At the place of use of a plurality of connected to one another by welding individual pipe line train produced steel tubes, as well as a method and apparatus for remunerate used during the construction of this pipe line train of individual steel tube

摘要

1481972 Steel pipe AEG-ELOTHERM GmbH 29 July 1974 [11 Aug 1973] 33457/74 Heading F2P [Also in Division C7] A steel pipe-length is heat-treated to impart to the pipe-length annular zones 3 of higher yield strength separated by narrower zones 4 of lower yield strength, the zones 3 having an average axial length of at least a quarter the diameter of the pipe. The pipe-lengths may be joined end-to-end by a weld seam 2.