초록 ▼

Cooling steam delivery tubes extend axially along the outer rim of a gas turbine rotor for supplying cooling steam to and returning spent cooling steam from the turbine buckets. Because of the high friction forces at the interface of the tubes and supporting elements due to rotor rotation, a low coe

Cooling steam delivery tubes extend axially along the outer rim of a gas turbine rotor for supplying cooling steam to and returning spent cooling steam from the turbine buckets. Because of the high friction forces at the interface of the tubes and supporting elements due to rotor rotation, a low coefficient of friction coating is provided at the interface of the tubes and support elements. On each surface, a first coating of a cobalt-based alloy is sprayed onto the surface at high temperature. A portion of the first coating is machined off to provide a smooth, hard surface. A second ceramic-based solid film lubricant is sprayed onto the first coating. By reducing the resistance to axial displacement of the tubes relative to the supporting elements due to thermal expansion, the service life of the tubes is substantially extended.

대표청구항 ▼

1. In a gas turbine having metal tubes for conveying a cooling medium and metal support surfaces for said tubes, a coating on one of said tubes and surfaces affording a low coefficient of friction between said one of said tubes and said surfaces at an interface therebetween, comprising:a first coati

1. In a gas turbine having metal tubes for conveying a cooling medium and metal support surfaces for said tubes, a coating on one of said tubes and surfaces affording a low coefficient of friction between said one of said tubes and said surfaces at an interface therebetween, comprising:a first coating of cobalt-based alloy overlying a base material of said one of said tubes and said surfaces and a second ceramic-based coating overlying said first coating.