S20C Carbon Steel Round Bar — Factory Direct Supplier | Huaxia-Steel

S20C carbon steel round bar is a low-carbon Japanese grade to JIS G4051 with a carbon content of approximately 0.18 – 0.23 %. It offers an excellent balance of strength, ductility, machinability and weldability, making it a popular choice for shafts, pins, studs, gears, machinery parts and cold-formed components. Huaxia-Steel supplies S20C round bar in hot-rolled, peeled, ground and cold-drawn conditions with full mill certification.

Product Overview

S20C is a general-purpose machine-structural steel that responds well to carburizing and through-hardening heat treatments. It is widely used in automotive, machinery and general engineering applications where moderate strength and good surface finish are required.

Specifications and Tolerance

Item	Specification
Standard	JIS G4051
Grade	S20C
Carbon	0.18 – 0.23 %
Diameter	10 mm – 300 mm; custom up to 500 mm
Length	3,000 mm – 12,000 mm; cut-to-length
Tolerance	h9, h11, k12 or JIS G3191
Straightness	≤ 1 mm/m typical, tighter on request
Surface	Black, peeled, turned, ground, polished

Mechanical Properties

Property	Typical Value
Tensile strength	≥ 400 MPa
Yield strength	≥ 245 MPa
Elongation	≥ 28 %
Reduction of area	≥ 50 %
Hardness as-rolled	120 – 160 HB typical

Equivalent Grades

S20C corresponds to several international low-carbon machine-structural grades. Buyers should confirm exact chemistry when substituting across standards.

JIS	DIN	AISI/SAE	GB	EN
S20C	1.0402 / C22	1020	20#	C22E
S25C	1.0406 / C25	1025	25#	C25E
S45C	1.0503 / C45	1045	45#	C45E

Heat Treatment and Surface

S20C can be supplied in several conditions to match downstream processing. Cold-drawn bars offer tighter tolerances and improved surface finish, while annealed bars provide maximum machinability.

• As-rolled / hot-rolled: general structural and machining use.
• Normalized: improved uniformity and toughness for welded parts.
• Annealed: best machinability and cold-forming properties.
• Cold-drawn / ground: precision shafts, pins and close-tolerance parts.
• Carburized: case-hardened surface with tough core for gears and wear parts.

Applications

• Machinery shafts, axles and pins.
• Automotive fasteners and small gears.
• Hydraulic cylinder rods (cold-drawn).
• General machine components and fixtures.
• Cold-headed and forged parts.
• Carburized wear components.

Quality Control

Each lot is tested for chemical composition, tensile properties, hardness and dimensional compliance. Mill test certificates to EN 10204 3.1 are standard; 3.2 and third-party inspection by SGS, TÜV or BV are available on request.

Packing and Shipping

Round bars are bundled with steel straps, ends protected, lightly oiled and wrapped in waterproof paper or VCI film for export. Marking includes grade, heat number, diameter, length, origin and destination.

Need a reliable carbon steel supplier for your next project? Huaxia-Steel supplies mill-certified carbon steel bars, plates, pipes, flanges and fittings with full inspection, export packing and fast delivery. Request a quote today and our team will reply within 24 hours.