DIN 2391

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

Chemical composition(%) of DIN2391

Grade	C max	Si max	Mn	P max	S max
St 35	0.17	0.35	≥0.40	0.025	0.025
St 45	0.21	0.35	≥0.40	0.025	0.025
St 52	0.22	0.55	≤1.60	0.025	0.025

Steel name	Steel number	C max	Si max	Mn	P max	S max	Al min
E215	1.0212	0.1	0.05	0.7	0.025	0.025	0.025
E235	1.0308	0.17	0.35	1.2	0.025	0.025	-
E355	1.058	0.22	0.55	1.6	0.025	0.025	-

Mechanical properties(Mpa) of DIN2391

Steel Grade		Minimum values for the delivery condition
Steel Name	Steel Number	BK		BKW		BKS			GBK		NBK
		Rm	A %	Rm	A %	Rm	ReH	A %	Rm	A %	Rm	ReH	A %
		Mpa		Mpa		Mpa	Mpa		Mpa		Mpa	Mpa
St 30 Si	1.0211	430	8	380	12	380	280	16	280	30	290 to 420	215	30
St 30 Al	1.0212	430	8	380	12	380	280	16	280	30	290 to 420	215	30
St 35	1.0308	480	6	420	10	420	315	14	315	25	340 to 470	235	25
St 45	1.0408	580	5	520	8	520	375	12	390	21	440 to 570	255	21
St 52	1.058	640	4	580	7	580	420	10	490	22	490 to 630	355	22

Inspection and test list for the DIN 2391 standard

Inspection or test types	Test frequency
	Internal test	Acceptance test
Chemical analysis	M	M
Tensile testing	M	One per tested batch
Flattening test or extension test	M	Two per tested batch
Dimension verification	M	M
Visual inspection	M	M
NDT in order to identify leaks	Individual	Individual

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.