Steel bridge structures dating back to the 19th and 20th centuries were most often erected using wrought steel (up to the end of the 19th century) and cast steel (20th century). Due to long-term operation, these steels show a tendency towards microstructure degradation processes (wrought steel to a greater extent than cast steel). The subject of the authors’ research were fragments of steel structures from the Pomorskie Bridges in Wrocław. The paper presents the results of impact resistance tests on wrought and cast steel originating from the structural elements of the Middle Pomorski Bridge (1885) and the Northern Pomorski Bridge (1930). It was demonstrated that the presence of degradation processes (consisting, among other things, of numerous nitride and carbide precipitates) in the microstructures significantly reduces the impact resistance of these steels.THE INFLUENCE OF THE MICROSTRUCTURAL DEGRADING PROCESES ON TO IMPACT RESISTANCE OF OLD BRIDGE STEEL MANUFACTURED
AT THE TURN ON 19th AND 20th CENTRURY
The most popular metallic material for bridge steel construction at the turn on 19th and 20th century was the puddled (the second half of 19th century) or cast steel (early 20th century). As a result of long-term operation, mentioned types of steel show a tendency to degradation processes at the microstructure level (the puddled steel more than cast one). The object of investigation were fragments of steel construction from Pomorskie Bridges i.e. Pomorski Środkowy (1885 year) and Pomorski Północny (1930 year). Two types of steel were tested; the puddled (from Pomorski Środkowy) and the cast (from Pomorski Północny). In this paper, the impact resistance test results have been presented. It has been shown that, the Microstructural degrading processes have significantly decreased the impact resistance of the tested steel. (…)
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Source: Logistyka Magazine
The influence of microstructure degradation processes on impact resistance – PDF file for download