It is generally agreed that extensive experimental validation is necessary, especially when the methods are applied to large pipeline projects, where a failure or even a leak could have significant consequences to the environment, loss of production and adversely affect the reputation of the owner/operator. (W 59) (1)

Experimental validation = Validação experimental

….A key report written by Leggatt in 1987 was never published outside TWI (although the conclusions arising from it were published in 1988). It is believed that this is the reason that R6 describes the work as having ‘limited validation’. (W 14) (2)

Limited validation = Validação limitada

in certain applications, saw cuts or machined holes and slots, as well as structures containing ‘real’ defects, may not be considered acceptable as planar for the purpose of NDT training or validation. Therefore, TWI has developed techniques for producing realistic imperfections/defects and, in the case of cracks, the desired morphology, including roughness, and angles of tilt and skew to the surface. (W 61) (3)

NDT validation = Validação NDT

(1) 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.

(2) Effects of Mechanical Loading on Residual Stress and Fracture: Part II: Validation of the BS 7910:2013 Rules

Isabel Hadley and Simon Smith 

TWI Ltd Cambridge, UK

Presented at Proceedings of the ASME 2014 Pressure Vessels & Piping Conference (PVP2014), July 20-24, 2014, Anaheim, California, USA.

(3) Manufacturing of welded joints with realistic defects

Marcello Consonni Author, Chen Fun Wee Coauthor and Charles Schneider Coauthor

TWI Ltd

Paper presented at NDT 2011 – 50th annual conference of the British Institute of Non-Destructive Testing, 13-15 Sept. 2011. Telford, UK.

The Vickers microhardness was measured on the coating sections using a Duramin hardness tester manufactured by Struers and a load of 300g. 10 indents were made, and the hardness value expressed as a mean value with standard deviation. (W 290) (1)

Mean value = Valor médio

The threshold value of 20 dB has been chosen as it represents an ultrasonically acceptable difference between an echo of significance and those which are considered to be spurious. (W 86) (2)

Threshold value = Valor limite

The actual results from Baldy do not report a threshold stress; instead, the occurrence of failure was recorded for different values of applied stress (typically four samples were tested at the same stress value). (W 208) (3)

Stress value = Valor de tensão

(1) Influence of spraying parameters on the properties of HVOF alumina coatings

M A Riley and A J Sturgeon, Cambridge, UK

Paper presented at International Thermal Spray Conference 2-4 May 2005, Basel, Switzerland.

(2) Coping with failed elements on an array: a modelling approach to the technical justification

Channa Nageswaran 

TWI Ltd Cambridge, UK

Paper from Insight vol.52, no.7, July 2010. pp.372 – 379.

(3) A review of the effect of cold-work on resistance to sulphide stress cracking

T Sourmail, TWI

Paper presented at Corrosion 2007, Paper 07104, March 11-15 2007 Nashville, Tennessee, USA.

European rail accidents such as the high-speed train disaster in Eschede, Germany, in June 1998 and the Ladbroke Grove accident in Britain in October 1999 are two examples of accidents which have highlighted the need to further improve crashworthiness of rail vehicles. In the event of impact the carriage crumple zone absorbs a significant amount of the crash energy, it is important however that the part of the rail vehicle containing passengers remains substantially intact. Premature failure of welds in the rail vehicle would not be desirable. (W 158) (1)

Rail vehicle = Veículo ferroviário

A specially developed test vehicle was used for thermal cycling, consisting of wire-bonded chains, in the form of a square, on either alumina or FR4 pcb substrates. (W 534) (2)

Test vehicle = Veículo de teste

Thermal imaging cameras are frequently used for detection of ice or hot spots on aircraft, and attempts have been made to produce images using lock-in and pulsed thermography (for example) to detect delaminations in composites. The initial proposal for Robair was to mount a small heat source on the robot vehicle, and to track this using a reflecting system to a high performance thermographic camera mounted on the ground. There was originally no possibility of mounting any system on the vehicle because of the weight. However, a lightweight camera was provided by Horton Levi and it was decided that this could also be mounted on the vehicle. (W 396) (3)

Robot vehicle = Veículo robô

(1) Friction stir weld integrity and its importance to the rolling stock industry

Blignault C1, Kallee S W1, Thomas W M1, Russell M J1

Author details

1Friction and Forge Processes Department, TWI, Ltd., UK.

Paper presented at Southern African Institute of Welding (SAIW) conference, Integrity of Welded Structures in the Energy, Processing and Transport Industries in Southern Africa, Gold Reef City, 28-29 May 2008.

(2) Glob top materials to chip on board components

S B Dunkerton 

TWI, Abington, Cambridge CB1 6AL, UK

Presented at ICAWT ’98, The 1998 International Conference on Advances in Welding Technology – ‘Joining applications in electronics and medical devices’, Columbus, Ohio, USA, 30 September – 2 October 1998.

(3) Eddy current and thermography application for robotic aircraft inspection

John R. Rudlin, TWI, Richard Fitch, Horton Levi Ltd, Gerhard Scheer, Kontrolltechnik GmbH,

Andreas Boenisch, Kontroll Technik, Germany 

Extended abstract of paper presented at BINDT Annual Conference 2002, Southport, 17 Sept. 2002.

