The Mechanical and Brittle Properties of Gas Pipeline in Service |
| M. Hagarová, J. Cervová, M. Fujda, M. Mihaliková and A. Lišková
Institute of Materials, Faculty of Metallurgy, Technical University of Košice, 042 00 Košice, Slovakia |
| Received: September 11, 2016; In final form: July 4, 2017 |
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| The paper deals with the determination of mechanical and brittle properties of gas pipeline after more than 40 years in operation. The heat affected zone in weld of pipeline is the risk area in terms of embrittlement structure, which resulted in an increase of yield strength and shift of transit temperature to more positive values. The specimens were cut from heat affected zone for this reason. The tensile test according to ISO 6892-1 showed the increase in yield strength: it had a value of 295 MPa at the beginning operation and 400 MPa after more than 40 years in pipeline operation was recorded. The transition temperature at the value of 20°C was determined by using the Charpy impact test according to EN 10045-1. The operators of gas pipelines report that the mean temperature on the outer surface of pipe is about 4°C during the winter. The risk of brittle fragile is very likely if the transition temperature is higher than operating temperature. |
DOI: 10.12693/APhysPolA.132.1238 topics: pipeline, steel, tensile test, Charpy impact test |