Title

SUPERCLEAN STEEL PRODUCTION TECHNOLOGY FOR GAS TURBINE COMPRESSOR DISCS AT VILLARES METALS S.A.

Authorship

Mantovani, Mário César; Oliveira, Paulo Augusto Morais de; Ura, Maurício Marino; Paula, Luciano Wagner de; Murari, Almir; Silva, Robson Leandro; Possente, Egberto Antonio; Trombini, Maurício; Ramos, Bruno Pessoa; Graciano, Gerson

Mantovani, Mário César

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Oliveira, Paulo Augusto Morais de

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Ura, Maurício Marino

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Paula, Luciano Wagner de

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Murari, Almir

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Silva, Robson Leandro

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Possente, Egberto Antonio

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Trombini, Maurício

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Ramos, Bruno Pessoa

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Graciano, Gerson

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DOI

10.5151/1982-9345-27938

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Abstract

The steel for gas turbine compressor discs (26NiCrMoV14.5) requires some mechanical properties like strength, impact, toughness, fatigue, and creep resistance in order to be used in such application. To achieve the properties required for the gas turbine compressor discs, the material should have very low contents of sulfur, phosphorus, antimony, tin and arsenic. The level of cleanliness should also be very high and this is possible by achieving low oxygen content keeping the deoxidation elements like silicon, manganese and even the aluminum in very low percentages. The main problem in refining such steel is to adjust a sufficiently low oxygen content to have a good desulfurization and at same time a good cleanliness without using silicon, manganese or aluminum as deoxidizers. Combination of initial selection material, steelmaking process control, forging sequence and heat treatment cycles can provide uniform mechanical properties throughout the gas turbine compressor discs. Villares Metals SA as a big player on special steels with complex process has been developing this kind of material for several years. The objective of this work is to show the process technology evolution involved in the production of this kind of steel under the discussed preconditions.

Keywords

Superclean steel, Inclusions, Heat treatment, Forging

Forging