During the last two years the activities of the Subcommission Vc have been concentrated to three major items:

• Revision of the Handbook on the examination of austenitic  welds (will probably be finished end of 1999)
• The problem of the ultrasonic inspection of welds with the TOFD-technique One first  reaction of SC Vc will be the initiation of a round robbin measurement on several welded specimens, representing different crack detection difficulties. A comparison with highly performant standard UT and RT techniques should be foreseen. This activity corresponds to the intention of the SC Vc to discuss the validation of ultrasonic techniques for weld inspection
• Definition of the acoustic properties of  the IIW-block No. 1 for a revised ISO 2400

The challenging requirement concerning a more stringent sound velocity definition to be carried out by certified organizations leads to a search for more simple acoustic measurement approaches to guarantee a constant and reproducible  acoustic behaviour of the block material. Modelling had been introduced to improve the understanding of the physical reasons for the observed discrepancies. There still is a tendency to take over at a revised ISO 2400 standard the recommendation  from the small IIW block which requires a minimum signal to noise ratio at 6 MHz L-waves or the comparison of shear wave velocities with two different polarizations. But for the time being it is not yet cleared if those requirements are sufficient to avoid  future problems.

Other items still on the agenda are:

• Modern imaging techniques for automatic ultrasonic inspection methods and their importance for the weld inspection, revision of a Manual for the automatic ultrasonic weld inspection.
• Acceptance criteria for the ultrasonic inspection of welds with special reference to the automatisation

Other specific aspects like the performance demonstration of an automatic inspection or the specific sensitivity calibration for the automatic ultrasonic weld inspection are under consideration.