0

Full Content is available to subscribers

Subscribe/Learn More  >

Development of Reduced Pressure Electron Beam Welding Process for Thick Section Pressure Vessel Welds

[+] Author Affiliations
K. R. Ayres, P. R. Hurrell, K. Bridger, L. D. Burling

Rolls-Royce plc, Derby, UK

C. M. Gill

Rolls Royce plc, Derby, UK

C. S. Punshon, Liwu Wei, N. Bagshaw

The Welding Institute (TWI) Ltd., Great Abington, Cambridge, UK

Paper No. PVP2010-25957, pp. 39-48; 10 pages
doi:10.1115/PVP2010-25957
From:
  • ASME 2010 Pressure Vessels and Piping Division/K-PVP Conference
  • ASME 2010 Pressure Vessels and Piping Conference: Volume 6, Parts A and B
  • Bellevue, Washington, USA, July 18–22, 2010
  • Conference Sponsors: Pressure Vessels and Piping Division
  • ISBN: 978-0-7918-49255 | eISBN: 978-0-7918-3878-5
  • Copyright © 2010 by Rolls-Royce plc

abstract

A reduced pressure electron beam (RPEB) process is being developed in the UK by ‘The Welding Institute’ (TWI) for the manufacture of thick section plate, forging and pipe welds. Potential gains include minimal distortion, fewer weld defects and rapid production times, compared to conventional arc welding processes. To date, RPEB welding equipment and parameters have been successfully developed and applied in a sealed chamber under partial vacuum (∼1mbar), to produce 1-pass seam welds in low alloy steel plates and forgings. Rolls-Royce commissioned TWI to produce RPEB welds in SA508 Grade 3 Class 1 steel forgings of between 100mm and 160mm thickness, as part of a feasibility study for nuclear pressure vessel applications. This paper presents results of micro-structural examinations, material property tests and residual stress analyses of RPEB welds in SA508 Grade 3 steel forgings, both in the as-welded condition and after post weld heat treatment (PWHT). This data was required in order to assess the structural integrity of the weldment. A narrow uniform fusion zone approximately 10mm wide and 3mm deep heat affected zone (HAZ) was produced. High hardness levels were measured in the weld HAZ, but the application of PWHT at 600°C had a beneficial tempering effect, reducing the maximum hardness to below 300Hv. A 3D finite element model was used and deep hole-drilling measurements were independently performed, to determine welding residual stress distributions. In both cases yield magnitude tri-axial tensile stresses were evaluated in the centre of the weld and adjacent HAZ, of up to +600MPa. This result is as expected since the centre region is the last to solidify and cool, with a high degree of restraint to weld shrinkage. However effective stress relaxation occurs during PWHT, mainly due to creep, reducing the maximum residual stress to about 100MPa (or 20% yield strength). This feasibility study has shown that RPEB welding is a viable method for fabricating large pressure vessels in low alloy steels. Sound joints can be produced in sections up to 160mm thick in a vacuum chamber. Further development work is being done by TWI in order to apply the technique out-of-chamber using a local vacuum seal.

Copyright © 2010 by Rolls-Royce plc

Figures

Tables

Interactive Graphics

Video

Country-Specific Mortality and Growth Failure in Infancy and Yound Children and Association With Material Stature

Use interactive graphics and maps to view and sort country-specific infant and early dhildhood mortality and growth failure data and their association with maternal

NOTE:
Citing articles are presented as examples only. In non-demo SCM6 implementation, integration with CrossRef’s "Cited By" API will populate this tab (http://www.crossref.org/citedby.html).

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In