Stainless Steel 431 Round Bar
➡️ SS 431 | UNS S43100 | EN 1.4057
➡️ ASTM, EN, JIS & International Standards
➡️ Supply Conditions
➡️ Multiple Diameters & Supply Lengths
➡️ Global Export & International Delivery
Country of Origin:
Europe, Japan, USA
Material Type:
Stainless Steel
UNS Number:
S43100
Wr. No.:
1.4057
MTC Available:
EN 10204 3.1
Product Description for Stainless Steel 431 Round Bar
Stainless Steel 431 Round Bar carries the UNS number S43100 and the material number 1.4057. Bar is supplied to ASTM A276 / A276M; tolerances, straightness and finish come from ASTM A484 / A484M. EN, JIS, GB/T and KS all carry an equivalent designation.
The grade is a nickel-bearing martensitic stainless steel with 15-17% chromium and 1.25-2.50% nickel. The higher chromium content gives better corrosion resistance than 410 or 420, while nickel improves toughness and hardenability. After hardening and tempering it develops high tensile strength with good impact resistance, making it a preferred grade for highly stressed shafts and bolting.
Stock diameters run from 3 mm to 500 mm, with bigger sections forged against order, and lengths are either random 3 to 6 m or cut to a stated size. Bar is supplied in the annealed (Condition A) or hardened and tempered condition, and can be hot finished, cold drawn, peeled, turned, ground or polished. The grade is hardenable by quenching and tempering, and bar is normally machined in the annealed condition before heat treatment.
Typical parts are propeller and pump shafts, bolting, spindles and highly stressed machined parts, ordered by the marine engineering, aerospace, defence, oil and gas and general engineering industries. An EN 10204 3.1 mill certificate covering heat analysis, mechanical test results and heat treatment condition is the normal documentation. Third party inspection, positive material identification and non-destructive examination can be added at order stage. The melting range is roughly 1425 – 1510 C. The bar is ferromagnetic in every condition. Density is around 7.70 g/cm3 and the modulus of elasticity about 200 GPa.
Common Applications of Stainless Steel 431 Round Bar
➡️ Machined shafts, spindles, valve stems, pump sleeves and pins for food, beverage, dairy and pharmaceutical equipment, where the passive chromium oxide film resists both product acids and caustic clean-in-place chemicals.
➡️ Fasteners, studs, bolts, threaded rod and anchor components produced from bar stock, chosen for corrosion resistance combined with the ductility needed for cold heading and thread rolling.
➡️ Chemical, water treatment and general process plant parts such as agitator shafts, flange blanks, nozzles and support components handling water, steam and mildly corrosive media free of significant chlorides.
➡️ Architectural and structural hardware including handrail stanchions, balustrade fittings, tension rods and bollards, where a bright ground or polished bar finish provides both appearance and low maintenance.
International Equivalent Grade for SS 431 Round Bar
Standard
Country / Region
Grade
ASTM A276 / A276M
USA
Type 431 (UNS S43100)
ASTM A479 / A479M
USA
Type 431 (UNS S43100)
ASME SA-479
USA
Type 431 (UNS S43100)
EN 10088-3
Europe / EU
1.4057 (X17CrNi16-2)
BS EN 10088-3
United Kingdom
1.4057 (X17CrNi16-2)
JIS G4303
Japan
SUS431
GB/T 1220
China
14Cr17Ni2 (S43110)
KS D 3706
South Korea
STS431
ISO 15510
International
X17CrNi16-2
Technical Specification for Stainless Steel 431 Round Bar
Specification
Value
Unit
Material
Stainless Steel
-
Grade
431 / UNS S43100 / W.Nr. 1.4057
-
Product Form
Round Bar / Rod
-
Standard
ASTM A276 / A276M and ASTM A479 / A479M
-
Diameter
3 - 500 (larger by forging on request)
mm
Length
3 - 6 (random mill length) or cut to length
m
Manufacturing Process
Hot rolled, forged or cold finished
-
Production Route
EAF + AOD / VOD refining, continuous cast or ingot, hot rolled or forged
-
Surface Finish
Hot-finished and pickled, cold-drawn, peeled, turned, ground or polished
-
Heat Treatment / Delivery Condition
Annealed (condition a) or hardened and tempered
-
Tolerance Standard
ASTM A484 / A484M
-
Carbon Equivalent (CEV)
Not applicable (CEV applies to carbon and low-alloy steels)
-
Density
7.70 (nominal)
g/cm3
Melting Range
1425 - 1510 (typical)
C
Thermal Conductivity at 100 C
20.2 (typical)
W/m.K
Coefficient of Thermal Expansion (0-100 C)
10.2 (typical)
10-6/K
Specific Heat (0-100 C)
460 (typical)
J/kg.K
Electrical Resistivity at 20 C
0.72 (typical)
micro-ohm.m
Modulus of Elasticity at 20 C
200 (typical)
GPa
Magnetic Properties
Ferromagnetic in all conditions
-
Applicable Testing / Inspection Standard
ASTM A370 (mechanical testing), ASTM E18 / E10 (hardness)
-
Certification / Inspection Documents
EN 10204 3.1 mill test certificate standard, 3.2 third-party, PMI, ultrasonic and dye-penetrant examination available on request
-
Technical Specifications
Get the key technical specifications for Stainless Steel 431 Round Bar
ASTM A276 / A276M and ASTM A479 / A479M is the usual ordering specification and ASTM A484 / A484M holds the tolerances. The European designation is 1.4057 (X17CrNi16-2). State the standard, the delivery condition and any supplementary testing when ordering.
