Tests & Inspection for Zirconium Tubes
The standard specification ASTM B523 (ASME SB-523) specified zirconium and zirconium alloy tubes for industrial applications. Distinguished from nuclear reactor applications, the industrial commercial grades of zirconium tubes are all hafnium-containing and are typically used for nonnuclear applications such as chemical processing equipment. There three industrial grades covered: Grade R60702 – unalloyed zirconium, Grade R60704 – zirconium-tin alloy, Grade R60705 – zirconium-niobium alloy, which are similar in properties to their nuclear-grade alloys. Since zirconium tubes are usually used under harsh conditions, a series of tests and inspection shall be conducted to ensure the quality.
Each heat lot of zirconium tubes manufactured to B530/ SB-523 shall take at least one longitudinal tension test in accordance with Test Methods E8. Tensile strength, yield strength, and elongation at 0.2% offset shall be determined. Chemical test shall be also conducted for each heat lot by PMI or any standard techniques. One flare test shall be conducted to make sure that the annealed tubes is capable of being flared without cracking. Specially, a reverse flare test shall be conducted welded tubing. The finished tubes shall be clean and have smooth ends, free of burrs, injurious internal and external imperfections. Dimensional examination shall focus on four aspects of the zirconium tubes: diameter, length, straightness, and squareness of cut. Besides, some nondestructive tests (NDT) are required separately for both welded and seamless tubes:
- For zirconium welded tubes: eddy current test (Practice E426), ultrasonic test (Practice E213), hydrostatic test or pneumatic test.
- For zirconium seamless tubes: eddy current test (Practice E426) and ultrasonic test (Practice E213).