Control of weld penetration in TIG welding: A review of factors affecting weld pool behaviour and of techniques to improve process control

TWI Industrial Member Report Summary 260/1985

W Lucas and Naseer-Ahmed 

In the welding of critical components it is always essential that a fully fused welded joint be obtained. However, under the conditions prevalent in practice, i.e. variations in process parameters, component dimensions and material composition, an inadequate or excessive level of weld penetration can result. This literature review was conducted to identify the major sources of variation and the process techniques which can be adopted to minimise their effect.

With regard to the overall aim of the project, i.e. the design and construction of prototype penetration control systems, it is noteworthy that, despite the seriousness of the problem, only one penetration control system is currently available; because this system uses a photodiode as the penetration sensor and must be placed beneath the joint, it has a limited field of application. It was, therefore, concluded that urgent attention should be given to research into penetration control systems with emphasis on front face monitoring techniques.