DIN 2391

DIN 2391 standard specifies the seamless steel tubes used for mechanical and automobile.

Chemical composition(%) of DIN2391

GradeC maxSi maxMnP maxS max
St 350.170.35≥0.400.0250.025
St 450.210.35≥0.400.0250.025
St 520.220.55≤1.600.0250.025

Steel nameSteel numberC maxSi maxMnP maxS maxAl min

Mechanical properties(Mpa) of DIN2391

Steel GradeMinimum values for the delivery condition
Steel NameSteel NumberBKBKWBKSGBKNBK
RmA %RmA %RmReHA %RmA %RmReHA %
St 30 Si1.02114308380123802801628030290 to 42021530
St 30 Al1.02124308380123802801628030290 to 42021530
St 351.03084806420104203151431525340 to 47023525
St 451.0408580552085203751239021440 to 57025521
St 521.058640458075804201049022490 to 63035522

Inspection and test list for the DIN 2391 standard

Inspection or test typesTest frequency
Internal testAcceptance test
Chemical analysisMM
Tensile testingMOne per tested batch
Flattening test or extension testMTwo per tested batch
Dimension verificationMM
Visual inspectionMM
NDT in order to identify leaksIndividualIndividual

What is the difference between Din 2391 and Din 3304?

DIN 2391 applies to seamless precision steel tubes and in compliance with ISO/DIN 3304, those tube dimensions have been selected from the range of manufacture dimensions which are mainly used as design elements.