Q355B Hot Rolled Carbon Steel Round Bar, Equivalent S355JR Carbon Steel Solid Round Bar

High tensile & yield strength for heavy load structural use
Good weldability and formability for fabrication
S355JR international equivalent grade, widely accepted in global market
Stable mechanical performance under low temperature
Wide diameter range, flexible cutting service available

Product Overview

Q355B hot rolled carbon steel round bar is a low alloy high strength hot rolled solid steel rod, equivalent international grade S355JR. It is manufactured strictly under GB/T 702, ASTM A675, EN 10060 standards. This grade features excellent mechanical strength, reliable impact resistance and good welding property. The surface is black finish with mill scale from hot rolling process. It is widely used for structural components, machinery parts, forging blanks, support frames and construction engineering. We can provide customized cutting length and inspection certificates for global customers.

Carbon Steel Round Bar

Chemical & Mechanical Property Snapshot

Item	Q355B (S355JR Equivalent)
C (Carbon)	≤0.20%
Si (Silicon)	≤0.50%
Mn (Manganese)	≤1.60%
P (Phosphorus)	≤0.035%
S (Sulfur)	≤0.035%
Yield Strength	≥355 MPa
Tensile Strength	470–630 MPa
Elongation	≥21%
Impact Test	B grade, room temperature impact

Detailed Technical Specifications

Specification Item	Details
Product Name	Q355B Hot Rolled Carbon Steel Round Bar
Equivalent Grade	S355JR
Production Standard	GB/T 702, ASTM A675, EN 10060
Diameter Range	Φ10 mm – Φ300 mm
Surface Condition	Black surface with mill scale
Tolerance	Standard hot-rolling industrial tolerance
Length	3m – 12m or customized cut length
MOQ	5 Ton
Lead Time	7–15 working days after deposit
Certification	MTC, Mill Test Certificate
Package	Bundled with steel strips, seaworthy packing

Size Specification Table

Type	Diameter Range	Common Available Diameters	Standard Length	Tolerance	Cutting Service
Hot Rolled Round Bar	Φ10 mm–Φ300 mm	Φ12, Φ14, Φ16, Φ18, Φ20, Φ25, Φ30, Φ40, Φ50, Φ60, Φ80, Φ100, Φ120, Φ150, Φ200, Φ250, Φ300	6 m / 12 m	Standard hot-rolling tolerance	Custom cut-to-length & zero-cut
Cold Drawn Bright Round Bar	Φ3 mm–Φ80 mm	Φ3, Φ4, Φ5, Φ6, Φ8, Φ10, Φ12, Φ14, Φ16, Φ20, Φ25, Φ30, Φ40, Φ50, Φ60, Φ70, Φ80	6 m / 12 m	±0.02–0.05 mm	Custom cut-to-length & zero-cut

Product Comparison Table

Comparison Item	Hot-Rolled Q355B Carbon Steel Round Bar	Cold-Drawn Carbon Steel Round Bar
Surface Condition	Black surface with mill scale	Smooth, bright precision surface
Available Grades	Q355B	1018, 1045, 20#, 45#
Equivalent International Grade	Q355B ≈ S355JR	1018 ≈ Q235B; 1045 ≈ 45#; 20# ≈ 1020; 45# ≈ 1045
Manufacturing Standard	GB/T 702, ASTM A675, EN 10060	GB/T 905, ASTM A108, EN 10278
Diameter Range	Φ10 mm–Φ300 mm	Φ3 mm–Φ80 mm
Dimensional Tolerance	Standard hot-rolling industrial tolerance	Ultra-tight tolerance ±0.02–0.05 mm
Processing Characteristics	Suitable for rough machining, forging blanks, and structural fabrication	Suitable for precision machining and finished components; reduces secondary machining
Typical Applications	Heavy load structural parts, machinery components, forging blanks, support frames	Precision shafts, mechanical pins, turned & milled components, gear blanks
Recommended Selection	Select for large-diameter, high strength structural, and rough-machining projects	Select for high-precision requirements, less material removal, and tight dimensional control

App Market

Reliable Steel Coil Solutions For Diverse Industrial Applications

Mechanical Shaft Components

Gear Blanks

Agricultural Machinery Parts

Product Packaging

Secure Export Packaging For Safe Handling And Delivery

FAQs

What is the equivalent grade of Q355B round bar?

Q355B hot rolled round bar is equivalent to S355JR. It can replace S355JR for most structural and mechanical projects.

What is the main difference between Q235B and Q355B round bar?

Q355B has much higher yield strength than Q235B. Q355B is selected for heavy load structures while Q235B is for general light structural use.

Can you cut Q355B round bar into custom lengths?

Yes. We provide custom cutting service according to your drawing requirements.

What certifications can you provide?

We supply Mill Test Certificate (MTC) with chemical and mechanical test data for each batch.

What is the MOQ and lead time?

MOQ is 5 tons, lead time 7–15 working days after receiving deposit.

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Q355B Hot Rolled Carbon Steel Round Bar, Equivalent S355JR Carbon Steel Solid Round Bar