The difference in the implementation of standards
Q235B and Q355B are commonly used structural steel materials, mainly used in fields such as architecture, bridges, and ships.
The differences between the two are as follows:
Chemical Composition Comparison
Q235B: Primarily consists of carbon, manganese, and silicon, with low carbon content. It is suitable for light-load and medium-strength applications.
Q355B: In addition to similar elements as Q235B, it has higher manganese content, offering increased tensile strength and wear resistance, making it suitable for projects with higher load-bearing requirements.
Mechanical Properties Comparison
Q235B: Yield strength is 235MPa, tensile strength ranges from 375MPa to 500MPa, suitable for low and medium-strength structural needs.
Q355B: Yield strength is 355MPa, tensile strength ranges from 490MPa to 630MPa, suitable for high-strength projects that require higher load-bearing capabilities.
Weldability and Machinability Comparison
Q235B: With its lower carbon content, Q235B exhibits good weldability and machinability, making it ideal for conventional structural components.
Q355B: While Q355B has slightly lower weldability compared to Q235B, it performs well under proper welding processes and is suitable for more complex structural fabrication.
Suitable Industries Comparison
Q235B: Widely used in construction, bridges, and lightweight structures; it is the preferred material for standard low-strength applications.
Q355B: Commonly used in heavy machinery, steel structures, bridges, and high-strength projects that require greater load-bearing capacity.
Q235B and Q355B each have their advantages. The choice of steel should be based on the specific requirements of the project. For typical light and medium-duty applications, Q235B is sufficient, while Q355B is more suitable for high-strength, high-load-bearing projects.
Equivalent Steel Grade
Steel grade Q235B equally the following grade
- China (GB) Q235B
- Japan (JIS) SS400B
- United States (ASTM): Gr.65
- International (IOS) E235B
- Europe (EN) S235JR
Steel grade Q355B equally the following grade :
- China (GB) Q355B
- Japan (JIS) SCM440B
- United States (ASTM): Gr.50
- International (IOS) E355B
- Europe (EN) S355JR
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FAQ
Q: What is material grade Q355B?
A: The Q355B equivalent ASTM material
ASTM A572 Grade 50 is a structural steel with high strength and low alloy content that is widely utilized in structural applications. Both Q355B and ASTM A572 Grade 50 have a minimum yield strength of 355 MPa (50 ksi) and possess similar mechanical properties.
Q: What is the difference between Q345 and Q355B?
A: Q345B and Q355B are two different steels, and their main differences are as follows: Different properties: Q345 is a low-alloy steel, while Q355 is a low-alloy, high-strength structural steel widely used in bridges, vehicles, ships, buildings, pressure vessels, special equipment, and other fields.
Q: What is the difference between A36 and Q355B?
A: A36 and Q355B are both structural steel grades, but A36 is an older American standard (ASTM A36) while Q355B is a newer Chinese standard. Q355B generally offers higher strength and potentially better performance in some applications, particularly where higher yield strength is needed.
Q: What is the Indian standard equivalent of Q355B?
A: India: IS 2062 E350 or IS 8500 FE 570 are Indian standards that can be considered as equivalents to Q355B, commonly used in structural applications in India.
Q: What is the European equivalent of Q355B steel?
A: S355JR steels from European British steel standard BS EN10025-2 low alloy high strength steels. These two steel materials Q355B and S355JR are totally equivalent in chemical composition and mechincal properties from the following comparasion data table.
Q: What is the difference between Q355B and Q235B?
A: Different chemical compositions: Q235B has carbon (C) ≤ 0.22%, manganese (Mn) ≤ 1.4%, silicon (Si) ≤ 0.35%, phosphorus (P) ≤ 0.045%, and sulfur (S) ≤ 0.045%, while Q355B has carbon (C) ≤ 0.20%, manganese (Mn) ≤ 1.70%, silicon (Si) ≤ 0.50%, phosphorus (P) ≤ 0.030%, and sulfur (S) ≤ 0.030%.
Q: What is Q355B equivalent to JIS material?
A: Q355 Equivalent Materials
Q355 can be replaced with equivalent materials, including A572 Grade 50 USA ASTM, Q355 China GB/T, and SPFC 590 Vietnam/Japanese JIS.
| Other steel plate | ||||
| Name | Material | Specification (mm) | Tons | Remark |
| Low Alloy | Q345A, Q345B, Q345C, Q345D, Q345E, Q390, Q420, Q460C, ST52-3, S355J2+N, SS400, SA302GrC, S275NL, 35CrMo | 6 - 350 | 5788.56 | Normalizing, tempered ,controlled rolling, hot rolling , Hot rolling,1st inspection, 2nd inspection, 3rd inspection |
| Pressure Vessel Plate | Q245R, Q345R, Q370R, 16MnDR, 09MnNiDR, 15CrMoR, 14Cr1MoR, 12Cr2Mo1R, SA516Gr60, SA516Gr70, SA516Gr485, SA285, SA387Gr11, SA387Gr12, SA387Gr22, P265,P295,P355GH,Q245R(R-HIC),Q345R(R-HIC) | 3 - 300 | 8650 | Normalizing, tempered ,controlled rolling, hot rolling , Hot rolling,1st inspection, 2nd inspection, 3rd inspection |
| High-Strength Plate | WH785D/E,Q960D/E, Q890D/E,WH60D/E,WH70B,Q550D,Q590D,Q690D/E | 8 - 120 | 3086.352 | Quenched and tempered |
| Wear-Resistant Plate | NM360, NM400, NM450, NM500 | 6 - 150 | 3866.297 | Quenched and tempered |
| Bridge Plate | Q235qC, Q345qC, Q370qC, Q420qC, Q345qDNH, Q370qDNH, A709 - 50F - 2, A709 - 50T - 2 | 8 - 200 | 2853.621 | Hot rolling, normalized ,hot rolling controlled rolling, quenched and tempered + toughness and brittleness |
