Stainless Steel 303 Round Bar
➡️ SS 303 | UNS S30300 | EN 1.4305
➡️ 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:
S30300
Wr. No.:
1.4305
MTC Available:
EN 10204 3.1
Product Description for Stainless Steel 303 Round Bar
Stainless Steel 303 Round Bar is a solid cylindrical bar produced from free-machining austenitic chromium-nickel stainless steel Type 303 (UNS S30300). The grade is a sulphur-bearing modification of Type 304, and bars are supplied principally to ASTM A582 / A582M, the specification covering free-machining stainless steel bars, with dimensional and surface requirements taken from ASTM A484 / A484M.
The controlled sulphur addition of 0.15% minimum forms manganese sulphide inclusions that break up the chip during turning, drilling and threading. This raises machinability to roughly 70-80% of free-cutting carbon steel, well above the 45% typical of Type 304, and allows faster feeds, longer tool life and better surface finish on automatic and CNC lathes. The trade-off is reduced corrosion resistance, lower toughness and poorer weldability compared with Type 304.
Bars are normally supplied in the annealed condition, either hot-finished, or cold-drawn, peeled, smooth-turned, centreless-ground or polished. Standard stock diameters run from about 3 mm to 250 mm in 3 to 6 m random or fixed lengths, with cut-to-length service widely available. The alloy cannot be hardened by heat treatment because of its austenitic structure, so strength is raised only by cold work.
Typical uses include shafts, spindles, bushings, screws, nuts, studs, valve bodies, gears, electrical switchgear parts and any high-volume turned component where machining cost dominates. It serves the general engineering, automotive, aerospace fastener, electrical, instrumentation, pump and valve, and hardware industries. Where the component will be welded or exposed to chlorides, Type 304 or 316 is normally specified instead, since the sulphide inclusions in 303 act as initiation sites for pitting and hot cracking.
Common Applications of Stainless Steel 303 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 303 Round Bar
Standard
Country / Region
Grade
ASTM A582 / A582M, ASTM A484 / A484M
USA
Type 303 (UNS S30300)
EN 10088-3
Europe / EU
1.4305 (X8CrNiS18-9)
BS EN 10088-3
United Kingdom
1.4305 (X8CrNiS18-9)
BS 970 Part 1 (superseded)
United Kingdom
303S31
JIS G4303
Japan
SUS303
GB/T 1220
China
Y12Cr18Ni9 (S30317)
KS D 3706
South Korea
STS303
ISO 15510
International
X8CrNiS18-9
Technical Specification for Stainless Steel 303 Round Bar
Specification
Value
Unit
Material
Stainless steel
-
Grade
303 / UNS S30300 / 1.4305
-
Product Form
Round bar / rod
-
Standard
ASTM A582 / A582M
-
Diameter
3 - 250 (available range)
mm
Length
3 - 6 (standard random or fixed)
m
Manufacturing Process
Hot rolled, forged or cold drawn
-
Production Route
EAF / AOD melting, continuous cast or ingot, hot rolling, cold finishing
-
Surface Finish
Hot-finished, cold-drawn, peeled, smooth-turned, centreless-ground, polished
-
Heat Treatment / Delivery Condition
Annealed (Condition A)
-
Tolerance Standard
ASTM A484 / A484M
-
Carbon Equivalent (CEV)
Not applicable to austenitic stainless steel
-
Density
7.90 (typical)
g/cm3
Melting Range
1400 - 1420 (typical)
deg C
Thermal Conductivity
16.2 at 100 deg C (typical)
W/m.K
Coefficient of Thermal Expansion
17.3 at 0 - 100 deg C (typical)
micro-m/m.K
Specific Heat
500 at 0 - 100 deg C (typical)
J/kg.K
Electrical Resistivity
0.72 (typical)
micro-ohm.m
Modulus of Elasticity
193 (typical)
GPa
Magnetic Properties
Essentially non-magnetic when annealed, may become slightly magnetic after cold work
-
Applicable Testing Standard
ASTM A370, ASTM E8 / E8M, ASTM E18, ASTM E415
-
Certification / Inspection Documents
EN 10204 Type 3.1 or 3.2 mill test certificate
-
Technical Specifications
Get the key technical specifications for Stainless Steel 303 Round Bar
Stainless Steel 303 Round Bar is ordered predominantly to ASTM A582 / A582M in the annealed condition. ASTM A582 specifies chemical composition and hardness limits rather than a full set of tensile minima, so tensile and yield figures quoted by suppliers are typical values derived from ASTM A276 / A479 practice and should be confirmed on the mill certificate when they are design-critical.
Dimensional tolerance, straightness, out-of-roundness and surface condition follow ASTM A484 / A484M, which sets different tolerance classes for hot-finished, cold-drawn, turned and ground bars. Cold-finished bars hold tighter diameter tolerances such as h9 to h11 and give better surface roughness for precision turning.
Annealing is carried out at approximately 1010-1120 deg C followed by rapid cooling, which dissolves carbides and restores maximum ductility and corrosion resistance. The grade cannot be hardened by quenching. Stress relief above 480 deg C is generally avoided because it can sensitise the structure.
