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GB/T 1591 Q390MB vs CSA G40.21 400A

Minimal Match — 35% match based on chemical composition and mechanical property overlap.

GB/T 1591 Q390MB (GB/T 1591:2018) and CSA G40.21 400A (CSA G40.21-13 (R2023)) are both steel grades. Both fall under the Structural Steel category. GB/T 1591 Q390MB is typically used for general structure for engineering (plates, strips, bars and sections), while CSA G40.21 400A is commonly used for atmospheric corrosion-resistant (weathering) structural steel; exposed bridge girders and structural members where high strength and weathering resistance are both needed. GB/T 1591 Q390MB is defined under Guobiao Standards (GB/T), originating from China, while CSA G40.21 400A is defined under Canadian Standards Association (CSA), originating from Canada.

As per chemical composition, GB/T 1591 Q390MB vs CSA G40.21 400A is a 64.5% match. As per mechanical properties, the match is 24.1%. Combined, this makes them a minimal match overall at 35%.

Frequently Compared With GB/T 1591 Q390MB:
CSA G40.21 260W AS/NZS 3679.1 300 CSA G40.21 300W AS/NZS 3679.1 350 CSA G40.21 350W CSA G40.21 400W CSA G40.21 480W ASTM A1008 SS Grade 80
Other Structural Steel Grades to Compare With GB/T 1591 Q390MB:
GOST 19281 09G2S ASTM A1008 SS Grade 50 ASTM A283C ASTM A572 Gr.65
Match Breakdown
CHEMISTRY MATCH
64.5%
MECHANICAL MATCH
24.1%
OVERALL
35%
Specifications
Property GB/T 1591 Q390MB CSA G40.21 400A
Standard GB/T 1591:2018 CSA G40.21-13 (R2023)
Category Structural Steel Structural Steel
C (%) <=0.15 <=0.23
Si (%) <=0.50 <=0.40
Mn (%) <=1.70 <=1.60
P (%) <=0.035 <=0.035
S (%) <=0.035 <=0.035
Nb (%) 0.01-0.05 Not specified
V (%) 0.01-0.12 Not specified
Ti (%) 0.006-0.05 Not specified
Cr (%) <=0.30 Not specified
Ni (%) <=0.50 Not specified
Cu (%) <=0.40 0.20-0.40
Mo (%) <=0.10 Not specified
N (%) <=0.015 Not specified
Al (%) >=0.015 Not specified
Matched by chemical composition and mechanical properties, not a formal equivalence claim. Always verify against the applicable standard before substitution.
Mechanical Properties
Property GB/T 1591 Q390MB CSA G40.21 400A
Tensile Strength 490-650 MPa 520-670 MPa
Yield Strength >=390 MPa 400 MPa min
Elongation >=20% 17% min
Condition Thermomechanical processed (TMCP), nominal thickness or diameter up to 16 mm (tensile strength: up to 40 mm) Not specified
Impact Not specified 27J at 0°C
Typical Applications
GB/T 1591 Q390MB
General structure for engineering (plates, strips, bars and sections)
CSA G40.21 400A
Atmospheric corrosion-resistant (weathering) structural steel; exposed bridge girders and structural members where high strength and weathering resistance are both needed
Key Differences
Can GB/T 1591 Q390MB Be Substituted With CSA G40.21 400A?
GB/T 1591 Q390MB and CSA G40.21 400A share some compositional similarity but differ enough that substitution should not be assumed. Review the differences above carefully, and consult the applicable standard or a metallurgist before using one in place of the other.
Forms & Sizes Available on M-EX
GB/T 1591 Q390MB
No active listings currently.
CSA G40.21 400A
Plate → (2 listings)
Thickness: 10–10 mm (0.39–0.39 in)
Width: 1500–1500 mm (59.06–59.06 in)
Length: 2800–4200 mm (110.24–165.35 in)
On M-EX Right Now
GB/T 1591 Q390MB
0 active listings and RFQs →
CSA G40.21 400A
2 active listings and RFQs →
Frequently Asked Questions
What is the difference between GB/T 1591 Q390MB and CSA G40.21 400A?
GB/T 1591 Q390MB specifies Nb, V, Ti, Cr which are not specified for CSA G40.21 400A.
Can GB/T 1591 Q390MB be substituted with CSA G40.21 400A?
GB/T 1591 Q390MB and CSA G40.21 400A share some compositional similarity but differ enough that substitution should not be assumed. Review the differences above carefully, and consult the applicable standard or a metallurgist before using one in place of the other.