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AISI 303 1.4305 SUS303 Austenitic Stainless Steel

Name: AISI 303 1.4305 SUS303 Austenitic Stainless Steel
Brand: Qilu
Rating: 5.0 (9 reviews)

Grade: AISI 303
Equivalent Steel: DIN X8CrNiS18-9/1.4305, JIS SUS303, GB Y1Cr18Ni9/Y12Cr18Ni9

303 Stainless Steel is an advanced free-machining austenitic stainless steel, specifically engineered for applications requiring high strength and exceptional machinability. Its chemical composition is precisely formulated, containing carbon (0.15%Max), high sulfur (0.15%Min), and key alloying elements such as nickel (8.00–10.00%) and chromium (17.00–19.00%).

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Model:
303
Brand:
Qilu

Product Description

Product Overview

AISI 303 (also known as 1.4305, SUS303, Y1Cr18Ni9) is a free‑machining austenitic stainless steel engineered for high‑precision machining, combining good corrosion resistance, consistent mechanical properties, and excellent chip control for turning, milling, drilling, and tapping operations. It is the preferred grade for automated machining lines, precision components, and high‑volume turned parts where machinability is critical.

Steel Equivalent Grades

AISI 303 has consistent cross‑standard equivalents for global manufacturing and supply chains:

Country	USA	EN	China	Japan
Standard	ASTM A581	EN10088-3	GB/T1220	JIS G4303
Grade	303	X8CrNiS18-9/1.4305	Y1Cr18Ni9/Y12Cr18Ni9	SUS303

Product Features

Chemical Composition

Grade	C	Si	Mn	P	S	Cr	Ni
303	0.15Max	1.00Max	2.00Max	0.20Max	0.15Min	17.00-19.00	8.00-10.00
X8CrNiS18-9/ 1.4305	0.10Max	1.00Max	2.00Max	0.045Max	0.15-0.35	17.00-19.00	8.00-10.00
SUS303	0.15Max	1.00Max	2.00Max	0.20Max	0.15Min	17.00-19.00	8.00-10.00
Y1Cr18Ni9	0.15Max	1.00Max	2.00Max	0.20Max	0.15Min	17.00-19.00	8.00-10.00

Mechanical Properties

1. Mechanical properties for Y1Cr18Ni9/Y12Cr18Ni9 from standard GB/T1220 and SUS303 from JIS G4303

Grade	Tensile strength	Yield strength	Alongation	Area of reduction	Hardness
Y1Cr18Ni9	520Mpa Min	205Mpa Min	40% Min	50% Min	HBW187Max
SUS303	520Mpa Min	205Mpa Min	40% Min	50% Min	HBW187Max

2. Mechanical properties for X8CrNiS18-9/1.4305 from standard EN10088-3

Steel grade

Size range

Tensile strength

Yield strength

Alongation

Impact value

at RT/J

Hardness

/HBW

L

Tr

L

Tr

X8CrNiS18-9/

1.4305

d≤160

500-750Mpa

190Mpa Min

35% Min

/

230Max

3. Mechanical properties at room temperature of steels in the COLD-WORKED condition from standard EN10088-3

Steel grade

Tensile strength level

0.2% proof strength

Tensile strength/Rm

Elongation

X8CrNiS18-9/

1.4305

C700

350Mpa Min

700-850Mpa

20% Min

C800

500Mpa Min

800-1000Mpa

12% Min

Supply Range, Sizes & Tolerances

Product Forms & Dimensions

Product type	Size range	Length
Hot rolled bar	Φ10-Φ130mm	5000-7000mm
Hot forged bar	Φ140-Φ600mm	2000-5800mm
Hot rolled plate/sheet	T:2-60mm; W:310-810mm	6000-12000mm
Hot forged plate	T:70-250mm; W:310-810mm	2000-5800mm
Hot Forged block	T: 260-500mm; W: 300-1000mm	2000-5800mm

Surface & Tolerance

Surface Finish	Turned	Milled	Grinding(Best)	Polished(Best)	Peeled(Best)	Black Forged	Black Rolled
Tolerance	+0/+3mm	+0/+3mm	+0/+0.05mm	+0/+0.05mm	+0/+0.1mm	+0/+5mm	+0/+1mm
Straighness	1mm/1000mm max.					3mm/1000mm max.

In Stock

Qilu steel stock hot rolled bar and forged bars more than ten thousands tons every month, below our our stock size.

1): Stock diameter for hot rolled bar

10	12	15	18	20	22	25	28	30	32	35	38	40	45	50
55	60	65	70	75	80	85	90	95	100	105	110	120	130	140
150	160	170	180

2) : Stock diameter for hot forged bar

200	210	220	230	240	250	260	270	280	290
300	310	320	330	340	350	360	370	380

3): We also have stocks for cold drawn sheet (from 0.2-3mm) and hot rolled plate (from 4mm to 60mm)

Since the stocks change everyday, if you want to know our stock available information, please contact our salesman.

Production & Quality

Melting Process: EF+LF+VD; EAF+LF+VD; optional ESR for high purity
Forging Temperature: 900–1200 °C, air cooling
Heat Treatment: Solution annealing at 1010–1150 °C, rapid cooling in the air or in the water
Aging: Heat to 850-930 °C
UT Test: EN10228‑3 class III / Sep 1921‑84 D/D

Application

303 stainless steel is widely used in components requiring high-precision, high-efficiency automated machining due to its excellent machinability, good corrosion resistance, and machinability. Its primary applications include:

Mechanical and automotive industries

Bolts, nuts, screws, shafts, pins, gears, pump shafts, valve cores, etc.

Electronics, Electrical, and Instrumentation

Sensor housings, connectors, precision instrument components, watch gears, etc.

Hardware and Consumer Goods

Kitchenware handles, cutlery accessories, high-end hardware fittings, musical instrument components, etc.

Other Fields

Non-implantable medical devices, fasteners for chemical processing equipment, etc.

Grade Comparison: 303 vs 304 vs 316

Property	303	304	316
Machinability	Best	Good	Fair
Corrosion Resistance	Moderate	Good	Excellent
Weldability	Poor	Very Good	Very Good
Key Feature	Free‑machining	General purpose	Marine/chemical
Typical Use	Machined parts	General components	Seawater, harsh chemicals

FAQ

Q1: What is the difference between 303 and 304?

A1: 303 contains added sulfur (≥0.15%) for superior machinability, while 304 has lower sulfur (≤0.03%) for better weldability and corrosion resistance. Use 303 for high-speed screw machine parts; use 304 for welded structures.