Hardening is carried out by austenitising at approximately 980-1065 C followed by oil quenching and tempering. Tempering above 600 C gives the best combination of strength and toughness; the 370-565 C range should be avoided because of temper embrittlement.
The route is either hot finishing, meaning rolling or forging with heat treatment and pickling, or cold finishing by drawing, peeling, turning or grinding. Size and finish class together decide the diameter, out of round, straightness and length tolerances.
The grade is normally supplied either annealed for machining or already hardened and tempered to an agreed strength class, commonly equivalent to the EN QT800 or QT900 condition.
Physical property figures are typical producer data rather than standard requirements. Mechanical testing follows ASTM A370, and the certificate records analysis, test results, heat treatment and heat number.
Chemical Composition for Stainless Steel 431 Round Bar
Element
Symbol
Min
Max
Unit
Carbon
C
-
0.20
%
Manganese
Mn
-
1.00
%
Silicon
Si
-
1.00
%
Phosphorus
P
-
0.040
%
Sulfur
S
-
0.030
%
Chromium
Cr
15.00
17.00
%
Nickel
Ni
1.25
2.50
%
Chemical Composition
View the chemical composition and applicable material limits for SS 431 Round Bar
Nickel at 1.25-2.50% is the key addition relative to 410. It allows the higher chromium content to be used without the steel becoming ferritic, so the steel remains fully hardenable while gaining corrosion resistance and toughness.
Chromium runs 15.00 to 17.00% here, and it is what makes the steel stainless: it builds the passive oxide film that resists attack. Nickel at 1.25 to 2.50% stabilises the structure and improves ductility and toughness. Beyond those, the standard controls only carbon, manganese, silicon, phosphorus, sulfur, chromium and nickel; nothing else is specified. Carbon is capped at 0.20%.
Manganese and silicon are deoxidisers left over from melting and contribute modest solid solution strengthening. Phosphorus and sulphur are kept to low maxima, since both damage hot workability, weldability and corrosion resistance unless machinability is the priority.
The ASTM, EN, JIS, GB/T and KS versions are close but not identical. Compare the heat analysis on the mill certificate with the standard actually ordered before accepting the material for critical service. Chemical analysis is carried out to ASTM A751. Where the composition table shows no limit for an element, the standard sets no requirement and the element need not be determined or reported.
Mechanical Properties for Stainless Steel 431 Round Bar
Mechanical Property
Value
Unit
Hardness (Condition A, annealed)
285 (max)
HBW
Hardness after hardening (ASTM A276 Table 3, oil quench from 1020 C)
40 (min)
HRC
Tensile Strength (hardened and tempered)
Set by the ordered EN 10088-3 +QT class or by agreement
MPa
Yield Strength 0.2% (hardened and tempered)
Set by the ordered EN 10088-3 +QT class or by agreement
MPa
Modulus of Elasticity
200 (typical)
GPa
Mechanical Properties
Check the key mechanical properties and performance requirements of SS 431 Round Bar
ASTM A276 limits annealed bar to 285 HBW and requires the material to be capable of 40 HRC minimum after oil quenching from 1020 C. ASTM A276 sets no tensile requirement for the hardened condition, so strength is ordered to an EN 10088-3 quenched and tempered class such as +QT800, or to an agreed hardness range stated on the purchase order.
