SS431 Stainless Steel Round Bar Supplier | AISI 431 / UNS S43100 Martensitic Shafting Bar

Name: SS431 Stainless Steel Round Bar Supplier | AISI 431 / UNS S43100 Martensitic Shafting Bar
Brand: Vertex Alloy
SKU: bbcc45d2-18d4-4f9e-8587-06d20be03f5e

Stainless SteelBar/Rod

SS431 stainless steel round bar supplied by Shanghai Vertex Alloy Co., Ltd — AISI 431 / UNS S43100 / EN 1.4057 / SUS431 / GB 14Cr17Ni2 nickel-bearing martensitic stainless shafting bar with 850–1,000 MPa tensile strength and the best corrosion resistance of the martensitic grades.

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Description (English)

Shanghai Vertex Alloy Co., Ltd (Vertex Alloy) supplies SS431 stainless steel round bar (AISI 431 / UNS S43100 / EN 1.4057 X17CrNi16-2 / JIS SUS431, equivalent to Chinese GB 14Cr17Ni2). 431 is a nickel-bearing martensitic stainless steel: 15–17% Cr with 1.25–2.50% Ni gives it the best corrosion resistance of any martensitic grade along with excellent tensile and torque strength — quenched-and-tempered bars deliver 850–1,000 MPa tensile strength and harden to ~50 HRC maximum. It is the classic material for pump shafts, propeller shafts, valve stems, turbine blades and high-strength fasteners. Supplied to ASTM A276 / A479 in Ø 8–300 mm rolled and forged bar, annealed or Q&T condition, with EN 10204 3.1 certificates and cut-to-length service. Contact us for the latest stock and pricing.

Size Range

OD:8–300 mm
L:3,000–6,000 mm

Grade Specification

System	Value
USA (AISI/ASTM)	431 (SS431)
🇺🇸 UNS	S43100
Europe (EN)	1.4057 / X17CrNi16-2
Japan (JIS)	SUS431
China (GB)	14Cr17Ni2 (formerly 1Cr17Ni2)
Bar Standard	ASTM A276 / A479
Aerospace Spec	AMS 5628

Chemical Composition

Element	Value
Cr	15.00–17.00
Ni	1.25–2.50
C	≤ 0.20
Mn	≤ 1.00
Si	≤ 1.00
P	≤ 0.040
S	≤ 0.030
Fe	Balance

Mechanical Properties

Property	Value
Tensile Strength	850–1,000 MPa
Yield Strength (0.2%)	≥ 650 MPa
Elongation (50 mm)	15–20%
Hardness	28–35 HRC (max 302 HB)
Impact Energy (Charpy V)	≥ 39 J
Max Hardness (hardened)	≈ 50 HRC

Physical Properties

Property	Unit	Value
Density	-	7.80 g/cm³
Elastic Modulus (25°C)	-	210 GPa
Thermal Conductivity (100°C)	-	24.9 W/(m·K)
CTE (0–315°C)	-	10.8 × 10⁻⁶ /K
Scaling Resistance	-	925°C intermittent / 870°C continuous
Magnetic	-	Yes

Applications

Marine:Propeller shafts;Marine hardware
Pumps & Valves: Pump shafts;Valve stems, spindles
Aerospace:Turbine blades;Structural fasteners
Oil & Gas:Valve parts, drilling equipment components
Pulp & Paper:Beater bars, doctor blades
Automotive:Suspension & steering components
Machine Tools:Spindles, lead screws
General: High-strength bolts, studs