Finite element models of various thick section components, including selected weld profiles, were created. Techniques to replicate the as-welded residual stress distributions were developed and validated against experimental data. Build up of the weld profile during the welding process was shown to be critical to development of the residual stress distribution which was thus difficult, but not impossible, to replicate.<\/p>\r\n
Application of appropriate creep models enabled assessment of various stress relief procedures. This stress relaxation modelling was successful.<\/p>\r\n
Mechanical tests on material that had undergone a simulated stress relief treatment showed:<\/p>\r\n
- \r\n
- Stress relief damage is detrimental to subsequent tensile strength, tensile ductility, impact strength and impact ductility.<\/li>\r\n
- The effects are consistent and predictable on a loss-of-effective-section basis. Continuum damage mechanics provides a suitable basis for modelling.<\/li>\r\n
- The effects on the brittle-ductile transition are more complex.<\/li>\r\n
- Damage accumulation during stress relaxation is directly proportional to the stress relaxed, and therefore to the plastic strain accumulated. This is consistent with constrained cavity growth.<\/li>\r\n<\/ul>\r\n
![\"\"](\"http:\/\/johnbrear-plantintegrity.com\/wp-content\/uploads\/2019\/01\/SRE-damage.png\")
Damage due to stress relief, determined from subsequent tensile and impact properties.<\/figcaption><\/figure>\r\n Publications based on this work include:<\/h4>\r\n
Brear, J.M.
\r\n\u201cStress relief embrittlement - revisited\u201d
\r\nECCC Int Conf \u2018Creep and Fracture in High Temperature Components \u2013 design and life assessment\u2019 EMPA, Zurich, 21-23 April 2009<\/p>\r\nBrear, J.M. and Jarvis, P.
\r\n\u201cLiving with creep damage\u2026 outside the creep range\u201d
\r\nKeynote paper at Baltica 7 \u2018Life Management and Maintenance for Power Plants\u2019, Helsinki,
\r\nVTT Symposium 246\/247, Espoo, Vol. 2 pp. 50-64, 12-14 June 2007
\r\nEnergy Materials, Vol 2, No 2, 2007, pp 109-116
\r\n <\/p>","protected":false},"excerpt":{"rendered":"The objectives of this work were: to establish procedures for modelling the residual stress distribution in thick-section PWR pressure vessel welds to assess the effects of stress relaxation treatments on welded joints to determine the effects of stress relief on subsequent mechanical properties Finite element models of various thick section components, including selected weld profiles, … Continue reading Stress relief of PWR pressure vessel welds<\/span>