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These row 1 and 2 hot-section turbine components are cast from Ni-and Co-base superalloy material, in an equiaxed, directionally solidified and single crystal morphologies. Repair of all these differently orientated grain structures on Ni-based blade materials will also be discussed. Some materials that have been weld and/or braze repaired include Co-based superalloys ECY 768, FSX-414, X-45 and Ni-base superalloys IN738, MarM247, GTD111, DS MarM247, DS GTD111, Rene N5 (but obviously are not limited to these superalloys).
Paper 2: Residual Stresses in Stainless Steel and Ferritic Steel Weld Repairs
By: P Hurrell, C Gill, D Hodgson, B Pellereau, S Garwood (Rolls-Royce) and M Smith, EDF-British Energy, UK Abstract: This presentation describes residual stress analyses of plate multi-pass groove welds, slot welds and ring welds. The specimens are comparable to shallow weld repairs performed on power plants, following removal of defects by machined grind-outs. Stainless steel (Type 304 and 316) plate welds were manufactured, as well as SA508 pressure vessel steel weld mock-ups of similar design. The plate welds were instrumented with thermocouples and subsequently sectioned to reveal fusion boundaries and HeatAffected Zone (HAZ) for the calibration of Finite Element (FE) model heat input. Residual stress measurements were also undertaken, to support the development and validation of FE models. Typically, it was necessary to use 3D FE modeling techniques to capture the features of stress fields developed in weld repairs. Cyclic strain hardening and tensile residual stress levels were determined to be greater in stainless steel weld repairs. Local stress concentrations are evident at the start and end of short repairs, especially in the case of steepsided slot welds. However, these stress concentrations are reduced if a tapered run-in and run-out are machined. Stress peaks at weld bead interruptions were also investigated and can be significant in the final capping layer, although these residual stresses are of short length-scale. Micro-structural Phase Transformation (PT) behaviour was investigated in SA508 steel weldments. Weld residual stress levels are reduced as a result of PT, but large tensile stresses can be induced in the HAZ and adjacent parent metal. Furnace post weld heat treatment of ferritic steel joints at 600°C produces effective stress relief and tempering. The structural integrity significance of these residual stress fields is also considered, in terms of crack driving forces applied to postulated weld defects.
Session 5 Repairs for Cyclical Service
Paper 1: Retrofitting Engineering for Fatigue Damaged Steel Structures
By: Dr. Chitoshi Miki, Tokyo Institute of Technology, Japan Abstract: In steel structures, many fatigue failures happened and repair and retrofitting works had been applied. The cases of fatigue damage and retrofitting works in steel structures are overviewed and technologies which were related to retrofitting works were summarized in this paper. As for bridge structures, many steel bridges have been constructed with the development of highway and railway networks. Welded girder bridges, which are sensitive to fatigue, have been positively adopted since 1960s. As a result, many fatigue failures have been observed in the U.S.A, Japan, and other countries since the 1960s . Because the causes of failures and repair measures for the cases are often referred from the repair cases reported in the past, it is very useful to gain knowledge from the past case studies and it is expected that such accumulated information will be of use in the maintenance technology. Therefore, repair cases for past fatigue failures must be collected so that anyone can refer to them. As a result of the activities of IIW-XIII-WG5, many repair cases for fatigue failures observed at various welded joints have been collected. The collected cases were arranged as a data-base which is available on the web. The damage cases were categorized as follows. •Welding defects were included at the time of fabrication. •An inappropriate structural detail of low fatigue strength had been adopted. •Stresses and deformations unforeseen in design occurred at joints of members. •The structure behaved in a manner not expected, such as vibration due to wind.
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Paper 3: Repairs for Offshore Structures
By: John Bruskotter, Bruskotter Consulting Services, LLC, USA Abstract: This presentation describes the challenges inherent in performing welding repairs in an offshore environment.
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IIW 2012
Table of Contents for the Digital Edition of IIW 2012
IIW 2012
Contents
Welcome Message
Annual Assembly Location
Colorado
Denver
General Information
IIW 65th Annual Assembly
IIW International Conference 2012 - Program
IIW International Conference 2012 - Abstracts
Speaker Bio Information
Smartphone App
Social Program
Technical Visits
Social Tours
Tour Schedule
Advertising Sponsor Profiles
Commission XIII Fracture Mechanics Seminar
IIW 2012 Sponsors
IIW 2012 - IIW 2012
IIW 2012 - Cover2
IIW 2012 - Contents
IIW 2012 - Welcome Message
IIW 2012 - 3
IIW 2012 - Annual Assembly Location
IIW 2012 - 5
IIW 2012 - Colorado
IIW 2012 - 7
IIW 2012 - Denver
IIW 2012 - 9
IIW 2012 - General Information
IIW 2012 - 11
IIW 2012 - 12
IIW 2012 - IIW 65th Annual Assembly
IIW 2012 - 14
IIW 2012 - 15
IIW 2012 - IIW International Conference 2012 - Program
IIW 2012 - 17
IIW 2012 - 18
IIW 2012 - 19
IIW 2012 - IIW International Conference 2012 - Abstracts
IIW 2012 - 21
IIW 2012 - 22
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IIW 2012 - 24
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IIW 2012 - Speaker Bio Information
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IIW 2012 - 45
IIW 2012 - 46
IIW 2012 - 47
IIW 2012 - Smartphone App
IIW 2012 - Social Program
IIW 2012 - Technical Visits
IIW 2012 - 51
IIW 2012 - Social Tours
IIW 2012 - 53
IIW 2012 - 54
IIW 2012 - Tour Schedule
IIW 2012 - Advertising Sponsor Profiles
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IIW 2012 - 58
IIW 2012 - 59
IIW 2012 - 60
IIW 2012 - Commission XIII Fracture Mechanics Seminar
IIW 2012 - IIW 2012 Sponsors
IIW 2012 - 63
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IIW 2012 - Cover3
IIW 2012 - Cover4
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