DIN 1629, DIN 1629 seamless steel pipes Sunny Steeel

What is DIN 1629?

DIN 1629 is a German standard that specifies the requirements for seamless circular steel tubes of non-alloy steels. These tubes are primarily used for mechanical and general engineering purposes, but they are not suitable for heat treatment or pressure purposes. The key points about DIN 1629 include:

DIN 1629 is the standard specifies the Seamless Circular Tubes of Non Alloys Steels with Special Quality Requirements.

DIN 1629 applications the overheated boilers, as minimum thickness ferrite and seamless steel pipes, and as heat exchangers via austenitic pipes.

Material Grades

St 37.0: Minimum yield strength 235 MPa
St 44.0: Minimum yield strength 275 MPa
St 52.0: Minimum yield strength 355 MPa

Dimensions

The standard specifies the outer diameter, wall thickness, and permissible tolerances for the tubes.

Mechanical Properties

The mechanical properties include tensile strength, yield strength, and elongation, which vary according to the material grade.

Chemical Composition

The steel used must meet specific chemical composition limits, including carbon, manganese, phosphorus, and sulfur content.

Manufacturing Process

Tubes must be manufactured using a seamless process and may be either hot-finished or cold-finished.

Testing Requirements

Various tests are required to ensure the quality of the tubes, including tensile tests, flattening tests, and hardness tests.

Note

DN — Nominal Diameter
NPS —Nominal Pipe Size

Hollow bar DIN1629 ST52

Field of application

1.1 This standard applies to seamless circular tubes and pipes(hereinafter briefly referred to as "tubes") made of unalloyed steels as listed in table 1. These tubes are predominantly used in the constructin of chemical plant, vessels, pipework and for general mechanical engineering purposes. They are designed to meet high performance requirements. Normally there are no limiting vaiues or the maximum permissible working pressure of these tubes. The permissi l working temperature shall not exceed 300℃ are specified in Appendix A.)

The limits of application and other specifications given in this standard shall apply except in cases here other specifications are contained in codes of practice for specific fields of application, e.g. the Technische Regeln fur Dampfkessel (TRD) (Technical rules on steam boilers) or the Technische Regeln fur Druckbehalter (TRB)

(Technical rules on pressure vessels), AD-Merkblatter (AD Instrucation sheets).

Chemical composition of steels for seamless circular tuves subject to special repuirements

steel grade		Type of deoxidization (R, killed (including semi-killed)) (RR, fully killed)	chemical composition, % by mass
Symbol	Material number		C	P	S	N¹)	Addition of nitrogen fixing elements (e.g.not less than 0,020% AItotal
St37.0	1.0254	R	0.17	0.040	0.040	0.009²)	-
St44.0	1.0255	R	0.21	0.040	0.040	0.009²)	-
St52.0³)	1.0421	RR	0.22	0.040	0.035	-	Yes

1) A content in excess of the maximum value started is permitted if a phosphorus content less than the maximum specifled by 0,005% P per 0,001% N is observed. However, the nitrogen content shall not exceed a value of 0.012% in the cast analysis and 0,014% in the product analysis.

2) The specified maximum values do not apply if the steels are supplied with the RR (instead of R) type of deoxidization

3) The content shall not exceed 0.55% Si and 1,06% Mn in the cast analysis or 0,60% Si and 1,70% Mn in the product analysis

table 3. Amounts by which the chemical composition in the product analysis may deviate from the limiting values applicable to the cast analysis {see table2}

Element	Amount by which the product analysis may deviate from the limiting values applicable to the analysis % by mass
C	+0,02
P	+0,010
S	+0,010
N	+0,001¹)

¹) A contant in excess of the maximum value stated is permitted if a phosphorus content less than the maximum specified by 0,005% P per 0,001% N is observed. However, the nitrogen contant shall not exceed a value of 0,012% in the cast analysis and 0,014% in the product analysis (this does not apply to the RR type of deoxidization.

table 4. Mechanical properties of tubes in the as delivered condition at room ternperature For wall thickness exceeding 65 mm, the values shall be agreed at the time of ordering

Steel grade		Upper yield stress ReH for wall thicknesses, in mm,			Tensile strangth Rm N/mm²	Elongation after fracture A5
Symbol	Material number	up to 16	over 16 up to 40	over 40 up to 65	Tensile strangth Rm N/mm²	lonigtudinal	transverse
St 37.0	1.0254	235	225	216	350²) to 480	25	23
St 44.0	1.0256	275¹)	265¹)	255¹)	420²) to 550	21	19
St 52.0	1.0421	355	345	335	500²) to 650	21	19

Steel-chemical composition (DIN1629)

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

Mechanical Properties(Mpa)

Steel grade	BK		BKW		BKS			GBK		NBK
Steel grade	Yield strength Rm N/mm min	Elongation% min	Yield strength Rm N/mm min	Elongation % min	Yield strength Rm N/mm min	Tensile Strength ReH N/mm min	Elongation % min	Yield strength Rm N/mm min	Elongation % min	Yield strength Rm N/mm min	Tensile Strength ReH N/mm min	Tensile Strength ReH N/mm 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

¹) For cold f inished tube in the NBK condition (annealed above the upper transformation point under shielding gas or in a vacuum), minimum values of yield stress lower than these valued by 20N/mm² are permitted.

²) For cold finished tubes in the NBK condition, minimum values of tensile strength lower than these values by 10N/mm² are permitted.

The main products of steel / steel grade

DIN1629 ST37.0
DIN1629 ST44.0
DIN1629 ST52.0

Size range(mm)

Out diameter:10-324mm
Wall Tickness:1-30mm
Length:14000mm max

Din 1629 seamless steel pipes application fields are: chemical plant, vessels, pipework construction and for common mechanical engineering purposes. Normally DIN 1629 standard are manufactured with no limiting working pressure values. Working temperature is limited below 300℃.