I. Basic Material

Item	Technical Parameters
Material Grade	303
Chinese National Standard Grade	Y1Cr18Ni9
UNS Grade	S30300
DIN Grade	1.4305 (X10CrNiS18-9)

II. Chemical Composition (Mass Fraction wt%)

C	Si	Mn	P	S	Cr	Ni	Mo
≤0.15	≤1.00	≤2.00	≤0.20	0.15～0.30	17.00～19.00	8.00～10.00	≤0.60 (Optional)

III. Mechanical Properties

Item	Mechanical Properties
Tensile Strength Rm	≥520 MPa
0.2% Proof Strength Rp0.2	≥205 MPa
Elongation after Fracture A	≥40%
Brinell Hardness	≤187 HB

IV. Dimensional Accuracy Specifications

Item	Technical Requirements
Common Diameter Range	φ3.0mm～φ300mm
Diameter Tolerance	Standard grade: h8, h9; High precision grade: h7, f7, g6, h6
Roundness	≤1/2 of diameter tolerance
Straightness	≤0.10mm/1000mm
Standard Length	3 meters for φ40mm and below; 6 meters for diameters above φ40mm (Custom lengths available)
End Face Requirements	Flat ends, chamfered and deburred

V. Processing Technology & Surface Roughness

Process Type	Complete Process Flow	Surface Roughness
Process 1	Hot rolled base material → Precision drawing → Centerless precision grinding	Ra 0.4～0.8μm
Process 2	Hot rolled base material → Peeling and straightening → Centerless precision grinding	Ra 0.4～0.8μm
Process 3	Hot rolled base material → Peeling and straightening → Centerless precision grinding → Polishing	Ra ≤0.2μm

VI. Physical Properties and Surface Quality

Item	Parameter Description
Material Density	7.93 g/cm³
Magnetism	Non-magnetic / Weakly magnetic (Annealed state)
Surface Appearance Quality	Free of cracks, peeling, pinholes, scale, rust and impact bruises

VII. Application Scenarios
Automatic lathe parts, CNC precision shafts, pin shafts, connectors, instrument components, electronic hardware, fasteners, precision transmission parts, free-cutting high-precision structural components