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2015 №07 (01) DOI of Article
10.15407/tpwj2015.07.02 		2015 №07 (03)

The Paton Welding Journal 2015 №07


The Paton Welding Journal, 2015, #7, 10-15 pages
 

Peculiarities of degradation of metal in welded joints of steam pipelines

V.V. Dmitrik1, O.V. Sobol1, M.A. Pogrebnoj1 And T.A. Syrenko2


1National Technical University «Kharkov Polytechnic Institute». 21 Frunze Str., 61002, Kharkov, Ukraine. E-mail: svarka126@ukr.net
2Kharkov Machine-Building College. 79 Plekhanovskaya Str., 61068, Kharkov, Ukraine
 
 
Abstract
Extension of life of steam pipelines, operated under creep conditions, determines the necessity of evaluation of their damageability and in many respects depends on carbide transformations in metal. The work considers peculiarities of diffusion and structure of carbide phases in metal of welded joints of pearlite steels after long-term operation. It is determined that concentration of coagulating carbide phases (M23C6, M7C3 etc.) at the boundaries of a-phase grains promotes for nucleation of creep pores and fatigue cracks, that causes brittle fracture of metal of welded joints. 18 Ref., 8 Figures.
 
Keywords: team pipeline welded joints, carbide phases, creep pores, fatigue cracks, damageability, operation life
 
 
Received:                18.02.15
Published:               13.10.15
 
 
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