DEGRADATION OF 0.5Cr-0.5Mo-0.25V STEEL MICROSTRUCTURE DURING EXPLOITATION
Journal Title: Materials Engineering - Materialove inzinierstvo (MEMI) - Year 2011, Vol 18, Issue 2
Abstract
Degradation of 0.5Mo-0.5Cr-0.25V material after long-term high-temperature service has been studied by means of microstructure and mechanical properties analysis. Samples were taken from the pipeline with steam leaking found after almost 200,000 h service at 565 °C. The microstructure and properties have been compared with similar materials at similar exposure conditions without any signs of the rupture. Highly tempered ferrite contains secondary particles of MC, M2C and a kind of Cr-rich carbide (M23C6 and/or M7C3) in all materials studied. The difference have been found in the values of hardness. Fractures of samples after the impact test at various temperatures with typical embrittled features are also described. Analysis of the material service history like warm and cold starts-up, conditions of thermal and mechanical fatigue, together with microstruc¬ture and mechanical properties lead to the conclusion that the material was overtempered. The exhaustion of material deformationability resulted in the rupture-leakage of a component in the place of highest stresses.
Authors and Affiliations
Anna Výrostková, Ján Kepič, Roman Macko, Viera Homolová
Keywords
Related Articles
- EP ID EP102915
- DOI -
- Views 129
- Downloads 0
Experimental analysis of influence of different lubricants types on the multi-phase ironing process
This paper is aimed at presenting results of an experimental analysis of the different types of lubricants influence on the multi-phase ironing process. Based on sliding of the metal strip between the two contact element...
STUDY ON PHYSICAL - MECHANICAL PROPERTIES OF ALKALI ACTIVATED MATERIALS BASED ON FLY ASH
Alkali activated materials are relatively new materials, thanks to their good mechanical, physical, thermal properties and at the same time environmental friendliness, they could be widely adopted in different fields. Th...
Mechanical properties of homogenized twin-roll cast and conventionally cast AZ31 magnesium alloys
The improvement of mechanical properties of magnesium alloys nowadays is very important, because of the variety of industrial applications. For this goal, the number of casting techniques and further treatments were deve...
NANOINDENTATION TEST FOR DLC COATING ANALYSIS
In this report the effects of the substrate on the microhardness of Diamond like carbon (DLC) thin films were investigated. The DLC coatings were deposited by Radio Frequency Plasma Actived Chemical Vapor Deposition (RF...
The effect of different shot peening intensities on fatigue life of AW 7075 aluminium alloy
In this study the effect of different shot peening intensities, from very light peening with ceramic beads to severe shot peening with high coverage, on the fatigue life of aircraft AW 7075 aluminium alloy was investigat...