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ST52 Material

Keywords: ST52 material, ST52 steel, ST52 structural steel, ST52 equivalent grades, ST52 steel pipe

What is ST52 Material?

The ST52 material is a non-alloy steel which is considered as a common structural steel, originating from the German standard DIN 17100. This steel is mainly characterized by its tensile strength and yield point. Used in civil construction, underground engineering, bridge construction, marine structures, container manufacturing, and automotive and machine building. It remains one of the most common structural steel grades worldwide.

The ST52-3 designation follows the old German DIN standard naming system: "St" stands for Steel (Stahl) , "52" represents the minimum yield strength of 52 kgf/mm² (approximately 510 MPa, corresponding to a minimum yield strength of ≥355 MPa for thickness ≤16mm) , and "3" indicates the quality level (ensuring certain impact toughness requirements).

ST52 Steel Material

⚠️ Important Note: DIN 17100 was officially withdrawn in 2004 and replaced by the European standard EN 10025. The direct equivalent grade for ST52 in the modern European standard is S355J2 (EN 10025-2). For hollow sections (square tubes, rectangular tubes, round tubes), the equivalent grade is S355J2H (EN 10210 / EN 10219).

ST52 Steel Chemical Composition:

The chemical composition of ST52 is carefully designed to ensure excellent weldability through low carbon content, while manganese (Mn) provides solid-solution strengthening to enhance material strength.

Element	Content (Max)	Function
Carbon (C)	≤ 0.22%	Controls weldability; low content prevents weld hardening
Silicon (Si)	≤ 0.55%	Deoxidizer; strengthens ferrite
Manganese (Mn)	≤ 1.60%	Solid-solution strengthening; improves material strength
Phosphorus (P)	≤ 0.040%	Strictly controlled to ensure plasticity
Sulfur (S)	≤ 0.040%	Strictly controlled to improve toughness
Copper (Cu)	≤ 0.55%	Trace alloying element
Nitrogen (N)	≤ 0.012%	Grain refinement control

ST52 is produced as a fully killed steel with fine grain treatment, ensuring consistent mechanical properties across different thicknesses.

ST52 Steel Mechanical Properties:

The mechanical properties of ST52 vary progressively with material thickness. The following table summarizes the core performance indicators required by the standard:

Thickness Range (mm)	Yield Strength (MPa)
≤ 16 mm	≥ 355
16 – 40 mm	≥ 345
40 – 63 mm	≥ 335
63 – 80 mm	≥ 325
80 – 100 mm	≥ 315

Data source: DIN 17100 / EN 10025 standards

Other Mechanical Properties

Property	Value	Notes
Tensile Strength	490 – 630 MPa	For all thickness ranges
Elongation (A)	≥ 22%	Longitudinal test specimen
Impact Energy (KV)	27 J @ 20°C	DIN 17100 standard requirement
Impact Energy (KV)	27 J @ -20°C	Corresponds to S355J2 requirement

Compared to ordinary structural steel ST37 (yield strength 235 MPa), ST52 offers a strength increase of over 50% . This allows for lighter sections under the same load, thus reducing structural weight and material costs.

International Equivalent Grades

Since DIN 17100 has been replaced by EN 10025, ST52 has clear equivalent grades in different standard systems.

Standard System	Equivalent Grade	Application
European (EN 10025-2)	S355J2	Plates, sections, general structures
European (EN 10210)	S355J2H	Hot-finished hollow sections (SHS, RHS, CHS)
European (EN 10219)	S355J2H	Cold-formed hollow sections
Chinese (GB/T 1591)	Q355B	Low-alloy high-strength structural steel
American (ASTM)	A572 Gr.50	High-strength low-alloy structural steel
Japanese (JIS)	SM490YA	Rolled steel for welded structures

Performance Advantages of ST52 Material

1. Excellent Weldability
● Low carbon content (≤0.22%) provides excellent weldability for all common welding processes (arc welding, MIG, TIG, SAW, etc.)

● For thickness ≤ 20mm: No preheating required when ambient temperature ≥5°C
● For thickness > 20mm: Preheat 50–100°C recommended; use low-hydrogen electrodes
● Post-Weld Heat Treatment (PWHT): Generally not required, except for heavy sections or critical applications

2. Superior Cold Formability
ST52 offers excellent cold formability for bending, flanging, stamping, and similar operations without cracking.

3. High Cost-Effectiveness
ST52 provides 30-40% material cost savings compared to medium-carbon alloy steels, while delivering sufficient strength and toughness.

