DIN 1629 seamless carbon steel pipe

DN 1629 is a German standard that specifies seamless round tubes of non-alloy steel for use in chemical plants, pressure vessels, piping systems, and general mechanical and engineering applications. The standard includes three basic steel grades (ST37, ST44, and ST52). It is a standard for seamless round tubes of non-alloy steel with special quality requirements.

There are three main grades of DIN 1629 pipes: ST37.0, ST44.0 and ST52.0. Different grades of DIN 1629 tubing differ in terms of material composition and mechanical properties, such as their different size ranges, tensile strength, mechanical strength, and chemical composition. The following will be a detailed analysis of DIN 1629 seamless carbon steel pipe:

Manufacturing process and material selection

DIN 1629 seamless carbon steel tubes are usually manufactured by hot rolling process. The production process includes:

Preforming and perforating: select the low carbon or medium carbon steel billet that meets the requirements, and form the capillary through the perforating process after preforming;
Hot rolling forming: after multiple rolling at high temperature, adjust the diameter and wall thickness, and improve the metal structure by heat treatment;
Sizing, straightening and post-treatment: After pickling, phosphating and other surface treatment, to ensure product dimensional accuracy and surface quality.
Packaging and storage: The finished steel pipe is packaged and stored in the warehouse after completion.

Chemical composition and mechanical properties

DIN 1629 steel pipe through the grade can be divided into ST37.0, ST44.0, ST55.0 three grades, each grade of chemical composition and mechanical properties are different.

Chemical composition

Symbol	Material Number	C	P	S	N¹)
St37.0	1.0254	0.17	0.040	0.040	0.009²)
St44.0	1.0255	0.21	0.040	0.040	0.009²)
St52.0³)	1.0421	0.22	0.040	0.035	-

Mechanical properties:
St37.0: Minimum yield strength 235MPa, minimum tensile strength 350MPa
St44.0: minimum yield strength 275MPa, minimum tensile strength 420MPa
St52.0: minimum yield strength 355MPa, minimum tensile strength 500MPa

Different grades of steel pipes will be different in chemical composition and heat treatment process to ensure that they can meet safety requirements under specific working conditions and have good processing and welding performance.

Dimensions and tolerances

The dimensions and tolerances of the pipes are also specified in DIN 1629. In general, the nominal diameter of seamless carbon steel pipes ranges from 15 mm to 500 mm, and the wall thickness varies according to the diameter.
Size DIN 1629
Wall thickness (mm) : 1 to 30
Outer diameter (mm) : 10 to 324
Length (mm) : 14000

Tolerance: Diameter tolerance is about ±1%, wall thickness tolerance is about ±10%.

DIN 1629 vs EN 10216

Item	DIN 1629	EN 10216
Status	Withdrawn	Current European standard series
Product	Seamless circular tubes	Seamless tubes
Main material scope	Non-alloy steel	Non-alloy and alloy steels, depending on part
Typical use	Historical pipework, vessels and engineering applications	Pressure purposes and other specified service conditions
Grade designation	St 37.0, St 44.0, St 52.0	EN-specific material grades
Use for new projects	Requires verification	Check applicable EN 10216 part
Replacement	Historical reference	Current standard to evaluate

International standard equivalence

DIN 1629 seamless carbon steel pipe has a high consistency with ASTM A53 and ASTM A106 standard products in terms of chemical composition and mechanical properties. Both are suitable for high temperature and high pressure medium transportation and structural parts manufacturing, and are often cross-referenced and selected in international engineering projects, thus providing technical support for transnational engineering design.

DIN 1629 seamless carbon steel pipe FAQ

1. Is DIN 1629 still a valid standard?

No. DIN 1629:1984-10 has been withdrawn. It may still appear in older engineering documents, equipment specifications, and replacement projects, but it should not automatically be treated as a current standard for new projects.

2. What is DIN 1629?

DIN 1629 was a German standard for seamless circular tubes made from non-alloy steel and subject to special technical delivery requirements. It covered applications such as pipework construction, chemical plants, vessels, and mechanical engineering.

3. What grades are specified in DIN 1629?

The main historical DIN 1629 grades were St 37.0, St 44.0, and St 52.0. These grades had different chemical composition and mechanical property requirements.

4.  What replaced DIN 1629?

There is no single one-to-one replacement grade for every DIN 1629 application. For current European projects involving seamless tubes for pressure purposes, the applicable EN 10216 standard should be reviewed based on the material, service conditions, temperature, and design requirements.

Conclusion

In summary, through a detailed analysis of DIN 1629 seamless carbon steel pipes, it can be understood that DIN 1629 seamless carbon steel pipes can achieve a variety of performance requirements from low carbon and high toughness to high strength and high load bearing under different material grades (such as St 35.8, St 37.8 and St 52.8 grades). The performance of DIN 1629 seamless carbon steel pipe also ensures its wide application in the fields of petroleum, chemical, mechanical and municipal engineering, while its high equivalence with ASTM standards also provides strong support for international engineering material selection.

Read more：What is a seamless steel pipe?