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GB/T 1591 Q390MD vs GB/T 1591 Q390NB

Strong Match — 94.1% match based on chemical composition and mechanical property overlap.

GB/T 1591 Q390MD (GB/T 1591:2018) and GB/T 1591 Q390NB (GB/T 1591:2018) are both steel grades. Both fall under the Structural Steel category. GB/T 1591 Q390MD is typically used for general structure for engineering (plates, strips, bars and sections), while GB/T 1591 Q390NB is commonly used for general structure for engineering (plates, strips, bars and sections). GB/T 1591 Q390MD is defined under Guobiao Standards (GB/T), originating from China, while GB/T 1591 Q390NB is defined under Guobiao Standards (GB/T), originating from China.

As per chemical composition, GB/T 1591 Q390MD vs GB/T 1591 Q390NB is a 91.2% match. As per mechanical properties, the match is 100%. Combined, this makes them a strong match overall at 94.1%.

Other Structural Steel Grades to Compare With GB/T 1591 Q390MD:
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
91.2%
MECHANICAL MATCH
100%
OVERALL
94.1%
Specifications
Property GB/T 1591 Q390MD GB/T 1591 Q390NB
Standard GB/T 1591:2018 GB/T 1591:2018
Category Structural Steel Structural Steel
C (%) <=0.15 <=0.20
Si (%) <=0.50 <=0.50
Mn (%) <=1.70 0.90-1.70
P (%) <=0.030 <=0.035
S (%) <=0.025 <=0.035
Nb (%) 0.01-0.05 0.01-0.05
V (%) 0.01-0.12 0.01-0.20
Ti (%) 0.006-0.05 0.006-0.05
Cr (%) <=0.30 <=0.30
Ni (%) <=0.50 <=0.50
Cu (%) <=0.40 <=0.40
Mo (%) <=0.10 <=0.10
N (%) <=0.015 <=0.015
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 Q390MD GB/T 1591 Q390NB
Tensile Strength 490-650 MPa 490-650 MPa
Yield Strength >=390 MPa >=390 MPa
Elongation >=20% >=20%
Condition Thermomechanical processed (TMCP), nominal thickness or diameter up to 16 mm (tensile strength: up to 40 mm) Normalized or normalizing rolled, nominal thickness or diameter up to 16 mm (tensile strength: up to 100 mm)
Typical Applications
GB/T 1591 Q390MD
General structure for engineering (plates, strips, bars and sections)
GB/T 1591 Q390NB
General structure for engineering (plates, strips, bars and sections)
Can GB/T 1591 Q390MD Be Substituted With GB/T 1591 Q390NB?
GB/T 1591 Q390MD and GB/T 1591 Q390NB overlap closely enough on chemistry and mechanical properties that GB/T 1591 Q390NB is often considered as a substitute for GB/T 1591 Q390MD in many applications. Always confirm the specific property range your application needs before substituting, and check with your supplier's mill certificate.
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GB/T 1591 Q390MD
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GB/T 1591 Q390NB
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Frequently Asked Questions
What is the difference between GB/T 1591 Q390MD and GB/T 1591 Q390NB?
Both grades share a similar composition profile; see the specification table above for the exact chemistry and mechanical property values.
Can GB/T 1591 Q390MD be substituted with GB/T 1591 Q390NB?
GB/T 1591 Q390MD and GB/T 1591 Q390NB overlap closely enough on chemistry and mechanical properties that GB/T 1591 Q390NB is often considered as a substitute for GB/T 1591 Q390MD in many applications. Always confirm the specific property range your application needs before substituting, and check with your supplier's mill certificate.