Publication details
SIMILAR AND DISSIMILAR WELD JOINTS OF CREEP-RESISTING STEELS
| Authors | |
|---|---|
| Year of publication | 2009 |
| Type | Article in Proceedings |
| Conference | METALL 2009 |
| MU Faculty or unit | |
| Citation | |
| Web | http://metal2014.tanger.cz/files/proceedings/metal_09/Lists/Papers/039_e.pdf |
| Field | Physical chemistry and theoretical chemistry |
| Keywords | similar/dissimilar weld joints; creep-resisting steels; mechanical tests; creep tests; light microscopy (LM); transmission electron microscopy (TEM); X-ray diffraction (XRD) |
| Description | One of critical parts of structural device in power industry is a weld joint, similar or dissimilar. In comparison to the base metal, the mechanical and structure characteristics of as-welded and after post weld heat treatment (PWHT) weld metal are different, i.e. hardness values of weld metal are significantly higher. Moreover, the heat-affected zone (HAZ) induces even structure differences comparing to the unaffected base metal. In a long-term service, materials properties of whole weld joint degrade. Unfortunately, each zone of weld joint degrades specifically that leads to profoundly different properties of weld zones and disallows to reliable predict a behaviour of the weld as a whole. Therefore, it is very important to determine possible degradation processes occurring in the weld joint inducing the properties changes during long-term service and to study the behaviour of each zone of the weld joint in these service conditions. The paper deals with the study of materials properties of similar and dissimilar weld joins of creep-resisting steels. Creep-resisting 9% Cr steels marked P91, P92 and a low-alloyed CrMoVW steel marked T23 as experimental materials were used. The structure and mechanical including creep behaviour of each zone of the weld joint during a long-term isothermal exploitation at 650 C in air atmosphere was observed. For this reason, the light microscopy (LM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and CALPHAD approach were used. Finally, all theoretical and experimental data were discussed with respect to the choice of weld metal, welding method, and PWHT. |