The delivery status of steel pipe (BK, BKW, BKS, GBK, NBK)
BK, BKW, BKS, GBK, NBK Designation Symbol Description Cold finished (hard) BK （ +C ） Tubes do not undergo heat treatment following the final cold forming and, thus, have a rather high resistance to deformation Cold finished (Soft) BKW （ +LC ） The final heat treatment is followed by cold drawing involving limited deformation. Appropriate further processing allows a certain degree of cold forming (e.g. bending, expanding) Cold finished and stress-relieved BKS （ +SR ） Heat treatment is applied following the last cold forming process. Subject to appropriate processing conditions, the increase in the residual stresses involved enables both forming and machining to a certain degree. Annealed GBK （ +A ） The last Cold forming process is followed by annealing in a controlled atmosphere. Normalized NBK （ +N ） The last cold forming process is followed by annealing above the upper transformation point in a controlled atmosphere. If you need steel ...
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