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GB/T 1591 Q550MC vs GB/T 1591 Q620MC

Close Alternative — 71% match based on chemical composition and mechanical property overlap.

GB/T 1591 Q550MC (GB/T 1591:2018) and GB/T 1591 Q620MC (GB/T 1591:2018) are both steel grades. Both fall under the Structural Steel category. GB/T 1591 Q550MC is typically used for general structure for engineering (plates, strips, bars and sections), while GB/T 1591 Q620MC is commonly used for general structure for engineering (plates, strips, bars and sections). GB/T 1591 Q550MC is defined under Guobiao Standards (GB/T), originating from China, while GB/T 1591 Q620MC is defined under Guobiao Standards (GB/T), originating from China.

As per chemical composition, GB/T 1591 Q550MC vs GB/T 1591 Q620MC is a 97% match. As per mechanical properties, the match is 19%. Combined, this makes them a close alternative overall at 71%.

Frequently Compared With GB/T 1591 Q550MC:
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 GOST 19281 09G2S
Match Breakdown
CHEMISTRY MATCH
97%
MECHANICAL MATCH
19%
OVERALL
71%
Specifications
Property GB/T 1591 Q550MC GB/T 1591 Q620MC
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 (%) <=2.00 <=2.60
P (%) <=0.030 <=0.030
S (%) <=0.030 <=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 (%) <=0.80 <=1.00
Ni (%) <=0.80 <=0.80
Cu (%) <=0.80 <=0.80
Mo (%) <=0.30 <=0.30
N (%) <=0.015 <=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 Q550MC GB/T 1591 Q620MC
Tensile Strength 670-830 MPa 710-880 MPa
Yield Strength >=550 MPa >=620 MPa
Elongation >=16% >=15%
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 Q550MC
General structure for engineering (plates, strips, bars and sections)
GB/T 1591 Q620MC
General structure for engineering (plates, strips, bars and sections)
Can GB/T 1591 Q550MC Be Substituted With GB/T 1591 Q620MC?
GB/T 1591 Q550MC and GB/T 1591 Q620MC 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 Q550MC
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GB/T 1591 Q620MC
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Frequently Asked Questions
What is the difference between GB/T 1591 Q550MC and GB/T 1591 Q620MC?
Both grades share a similar composition profile; see the specification table above for the exact chemistry and mechanical property values.
Can GB/T 1591 Q550MC be substituted with GB/T 1591 Q620MC?
GB/T 1591 Q550MC and GB/T 1591 Q620MC 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.