Heat treatment of long term serviced Cr - Mo cast steel

• Autorzy: Golański G. , Kupczyk J. , Kolan C.
• Języki publikacji: EN

Abstrakty

EN

The paper presents results of research on the influence of heat treatment on the structure and properties of L20HM cast steel after long term operation at elevated temperature. Investigated cast steel was taken out from an outer frame of a steam turbine serviced for 167 424 hours at the temp. of 535 °C and pressure 12.75 MPa. In post-operating condition the investigated cast steel was characterized by mechanical properties below the required minimum and by high brittleness. Performed research on the influence of austenitizing parameters has revealed that the range of austenitizing temperatures for the examined cast steel: A_c3 +30 ÷ 60 °C ensures obtaining of a fine austenite grain, homogeneous in size. It has been proved that tempering of bainititc - ferritic structure above 680 ÷ 690 °C causes an increase of impact energy along with a decrease of mechanical properties below the required minimum. Moreover, it has been noticed that applying of under-annealing instead of tempering, after full-annealing, guarantees the required impact energy of KV > 27J, with the mechanical properties similar to those after service.

Słowa kluczowe

EN

heat treatment; mechanical properties; Cr-Mo cast steel

PL

obróbka cieplna; właściwości mechaniczne; staliwo Cr-Mo

• Wydawca: Komisja Odlewnictwa Polskiej Akademii Nauk Oddział w Katowicach
• Czasopismo: Archives of Foundry Engineering
• Rocznik: 2010
• Tom: Vol. 10, iss. 1
• Strony: 45--50
• Opis fizyczny: Bibliogr. 12 poz., rys., tab., wykr.

Twórcy

autor

Golański G.

autor

Kupczyk J.

autor

Kolan C.

• Institute of Materials Engineering, Czestochowa University of Technology Armii Krajowej 19, Czestochowa, Poland,

Bibliografia

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