A36 Carbon Steel Square Bar | ASTM A675 Hot Rolled & Cold Drawn Square Steel Bar

Stable mechanical performance consistent with ASTM standards
Great weldability and easy machining for fabrication
Dual surface options: black hot rolled / bright cold drawn
Reliable ductility for machinery structural parts
Complete size range for American market projects

Product Overview

A36 Carbon Steel Square Bar is manufactured following ASTM A675 specification, widely used for American-standard machinery and structural components. It is available in hot rolled and cold drawn production processes. Hot rolled A36 square bar has black oxide surface, while cold drawn type provides bright smooth surface with tighter dimensional tolerance.

A36 is a popular mild carbon structural steel with balanced strength and ductility, easy to cut, bend and weld. It is commonly used for machinery frames, support brackets, structural assemblies and general metal fabrication for North American projects. Custom cut lengths can be provided to match different project specifications.

Carbon Steel Square Bar

Chemical & Mechanical Property Snapshot

Item	A36 Carbon Steel Square Bar (ASTM A675)
Carbon (C)	≤0.29%
Silicon (Si)	≤0.40%
Manganese (Mn)	≤1.03%
Phosphorus (P)	≤0.040%
Sulfur (S)	≤0.050%
Yield Strength (Min)	250 MPa
Tensile Strength	400–550 MPa
Elongation (Min)	≥20%
Impact Test	Optional Charpy impact test upon request

Detailed Technical Specifications

Specification Item	Parameter
Product Name	A36 Carbon Steel Square Bar
Standard	ASTM A675
Production Process	Hot-Rolled / Cold-Drawn
Size Range	Hot Roll:10×10–200×200 mm; Cold Drawn:5×5–50×50 mm
Surface Condition	Hot-rolled black surface / Bright cold-drawn surface
Dimensional Tolerance	Hot Roll: ±0.5–2 mm; Cold Drawn: ±0.1–0.3 mm
Length	3m–12m or customized cut length
MOQ	5 Ton
Lead Time	7–15 working days
Package	Steel bundle with metal strapping, waterproof wrapping

Size Specification Table

Type	Size Range	Available Side Dimensions (mm)	Tolerance
Hot Rolled Carbon Steel Square Bar	10×10 mm–200×200 mm	10, 12, 16, 20, 25, 30, 40, 50, 60, 80, 100, 120, 150, 200	±0.5–±2 mm
Cold Drawn Carbon Steel Square Bar	5×5 mm–50×50 mm	5, 6, 8, 10, 12, 14, 16, 20, 25, 30, 40, 50	±0.1–±0.3 mm

Product Comparison Table

Comparison Item	Q235B Carbon Steel Square Bar	Q355B Carbon Steel Square Bar	S235JR Carbon Steel Square Bar	S355JR Carbon Steel Square Bar	A36 Carbon Steel Square Bar
Equivalent Standard	GB/T 702	GB/T 702	EN 10059	EN 10059	ASTM A675
Manufacturing Process	Hot-Rolled / Cold-Drawn	Hot-Rolled / Cold-Drawn	Hot-Rolled / Cold-Drawn	Hot-Rolled / Cold-Drawn	Hot-Rolled / Cold-Drawn
Size Range	Hot Roll: 10×10–200×200 mm; Cold Drawn: 5×5–50×50 mm	Hot Roll: 10×10–200×200 mm; Cold Drawn: 5×5–50×50 mm	Hot Roll: 10×10–200×200 mm; Cold Drawn: 5×5–50×50 mm	Hot Roll: 10×10–200×200 mm; Cold Drawn: 5×5–50×50 mm	Hot Roll: 10×10–200×200 mm; Cold Drawn: 5×5–50×50 mm
Surface Condition	Hot-rolled black surface / Bright cold-drawn surface	Hot-rolled black surface / Bright cold-drawn surface	Hot-rolled black surface / Bright cold-drawn surface	Hot-rolled black surface / Bright cold-drawn surface	Hot-rolled black surface / Bright cold-drawn surface
Dimensional Tolerance	Hot Roll: ±0.5–2 mm; Cold Drawn: ±0.1–0.3 mm	Hot Roll: ±0.5–2 mm; Cold Drawn: ±0.1–0.3 mm	Hot Roll: ±0.5–2 mm; Cold Drawn: ±0.1–0.3 mm	Hot Roll: ±0.5–2 mm; Cold Drawn: ±0.1–0.3 mm	Hot Roll: ±0.5–2 mm; Cold Drawn: ±0.1–0.3 mm
Yield Strength (Min)	235 MPa	355 MPa	235 MPa	355 MPa	250 MPa
Main Application	General steel structures, mechanical frames, mold blanks	Heavy-load supports, engineering structures, lifting parts	European-standard structural fabrication, mechanical bases	High-strength European engineering structures	American-standard machinery, structural components
Cost Level	Medium	Medium-High	Medium	Medium-High	Medium
Feature	Good weldability & machinability	High strength, good impact resistance	Excellent weldability, CE compliance	High strength, CE certified	Stable performance, ASTM standard

App Market

Reliable Steel Coil Solutions For Diverse Industrial Applications

Hardware Stamping Blanking

Steel Structure Support

Machine Frame

Product Packaging

Secure Export Packaging For Safe Handling And Delivery

FAQs

What standard is A36 square bar?

A36 carbon steel square bar complies with ASTM A675 standard for hot rolled and cold drawn solid square steel bars.

What is the difference between A36 and Q235B square bar?

A36 follows ASTM standard for North American projects with minimum yield strength 250MPa, Q235B follows GB standard with 235MPa yield strength for general domestic structures.

Can A36 square bar be welded?

Yes, A36 carbon steel has excellent weldability using common welding procedures.

What surface options are available?

Hot rolled black oxide surface and bright cold-drawn surface with tighter dimensional tolerance for precision machining.

Can we order custom cut lengths of A36 square bar?

Custom cutting service is available. MOQ 5 tons, production lead time 7–15 working days.

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A36 Carbon Steel Square Bar | ASTM A675 Hot Rolled & Cold Drawn Square Steel Bar