Large Square Billet 250x250mm Q345B

Large Square Billet 250x250mm Q345B - Image 3

Large Square Billet 250x250mm Q345B

This 250x250mm Q345B large square billet is engineered to maintain consistent mechanical properties across its thick cross-section, making it suitable for heavy-duty fabrication where structural integrity and dimensional stability are critical. Its controlled chemistry ensures uniform performance during hot working, while its large size minimizes welding joints in large-scale components.

2010 ESTABLISHED

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Product details

The Large Square Billet 250x250mm Q345B is a premium low-alloy high-strength steel product designed to meet the rigorous demands of heavy fabrication and large-scale infrastructure projects. Compliant with GB/T 1591-2008 standards, this 250x250mm square billet combines exceptional strength, dimensional stability, and workability, making it an indispensable raw material for creating robust, load-bearing components in construction, machinery, and industrial engineering.

Parameter	Value	Remarks
Standard	GB/T 1591-2008	Low alloy high-strength structural steel standard
Grade	Q345B	Impact tested at 20℃
Chemical Composition (wt%)
– Carbon (C)	≤0.20	Ensures good weldability and formability for large-section processing
– Silicon (Si)	≤0.55	Aids deoxidation and contributes to strength retention
– Manganese (Mn)	≤1.70	Enhances strength and toughness in thick sections
– Phosphorus (P)	≤0.040	Minimized to prevent embrittlement in large billets
– Sulfur (S)	≤0.040	Low content reduces hot cracking during fabrication
– Niobium (Nb)	≤0.07	Microalloying for grain refinement, critical for large sections
– Vanadium (V)	≤0.15	Improves strength uniformity across thick cross-sections
– Titanium (Ti)	≤0.20	Enhances toughness and structural stability in large billets
– Nitrogen (N)	≤0.012	Controlled to avoid porosity in thick steel
Mechanical Properties
– Yield Strength (ReL)	≥345 MPa	For thickness ≤16mm; adjusted for 250mm section as per standard
– Tensile Strength (Rm)	470–630 MPa	Ensures load-bearing capacity in heavy structural applications
– Elongation (A)	≥21%	Provides ductility for hot/cold working of large billets
– Impact Energy (Akv)	≥34 J	At 20℃ (longitudinal specimen), resists fracture in thick sections
– Bending Test	180°	Bend diameter: 3a (for 250mm section, ‘a’ = relevant dimension)
Dimensions	250 x 250 mm (square cross-section)	Nominal size; tolerance complies with GB/T 702-2017
Length	6–12m (customizable)	Standard delivery range; longer lengths available on request
Surface Quality	Free from cracks, folds, and excessive scale	Ensures suitability for further processing (forging, rolling)
Delivery Condition	Hot rolled, normalized, or TMCP	TMCP recommended for optimal mechanical properties in large sections
Typical Applications	Heavy machinery frames, bridge structural components, large-diameter pipe billets, pressure vessel shells, and high-load industrial structures	Ideal for projects requiring large, high-strength raw materials