Technical Characteristics of DIN 1629 Seamless Precision Steel Tube

In the field of precision machinery manufacturing, material selection often determines the ultimate performance of a product. As a leading representative of German industrial standards, DIN 1629 seamless precision steel tube, with its unique material formulation and precision processing, is providing reliable tubing solutions for the global high-end equipment manufacturing industry.

Material System and Chemical Composition Advantages:
DIN 1629 steel tube utilizes a carefully designed St37.0-St52.0 carbon-manganese steel system with precisely controlled chemical composition: a carbon content (C) ≤ 0.20% ensures excellent weldability, a manganese content (Mn) of 0.40-1.60% provides excellent hardenability, and a phosphorus and sulfur (P/S) content of ≤ 0.040% significantly enhances material purity. This balanced alloy design ensures the steel tube maintains high strength while also achieving excellent ductility and toughness.

Innovative Production Process Analysis:
This product utilizes a three-step production process of "hot rolling + cold drawing + bright annealing," which offers significant technical advantages. First, hot-rolling at 1000°C creates a uniform initial tube billet. Dimensional accuracy is then controlled through a precision cold drawing process. Finally, a bright annealing treatment at 650°C for 4 hours effectively eliminates processing stresses and optimizes the crystal structure. This process combination ensures the steel pipe achieves excellent mechanical properties, with a yield strength of ≥235 MPa and an elongation of ≥25%.

DIN1629 Material Grade:

The DIN 1629 standard classifies materials based on their minimum tensile strength. The standard includes three main grades, with St 37.0 and St 52.0 being the most common. Their mechanical properties are as follows:

St 37.0: Tensile strength 350–480 MPa, yield strength ≥ 235 MPa, elongation ≥ 25%.
St 44.0: Tensile strength 420–550 MPa, yield strength ≥ 275 MPa, elongation ≥ 21%.
St52.0: Tensile strength 500–650 MPa, yield strength ≥ 355 MPa, elongation ≥ 21%.

Core Technological Innovations:
Three-roll cross-rolling technology: Utilizing a German MEER three-roll tube mill, this achieves ultra-high-precision wall thickness control of ±0.05mm, with a tolerance of ≤±10%, far exceeding the industry average.
Inner Surface Treatment: Innovative inner bore honing technology achieves an inner surface roughness of Ra ≤0.8μm, making it particularly suitable for high-precision hydraulic systems.
Anti-corrosion Treatment: Phosphate conversion treatment creates a dense 3-5μm protective layer, significantly enhancing corrosion resistance.

Product Specifications and Applications;
Our products cover a wide range of specifications, including seamless pipes ranging from 10-426mm in diameter and precision cold-drawn pipes from 6-120mm, meeting diverse industrial needs. They are particularly suitable for:

Engineering machinery hydraulic cylinders
Automotive drive shaft systems
High-pressure fluid transmission pipelines

Quality Control and International Certifications:
Hunan Standard Steel Co., Ltd. (HSCO) strictly adheres to EN 10246-3 eddy current testing. Our products are dual-certified to DIN 1629-1984 and EN 10297-1:2018. They also comply with ASTM A519/A519M-2021 and JIS G3441:2019 international standards and have been successfully used in key projects for renowned companies such as Sany Heavy Industry and BYD. The company maintains a large steel pipe storage center in East China, stocking 8,000 tons of core specifications from 30-200mm in diameter, ensuring fast delivery.

Read more: Seamless Steel Pipe Sizes and Weights