News - DIN2391 Seamless Steel tube Introduction

DIN 2391seamless steel pipe is a high precision steel pipe that is processed by cold rolling or cold drawing; Full name: Cold rolled or cold drawn precision seamless steel pipe. Due to the advantages of no oxide layer on the inner and outer walls of precision seamless steel pipes, no leakage under high pressure, high precision, high smoothness, no deformation during cold bending, flaring, flattening, and no cracks, they are mainly used to produce products for pneumatic or hydraulic components.

DIN 2391 Steel pipe grade and chemical composition

Steel Grade	Chemical composition （%）
Steel name	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

DIN 2391 Steel pipe Mechanical properties

Steel Grade	BK		BKW		BKS			GBK		NBK
Steel Grade	Rm N/mm min	A% min	Rm N/mm min	A% min	Rm N/mm min	ReH N/mm min	A% min	Rm N/mm min	A% min	Rm N/mm min	ReH N/mm min	A% min
St35	480	6	420	10	420	315	14	315	25	340-470	235	25
St45	580	5	520	8	520	375	12	390	21	440-570	255	21
St52	640	4	580	7	580	420	10	490	22	490-630	355	22

Din2391 delivery condition

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	The final heat treatment is followed by cold drawing involving limited deformation. Appropriate further processing allows a certain degree of cold forming (eg. bending, expanding)
Cold finished (Soft)	(+LC)
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.

Produce Process and advantages

Steel billet material, after precision drawing, oxidation free and bright heat treatment (NBK state), non-destructive testing, high-pressure flushing and acid pickling of the inner hole of the steel pipe, anti rust oil treatment for the inner and outer walls of the steel pipe, and dust prevention treatment for both ends of the cover.

1. Th inner and outer walls of the steel pipe have no oxide layer;

2.Withstand high pressure, no leakage, high precision, high smoothness;

3. Cold bending without deformation, expansion, flattening without cracks;

4. The surface rust prevention treatment.

DIN 2391 seamless steel pipe Application

Hydraulic system, injection molding machine, hydraulic machine, shipbuilding, EVA foaming hydraulic machinery, steel pipe for precision hydraulic cutting machine, shoemaking machinery, hydraulic equipment, high-pressure oil pipe, hydraulic oil pipe, ferrule joint, steel pipe joint, rubber machinery, forging machinery, die-casting machinery, engineering machinery, high-pressure steel pipe for concrete pump truck, sanitation vehicle, automobile industry, shipbuilding industry. Diesel engine, internal combustion engine, air compressor, construction machinery, agricultural and forestry machinery, etc., equipped with steel pipe joints, sleeve joints, and high-pressure oil pipes.

Post time: May-18-2023