This standard is included in DIN Handbook 403. Covers welded circular tubes and pipes (hereinafter briefly referred to as ('tubes') with a longitudinal or spiral weld, made of unalloyed steel as listed in table 2. These tubes are predominantly used in the construction of chemical plant, vessels, pipework and for general mechanical engineering purposes. The maximum permissible working pressure and permissible working temperature are specified in table 1. (The upper yield stress values for tubes at temperatures up to 300 Deg C are specified in Appendix A.)