Product Consistency Test Results for the High-Chromium Matrix Glasses

This paper describes the provisional material specifications of the high chromium (Cr) ferritic steel for the Sodium cooled Fast Reactor (SFR) and development of creep-fatigue assessment procedure for the welded joint made of the steel. Based on the test results, it was revealed that tungsten (W) should be diminished to achieve better creep-fatigue strength and toughness after long term aging at elevated temperature. Metallurgical examinations using a scanning electron microscope showed that W precipitated on the grain boundaries as “Laves phase” during aging process. The toughness of the steel which contained much W might be degraded by such coarse precipitations on the grain boundaries. As a result, provisional specifications of the high Cr ferritic steel for SFR pipes and tubes were proposed. Creep-fatigue strength assessment procedure for the welded joints made of the steels was also investigated. An assessment procedure using 2-element model was proposed and verified by comparing with some creep-fatigue test results. The creep-fatigue lives observed in the experiments were well predicted by the proposed assessment procedure, but the failure of the welded joints really occurred in the heat affected zone (HAZ) in some creep-fatigue tests. Since the HAZ was not taken into account in the procedure, there were obviously some rooms for improvement. Creep-fatigue failure mechanisms of the welded joint must be investigated and the characteristics of the HAZ must be formulated for more precise creep-fatigue strength assessment.

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Abrasion Resistance of as-Cast High-Chromium Cast Iron

Scientific Proceedings Faculty of Mechanical Engineering ◽

10.2478/stu-2014-0013 ◽

2014 ◽

Vol 22 (1) ◽

pp. 75-80 ◽

Cited By ~ 2

Author(s):

Marcela Pokusová ◽

Igor Berta ◽

Ľubomír Šooš

Keyword(s):

Wear Resistance ◽

Abrasion Resistance ◽

Test Results ◽

Austenitic Matrix ◽

Cast Irons ◽

High Chromium ◽

High Chromium Cast Iron ◽

Heat Treated ◽

The Matrix ◽

Chromium Cast Iron

AbstractHigh chromium cast irons are widely used as abrasion resistant materials. Their properties and wear resistance depend on carbides and on the nature of the matrix supporting these carbides. The paper presents test results of irons which contain (in wt.%) 18-22 Cr and 2-5 C, and is alloyed by 1.7 Mo + 5 Ni + 2 Mn to improve the toughness. Tests showed as-cast irons with mostly austenitic matrix achieved hardness 36-53 HRC but their relative abrasion-resistance was higher than the tool steel STN 19436 heat treated on hardness 60 HRC.

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