DIN 2391 Standard Specification

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

The main products of steel / steel grade: DIN2391-1(ST35, ST45, ST52).

Application:

• for Atuo usd;
• for machinery use;
• Oil cylinder tube;
• Motorcycle shock reducer steel tubes;
• Auto shock reducer inner cylinder

Steel pipe features specifications

O.D.(mm)	Wall Thickness Unit(mm)
	2	2.5	3	3.5	4	4.5	5	6	6.5-7	7.5-8	8.5-9	9.5-10	11	12
Φ25-Φ28	●	●	●	●	●	●
Φ32		●	●	●	●	●	●
Φ34-Φ36		●	●	●	●	●	●
Φ38		●	●	●	●	●	●
Φ40			●	●	●	●	●
Φ42			●	●	●	●	●
Φ45			●	●	●	●	●	●
Φ48-Φ60			●	●	●	●	●	●	●
Φ63.5				●	●	●	●	●	●	●
Φ68-Φ73					●	●	●	●	●	●
Φ76					●	●	●	●	●	●	●	●	●	●
Φ80					●	●	●	●	●	●	●	●	●	●
Φ83					●	●	●	●	●	●	●	●	●	●
Φ89					●	●	●	●	●	●	●	●	●	●
Φ95					●	●	●	●	●	●	●	●	●	●
Φ102					●	●	●	●	●	●	●	●	●	●
Φ108					●	●	●	●	●	●	●	●	●	●
Φ114						●	●	●	●	●	●	●	●	●
Φ121						●	●	●	●	●	●	●	●	●
Φ127						●	●	●	●	●	●	●	●	●
Φ133						●	●	●	●	●	●	●	●	●
Φ140							●	●	●	●	●	●	●	●
Φ146							●	●	●	●	●	●	●	●
Φ152							●	●	●	●	●	●	●	●
Φ159							●	●	●	●	●	●	●	●
Φ168							●	●	●	●	●	●	●	●

DIN 2391 seamless precision steel tubes mechanical properties(Mpa)

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

DIN 2391 seamless precision tubes applications – Used in Hydraulic & pneumatic cylinder, Mechanical and Automotive engineering.

DIN 2391 seamless precision steel tubes chemical composition(%)

Grade		Chemical element (%)
Symbol	Material No.	C	Si	Mn	P	S
St 30 Si	1.0211	≤0.10	≤0.10	≤0.55	≤0.025	≤0.025
St 30 Al	1.0212	≤0.10	≤0.05	≤0.55	≤0.025	≤0.025
St 35	1.0308	≤0.17	≤0.35	≥0.40	≤0.025	≤0.025
St 5	1.0408	≤0.21	≤0.35	≥0.40	≤0.025	≤0.025
St 52	1.058	≤0.22	≤0.55	≤1.60	≤0.025	≤0.025

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

JIS Number and Corrensponding Foreign Standards

JIS			ASTM			BS			DIN			NF			ISO			Index Number
Standard Number	Grade	Tupe	Standard Number	Grade	Tupe	Standard Number	Grade	Tupe	Standard Number	Grade	Tupe	Standard Number	Grade	Tupe	Standard Number	Grade	Tupe
G3445	STKM11A	C	A512	MT1010	C	1717	ERWC1	C	2391	St30Si	C				3304	R28	C	C017
			A513	MT1010	C					St30A1	C				3305	"	C
									2393	St28	C				3306	"	C
										RSt28	C
									2394	St28	C
										USt28	C
										RSt28	C
	STKM12A	C	A512	MT1015	C	1717	ERWC2	C	2391	St37-2					3304	R33	C
			A513	MT1015	C	6323	HFS3	C		RSt37-2					3305	"	"
	STKM12B	C	A512	MT1015	C				2394	St37-2					3306	"	"
			A513	MT1015	C					Ust38-2
			A519	MT1015	C					RSt-2
	STKM12C	C				1717	CEWC2	C				A49-322	TU37b	C
						"	CFSC3	C				A49-327	TU37b	C
						6323	CFS3	C
						"	CFS3A	C
	STKM13A	C	A312	MT1020	C	1717	ERWC3	C	2391	St45	C	A49-324	TU37b	C	2937	TS4	C
			A513	MT1020	C				2393	St44-2	C	A49-330	TU37b	C	3304	R37	"
									2394	St44-2	C	A49-343	TU38b	C	3305	"	"
	STKM13B	C	A513	MT1020	C										3306	"	"
	STKM13C	C				1717	CEWC3	C
						"	CFSC4	C
						6323	CFS4	C
	STKM14A	C	A513	MT1020	C	6323	HFS4	C							2937	TS9	C
															3304	R42	"
	STKM14B	C				6323	HFS5	C							3305	R42	C
	STMK14C	C													3306	"	"
	STKM15A	C	A513	1030	C
			A519	1030	C
	STKM15C
	STKM16A	C	A519	1040	C							A49-311	TUXC35	C
												A49-312	TUXC35	C
	STKM16C	C
	STKM17A	C	A519	1050	C	6323	HFS8	C
	STKM17C	C				6323	CFS8	C
	STKM18A	C	A519	1518	C	1717	ERWC5	C				A49-310	TU52b	C
												A49-311	TU52b	C
												A49-312	TU52b	C
	STKM18B	C										A49-321	TU52b	C
												A49-323	TU52b	C
												A49-326	TU52b	C
	STKM18C	C										A49-330	TU52b	C
												A49-341	TS42a	C
												"	TS47a	C
												A49-343	TS18M5	C
	STKM19A	C	A519	1524	C				2391	ST52	C				2937	TS18	C
									2393	ST52-3	C				2938	Gr.1	C
									2394	ST52-3	C				3304	R50	C
															3305	R50	C
															3306	R50	C
	STKM20A	C
G3441	SCr420TK	Cr																C018
	SCM415TK	CrMo
	SCM418TK	CrMo				6323	CFS10	CrMo
	SCM420TK	CrMo	A519	5120	CrMo
	SCM430TK	CrMo	A519	4130	CrMo
	SCM435TK	CrMo	A519	4135	CrMo
	SCM440TK	CrMo	A519	4140	CrMo	6323	CFS10	CrMo

The values stated in inch-pound units are to be regarded as the standard.