Weld reinforcements such as crown, unground root and root backing bars will limit access for scanning and provide a source of geometry signals. The following figures demonstrate preferred probe placement for several weld configurations. Usually two shear angles are used for a proper inspection. Image MAP Click on a joint and access to Figure 3 to 14 Special Testing Problems Many of the applications in ultrasonic testing can be simple adaptations of the most common compression or shear wave techniques. However, some applications may involve extra considerations such as unique geometries, harsh environments or difficult access.
Some solutions require special equipment.
An example is very high temperature environments. Probes may be expected to perform simple thickness testing functions but the operating temperatures may be sufficiently high to melt solder joints in wiring and depolarize normal piezoelectric material. For such applications special probes are designed using high temperature piezoelectric materials and electrical contacts are maintained by spring loading mechanical contacts against the element. Some codes do not adequately address the needs of some industries. Standard 45 refracted angles best adapted to maximize response off the corner reflectors will not adequately detect midwall defects by simply positioning a probe midway between ID and OD exit point maximums.