Partial safety factors (PSFs) have been derived in the last decade for two assessment codes, BS 7910:2005 and API 579-1/ASME FFS-1, enabling the reliability level of a defect-containing structure to be estimated by a deterministic assessment instead of invoking a complex and time-consuming full reliability analysis. (W 517) (1)

Safety factor = Fator de segurança

As in other tests, a welding factor can be determined, in this case from the ratio of the impact energy for the welded specimen to that of the un-welded reference specimen. (W 391) (2)

Welding factor = Fator de soldagem

Work conducted at TWI confirms that the existing flat plate solutions for embedded flaws in BS 7910 are indeed pessimistic [10]. Initially it was thought that they could be improved by applying a correction to the reference stress solution. Unfortunately, the correction factor depends on flaw height and length so a single correction is not possible. (W 59) (3)

Correction factor = Fator de correção

(1) Reliability analysis of defect-containing structures using partial safety factors

Liwu Wei 

TWI Ltd, Granta Park

Great Abington

Cambridge, CB21 6AL, UK

Paper presented at ASME 28th International Conference on Ocean, Offshore and Arctic Engineering, OMAE 2009, Honolulu, Hawaii, 31 May – 5 June 2009. Paper# OMAE 2009 – 80165.

(2) Mechanical testing of plastics welds

Mike Troughton 

Paper presented at Institute of Mechanical Engineers Seminar on Plastics & Polymers, September 2002.

(3) Assessment of Flaws in Pipe Girth Welds

Henryk Pisarski

TWI Ltd, Great Abington, Cambridge, CB21 6AL, UK

Paper presented at the CBMM-TMS International Conference on Welding of High Strength Pipeline Steels

Araxá, Brasil

28-30 November 2011.

Many people, seeing the bolt fracture face in Fig.4a will correctly recognise a fatigue failure. (W 251) (1)

Fatigue failure = Falha de/por fadiga

Although hardness levels around 400HV and above are certainly more likely to give interface failure, there appears to no ideal answer, as material thickness and material type can also have an effect.(W 306) (2)

Interface failure = Falha na interface (ligação física ou lógica entre dois sistemas)

Interesting features included the formation of the shear bands in the joint area indicating ductile failure in the thermoplastic interlayer.(W 524) (3)

Ductile failure = Falha dúctil

(1) Reliable technical failure investigation

Richard Pargeter 

TWI Ltd

Chapter from:

Pressure Systems Casebook: Causes and Avoidance of Failures and Defects John Wintle (Editor)

London, Professional Engineering Publishing, 2004.

ISBN: 1860584217.

(2) The resistance spot welding of high and ultra-high strength steels

Steve Westgate CEng, SenMWeldI 

TWI Ltd, UK

Paper presented at the 3rd International Seminar on Advances in Resistance Welding, Berlin 16-17 November 2004.

(3) Polymer coated material (PCM) joining technology for manufacture and repair of dissimilar material structures

R J Wise and K Gosai

Paper presented at International Conference: Joining and Repair of Plastics and Composites, 16 – 17 March 1999, London.

One important feature that must be considered for structural application of friction welding is the effect of the microstructural change, from typically a fully equiaxed structure to a fully transformed condition at the weld, on the Ti-6Al-4V fatigue behaviour. (W 516) (1)

Important feature = Característica importante

Since the potential consequences of a nuclear release are severe, and the chain of interacting events leading to the final event of core damage is complex, rigorous probabilistic risk assessments (PRA) are required. PRA have been performed in nuclear safety assessments for many nuclear power plants in the UK. The use of this extensive PRA information is a key feature of the methodology presented in Volume 2 in the quantitative risk assessments. (W 384) (2)

Key feature = Característrica -Chave

National certification schemes for welding inspectors have existed for many years, some of which are available internationally. [8,9] ISO 3834 requires welding inspectors to be competent but does not require any particular qualification or certification. However, the take up of the welding inspector certification schemes has generally been extraordinarily high (many tens of thousands) reflecting the fact that certified welding inspectors is a common feature in the specification of manufacturing or construction contracts world-wide. (W 82) (3)

Common feature = Característica comum

(1) Mechanical Properties of Friction Welds in High Strength Titanium Alloys

A Wisbey, I C Wallis, H S Ubhi, P Sketchley*, C M Ward-Close and P L Threadgill*

Mechanical Sciences Sector, DERA, Farnborough, UK 

* TWI, Cambridge, UK

Presented at ‘Titanium ’99’, 9th World Titanium Conference, St. Petersburg, Russia, June 1999.

(2) Risk-based inspection and maintenance – industry feedback and user needs

Brian J Cane 

Paper presented at Risk Based Management Seminar, IoM, London, 21-23 October 2002.

(3) The special importance of personnel competence in welding fabrication

Importance particuliere de la competence des personnels dans la fabrication soudee

Eur Ing T. J. Jessop and Eur Ing C. J. Eady

TWI Ltd

Paper presented at European Symposium on Pressure Equipment, ESOPE 2010. Paris, 28 – 30 Sept. 2010.

The results of using optical fibre delivered laser power to remove the surface of a range of representative and large scale concrete samples will be described. (W 83) (1)

Optical fibre = Fibra ótica

TWI has recently invented a new method for improving the control of induction welding thermoplastic composites without additional susceptors. Inserting a thin electrically-insulating layer (gauze) between adjacent layers containing nonaligned carbon fibres prevents electrical pathways from being formed and volumetric heating is disabled. (W 20) (2)

Carbon fibre = Fibra de carbono

The laser beam excitation and manipulation, allows for a very compact laser source, which can also be delivered to the work-piece by a separate delivery fibre giving it much of the flexibility of the Nd:YAG lasers. (W 222) (3)

Delivery fibre = Fibra de entrega

(1) Fibre lasers for surface removal of contaminated concrete in the nuclear sector

Paul Hilton 

Paper presented at 2010 ICALEO Proceedings Anaheim, CA, USA, 26 – 30 Sept. 2010, Paper 1305.

