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GB/T 1591 Q355NB vs GB/T 1591 Q355MB

Strong Match — 95% match based on chemical composition and mechanical property overlap.

GB/T 1591 Q355NB (GB/T 1591:2018) and GB/T 1591 Q355MB (GB/T 1591:2018) are both steel grades. Both fall under the Structural Steel category. GB/T 1591 Q355NB is typically used for general structure for engineering (plates, strips, bars and sections), while GB/T 1591 Q355MB is commonly used for general structure for engineering (plates, strips, bars and sections). GB/T 1591 Q355NB is defined under Guobiao Standards (GB/T), originating from China, while GB/T 1591 Q355MB is defined under Guobiao Standards (GB/T), originating from China.

As per chemical composition, GB/T 1591 Q355NB vs GB/T 1591 Q355MB is a 92.5% match. As per mechanical properties, the match is 100%. Combined, this makes them a strong match overall at 95%.

Frequently Compared With GB/T 1591 Q355NB:
GOST 19281 09G2S CSA G40.21 300W CSA G40.21 400W ASTM A1008 SS Grade 50 ASTM A572 Gr.65
Other Structural Steel Grades to Compare With GB/T 1591 Q355NB:
CSA G40.21 260W AS/NZS 3679.1 300 AS/NZS 3679.1 350 CSA G40.21 350W CSA G40.21 400A CSA G40.21 480W ASTM A1008 SS Grade 80
Match Breakdown
CHEMISTRY MATCH
92.5%
MECHANICAL MATCH
100%
OVERALL
95%
Specifications
Property GB/T 1591 Q355NB GB/T 1591 Q355MB
Standard GB/T 1591:2018 GB/T 1591:2018
Category Structural Steel Structural Steel
C (%) <=0.20 <=0.14
Si (%) <=0.50 <=0.50
Mn (%) 0.90-1.65 <=1.60
P (%) <=0.035 <=0.035
S (%) <=0.035 <=0.035
Nb (%) 0.005-0.05 0.01-0.05
V (%) 0.01-0.12 0.01-0.10
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 Q355NB GB/T 1591 Q355MB
Tensile Strength 470-630 MPa 470-630 MPa
Yield Strength >=355 MPa >=355 MPa
Elongation >=22% >=22%
Condition Normalized or normalizing rolled, nominal thickness or diameter up to 16 mm (tensile strength: up to 100 mm) Thermomechanical processed (TMCP), nominal thickness or diameter up to 16 mm (tensile strength: up to 40 mm)
Typical Applications
GB/T 1591 Q355NB
General structure for engineering (plates, strips, bars and sections)
GB/T 1591 Q355MB
General structure for engineering (plates, strips, bars and sections)
Can GB/T 1591 Q355NB Be Substituted With GB/T 1591 Q355MB?
GB/T 1591 Q355NB and GB/T 1591 Q355MB overlap closely enough on chemistry and mechanical properties that GB/T 1591 Q355MB is often considered as a substitute for GB/T 1591 Q355NB 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 Q355NB
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GB/T 1591 Q355MB
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Frequently Asked Questions
What is the difference between GB/T 1591 Q355NB and GB/T 1591 Q355MB?
Both grades share a similar composition profile; see the specification table above for the exact chemistry and mechanical property values.
Can GB/T 1591 Q355NB be substituted with GB/T 1591 Q355MB?
GB/T 1591 Q355NB and GB/T 1591 Q355MB overlap closely enough on chemistry and mechanical properties that GB/T 1591 Q355MB is often considered as a substitute for GB/T 1591 Q355NB in many applications. Always confirm the specific property range your application needs before substituting, and check with your supplier's mill certificate.