Verification normally includes chemical analysis by optical emission spectrometry to ASTM E415, tensile testing to ASTM A370 / E8, and Brinell or Rockwell hardness to ASTM E10 / E18. Positive material identification, ultrasonic testing, dye-penetrant examination and intergranular corrosion testing to ASTM A262 can be added by agreement. Bars are supplied with an EN 10204 Type 3.1 certificate as standard.
Chemical Composition for Stainless Steel 303 Round Bar
Element
Symbol
Min
Max
Unit
Carbon
C
-
0.15
%
Manganese
Mn
-
2.00
%
Silicon
Si
-
1.00
%
Phosphorus
P
-
0.20
%
Sulfur
S
0.15
-
%
Chromium
Cr
17.00
19.00
%
Nickel
Ni
8.00
10.00
%
Molybdenum
Mo
-
0.60
%
Iron
Fe
Balance
Balance
%
Chemical Composition
View the chemical composition and applicable material limits for SS 303 Round Bar
Chromium at 17.00-19.00% is the element responsible for the passive chromium-oxide film that provides corrosion resistance in atmospheric, mild chemical and food-handling environments. Nickel at 8.00-10.00% stabilises the face-centred cubic austenitic structure, giving high ductility, good low-temperature toughness and resistance in reducing media.
What separates Type 303 from Type 304 is the sulphur, held to 0.15% minimum. Sulphur combines with manganese to form manganese sulphide stringers. These break the chip and lubricate the cutting edge, so the grade machines much faster than Type 304. The same inclusions interrupt the passive film and act as pit initiation sites, so corrosion resistance and fatigue strength both drop.
Phosphorus is permitted up to 0.20%, higher than in Type 304, because it further assists machinability. Carbon at 0.15% maximum is comparatively high for an austenitic grade and increases the risk of chromium-carbide precipitation in the 425-815 deg C sensitisation range. Manganese up to 2.00% is required to tie up the sulphur as manganese sulphide rather than iron sulphide, which would cause hot shortness during hot working. An optional molybdenum addition up to 0.60% may be present and slightly improves pitting resistance. This composition makes the grade unsuitable for welded assemblies.
Mechanical Properties for Stainless Steel 303 Round Bar
Mechanical Property
Value
Unit
Tensile Strength
620 (typical, annealed cold-finished)
MPa
Yield Strength 0.2% Proof
415 (typical, annealed cold-finished)
MPa
Elongation in 50 mm
25 (typical, minimum)
%
Reduction of Area
40 (typical, minimum)
%
Hardness
262 max (cold-finished, per ASTM A582)
HBW
Hardness
100 max (annealed hot-finished)
HRB
Impact / Charpy V-Notch
Not required by ASTM A582
J
Modulus of Elasticity
193
GPa
Mechanical Properties
Check the key mechanical properties and performance requirements of SS 303 Round Bar
ASTM A582 / A582M controls Stainless Steel 303 Round Bar primarily through hardness limits, with a maximum of 262 HBW for cold-finished annealed bar. Tensile and yield figures are therefore reported as typical values rather than mandatory minima, and a purchaser needing guaranteed tensile properties should state this on the order so that testing to ASTM A370 is performed and reported.
In the annealed condition the bar shows moderate strength with useful ductility. Cold drawing work hardens the bar, raising tensile and yield strength while cutting elongation, so a cold-drawn 20 mm bar tests stronger than a hot-finished 150 mm bar from the same heat. Properties therefore vary with both diameter and finish, and values should always be read against the delivered condition.
The grade cannot be strengthened by quench-and-temper heat treatment because the austenitic structure does not transform. Where higher strength is needed, either a heavier cold-drawn reduction or a different family such as 17-4 PH must be selected.
Impact toughness is lower than Type 304 because the sulphide stringers reduce transverse ductility, and fatigue performance is likewise reduced. For rotating shafts under reversed bending the lower fatigue limit should be allowed for in design.
Dimension / Sizes for Stainless Steel 303 Round Bar
Dimension / Size
Value
Unit
Diameter (available range)
3 - 250
mm
Standard Length
3 - 6
m
Custom Length
Cut to length on request
-
Diameter Tolerance
Per ASTM A484 / A484M, class depends on size and finish
-
Diameter Tolerance (cold-finished)
h9 / h10 / h11 or as agreed
-
Length Tolerance
Per ASTM A484 / A484M or as agreed
-
Straightness Tolerance
Per ASTM A484 / A484M or as agreed
-
End Condition
Square cut, saw cut, chamfered or as ordered
-
Surface Finish
Hot-finished, cold-drawn, peeled, turned, ground, polished
-
Cut-to-Length Availability
Available
-
Dimensional Standard
ASTM A484 / A484M
-
Dimensions & Sizes
Explore available diameters, lengths, and dimensional requirements for SS 303 Round Bar
Pricing for Stainless Steel 303 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
Get current Stainless Steel 303 Round Bar pricing based on size, quantity, grade, finish, and delivery requirements.
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 303 Round Bar?
What standard does Stainless Steel 303 Round Bar comply with?
What are the equivalent grades of Stainless Steel 303 Round Bar?
Can Stainless Steel 303 be welded?
Can Stainless Steel 303 Round Bar be hardened by heat treatment?
What sizes and lengths are available?
How does the corrosion resistance of 303 compare with 304?
Is Stainless Steel 303 Round Bar magnetic?
Request A Quote
Need a specific grade, size or quantity? Get pricing and availability for your requirement.