TWI developed the new nozzle to supply gas at a very high velocity. The molten metal can be blasted away from the cut once it is melted by the laser beam. The continuous and immediate removal of the molten metal, together with the cooling effect of the gas, prevents sideways heat transfer and the metal beyond the gas jet zone remains unaffected. (Welding 80) (1)

High velocity = Alta velocidade

Computational estimates of gas velocity and in-flight particle velocity have been made focusing specifically on the influence that these factors have on the process deposition efficiency. Differences will be discussed in terms of powder feedstock characteristics and the underlying physical and mechanical properties of the powders and substrates. (W 291) (2)

Particle velocity = Velocidade da partícula

A wave mode with low dispersion (frequency dependence of phase velocity) can be selected so that the rate at which the wave pulse spreads out in time is small.  The pipe acts as a wave guide, an effect that can be demonstrated at audible frequencies by someone whispering from one end down a long length pipe to be heard at the other. (W 181) (3)

Phase velocity = Velocidade da fase

(1) Dross-free laser cutting stainless steel

Case Study

www.twi-global.com/news-events/case-studies/dross-free-laser-cutting-stainless-steel-040/ – 2014-05-06.

(2) Production of titanium deposits by Cold Gas Dynamic Spray

T. Marrocco, D.G. McCartney, P.H. Shipway, Nottingham/UK

A.J. Sturgeon, Cambridge/UK

Paper presented at International Thermal Spray Conference 2-4 May 2005, Basel, Switzerland.

(3) The early days of laser cutting

P A Hilton 

11th Nordic Conference in Laser Processing of Materials, Lappeenranta, Finland, August 20-22, 2007.

The paper presents an assessment of the design fatigue limits of a pressure vessel that has been in service for hydrocarbon gas separation on an offshore installation. (W 23) (1)

Pressure vessel = Recipiente sob presssão

The prototype ocean viewer vessel has a 24m long aluminium planing mono-hull. It provides more than 25kt speed for the transit to the offshore reefs, ensuring a one hour transit maximum and hence two turnaround reef excursions per day. (W 488) (2)

Viewer vessel = Recipiente de visualização

Metallography – the cracking observed in the test blocks was similar to that observed on a sample of service disbonding from a reactor vessel. (W 210) (3)

Reactor vessel = Recipiente de reação

(1) Comparison of Approaches to Design Fatigue Assessment With Reference to a Pressure Vessel Designed to an Old Standard

J B Wintle, E Soileux, E Hutchison 

TWI Ltd, 

Cambridge, UK 

Proc of European Symposium on Pressure Equipment (ESOPE) 2013, 8-10 October, Paris, France.

(2) Application of friction stir welding for the manufacture of aluminium ferries

Stephan W. Kallee, Senior Project Leader

E Dave Nicholas, Technology Manager

Paul M. Burling, Principal Composite Engineer

TWI Ltd

Paper presented at the 4th International Forum on Aluminium Ships, New Orleans, 10-11 May 2000.

(3) Disbonding of austenitic stainless steel cladding following high temperature hydrogen service

M F Gittos, J L Robinson and T G Gooch

IIW document Commission IX-2234-07. February 2007.

In most cases of overlaying, it is necessary to control the dilution within close limits as an uneven chemistry can reduce the service life. There are a number of variables which affect dilution such as the welding current, the arc voltage, current polarity, electrode diameter, electrode extension, weld-bead separation, welding speed, electrode grinding angle, welding position, shielding gas composition, etc. (W 81) (1)

Arc voltage = Tensão do arco

Studies that have reported changing the voltage have found that FFR increases away from the optimum voltage.[Carter, 1998 and Willingham, 1986] The effect of current on FFR has also been modelled [Redding, 2002] and the reduction in FFR at the spray transition current observed. (W 55) (2)

Optimum voltage = Tensão ideal

The bias voltage level was set to 15V and the track resistance and inter-track leakage limits set to 1.2k ohms and 100 micro-amps respectively. The bias voltage was then switched on and the status of the test samples monitored over a period of up to 1000 hours. (W 534) (3)

Bias voltage = Tensão de polarização

(1) CRA Weld Overlay – Influence of welding process and parameters on dilution and corrosion resistance

Paper presented at Stainless Steel World America 2010, Houston, Texas, USA, 5-7 October 2010.

V Kumar, C Lee, G Verhaeghe, S Raghunathan, 

TWI Limited, Granta Park, Great Abington, Cambridge CB21 6AL, United Kingdom.

(2) The Effect Of Metal Transfer Modes On Welding Fume Emission In MIG/MAG Welding

Eur Ing Geoff Melton 

TWI Ltd., Granta Park, Abington, Cambridge, UK.

Eighth European Conference on Joining Technology, Eurojoin 8, Pula, Croatia, 24 – 26 May 2012.

(3) Glob top materials to chip on board components

S B Dunkerton 

TWI, Abington, Cambridge CB1 6AL, UK

Presented at ICAWT ’98, The 1998 International Conference on Advances in Welding Technology – ‘Joining applications in electronics and medical devices’, Columbus, Ohio, USA, 30 September – 2 October 1998.