I. Basic Material

Item	Technical Parameters
Base Material Grade	431
Chinese National Standard Grade	17Cr16Ni2 (1Cr17Ni2)
UNS Grade	S43100
DIN Grade	1.4057
Surface Treatment	Chrome Plated
Chrome Plated Coating Thickness	Diameter ≤φ20: 15μm; Diameter＞φ20: 20μm, thickness customizable on demand
Surface Hardness after Chrome Plated	HV800～1100
Common Diameter Range	φ3.0mm～φ300mm
Diameter Tolerance	Standard: h8, h9; High Precision: h7, f7, g6, h6
Roundness	≤1/2 diameter tolerance
Straightness	≤0.10mm/1000mm
Standard Length	Fixed length of 3 meters for φ40mm and below; fixed length of 6 meters for diameters above φ40mm, customized fixed lengths available for large specifications
End Face Requirements	Flat ends, chamfered and deburred

II. Chemical Composition of Base Material (Mass Fraction wt%)

C	Si	Mn	P	S	Cr	Ni
≤0.20	≤1.00	≤1.00	≤0.040	≤0.030	15.00～17.00	1.50～2.50

III. Mechanical Properties

Item	Mechanical Properties
Tensile Strength Rm	≥860 MPa
Yield Strength Rp0.2	≥655 MPa
Elongation after Fracture A	≥15%
Base Material Hardness	260～300 HB

Quenching and Tempering	QT800	QT900
Tensile Strength Rm (MPa)	800～950	900～1050
Yield Strength Rp0.2 (MPa)	≥600	≥700
Elongation after Fracture A5 (%)	≥13	≥12
Room-temperature Impact Energy KV₂ (J)	≥25	≥20
Brinell Hardness HB	240～290	270～320
Rockwell Hardness HRC	23～30	27～35

IV. Machining Process & Surface Roughness

Process Type	Complete Process Flow	Surface Roughness
Process 1	Hot-rolled base material → Precision drawing → Centerless precision grinding → Polishing → Chrome Plated → Polishing	Ra ≤0.2μm
Process 2	Hot-rolled base material → Peeling and straightening → Centerless precision grinding → Polishing → Chrome Plated → Polishing	Ra ≤0.2μm
Process 3	Forged round bar → Turning finishing → Centerless precision grinding → Polishing → Chrome Plated → Polishing	Ra ≤0.2μm

V. Coating & Physical Properties

Item	Parameter Description
Coating Adhesion	No peeling or flaking, passes bending resistance test
Corrosion Resistance	Combines high strength and corrosion resistance; wear resistance, rust prevention and moisture resistance are greatly improved after Chrome Plated
Coefficient of Friction	Dense and smooth surface layer with low friction coefficient, scratch-resistant and wear-resistant
Magnetism of Base Material	Magnetic

VI. Application Scenarios
High-pressure piston rods, heavy-duty valve stems, shaft components for marine equipment, high-strength transmission shafts for chemical industry, precision hydraulic and pneumatic fittings, wear-resistant and anti-corrosion mechanical structural shafts.