DIN 1629 seamless carbon steel pipe

DIN 1629 is the standard for seamless round tubes of non-alloy steel with special quality requirements. It is a German standard that specifies the requirements for non-alloy steel seamless round steel pipes. These steel pipes are mainly used in mechanical manufacturing and general engineering purposes, as well as the transportation of liquids and gases, such as the manufacture of mechanical structural components, and the transportation of oil and natural gas.

There are three main grades of DIN 1629 pipes: ST37.0, ST44.0 and ST55.0. 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%.

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.

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.