4. Good Fatigue and Corrosion Resistance
The optimized micro-alloy composition provides better fatigue resistance under alternating loads and can form a dense oxide film to improve corrosion resistance.

Product Forms and Supply Specifications

ST52 material is available in various product forms to meet a wide range of applications, from light structures to heavy engineering.

Product Type	Production Process	Size Range	Applicable Standard
Seamless Steel Pipe	Hot-rolled / Cold-drawn	OD 10.3 – 660 mm	DIN 1629 / DIN 2448
ERW Steel Pipe	High-frequency welding	OD 21.3 – 660 mm	DIN 2458
LSAW Steel Pipe	Longitudinal SAW	OD 406 – 1219 mm	Custom
Square / Rectangular Tube	Cold-formed	Custom dimensions	EN 10219 / EN 10210
Steel Plate	Hot-rolled / Controlled rolling	Thickness 8 – 100 mm	DIN 1543

Dimensional Tolerances (per DIN 1629/2448):
● Outer Diameter: ±1%
● Wall Thickness: ±10%
● Straightness: ≤ 1.5 mm/m
● Length: 3 – 12 m (custom up to 18 m)

Surface Finishes: Black (with mill scale), galvanized, painted, etc.

Main Application of ST52 Steel

Thanks to its excellent combination of properties, ST52 is widely used across the following industries:

1. Building & Infrastructure
Steel structure frames, bridge support structures
Tower crane structural components, municipal pipe supports
Scaffolding systems

2. Machinery Manufacturing
Equipment frames, medium-duty drive shafts
Gear blanks, pressure vessel shells
Construction machinery undercarriage components
Crane booms

3. Fluid Conveyance Systems
Medium-to-high pressure water and air pipelines
Oil and natural gas transmission pipelines
Chemical industry medium-pressure fluid conveyance (non-corrosive media, ≤10MPa)

4. Automotive & Agricultural Machinery
Commercial vehicle frames, agricultural machinery chassis
Trailer load-bearing structures, automotive bumper skeletons

5. Shipbuilding
Hull structural components (subject to certification)

6. General Structures
Hardware and mechanical structural components
Imported equipment localization replacement parts
Large equipment auxiliary structural components

⚠️ Not Recommended For: High-temperature service above 300°C, corrosive environments without additional protection, or cryogenic (ultra-low temperature) applications.

Quality Assurance & Certifications

ST52 products are typically supplied with the following quality documentation:

● EN 10204 Type 3.1 Material Test Certificate (heat traceable)
● Dimensional Inspection Report
● DIN 17100 / DIN 1629 / DIN 2448 Compliance Certificate
● NDT Reports (if applicable)

△ Optional Third-Party Inspection: SGS, BV, LR, TÜV, etc.

FAQ:

Q1: What is the difference between ST52 and S355J2?
ST52-3 is the original grade under the now-withdrawn DIN 17100 standard. S355J2 is its direct equivalent under the current EN 10025-2 standard. Their chemical composition and mechanical properties are essentially identical, but S355J2 is the current, compliant grade for the European market.

Q2: What is the difference between ST52 and ST37?
ST52 has a much higher yield strength (355 MPa) compared to ST37 (235 MPa). ST52 is considered a "higher-grade" steel with stricter chemical composition control, while ST37 is a general-purpose structural steel.

Q3: Can ST52 be used for pressure vessels?
Yes, for non-critical, ambient-temperature pressure applications (water, air, oil). For pressure applications governed by EN 13445 or ASME B31.3, P355N (EN 10216-1) is recommended as it has stricter requirements.

Q4: What is the impact test temperature for ST52?
DIN 17100 requires 27J @ 20°C. For -20°C impact energy guarantee, you must specify the S355J2 requirement.

Q5: What is the equivalent grade for ST52 square/rectangular tubes?
S355J2H (EN 10210 for hot-finished / EN 10219 for cold-formed).

Q6: What should I consider when purchasing ST52?

1. Confirm impact grade: JR (room temperature) or J2 (-20°C)
2. Confirm product form: seamless, welded, square/rectangular tube, or plate
3. Confirm standard: acceptance of S355J2/S355J2H equivalent

Conclusion:

ST52 material (and its modern equivalent S355J2H) is a workhorse material in the global structural engineering field, thanks to its high strength, excellent weldability, good cold formability, and outstanding cost-effectiveness.

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