Delivery condition decides everything here. Annealed bar is sold for machining, and the properties that matter in service come from the heat treatment applied afterwards. Hardness is checked to ASTM E10 or E18 and tensile properties to ASTM A370. If bar is ordered heat treated, put the target strength or hardness range on the order.
For design, use the specified minima of the standard and condition ordered and take the real numbers from the mill certificate. Section size matters too, since diameter affects cooling rate during heat treatment and how much hot or cold work the bar has seen.
Component selection is normally driven by the strength and hardness needed in service, with the tempering temperature chosen to balance them against toughness and corrosion resistance. Machining is carried out in the annealed condition, and allowance should be made for the small dimensional change that occurs during hardening. Where higher corrosion resistance is required at similar strength, a precipitation-hardening grade is usually the alternative considered.
Dimension / Sizes for Stainless Steel 431 Round Bar
Dimension / Size
Value
Unit
Diameter (standard supply range)
3 - 500 (larger by forging on request)
mm
Standard Length
3 - 6 (random mill length)
m
Custom Length
Cut to length available on request
-
Diameter Tolerance
Per ASTM A484 / A484M, varies with size and finish class
-
Length Tolerance
Per ASTM A484 / A484M or as agreed on the order
-
Straightness Tolerance
Per ASTM A484 / A484M or as agreed on the order
-
End Condition
Square cut, saw cut, chamfered or as ordered
-
Surface Finish
Hot-finished and pickled, cold-drawn, peeled, turned, ground or polished
-
Available Size Range (cold-finished bar)
3 - 100 (typical commercial capability)
mm
Available Size Range (hot-finished and forged bar)
16 - 500 (typical commercial capability)
mm
Cut-to-Length Availability
Available, tolerance to be agreed at order stage
-
Applicable Dimensional Standard
ASTM A484 / A484M
-
Dimensions & Sizes
Explore available diameters, lengths, and dimensional requirements for SS 431 Round Bar
Pricing for Stainless Steel 431 Round Bar
Round Bar Prices are generally quoted per kilograms or meters tonnes and can fluctuate with the global raw material and market prices. The final price will depend on a variety of factors, including the grade size, diameter, length, surface finish, the quantity and whether the bars are cut to length or in standard lengths.
For smaller quantities, we can also quote per metre or per piece basis once the required dimensions have been confirmed. Container-loads or orders that are larger in size are typically priced per tonne, based upon the specifications required and the supply conditions.
Please provide your desired dimensions, grades, length number, and end for a current quote including the lead time applicable and details for certification.
Pricing
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Why Choose Us
Euro Steel Bars is an international distributor, stockist and exporter of stainless round steel bars that cover carbon, stainless alloy, special grades. We stock a variety of sizes and grades. We guarantee every order with mill test certificates as well as full quality-assurance documentation. Our name speaks to our roots: European-sourced materials that is backed by the certificates and rigor that buyers from Asia as well as the Gulf and Africa are looking for.
Each bar we deliver is accompanied by EN 10204 3.1 mill test certificates as well as complete documentation of quality, so what you receive corresponds to what’s written in the documents. We carry a selection of sizes and grades ready for transport, and cut length upon the request of customers, which results in quicker lead times, whether you’re ordering just a one-off spec or a complete project tonnage.
We operate an actual wholesale business that is that is supported with an internationally-operated supply chain therefore we are able to serve fabricators sourcing one grade the same way in the same way as an EPC contractor who is placing a large order. Our clients include manufacturers, fabricators EPC construction companies, engineers oil and gas projects as well as construction companies. we design our inventory as well as documentation to show what buyers need to bring projects forward.
Our customers trust us across Qatar, Oman, Bahrain, Kuwait, Jordan, Malaysia, Singapore, Thailand, Taiwan, Turkey, Italy and South Africa. If you’re looking to source an Gulf energy project, or a construction project within Southeast Asia, you get the same quality of certified material, the exact documentation, and the exact delivery procedure.
Frequently Asked Questions
What is Stainless Steel 431 Round Bar?
What standard does Stainless Steel 431 Round Bar comply with?
What are the equivalent grades of Stainless Steel 431 Round Bar?
What sizes and lengths are available in Stainless Steel 431 Round Bar?
What are the key mechanical properties of Stainless Steel 431 Round Bar?
What is the typical chemical composition of Stainless Steel 431 Round Bar?
Can Stainless Steel 431 Round Bar be supplied cut to length or with a specific surface finish?
How does 431 compare with 410 round bar?
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