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Zirconium and zirconium alloys are used extensively in the industrial sector for a variety of applications, with seamless tube being one of the most popular forms. A regulation governing the implementation and use of seamless zirconium and zirconium alloy tubes is GB 8768-88 – Zirconium and Zirconium Alloys Seamless Tubes.
This regulation is jointly issued by the China Standard Certification Center (CSCC) and the China Material Testing Center (CNMC). It is based on the Chinese national standard specification, GB/T8768-88, which is developed by the China National Standardization Management Committee.
The purpose of GB8768-88 is to establish a unified technical requirement criteria for the production and testing of zirconium and zirconium alloy seamless tubes. This document covers products made of rutile zirconium, hafnium zirconium and other zirconium alloys. Zirconium alloy tubes are made from powders, drawn from rods, and cut from plate/billet. The document also includes the technical requirements for the design and manufacture of zirconium and zirconium alloy seamless tubes, as well as the test method for acceptance.
Manufacturers of seamless zirconium and zirconium alloy tubes must meet the requirements of GB8768-88 in the production and delivery of products. The qualifications of the manufacturer are related to the organization standard, process, welding technology and other related technical requirements.
GB8768-88 divides zirconium and zirconium alloy seamless tube products into four grades. This separation is based on impurity content and choice of alloying elements. Class A differentiated products are those made with not more than 0.03% impurity, while Class B differentiated products must have not more than 0.06% impurity. Classes C and D have differing impurities, but no less than 0.10%.
In regard to strength testing requirements, Class A seamless zirconium and zirconium alloy tubes must have a tensile strength of not less than 180MPa, while Class B products must have a tensile strength of not less than 175MPa. Although no requirements for strength testing are intact for Classes C and D, requirements for reduction in area are included.
Implementing GB 8768-88 is beneficial for many reasons. It helps ensure product quality and safety through regulating manufacturing, testing and acceptance processes. Additionally, it provides clear standards in order to facilitate the development of novel products, as well as improving the technological progress and market competition.
GB 8768-88 should be implemented for the production and use of seamless zirconium and zirconium alloy tubes in the industrial sector. The regulation is beneficial for production, testing and acceptance processes, as well as providing clear standards which facilitates product development.
