Equivalent Materials
AISI 1006 serves as a comparable alternative to ST37. Both materials share similar carbon content, excellent weldability and ductility, making them ideal for structural applications. Surface treatments like galvanization or painting significantly enhance corrosion resistance for both grades.
Since DIN 17100 was replaced by EN 10025, S235JR is the direct modern successor with Werkstoffnummer 1.0037. Engineers working across international standards regularly cross-reference Q235B under GB/T 700 and SS400 under JIS G3101.
| Region | Spec | Designation | Yield (MPa) | UTS (MPa) | Elongation (%) |
|---|---|---|---|---|---|
| Germany | DIN 17100 | ST37-2 | 235 | 360-510 | 25 |
| Europe | EN 10025-2 | S235JR | 235 | 360-510 | 26 |
| USA | ASTM A36 | A36 | 250 | 400-550 | 20 |
| China | GB/T 700 | Q235B | 235 | 370-500 | 26 |
| Japan | JIS G 3101 | SS400 | 245 | 400-510 | 21 |
| Russia | GOST 380 | St3sp | 235 | 370-490 | 25 |
| India | IS 2062 | E250 | 250 | 410-540 | 23 |
| UK | BS 4360 | 40A | 235 | 360-510 | 25 |
| France | NFA 35-501 | E 24-2 | 235 | 360-510 | 25 |
| Italy | UNI 7070 | Fe 360 B | 235 | 360-510 | 25 |
Most grades share a 235 MPa yield, with the American and Indian designations reaching 250 MPa. Substitution requires verification against job requirements, applicable codes, and engineering approval.
Characteristics
ST37 steel offers a unique balance of strength, ductility, and affordability. Compared to other carbon steels, it is relatively soft and moldable. However, it lacks robust corrosion resistance compared to other carbon steels, requiring adequate surface treatment to increase longevity.
Uses
- Automotive industry, machinery parts, building construction, and infrastructure projects due to cost-effectiveness
- Bridges, buildings, and large-scale structural works due to load-bearing capabilities
- Applications where design flexibility and varied shapes are required
- Heavy load-bearing structures where deformation resistance is critical
Physical Properties
| Property | Value |
|---|---|
| Density | 7.8 g/cm3 |
| Melting Point | ~1470 C |
| Thermal Conductivity | 53 W/mK |
| Electrical Conductivity | 6.9% IACS |
Mechanical Properties
The cooling rate significantly impacts hardness, as faster rates increase hardness while slower rates enhance ductility. Compared to ASTM A36, ST37 offers lower tensile strength and yield strength but superior ductility. Carburizing can significantly improve wear resistance by enriching the surface with carbon.
| Steel Grade | Tensile Strength (Rm) N/mm2 | Upper Yield Point (ReH) N/mm2 |
|---|---|---|
| St 37-2 | 360 up to 510 | Varies by thickness (235-195 min.) |
Elongation at Rupture: Longitudinal 17-26% (depending on thickness); Transverse 15-24% (depending on thickness).
Chemical Composition
The primary constituents are iron, carbon, and manganese. Carbon content should not exceed 0.9% to avoid cementite formation vulnerability.
| Steel Grade | Carbon (%) | Phosphorus (%) | Sulfur (%) | Nitrogen (%) |
|---|---|---|---|---|
| St 37-2 | 0.17-0.20 | <=0.050 | <=0.009 | - |
How Does ST37 Compare to ASTM A36?
| Property | ST37-2 | ASTM A36 |
|---|---|---|
| Yield | 235 MPa | 250 MPa |
| Tensile Strength | 360-510 MPa | 400-550 MPa |
| Carbon (max) | 0.17-0.20% | 0.26% |
| Elongation | 25% | 20% |
A36 permits higher carbon content and a tensile strength of 400 to 550 MPa, but lower elongation at 20% versus 25%. That makes ST37-2 more suitable for forming operations. The two often appear in similar structural applications, but verify against the governing code before substituting, since ASME and similar codes may reference the ASTM designation for pressure vessel and component work.
What Changed With S235JR and EN 10025?
S235JR replaced ST37-2 when the EN 10025 standard superseded DIN 17100. Both share a 235 MPa yield and a similar tensile range. The critical addition is impact testing: S235JR requires a Charpy V-notch energy of 27 J at +20 C.
EN 10025 introduced quality tiers (JR, J0, J2) for tighter control over toughness. For new designs, S235JR is the correct call, while the older ST37 designation remains valid for legacy drawings and maintenance of existing structures.
Weldability Comparison
All counterparts in this family are readily weldable. The carbon equivalent formula, CE = C + Mn/6 + (Cr + Mo + V)/5 + (Ni + Cu)/15, is useful for comparison: when CE stays below 0.45, joining methods like SMAW, MIG, and TIG work without special precautions or preheating on plates under 25 mm. ST37-2's low carbon cap gives it one of the lowest carbon equivalents among its counterparts, making it particularly suitable for welded assemblies.
Plating or powder coat near weld zones can cause adhesion failures if masking is not called out in the control plan, so specify which features to mask before coating.
Frequently Asked Questions About ST37 Equivalent Materials
What material is equivalent to ST37? S235JR (EN 10025-2) is the direct modern replacement with nearly identical properties. A36 serves as the American counterpart, Q235B is the Chinese match under GB/T 700, and SS400 fills the same role under Japan's JIS G 3101. Each shares a similar yield but differs in composition limits, testing protocols, and allowable elongation, so verify alloy composition through independent testing when switching between grades.
What is ST37? ST37 is a mild steel designation from the older German DIN system, with Werkstoffnummer 1.0037. The 'ST' stands for Stahl (steel), and '37' refers to the minimum ultimate tensile strength of 370 MPa. Common applications include structural frames, bridges, storage tanks, and general industrial fabrication.
What is the difference between ST37 and S235? S235JR replaced ST37 when EN 10025 superseded DIN 17100. Both share a 235 MPa yield and similar tensile range. S235JR adds a mandatory Charpy impact test of 27 J at +20 C, and its quality tiers (JR, J0, J2) let engineers select toughness for the service temperature.
What is the difference between ST37 and ST52? ST37-2 has a 235 MPa yield and 360 to 510 MPa tensile range, while ST52-3 delivers 355 MPa yield and 490 to 630 MPa. ST37 suits structures with moderate load requirements, and ST52 handles higher-performance demands. Both are weldable, though ST52 may require preheating on thicker sections.
