GB/T 1591:2018 Q355MB Steel: Specifications & Listings

GB/T 1591:2018 Q355MB: Q355MB: high strength low alloy structural steel, thermomechanical processed (TMCP), quality grade B. Specified in GB/T 1591:2018.

Category: Structural Steel
Grade Details
GradeGB/T 1591:2018 Q355MB
Standard GB/T 1591:2018
ApplicationsGeneral structure for engineering (plates, strips, bars and sections)
Grade ComparisonCompare With a Specific Grade →
Grade Standard Match
GB/T 1591 Q355MC GB/T 1591:2018 Strong Match
GB/T 1591 Q355MD GB/T 1591:2018 Strong Match
GB/T 1591 Q355ME GB/T 1591:2018 Strong Match
GB/T 1591 Q355MF GB/T 1591:2018 Strong Match
GB/T 1591 Q355NB GB/T 1591:2018 Strong Match
GB/T 1591 Q355NC GB/T 1591:2018 Strong Match
GB/T 1591 Q355ND GB/T 1591:2018 Strong Match
GB/T 1591 Q355NE GB/T 1591:2018 Strong Match
Matched by chemical composition and mechanical properties, not a formal equivalence claim. Always verify against the applicable standard before substitution.
Chemical Composition (%)
C Si Mn P S Nb V Ti Cr Ni Cu Mo N Al
<=0.14 <=0.50 <=1.60 <=0.035 <=0.035 0.01-0.05 0.01-0.10 0.006-0.05 <=0.30 <=0.50 <=0.40 <=0.10 <=0.015 >=0.015
Mechanical Properties
Tensile Strength 470-630 MPa
Yield Strength >=355 MPa
Elongation >=22%
Condition Thermomechanical processed (TMCP), nominal thickness or diameter up to 16 mm (tensile strength: up to 40 mm)

More data from GB/T 1591:2018

From the standard
Upper yield strength by thickness 6 thickness ranges
Thickness or diameter (mm)Upper yield strength ReH, min (MPa)
up to 16355
over 16 to 40345
over 40 to 63335
over 63 to 80325
over 80 to 100325
over 100 to 120320
Thermomechanical processed (TMCP) condition.
Source: GB/T 1591:2018, Table 10
Tensile strength by thickness 5 thickness ranges
Thickness or diameter (mm)Tensile strength Rm (MPa)
up to 40470-630
over 40 to 63450-610
over 63 to 80440-600
over 80 to 100440-600
over 100 to 120430-590
Thermomechanical processed (TMCP) condition.
Source: GB/T 1591:2018, Table 10
Elongation after fracture single value
Elongation A, min
22 %
Single value printed for all thicknesses.
Source: GB/T 1591:2018, Table 10
Charpy V-notch impact energy 1 test temperature(s)
Test temperatureLongitudinal KV2, min (J)Transverse KV2, min (J)
20 deg C3427
Standard 10 mm x 10 mm x 55 mm specimen.
Source: GB/T 1591:2018, Table 11

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