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303 Stainless Steel Round Bar is an austenitic free-cutting stainless steel, which significantly improves machinability through the addition of sulfur (S) element, while retaining good corrosion resistance. Widely used in precision parts, automation equipment, medical equipment and other fields, it is the ideal material for high efficiency and high precision machining. We have complete testing, provide spectral analysis report, hardness test and surface flaw proof for each batch, support free sample test cutting, non-standard customisation (diameter Φ1mm-Φ300mm).

Product Parameter (Specification)

Products description:

Product information	parameter	Product intormation	Parameter
Product name	Stainless steel round bar	Standard	ASTM, JIS, DIN, EN
Length	Customised to customer requirements	Certification	ISO, SGS
Grade-ASTM	201, 202, 302, 303, 304, 304L, 310, 310S, 316, 316L, 321, 410, 431, 430F, 904L & other	Price term	FOB
Technique	Cold rolled hot rolled	Payment terms	T/T L/C
Packaging and delivery
Note : bundle, plastic bags, thin film, wooden pallet, standard seaworthy export packing or as customer demands

Product Feature and Application

Precision machinery and automation equipment

Applicable parts: gears, shafts, bearing bushings, screws, connectors

Advantages: high dimensional stability, reduced machining deformation, improved assembly accuracy.

Medical instruments and surgical tools

Applicable parts: surgical forceps, orthopaedic screws, dental drills (subsequent electrolytic polishing required)

Advantages: easy to sterilise, resistant to saline corrosion, meets the requirements of medical grade materials.

Automotive industry

Applicable parts: sensor housings, fuel injection system components, transmission pins

Advantages: oil resistance, vibration resistance, not easy to fatigue fracture in long-term use.

Food Processing and Packaging Machinery

Applicable parts: filling valves, conveyor screws, food moulds

Advantages: meet FDA contact standards, resistant to lactic acid, acetic acid and other food-grade corrosive media.

Chemical and Energy Equipment

Applicable parts: pump valve fittings, flange bolts, heat exchanger brackets

Advantage: Longer life than ordinary carbon steel in weak acid and alkaline environment.

Electronic and electrical appliances

Applicable parts: semiconductor fixtures, conductive terminals, shell structure parts

Advantage: non-magnetic, to avoid electromagnetic interference, the surface can be plated with nickel / chrome to enhance the conductivity.

Production Details

303 stainless steel is based on 304 stainless steel with the addition of sulfur (S) and phosphorus (P) to improve the cutting performance of easy-to-cut austenitic stainless steel. Its standard chemical composition is as follows:

1.Major Elements:

Element	Chromium (Cr)	Nickel (Ni)	Carbon (C)	Manganese (Mn)	silicon (Si)	sulfur (S)	phosphorus (P)
Content(%)	17-19	8-10	MAX 0.15	MAX 2	MAX 1	0.15-0.35	MAX 0.20

2.Mechanical properties

Condition	Tensile strength (MPa)	Yield strength (MPa)	Elongation (%)	Hardness (HB)
Data	≥500	≥190	≥40	≤187

3.Physical properties

Condition	Density	Melting point	Thermal conductivity	Resistivity
Data	7.93 g/cm³	1400-1450°C	16.3 W/m-K (at 100℃)	0.72 Ω-m

4.Temperature resistance characteristics

Long-term working temperature: -20℃~+400℃, short-term up to +800℃, but will oxidise.

Low temperature properties: maintain toughness to -196℃, no brittle transformation.

High temperature attention: Above 500℃, carbides may precipitate at grain boundaries, need to avoid sensitisation interval 450~850℃. Sulfur (S) may cause thermal embrittlement at high temperatures, avoid hot forging or welding.

Surface Treatment Options

Type	Description	Applicable Scene
Pickled surface	Matte grey-white, remove oxide skin	General industrial parts, subsequent processing
Polished surface	Mechanically polished to Ra≤0.8μm (mirror surface)	Medical devices, food equipment
Grinding surface	Precision grinding, dimensional tolerance ±0.02mm	Shafts, precision parts

FAQ

Q: What is the difference between 303 stainless steel and 304 stainless steel?

A: 303: sulfur (0.15% ~ 0.35%), easy to cut, but slightly worse corrosion resistance, not weldable, suitable for precision machining parts.
304: low carbon (≤ 0.08%), stronger corrosion resistance, can be welded, but poor cutting performance.

Q: How is the corrosion resistance of 303 stainless steel?

A: Resistant to weak acids, alkalis and atmospheric corrosion, but not as good as 304/316.
Not recommended for: seawater, hydrochloric acid and other highly corrosive environments.

Q: Can 303 stainless steel be welded?

A: Welding is not recommended! The element sulphur can cause thermal cracking. When welding is required, it is recommended to use 304 or 316 stainless steel instead.

Q: Is it safe to use 303 stainless steel in the food industry?

A: It meets FDA contact standards, but make sure the surface is polished to Ra ≤ 0.8μm to avoid sulphide residues.
Long-term contact with acidic foods (e.g. lemon juice) is recommended to use 316 stainless steel.

Q: What are the price factors for 303 stainless steel round bar?

A: Raw materials (nickel price fluctuations), dimensional accuracy, surface treatment (such as mirror polishing markup 20% to 30%).

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