High strength Material for turbine engine components

There are essential differences in the structure and service conditions of industrial and aero-gas turbines that prevent the direct use of standard alloys in the design of industrial engines. Different alloys are used. Blades for industrial gas turbines are often made from super alloys containing high chromium concentration that have been evaluated for service in vigorous conditions whilst those for aero gas engines are made from low carbon high strength alloys.

Blades made for industrial gas turbines are significantly larger than those for aero-engines. It results into significant differences in the process factors during directional solidification that could influence the structural and properties of the casting. In specific, slow heat flow through larger castings will influence the cooling rate and the larger mass of molten metal could cause issues in the containment by current moulding materials.

Industries demand longer lives from the aero-gas turbines that requires better corrosion resistance. Practical engine trials that are significant in the evaluation of aero engines, are impractical for industrial gas turbines, consequently suitable component design by using materials required for service in the required environment.

The industrial gas turbines are made from alloy that is directionally solidified by using lab and commercial observation. The operation of industrial gas turbines with specific emphasis on long term properties and on both the anisotropy and heterogeneity of the castings.

A major part of the turbine design is the selection or development of alloys suitable for application in the turbine. As long as candidate alloys are chosen, basic tests are performed on the alloys that are already selected such as nickel base super alloys Inconel 617. These alloys have very high strength and oxidation resistance at atmospheric pressure.

Initial oxidation tests are performed on the test materials to ensure that they can perform properly and can benefit the boiler research. Higher heating value also signifies the performance of alloys. Ferritic stainless steels comprising of 9 to 12% are presently used at steam temperatures up to 600oC. Most studies of the upper temperature limit are up to 650oC with high temperature strength as a limiting factor.

Austenitic stainless steels keep their strength at higher temperature as compare to ferritic alloys. Although vigorous thermal fatigue issues prevented their regular use at the original design temperatures and pressures. As thermal fatigue becomes more a problem in thicker component parts, austenitic alloys are still useful in the specific thinner components. They are used in boiler sections of advanced power stations.

Advancements in the application materials have contributed in a major way in the development of gas turbine engines with higher power ratings and efficiency levels. Enhancements in the design of gas turbine engines over the years have been possible due to the development f materials with improved performance. Gas turbines are widely used in aircraft engines and land based applications for power production.

The major use of Inconel wire made from alloy 617 is in the improvement of high temperature creep rupture strength without affecting oxidation and corrosion resistance. It is commonly used in manufacturing combustion system components for higher creep rupture strength.