The definition of the status and nomenclature of heat treatment of steel tubes

Condition and marking of the heat treatment of tubes according to EN 10052 and EN 10305-1

+C Cold drawn / hard. After the last cold forming with no heat treatment.
+LCCold drawn / soft. After the last heat treatment there is a subsequent slight finishing pass (cold drawing).
+SR Cold drawn and annealed to remove stresses. After the final cold drawing tubes are annealed in a protective atmosphere to remove the tension.
+A After the final cold drawing tubes are annealed (soft) in a protective atmosphere.
+N Normalized. After the final cold drawing tubes are normalized in a protective atmosphere.

Condition and marking of heat treatment of tubes according to DIN 2391-2

BK Cold drawn / hard. After the last cold forming no heat treatment.
BKW Cold drawn / soft. After the last heat treatment there is a subsequent slight finishing pass (cold drawing).
BKS Cold drawn and annealed to remove stresses. After the final cold drawing tubes are annealed in a protective atmosphere to remove the tension.
GBK After the final cold drawing tubes are annealed (soft) in a protective atmosphere.
NBK Normalized. After the final cold drawing tubes are normalized in a protective atmosphere.

Marking of the material condition depending on the heat treatment according to CSN and STN 42 0002 and 42004 (the first digit after a number of steel)

0No heat treatment
1Normalized (annealed)
2Annealed (indicate the type)
3Soft annealed
4Quenched and low tempered
5Normalized (annealed) and tempered
6Heat treated to achieve a minimum tensile within a specified range
7Heat treated to achieve an average tensile within a specified range
8Heat treated to achieve a maximum tensile within a specified range
9Specific (upon agreement)

Production marking and steel condition of Zeleziarne Podbrezova according to ASTM A519

CW Cold drawn
A Annealed
N Normalized
SR Annealed to relieve stresses
NTNormalization and tempering
QTQuenched and tempered


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