Understanding the difference between ST37 and A283 carbon steel plates is crucial for engineers and metal buyers. Both are carbon structural steels, but ST37 (a DIN 17100 grade) is an unalloyed mild steel, while ASTM A283 is a low-carbon alloy steel with four distinct grades (A, B, C, D). In simple terms, ST37 is essentially plain carbon steel, sometimes called “iron sheet” and is produced as hot-rolled coils or sheets up to about 16 mm thick. In contrast, A283 steel plate is made to ASTM standards in grades A–D, with each grade offering different strength and carbon content. These structural plates can be much thicker – up to 120 mm for A283 – and often include small alloying elements for controlled properties. As a result, ST37 and A283 plates exhibit different chemical compositions, mechanical properties, and price points.
Chemical Composition of ST37 and A283
The chemical composition is a primary difference between ST37 and A283 steel plates. Under DIN 17100, ST37 (often called St37-2) is a plain carbon structural steel with max carbon ~0.17–0.21% and trace impurities (P, S ≤0.050%). It contains little or no deliberate alloying elements, so its weldability and ductility are high. In contrast, ASTM A283 (Grade C or D) is a low-carbon alloy plate. A283 Grade C allows up to 0.24% C and Grade D up to 0.27% C, plus manganese up to 0.90% and small amounts of copper (min 0.20% if copper steel). Phosphorus and sulfur are limited (≤0.035–0.040% each) in both steels for quality, but A283’s carbon can be higher. In summary:
ST37 (DIN 17100) – Plain carbon steel: ~0.17% C, Mn ≈0.20–0.50%, P,S ≤0.050%. No special alloying (sometimes trace Al to meet standard).
A283 (ASTM) – Low-carbon alloy steel: Grade C: C≤0.24%; Grade D: C≤0.27%; Mn≤0.90%, P≤0.035%, S≤0.040%. Contains Cu≥0.20% if specified; Si ≤0.40%.
The result is that A283 plates generally have higher carbon (especially grades C/D) and thus higher strength, while ST37 has lower carbon and superior weldability. This chemical contrast underlies many of their differences.
Mechanical Properties and Strength
The mechanical properties of ST37 and A283 plates differ accordingly. A typical ST37-2 plate has a minimum yield strength around 235 MPa (for thickness ≤16 mm) and ultimate tensile roughly 360–510 MPa. (ST37’s exact yield drops for thicker plates, but it remains in the 235 MPa range for most structural sections.) In contrast, ASTM A283 steel plates have higher strength: for example, Grade C typically has yield ~205 MPa and tensile 380–515 MPa, while Grade D has yield ~230 MPa and tensile 415–550 MPa. Grade C is often chosen for moderate strength (and is very popular), whereas Grade D offers higher strength.
Put simply, A283 grade C/D plates exceed the strength of ST37: A283C/D are designed for “low- and intermediate-tensile” service, whereas ST37 (similar to EN S235JR) has moderate strength. However, both materials have good ductility. The lower carbon ST37 is more ductile and weldable than A283; its combination of strength (~235 MPa yield) and good elongation made it a standard for European structural steel. Conversely, A283 plates sacrifice some ductility for higher hardness and pressure tolerance.
Thickness, Production and Packaging
Another practical difference is thickness and supply form. ST37 steel plate (or coil) is typically supplied in thicknesses from 0.5 mm up to 16 mm, generally produced as hot-rolled coils or cut plates. It is sold in coils or cut lengths (“sheet iron” form), reflecting its use as a general structural steel. ASTM A283 plates, however, can be manufactured in much thicker sections – up to 120 mm or more – because A283 is also used for tanks and heavy structural components. The packaging differs accordingly: ST37 often comes as rolled coils or thin sheets, while A283 plates are bundled or cribbed like heavy plates. These handling differences also affect cost and logistics.
Price and Availability
Cost is a key distinction. ST37 steel is typically less expensive than A283. Because ST37 is essentially mild carbon steel (close to pure iron quality), it is very common and economical. In fact, ST37 is often called “sheet iron” or “plain carbon sheet”, highlighting its low price and softness. The lower carbon content and simpler production make ST37 generally cheaper per kilogram. By contrast, A283 plates (especially Grades C and D) are alloy steels meeting stricter standards, so they command a higher price. In practice, you will often find ST37 sold as the most economical option for general steel needs.
Market prices can also vary by supplier and country. For example, in the Iranian market, the well-known Mobarakeh Steel plant produces both ST37 and A283, and its prices often set a regional benchmark. Exchange rates, supply-demand, and certification (mill test reports, tight chemical specs) can further influence price. In short, if budget is a major concern and only low to moderate strength is needed, ST37 plates are the more cost-effective choice; if you need higher strength or thicker sections to withstand pressure, you may pay more for A283 grades.
Industrial Applications of ST37 and A283 Carbon Steel Plates
The applications of ST37 and A283 reflect their properties:
ST37 CarbonSteel Plate: Thanks to its high ductility and good weldability, ST37 (black plate) is widely used in civil construction and general engineering. It is the workhorse for beams, channels, angles, and steel profiles. Common uses include building frames, windows/doors, tanks and small vessels, automotive parts, riveted or welded structures, and general fabrication. Because it bends and welds easily, ST37 steel sheets also serve in light machinery, manufacturing equipment, and architectural components.
A283 Carbon Steel Plate: With its multiple grades and higher strength, A283 is chosen for heavier structural uses. Typical industries and uses include bridge and road construction, shipbuilding, fabrication of pressure tanks and vessels, machinery and equipment, and industrial piping and profiles. For example, A283 plates (often grade C) are used to build storage tanks, boilers, and pressure vessels that require a balance of strength and weldability. They are also used in crane structures, architectural supports, and large welded containers. In these applications, the added strength of A283 can carry higher loads or internal pressure.
Both steels may undergo surface treatments (e.g. galvanizing or painting) for corrosion resistance, but that is independent of their grade differences.
Conclusion and When to Choose Each Plate
In summary, the difference between ST37 and A283 Carbon steel plates comes down to composition, strength, and intended use. ST37 (DIN 17100) is a plain low-carbon steel (C≈0.17%) ideal for general structures; it is very ductile, weldable, and economical. A283 (ASTM) is a low-carbon alloy plate (C up to 0.24–0.27%) with grades A–D offering higher yield and tensile strength. A283’s higher carbon content and alloying mean it is better for thicker, high-load or pressure-bearing plates, at a higher cost.
When to choose one over the other: For light-to-moderate structural projects where ease of welding and cost are paramount (e.g. simple building frames, common profiles, automotive parts), ST37 is usually the right choice. If your project involves large load-bearing components, thick plates, or pressure vessels (e.g. storage tanks, bridges, heavy machinery), then A283 plates (often Grade C/D) provide the extra strength needed. Always check the required standards and ask for a mill test report to confirm the grade.
For detailed specifications, you can refer to the DIN 17100 ST37 standard for composition and properties and to ASTM A283/A283M for the exact requirements of each grade.
Ready to specify? Contact a steel plate supplier for current pricing and availability. For example, you can view our ST37 steel plate options and request a quote. Suppliers can advise on which plate best matches your requirements and provide up-to-date quotes or price lists.
Internal link: For more on ST37 steel, see ST37 carbon steel coils on our product page.
Outbound sources: Authoritative standards and supplier data (ASTM A283, DIN 17100) confirm the above differences
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Feel free to compare these specifications or consult engineering references for more detail.