15% of Mn,
• 24 to 30% of Cr,
• 6.1 to 9.8% of Mo,
• 10 to 15% of Ni,
• 0.1 to 0.4% of N,
• 0.2 to 1.5% of Si,
• at least one of
• 0.1 to 5% of Nb
• 0.1 to 5% of Ta and
• 0.1 to 5% of W, the total content of Nb, Ta and W being or less;
• and
• the balance substantially Fe and inevitable impurities, and has a two-phase structure formed of an austenitic phase and an eutectic carbide phase.

An engine valve having improved high-temperature wear resistance and having a valve face coated with an Fe-based alloy powder, said engine valve being characterized in that the Fe-based alloy forming said coated valve face has a composition consisting essentially of, by weight:

• 0.7 to 1.5% of C,
• 10 to 15% of Mn,
• 24 to 30% of Cr,
• 6.1 to 9.8% of Mo,
• 10 to 15% of Ni,
• 0.1 to 0.4% of N,
• 0.2 to 1.5% of Si,
• 0.05 to 1% of Co and
• the balance substantially Fe and inevitable impurities, and has a two-phase structure formed of an austenitic phase and an eutectic carbide phase.

An engine valve having improved high-temperature wear resistance and having a valve face coated with an Fe-based alloy powder, said engine valve being characterized in that the Fe-based alloy forming said coated valve face has a composition consisting essentially of, by weight:

• 0.7 to 1.5% of C,
• 10 to 15% of Mn,
• 24 to 30% of Cr,
• 6.1 to 9.8% of Mo,
• 10 to 15% of Ni,
• 0.1 to 0.4% of N,
• 0.2 to 1.5% of Si,
• 0.05 to 1% of Co
• at least one of
• 0.1 to 5% of Nb,
• 0.1 to 5% of Ta and
• 0.1 to 5% of W, the total content of Nb, Ta and W being limited to 5% or less, and
• the balance substantially Fe and inevitable impurities, and has a two-phase structure formed of an austenitic phase and an eutectic carbide phase.

A method of forming a high-temperature wear resistant valve face on an engine valve by coating the valve face with an Fe-based alloy having a composition consisting essentially of, by weight:

• 0.7 to 1.5% of C,
• 10 to 15% of Mn,
• 24 to 30% of Cr,
• 6.1 to 9.8% of Mo,
• 10to 15% of Ni,
• 0.1 to 0.4% of N,
• 0.2 to 1.5% of Si, and
• the balance substantially Fe and inevitable impurities, with the resultant coating having a two-phase structure formed as an austenitic phase and an eutectic carbide phase.