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GB/T 1591 Q620MD vs GB/T 1591 Q690MC

Close Alternative — 70% match based on chemical composition and mechanical property overlap.

GB/T 1591 Q620MD (GB/T 1591:2018) and GB/T 1591 Q690MC (GB/T 1591:2018) are both steel grades. Both fall under the Structural Steel category. GB/T 1591 Q620MD is typically used for general structure for engineering (plates, strips, bars and sections), while GB/T 1591 Q690MC is commonly used for general structure for engineering (plates, strips, bars and sections). GB/T 1591 Q620MD is defined under Guobiao Standards (GB/T), originating from China, while GB/T 1591 Q690MC is defined under Guobiao Standards (GB/T), originating from China.

As per chemical composition, GB/T 1591 Q620MD vs GB/T 1591 Q690MC is a 97.1% match. As per mechanical properties, the match is 15.9%. Combined, this makes them a close alternative overall at 70%.

Other Structural Steel Grades to Compare With GB/T 1591 Q620MD:
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 400A CSA G40.21 400W CSA G40.21 480W ASTM A1008 SS Grade 50 ASTM A1008 SS Grade 80 ASTM A283C
Match Breakdown
CHEMISTRY MATCH
97.1%
MECHANICAL MATCH
15.9%
OVERALL
70%
Specifications
Property GB/T 1591 Q620MD GB/T 1591 Q690MC
Standard GB/T 1591:2018 GB/T 1591:2018
Category Structural Steel Structural Steel
C (%) <=0.18 <=0.18
Si (%) <=0.60 <=0.60
Mn (%) <=2.60 <=2.00
P (%) <=0.030 <=0.030
S (%) <=0.025 <=0.030
Nb (%) 0.01-0.11 0.01-0.11
V (%) 0.01-0.12 0.01-0.12
Ti (%) 0.006-0.05 0.006-0.05
Cr (%) <=1.00 <=1.00
Ni (%) <=0.80 <=0.80
Cu (%) <=0.80 <=0.80
Mo (%) <=0.30 <=0.30
N (%) <=0.025 <=0.015
B (%) <=0.004 <=0.004
Al (%) >=0.015 >=0.015
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 Q620MD GB/T 1591 Q690MC
Tensile Strength 710-880 MPa 770-940 MPa
Yield Strength >=620 MPa >=690 MPa
Elongation >=15% >=14%
Condition Thermomechanical processed (TMCP), nominal thickness or diameter up to 16 mm (tensile strength: up to 40 mm) Thermomechanical processed (TMCP), nominal thickness or diameter up to 16 mm (tensile strength: up to 40 mm)
Typical Applications
GB/T 1591 Q620MD
General structure for engineering (plates, strips, bars and sections)
GB/T 1591 Q690MC
General structure for engineering (plates, strips, bars and sections)
Can GB/T 1591 Q620MD Be Substituted With GB/T 1591 Q690MC?
GB/T 1591 Q620MD and GB/T 1591 Q690MC are a close alternative rather than a direct substitute. Some properties overlap well, but check the specific chemistry and mechanical rows above against your application's requirements before treating them as interchangeable.
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GB/T 1591 Q620MD
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GB/T 1591 Q690MC
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Frequently Asked Questions
What is the difference between GB/T 1591 Q620MD and GB/T 1591 Q690MC?
Both grades share a similar composition profile; see the specification table above for the exact chemistry and mechanical property values.
Can GB/T 1591 Q620MD be substituted with GB/T 1591 Q690MC?
GB/T 1591 Q620MD and GB/T 1591 Q690MC are a close alternative rather than a direct substitute. Some properties overlap well, but check the specific chemistry and mechanical rows above against your application's requirements before treating them as interchangeable.