DIN stands for “Deutsches Institut für Normung”. It means “German institute for standardization”. Founded in 1917, it is not only a German national standardization organization, but also a member agency on behalf of Germany membership in ISO. It is headquartered in Berlin. As a standardizing competent authority in Germany, DIN participates in international and regional non-governmental standardizing institutions. It is also a registered private association with about 6,000 industrial companies and organizations for their members. Currently, there are 123 standard committees and 3655 working committees.

DIN standard was developed in Germany and are recognized worldwide as the efficient method for evaluating steel tubes. Through common cooperation, it aims to promote their applications so as to contribute to rationalization, quality assurance, safety and mutual understanding in economy, technology, science, management, public affairs, etc. There are mainly two product certification marks, namely “DIN Mark” and “DIN Inspection and Supervision Mark”. In addition, there is a quality certification system.