What is the difference between S235JR and S355JR?
Overview
Square and rectangular tubes are an excellent type of construction steel, widely used in bridges, construction, and machinery manufacturing. S235JR and S355JR are two common grades, differing slightly in chemical composition, mechanical properties, and applications. This article will briefly introduce these two grades of square and rectangular tubes to help readers better understand and use them.
Chemical Composition
The chemical composition of S235JR mainly includes elements such as carbon, silicon, manganese, phosphorus, and sulfur, with the following content ranges: C≤0.21%, Si≤0.50%, Mn≤1.60%, P≤0.04%, S≤0.04%. In addition, S235JR also contains trace elements such as chromium, nickel, and molybdenum, which help improve its mechanical properties and corrosion resistance.
The chemical composition of S355JR is similar to that of S235JR, but the content ranges of each element are slightly different. Its C ≤ 0.20%, Si ≤ 0.50%, Mn ≤ 1.70%, P ≤ 0.04%, S ≤ 0.04%. Compared to S235JR, S355JR has a higher manganese content, which helps to improve its strength and toughness.
Chemical Composition Comparison
| Element | S235JR (%) | S355JR (%) |
|---|---|---|
| Carbon (C) | ≤0.22 | ≤0.20 |
| Silicon (Si) | ≤0.55 | ≤0.55 |
| Manganese (Mn) | ≤1.70 | ≤1.60 |
| Phosphorus (P) | ≤0.045 | ≤0.035 |
| Sulfur (S) | ≤0.045 | ≤0.035 |
Mechanical Properties
S235JR has a tensile strength of 440-590MPa, a yield strength of ≥235MPa, and an elongation of ≥21%. S355JR, on the other hand, has a tensile strength of 490-690MPa, a yield strength of ≥355MPa, and an elongation of ≥18%. It is evident that S355JR has higher strength and toughness than S235JR. Furthermore, both types of channel steel exhibit high fatigue strength and wear resistance, maintaining stable performance in complex working environments.
Mechanical Properties Comparison
| Property | S235JR (MPa) | S355JR (MPa) |
|---|---|---|
| Yield Strength (Re) | ≥235 | ≥355 |
| Tensile Strength (Rm) | 360-510 | 470-630 |
| Elongation (A) | ≥18% | ≥22% |
Applications
S235JR, as a common construction steel, is suitable for the manufacture of general structures and mechanical parts, such as bridges, building frames, vehicles, and ships. The S355JR, with its higher strength and toughness, is suitable for manufacturing structural components and parts that require higher strength, such as heavy machinery, high-strength bridges, and high-rise buildings.
S235JR and S355JR SHS Tube in stock
