Chinese‑American‑European Steel Grade Comparison
Compare Chinese, American and European steel grades: Q235, A36, S235, Q355, A572 Gr.50, S355 and more, with yield strength, tensile strength and standard refere
Steel Grade Comparison among Chinese, American and European Standards
I. Steel Grade Comparison
1.1 Carbon Structural Steel
|
Region |
Standard No. |
Grade |
Yield Strength Fy |
Tensile Strength Fu / Remarks |
|
China |
GB/T 700-2006 |
Q235 |
≥ 235 MPa |
370~500 MPa, most commonly used carbon structural steel |
|
USA |
ASTM A36/A36M-19 |
A36 |
≥ 250 MPa |
400~550 MPa, the most widely used structural steel |
|
Europe |
EN 10025-2:2019 |
S235 |
≥ 235 MPa |
360~510 MPa, base grade for structural steel |
Key difference: the mechanical properties are close, but the standard systems are completely different. For thickness ≤ 16 mm, A36 provides Fy = 250 MPa, while Q235 provides Fy = 235 MPa at the same thickness — a difference of one strength grade.
1.2 High-Strength Low-Alloy Steel
|
Region |
Standard No. |
Grade |
Yield Strength Fy |
Tensile Strength Fu / Remarks |
|
China |
GB/T 1591-2018 |
Q355 (replacing Q345) |
≥ 355 MPa |
470~630 MPa, implemented in Feb 2019 |
|
China (old) |
GB/T 1591-2008 |
Q345 |
≥ 345 MPa |
Still in service; pay attention to the year of revision |
|
USA |
ASTM A572/A572M-22 |
A572 Gr.50 |
≥ 345 MPa |
≥ 450 MPa; five grades: 42/50/55/60/65 |
|
USA |
ASTM A992/A992M-22 |
A992 |
≥ 345 MPa |
≥ 450 MPa, specifically for wide-flange W-shape beams/columns |
|
Europe |
EN 10025-2:2019 |
S355 |
≥ 355 MPa |
470~630 MPa, mechanical properties almost identical to Q355 |
Important note: in the 2018 Chinese revision, Q345 was upgraded to Q355 (the Q355 series is a standard upgrade of the former Q345 series, with nominal yield strength raised to 355 MPa; in engineering practice it is generally treated as the continuation/replacement of Q345, but the governing standard and additional performance requirements shall still be checked). In overseas projects, if the contract specifies Q345 but the material certificate supplies Q355, this shall be recognized as an upgraded replacement, not as material substitution.
A992 is unique to the United States. A992 and A572 Gr.50 have similar strength, but A992 imposes additional requirements on chemical composition, weldability and yield-to-tensile ratio, and is intended mainly for W-shapes; engineering substitution requires checking the material certification.
1.3 High-Strength Structural Steel
|
Region |
Standard No. |
Grade |
Yield Strength Fy |
Tensile Strength Fu / Remarks |
|
China |
GB/T 1591-2018 |
Q390 / Q420 / Q460 |
≥ 390/420/460 MPa |
Q460 is the highest grade |
|
USA |
ASTM A913/A913M |
A913 Gr.65 |
≥ 450 MPa |
High-strength low-alloy special sections |
|
Europe |
EN 10025-2:2019 |
S420 / S460 |
≥ 420/460 MPa |
— |
1.4 Quick Look-up of Approximate Grade Equivalence
|
China |
USA |
Europe |
|
Q235 |
A36 |
S235 |
|
Q355 |
A572 Gr.50 ≈ A992 |
S355 |
|
Q390 |
A572 Gr.60 |
S420 |
|
Q460 |
A913 Gr.65 |
S460 |
Equivalence ≠ identity: actual substitution requires checking carbon equivalent (Ceq), Charpy V-notch impact toughness, and applicable thickness range.
II. Plates and Sections
2.1 Chinese Standard System
· GB/T 1591-2018 — High-strength low-alloy structural steel (Q355 / Q235, main steel for communication towers).
· GB/T 706-2016 — Hot-rolled sections (equal-leg angles, unequal-leg angles, channels, I-beams).
· Common steels for communication towers: angle steel (main / bracing members), steel tubes (monopole tower / pole segments), steel plates (flanges, stiffeners).
2.2 US Standard System
· AISC 14th — US Steel Construction Manual; ASTM A6/A6M-20 — general requirements for plates and sections.
· ASTM A36/A36M — carbon structural steel (≈ Q235, for flanges and connection plates).
· ASTM A572 Gr.50 — high-strength low-alloy structural steel (≈ Q355, main steel for communication towers).
