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GB/T 1591 Q420MD vs CSA G40.21 400A

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

GB/T 1591 Q420MD (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 Q420MD 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 Q420MD 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 Q420MD vs CSA G40.21 400A is a 61.7% match. As per mechanical properties, the match is 31.3%. Combined, this makes them a minimal match overall at 35%.

Frequently Compared With GB/T 1591 Q420MD:
GOST 19281 09G2S 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 50 ASTM A1008 SS Grade 80 ASTM A283C ASTM A572 Gr.65
Match Breakdown
CHEMISTRY MATCH
61.7%
MECHANICAL MATCH
31.3%
OVERALL
35%
Specifications
Property GB/T 1591 Q420MD CSA G40.21 400A
Standard GB/T 1591:2018 CSA G40.21-13 (R2023)
Category Structural Steel Structural Steel
C (%) <=0.16 <=0.23
Si (%) <=0.50 <=0.40
Mn (%) <=1.70 <=1.60
P (%) <=0.030 <=0.035
S (%) <=0.025 <=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 (%) <=0.80 Not specified
Cu (%) <=0.40 0.20-0.40
Mo (%) <=0.20 Not specified
N (%) <=0.025 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 Q420MD CSA G40.21 400A
Tensile Strength 520-680 MPa 520-670 MPa
Yield Strength >=420 MPa 400 MPa min
Elongation >=19% 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 Q420MD
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 Q420MD Be Substituted With CSA G40.21 400A?
GB/T 1591 Q420MD 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 Q420MD
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 Q420MD
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 Q420MD and CSA G40.21 400A?
GB/T 1591 Q420MD specifies Nb, V, Ti, Cr which are not specified for CSA G40.21 400A.
Can GB/T 1591 Q420MD be substituted with CSA G40.21 400A?
GB/T 1591 Q420MD 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.