What Q460C Steel Is
Q460C is a high-strength low-alloy structural steel specified in GB/T 1591, where Q denotes yield strength, 460 is the minimum yield strength in MPa for thickness up to 16 mm, and C is the quality grade requiring a Charpy V-notch impact test of 34 J at 0 degrees C. The steel achieves its strength through controlled alloying and microalloying rather than heavy carbon content, which keeps it weldable.
Chemical Composition
The composition is balanced for strength and weldability:
Carbon: maximum 0.20 percent
Silicon: maximum 0.55 percent
Manganese: 1.00-1.70 percent
Phosphorus and sulphur: each maximum 0.030 percent
Microalloys: niobium, vanadium and titanium may be added singly or in combination to refine the grain structure
Mechanical Properties
For plate thickness up to 16 mm, Q460C offers a minimum yield strength of 460 MPa and a tensile strength of 550-720 MPa with an elongation of at least 17 percent. The values adjust slightly for thicker plate, and the C quality grade guarantees an impact energy of 34 J at 0 degrees C, which suits outdoor structures in cold climates.
Weldability and Fabrication
With controlled carbon and carbon equivalent, Q460C can be welded using standard arc processes with appropriate consumables and preheat. Plate can be cut by plasma or flame, formed by bending and rolled into cylinders. Because of the higher strength, welding procedure qualification should follow the applicable code, and low-hydrogen electrodes are recommended.
Typical Applications
Heavy structural plate for bridges, stadiums and high-rise buildings
Booms, frames and structural parts of cranes and construction machinery
Pressure vessels, storage tanks and penstocks in moderate service
Mining equipment, transport frames and heavy fabrication
Frequently Asked Questions
Q: What does Q460C mean in GB/T 1591?
Q460C is a high-strength low-alloy steel with 460 MPa minimum yield strength for thickness up to 16 mm and a Charpy V-notch impact requirement of 34 J at 0 degrees C.
Q: Is Q460C weldable?
Yes, with controlled carbon equivalent and appropriate welding procedure, including low-hydrogen consumables and preheat where required.
Q: What thickness range is available?
Q460C plate is commonly supplied from 3 mm up to 120 mm, with thicker plate available by arrangement.
Q: How does Q460C compare with Q345B?
Q460C offers a minimum yield of 460 MPa versus 345 MPa for Q345B, allowing thinner and lighter members for the same load, at a higher material cost.
Q: What test certificates are supplied?
Plates are delivered with mill certificates including heat number, chemical analysis and mechanical test results in accordance with GB/T 1591.