· Tubular sections: HSS (Hollow Structural Sections), e.g. HSS6×6×3/8; angle steel: imperial designation, e.g. L4×4×1/4.
· Flange thick plate: t ≥ 16 mm (5/8") commonly used; stiffener: 8~12 mm; connection plate: 6~10 mm.
2.3 European Standard System
· EN 10025-2:2019 — hot-rolled structural steel (S235 / S275 / S355, corresponding to Q235 / Q345 / Q355).
· EN 10210-1:2006 — non-alloy structural steel tubes (hot-finished hollow sections, circular / rectangular).
· EN 10025-2 — S355JR / S355J2 (commonly used for communication tower main steel, equivalent to Q355).
· European angle steel: L series (e.g. L90×90×8); tubular sections: CHS (Circular Hollow Section), e.g. CHS 114×5.
III. Bolts
3.1 Chinese Bolt Grade System
|
Standard No. |
Grade |
Yield Strength Fy |
Tensile Strength Fu |
Remarks |
|
GB/T 3098.1-2010 |
Grade 4.8 |
≥ 320 MPa |
≥ 400 MPa |
General-purpose bolt, commonly used for communication towers |
|
GB/T 3098.1-2010 |
Grade 6.8 |
≥ 480 MPa |
≥ 600 MPa |
General-purpose bolt, commonly used for communication towers |
|
GB/T 3098.1-2010 (JGJ 82-2011) |
Grade 8.8 |
≥ 640 MPa |
≥ 800 MPa |
High-strength bolt, commonly used for communication towers |
|
GB/T 3098.1-2010 (JGJ 82-2011) |
Grade 10.9 |
≥ 900 MPa |
≥ 1040 MPa |
High-strength bolt |
|
GB/T 3098.1-2010 |
Grade 12.9 |
≥ 1080 MPa |
≥ 1220 MPa |
High-strength bolt, special-purpose |
Marking rule (GB/T 3098.1): the integer part = 1/100 of the tensile strength (MPa); the decimal part = the yield-to-tensile ratio. Example: Grade 8.8 → tensile strength 800 MPa, yield strength = 800 × 0.8 = 640 MPa.
Hex-head bolt classification
· Grade C (coarse hex head) — GB/T 5780 (Grade C, rough surface).
· Grade A (precision hex head) — GB/T 5782 (Grade A, higher precision).
3.2 US Bolt Grade System
|
Standard No. |
Grade |
Yield Strength Fy |
Tensile Strength Fu |
Remarks |
|
ASTM F3125/F3125M-22 |
A325 |
≥ 660 MPa |
≥ 830 MPa (120 ksi) |
High-strength structural bolt (imperial) |
|
ASTM F3125/F3125M-22 |
A490 |
≥ 890 MPa |
≥ 1040 MPa (150 ksi) |
Higher strength, heat-treated alloy steel |
|
ASTM A307-14 |
A307 |
— |
≥ 410 MPa |
Carbon-steel bolt for light-duty use (non-high-strength) |
F3125 consolidation: ASTM F3125 is the new consolidated 2022 standard, incorporating the former A325, A325M, A490, A490M, F1852 (twist-off type) and F2280 (enhanced type). Current projects still customarily call them “A325 / A490”, but the actual delivery document shall specify F3125.
· A325 has two types: Type 1 (alloy/carbon steel), Type 3 (corrosion-resistant steel).
· A490 has only Type 1 and does not permit galvanizing (unlike A325).
3.3 European / ISO Bolt Grade System
|
Standard No. |
Grade |
Yield Strength Fy |
Tensile Strength Fu |
Remarks |
|
ISO 898-1:2013 |
Grade 6.8 |
≥ 480 MPa |
≥ 600 MPa |
Numerically identical to GB/T 3098.1 |
|
ISO 898-1:2013 |
Grade 8.8 |
≥ 640 MPa |
≥ 800 MPa |
Numerically identical to GB/T 3098.1 |
|
ISO 898-1:2013 |
Grade 10.9 |
≥ 940 MPa |
≥ 1040 MPa |
High-strength bolt |
|
EN 14399 series |
8.8 / 10.9 |
same as above |
same as above |
Pretensioned bolt assemblies (European pretension system) |
Important: ISO 898-1 = GB/T 3098.1; their technical content is identical, both originating from ISO 898-1. Therefore Chinese Grade 8.8 and European Grade 8.8 are fully equivalent.
3.4 Summary Comparison Table for Bolt Grades
|
China GB/T 3098.1 |
USA ASTM |
Europe ISO |
Tensile Strength |
|
Grade 4.8 |
A307 |
— |
400 MPa |
|
Grade 6.8 |
— |
Grade 6.8 |
600 MPa |
|
Grade 8.8 |
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