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JA In the field of mechanical manufacturing and processing, ordinary carbon steel is the most widely used material due to its balance of strength, machinability, and low cost. When holding technical drawings, we frequently encounter two names: SS400 and CT3.
Many newcomers to the profession often confuse or are unclear about the difference between these two types of steel. So what is SS400 steel? What are the characteristics of CT3 steel? Let's delve into a comparison of SS400 and CT3 with the experts at Metaltech 1 to get the most accurate understanding.
1. What is SS400 steel?
SS400 steel is a common hot-rolled carbon steel grade, manufactured according to Japanese industrial standards (JIS G3101). It is one of the most widely used steel grades in the world today.
Meaning of the name SS400:
- SS (Steel Structural): An abbreviation for the English term "Structural Steel".
- 400: This indicates a minimum tensile strength of 400 MPa (or 400 N/mm²).
Key features: SS400 steel has a low carbon content (below 0.25%), therefore it has excellent ductility, making it easy to perform laser cutting, bending, and forming processes, and especially has extremely excellent weldability (no weld cracking).
2. What is CT3 steel grade?
CT3 steel (also written as CT3) is a common structural carbon steel produced according to the standards of the Russian Federation (GOST 380-88 or GOST 380-2005). In Vietnam, due to historical factors, the Russian steel standard (TCVN inherited from GOST) was once used as the main standard, so CT3 steel is very common in the drawings of previous generations of engineers.
Meaning of the name CT3:
- C (Carbon): Low-carbon steel.
- T (Steel): Symbols for general structural steel.
- 3: This is the grading number for steel (based on its mechanical composition). The higher the number, the higher the tensile strength and yield strength, but the lower the ductility.
Key features: Similar to SS400, CT3 steel has good weldability, high ductility, and can withstand medium static and impact loads.
3. Detailed comparison of SS400 and CT3: What are the differences?
In fact, in the mechanical engineering industry, engineers often consider SS400 and CT3 to be two equivalent steel grades (equivalent in terms of application and mechanical properties). The biggest difference is simply that they are named according to two different national standards (Japan and Russia).
However, upon closer examination of the specifications, they still exhibit minor discrepancies. Below is a detailed comparison table of the SS400 and CT3:
| Comparison criteria | SS400 steel (JIS G3101 standard – Japan) | Steel grade CT3 (GOST 380 standard – Russia) |
| Yield Strength | ≥ 245 MPa (Thickness ≤ 16 mm) | 205 – 255 MPa (Depending on thickness) |
| Tensile Strength | 400 – 510 MPa | 370 – 480 MPa |
| Relative elongation | ≥ 21% | 22% – 26% |
| Carbon content (C) | No specific regulation (Usually ≤ 0.2%) | 0.14% – 0.22% |
| Manganese (Mn) content | No specific regulations | 0.40% – 0.65% |
| Phosphorus (P) / Sulfur (S) content | Maximum 0.050% (for each type) | Maximum 0.040% / 0.050% |
| Cold | Excellent, no preheating required before soldering. | Excellent, no preheating required before soldering. |
Comment: It can be seen that SS400 steel has a slightly higher tensile strength than CT3. However, in most typical structural projects, both materials are completely interchangeable.
4. Practical applications in mechanical processing
Thanks to their ductility, ease of shaping, and low material costs, both SS400 and CT3 are widely used. At Metaltech 1, we regularly import SS400/CT3 billets in the form of plates, profiles (U, I, V, H), and tubes to serve various projects:
- Laser cutting and bending services: We manufacture base plates, connecting flanges, industrial machine frames and casings, electrical cabinet housings, and heavy-duty shelving.
- Steel structure fabrication & assembly welding: Fabrication of factory building frames, cranes, load-bearing machinery foundations, silos, and non-corrosive water/chemical storage tanks.
- Transportation sector: Truck chassis, shipbuilding details.
Precision machining of SS400 / CT3 steel at Metaltech 1
Understanding the properties of the material is the first step in creating a quality product. The second step is the processing technology. No matter how good the SS400 steel blank is, if the cutting machine creates large burrs, or the bending machine makes the wrong angle, the product will not meet the standard.
With the advantage of owning a modern Fiber Laser cutting system, CNC bending machines, and a team of multi-technological welders (MIG/TIG/Laser), Metaltech 1 confidently provides comprehensive fabrication services for SS400/CT3 steel components with the lowest tolerances and fastest turnaround times in the Dong Nai area.
Do you have detailed drawings for sheet metal or pipe fabrication? Contact us today for assistance with material breakdown and the most competitive pricing!
