Close Alternative — 71.1% match
based on chemical composition and mechanical property overlap.
GB/T 1591 Q620MD (GB/T 1591:2018) and GB/T 1591 Q690MD (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 Q690MD 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 Q690MD is defined under Guobiao Standards (GB/T), originating from China.
As per chemical composition, GB/T 1591 Q620MD vs GB/T 1591 Q690MD is a 98.7% match.
As per mechanical properties, the match is 15.9%.
Combined, this makes them a close alternative overall at 71.1%.
Other Structural Steel Grades to Compare With GB/T 1591 Q620MD:
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 Q690MD
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 Q690MD
General structure for engineering (plates, strips, bars and sections)
Can GB/T 1591 Q620MD Be Substituted With GB/T 1591 Q690MD?
GB/T 1591 Q620MD and GB/T 1591 Q690MD 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.
What is the difference between GB/T 1591 Q620MD and GB/T 1591 Q690MD?
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 Q690MD?
GB/T 1591 Q620MD and GB/T 1591 Q690MD 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.