Prior to making production welds on titanium, procedures and techniques should be closely evaluated. Tensile and bend tests on trial welds made under conditions intended for production are the acceptance criteria. Impact or notch tensile tests may also be required, particularly for low temperature applications. Once good procedures are established, as evidenced by tensile and bend tests, they should be strictly followed in subsequent production welding.
Bend tests evaluate ductility.
For this reason, the bend test made on pre-production trial welds or on extensions of production welds made for that purpose, provides a good evaluation of weld quality. A bend sample in which the weld is positioned perpendicular to the bend axis assures uniform straining of weld metal and heat-affected zones, thereby giving more meaningful results. Table 25 lists weld bend radii for various titanium alloys. Good quality welds should be capable of being bent to the indicated radii without cracking. Problems with titanium welds are generally a result of contamination due to inadequate shielding.