Q355 Equivalent Material Guide: International Standards, Properties, and Applications

Q355 steel is one of the most widely used structural steels in China, commonly applied in buildings, bridges, machinery, and welded structures. For international engineers and buyers, the most frequent question is:

“What is Q355 equivalent to in EN, ASTM, and JIS standards?”

This guide provides a clear comparison of Q355 equivalents, chemical composition, mechanical properties, and important engineering notes—making it easier for global buyers to select the right material.

What Is Q355 Steel?

Q355 is a Chinese low-alloy high-strength structural steel defined in GB/T 1591-2018, with a minimum yield strength of 355 MPa. It is commonly used in:

• Steel structures
• Factory buildings
• Bridges
• Machinery components
• Construction equipment

Q355 is available in multiple grades—B, C, D, and E—to support different welding, toughness, and low-temperature requirements. Because of its balanced strength and weldability, Q355 material has become a major option for global engineering companies.

Q355 vs S355: Are They Equivalent?

1. Strength Comparison

Property	Q355	S355
Minimum Yield Strength	≥355 MPa	≥355 MPa
Tensile Strength	470–630 MPa	470–630 MPa
Elongation	Similar	Similar

2. Impact Toughness

Grade	Temperature	Requirement
Q355B	+20°C	≥27 J
Q355C	0°C	≥27 J
Q355D	−20°C	≥27 J
Q355E	−40°C	≥27 J
S355JR	+20°C	≥27 J
S355J0	0°C	≥27 J
S355J2	−20°C	≥27 J
S355NL	−50°C	Higher notch toughness

3. Conclusion

Q355 is generally equivalent to S355 in both strength and performance.

• Q355B is comparable to S355JR
• Q355C is comparable to S355J0
• Q355D is comparable to S355J2
• Q355E is similar to S355NL in impact test temperature, but note: S355NL is a normalized/normalized rolled steel with stricter requirements on chemical composition for improved weldability compared to the as-rolled or TMCP state of Q355E.

*For most structural applications, Q355 can be considered a functional equivalent to S355 when the correct grade is selected and approved by the project’s design authority.

For a broader understanding of S-series structural steels, you may also read our detailed comparison guide: S235/S275/S355 Structural Steel Comparison.

Q355 Equivalent Materials (EN, ASTM, JIS)

Below is the commonly accepted international equivalence:

Chinese Standard	Equivalent Standard	Grade
GB/T 1591	EN 10025-2	S355JR / S355JO / S355J2
GB/T 1591	ASTM A572	Grade 50 (based on yield strength)
GB/T 1591	JIS G3106	SS490*

*Note: SS490 comparison is based mainly on tensile properties; confirm yield strength, impact toughness, and specification requirements before substitution.

Chemical Composition of Q355 Steel

Below is the chemical composition of Q355 according to GB/T 1591-2018 (for thickness ≤ 16 mm, maximum values unless noted):

Element	Q355B	Q355C	Q355D	Q355E
C	≤0.24%	≤0.22%	≤0.20%	≤0.18%
Si	≤0.55%	≤0.55%	≤0.55%	≤0.55%
Mn	≤1.60%	≤1.60%	≤1.60%	≤1.60%
P	≤0.035%	≤0.035%	≤0.030%	≤0.025%
S	≤0.035%	≤0.035%	≤0.030%	≤0.020%
Nb+V+Ti	≤0.12%	≤0.12%	≤0.12%	≤0.12%

*Values follow GB/T 1591-2018

Mechanical Properties of Q355 Steel

Grade	Yield Strength (MPa)	Tensile Strength (MPa)	Elongation (%)	Impact Temperature
Q355B	≥355	470–630	≥22	20°C
Q355C	≥355	470–630	≥22	0°C
Q355D	≥355	470–630	≥22	−20°C
Q355E	≥355	470–630	≥22	−40°C

*The above are the minimum requirements per GB/T 1591-2018 for rolled sections and plates. Q355E provides enhanced low-temperature toughness, suitable for cold regions, offshore structures, and energy projects.

How to Select Q355B/C/D/E

Application Scenario	Recommended Grade
General construction	Q355B
Welding-focused structures	Q355C
Outdoor / cold regions	Q355D
Extremely low temperature	Q355E

Key Differences

• E-grade used in low-temperature engineering & critical welded structures
• B → E indicates improved impact toughness
• The letter defines the temperature for Charpy V-notch impact test
• Composition is similar; toughness and service temperature differ

Can Q355 Replace S355 or ASTM Steel in Engineering Projects?

Yes—Q355 steel can replace S355 and A572 Gr.50 in many applications such as:

• Industrial buildings
• Prefabricated steel structures
• Heavy machinery components
• Platforms and support frames

However, the substitution is not automatic. It requires:

• Documentation Review: Ensuring the Mill Test Certificate (MTC) for the supplied Q355 meets all specified chemical and mechanical properties.
• Design Approval: The responsible engineer must approve the material change based on the project’s governing codes.
• Grade-to-Grade Matching: Selecting the correct Q355 grade (B, C, D, E) to match the required impact toughness of the original specification.

Conclusion: Confirming the Right Q355 Equivalent Material

To summarize:

• The closest European EN equivalent to Q355 is the S355 series.
• A commonly referenced ASTM equivalent is A572 Grade 50.
• Always match the impact toughness grade (B, C, D, E) to your project’s service temperature and design requirements.
• Technical documentation such as Mill Test Certificates (MTC) with full chemical and mechanical test reports are essential for verification.

Now that the equivalence is clear, the next step is selecting the right product form.
To ensure structural safety, selecting the appropriate Q355 grade is critical. Ready to proceed? Choose the product that matches your project’s needs:

• Q355 H Beam: Ideal for beams, columns, and framing structures.
• Q355 Steel Plate: Suited for welded bases, platforms, and fabrications.
• Q355NH Bridge Steel Plate

Frequently Asked Questions About Q355 Steel Equivalent

• Q1. What is Q355 steel equivalent to?
  Q355 steel is generally considered equivalent to the EN S355 structural steel series in terms of yield strength and mechanical performance. The closest European equivalents are S355JR, S355J0, and S355J2, depending on impact test temperature requirements. In ASTM standards, Q355 is commonly compared to ASTM A572 Grade 50 based on minimum yield strength.
• Q2. Is Q355 the same as S355?
  Q355 and S355 are not identical standards, but they are functionally equivalent for most structural applications. Both have a minimum yield strength of 355 MPa and similar tensile strength ranges. The main differences lie in standard specifications, chemical composition limits, and delivery conditions. Grade matching, such as Q355B vs S355JR, is essential for correct substitution.
• Q3. What is the ASTM equivalent of Q355 steel?
  The most commonly referenced ASTM equivalent of Q355 steel is ASTM A572 Grade 50. This comparison is based primarily on yield strength. However, impact toughness, chemical composition, and specification requirements should always be reviewed before making a direct substitution.
• Q4. Which Q355 grade matches S355JR?
  Q355B is generally considered comparable to S355JR. Both grades require Charpy V-notch impact testing at +20°C and share similar mechanical property ranges. For projects requiring lower temperature toughness, Q355C, Q355D, or Q355E should be selected to match S355J0, S355J2, or S355NL respectively.
• Q5. Can Q355 replace S355 or ASTM A572 Grade 50?
  Yes, Q355 steel can replace S355 and ASTM A572 Grade 50 in many structural and fabrication applications. However, substitution should be approved by the project’s design authority and supported by Mill Test Certificates confirming compliance with chemical composition, mechanical properties, and impact toughness requirements.