(2) Novel Induction Heating Technique for Joining of Carbon Fibre Composites

Chris Worrall and Roger Wise 

TWI Ltd, Granta Park Great Abington, Cambridge, CB21 6AL, UK

Paper presented at SEICO 14: 35th International Technical Conference & Forum “Low Cost Composite Processing, from Aerospace OOA to Automotive Thermoplastic”, 2014.

(3) Innovation in materials joining technologies

Authors: Sue Dunkerton 1 and Jon Simpson 2 

1 TWI Ltd., Granta Park, Gt Abington, Cambridge, CB1 6AL, UK

2 TWI Training & Certification (S.E.Asia) Sdn. Bhd., No 8 Jalan TSB 10, Sg. Buloh Industrial Park, 4700 Sg Buloh Selangor Darul Ehsan, Malaysia

Paper presented at IMTCE 2006, 17-20 July 2006, Kuala Lumpur, Malaysia.

Three-dimensional elastic-plastic finite element analyses have been conducted on pipes containing circumferential embedded flaws and subject to global bending load. (W 105) (1)

Embedded flaws = Falhas embutidas, incorporadas, integradas

The study concluded that touching co-planar flaws evolve into a bounding flaw in a similar manner to that observed in fatigue. (W 63) (2)

Bounding flaw = Falha delimitadora

In the NESC-1 Spinning Cylinder test, a large surface-breaking flaw in a thick steel cylinder component was subjected to high primary and secondary stresses produced by combined rotation and thermal shock loading. (W 382) (3)

Surface-breaking flaw = Falha de quebra de superfície

(1) Approaches for Determining Limit Load and Reference Stress for Circumferential Embedded Flaws in Pipe Girth Welds

Mohamad J Cheaitani 

TWI Ltd Granta Park, Great Abington, Cambridge CB21 6AL, UK

Pipeline Technology Conference, Ostend, Belgium 2009.

(2) > Technical Knowledge > Published Papers > The History of BS 7910 Flaw Interaction Criteria

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The History of BS 7910 Flaw Interaction Criteria

Bostjan Bezensek* 

Hunting Energy Services (UK) Ltd

Badentoy Park, Portlethen, Aberdeen AB12 4YB

John Sharples

Serco Technical Consultancy Services,                          

Birchwood park, Warrington, Cheshire WA3 6GA

Isabel Hadley (TWI Ltd) 

Henryk Pisarski (TWI Ltd) 

Paper presented at ASME 2011 Pressure Vessels and Piping Division Conference, Baltimore, Maryland USA, 17-21 July 2011. Paper PVP2011-57857.

(3) Analysis of crack arrest event in NESC-1 spinning cylinder experiment

W Xu, J B Wintle, C S Wiesner and D G Turner+

Paper published in International Journal of Pressure Vessels & Piping, Volume 79, Issue 11, November 2002, pp. 777-787. by Elsevier www.elsevier.com/locate/ijpvp

+ Current address: MBDA (UK) Ltd, Six Hills Way, Stevenage, UK

Activated fluxes that increased weld pool penetration of TIG welding (A-TIG fluxes) were first utilised in the late 1950s by the EO Paton Institute of Electric Welding in the former Soviet Union. The use of these fluxes reduces both the need for edge preparations and increases productivity due to the reduction in the number of weld passes required to make the joint. ( W 543) (1)

TIG flux = Fluxo de TIG

The use of activating fluxes for TIG welding was first reported by the EO Paton Institute of Electric Welding in the former Soviet Union in the 1950s. More recently activating fluxes have become commercially available from several sources. These fluxes claim to be suitable for the welding of a range of materials, including C-Mn steel, Cr-Mo steels, stainless steels and nickel-based alloys. (W 129) (2)

Activating flux = Fluxo de ativação

In a possible application, the hydrogen flux would be measured on welds at a temperature where the risk of cracking is still low. Provided this measurement can be interpreted, it would be possible to rapidly estimate the risk of cracking and allow the operator to decide ‘on the spot’ whether the weld should be maintained at some safe (high enough) temperature for a further length of time, or allowed to cool down. (W 62) (3)

Hydrogen flux = Fluxo de hidrogênio

(1) Developments in A-TIG welding

David Howse 

Presented at International Conference on ‘Exploiting advances in arc welding technology’, Cambridge, UK, 30-31 March 1998.

(2) Investigation of the A-TIG mechanism and the productivity benefits in TIG welding

V Kumara, Bill Lucasa, D Howsea, G Meltona, S Raghunathan a  and Louriel Vilarinhob

aTWI Limited, Cambridge, United Kingdom

bFederal University of Uberlandia, Brazil

Paper presented at 15th International Conference on the Joining of Materials (JOM 15) and 6th International Conference on Education in Welding (ICEW 6) Helsingor, Denmark, 3-6 May 2009.

(3) Novel Control of Weld Metal Hydrogen Cracking in the Welding of Thick Steels

Joanna Nicholas and Richard Pargeter

TWI Ltd, Granta Park, Great Abington, Cambridge, CB21 6AL

Paper presented at the International Steel and Hydrogen Conference

28 September 2011.