303 Stainless Steel - DIN 1.4305 - X8CrNiS18-9 - ~SUS 303

As with other austenitic stainless steels, 303 has good toughness and is non-magnetic. The added Sulphur makes the steel better machinable but affects the corrosion resistance and lowers the toughness of the steel slightly. Apart from better machining the added Sulphur helps break chips into smaller, more manageable pieces, contributes to a smoother and more consistent finish and can extend tool life. 

Purchase 303 Stainless Steel Online

Select Your Steel Length below

Imperial and Metric Steel Sizes for Sale

Imperial Steel Size

steel type image
$mart Flat Stock [$mart]

Standardized Precision Blanks

steel type image
Cold Finished Rounds [CF]

Precision Round Bars

Metric Steel Size

steel type image
$mart Flat Stock Metric [$martM]

Standardized Precision Blanks Metric

steel type image
Cold Finished Rounds Metric [CFM]

Precision Round Bars Metric

You can easily reach out to one of our order consultants to find the exact steel products you need.
chat icon
Any Questions?
Icon of an atom

303 Stainless Steel: Standard values

Working hardness: 215 HB - 250 HB (delivery condition)
Delivery condition: max. 250HB

Chemical composition in %

C

0.000000

0

0.100000

0.1
Si

0.000000

0

1.000000

1
Mn

0.000000

0

2.000000

2
P

0.000000

0

0.045000

0.045
S

0.150000

0.15

0.350000

0.35
Cr

17.000000

17

19.000000

19
Ni

8.000000

8

10.000000

10
Cu

0.000000

0

1.000000

1
N

0.000000

0

0.110000

0.11

303 Stainless Steel: Technical Data

Icon of a spanner

303 Stainless Steel: Technical Properties

Corrosion resistant austenitic stainless chrome-nickel-steel with additional sulphur content that allows excellent milling, however, not forgeable, non-weldable (cracking), limited polishing properties. Average mechanical properties, non-magnetisable and conditionally acid resistant.

Icon of a check mark

303 Stainless Steel: Applications

food industry, photographic industry, paint industry, oil industry, soap industry, paper industry, textile industry, mechanical engineering, turned parts, fittings construction, kitchen equipment, decoration

Chemical designation: Working hardness: 215 HB - 250 HB (delivery condition)
Delivery condition: max. 250HB

C

0.000000

0

0.100000

0.1
Si

0.000000

0

1.000000

1
Mn

0.000000

0

2.000000

2
P

0.000000

0

0.045000

0.045
S

0.150000

0.15

0.350000

0.35
Cr

17.000000

17

19.000000

19
Ni

8.000000

8

10.000000

10
Cu

0.000000

0

1.000000

1
N

0.000000

0

0.110000

0.11

Corrosion resistant austenitic stainless chrome-nickel-steel with additional sulphur content that allows excellent milling, however, not forgeable, non-weldable (cracking), limited polishing properties. Average mechanical properties, non-magnetisable and conditionally acid resistant.

food industry, photographic industry, paint industry, oil industry, soap industry, paper industry, textile industry, mechanical engineering, turned parts, fittings construction, kitchen equipment, decoration

303 General Information

Where can 303 stainless be used?

Due to its good machinability this steel grade is used for applications that require parts to be easily machined: shafts, springs bushings, nuts and bolts, valves, components in the automotive industry as well as in the machining industry.

Is the 303 a stainless steel?

With a mass fraction of 17 - 19% chromium the 303 is a stainless steel.

Is the 303 corrosion resistant?

The 303 is corrosion resistant due to its chrome content of 17 - 19%. Furthermore it contains a mass fraction of 8 - 10% of nickel which can enhance the corrosion resistance of a steel grade. 

General corrosion

Sulphur makes this steel grade vulnerable to pitting corrosion, therefore should be avoided for environments over 140°F (60°C) containing chloride. This steel grade is better suited in mild environments, when exposed to moist environments, like a marine environment, pitting as well as a film of rust will form. For more corrosion resistance it is better to use a steel with more chromium and nickel content.

Is stainless steel 303 magnetizable?

In general the 303 is not magnetic in its annealed condition. By cold working this material grade though the crystal structure can be altered to become partially or fully magnetic. By annealing the material the process is reversed and the material goes back to its non-magnetic state. 

Heat resistance of the 303 stainless steel

303 stainless steel has good oxidation resistance when the material is sporadically exposed to temperatures of 1400°F (760°C) as well as continuous service at 1598°F (870°C). The latter is not recommended, as this steel grade is sensitive to carbide precipitation with continuous use at a temperature range of 797 - 1580°F (425 - 860°C).

303 stainless steel heat treatment

303 is not hardenable by heat treatment. Cold working this steel grade can increase hardness and tensile strength.

Annealing stainless steel 303

Heat the material to 1850°F (1010°C) following with a quenching in water or cool rapidly by other means. To prevent embrittlement and loss of corrosion resistance, temperatures between 800 - 1500°F (427 - 816°C) should be avoided for prolonged exposure.

Stress relieving 303 stainless

To improve stability and to reduce the risk of distortion the 303 can be stress relieved by heating it to a range of 1099 - 1299°F (593 - 704°C) and then cooled down slowly.

Hardening stainless steel 303

This steel grade cannot be hardened by heat treatment. This steel grade can be cold work hardened for improved strength and hardness. By cold working this material the crystal structure is deformed resulting in increased hardness.

303 stainless steel dimensional changes

As for all materials the 303 stainless steel can undergo dimensional changes when heated or cooling. When under constant load at higher temperatures the 303 can experience creep, a slow and time dependent deformation. 

303 stainless steel Electrical Discharge Machining (EDM)

With the right choice of electrodes, dielectric fluid and machining parameters the 303 stainless steel can be EDM’d which makes machining complex and intricate  shapes with tight tolerances achievable. As a non contact machining process EDM generates little heat, another advantage for the 303 as it means that the properties of this grade will not be affected.

303 stainless steel surface treatment

To enhance 303’s properties there are various surface treatments. Here are a few examples:

303 stainless steel passivation

This treatment removes surface contamination and increases the corrosion resistance of the material by treating the surface with an acid solution that leaves a passive chromium layer.

Electro polishing 303 stainless steel

An electric current is used to remove a very thin layer of material which leaves a smooth and shiny surface. This is a non-mechanical process and is not to be confused with passivation which does not use an electric current. 

AISI 303 ceramic coating

Ceramic coating will create a hydrophobic layer which repels water and other contaminants which might damage the surface. It enhances the wear resistance and provides thermal insulation which is an advantage in high temperature and abrasive environments.

AISI 303 chemical coloring

Different colors can be achieved by chemically coloring the 303, depending on the thickness of the oxide layer, colors range from bronze, the thinnest oxide layer, to green, the thickest layer. The color sequence is bronze, blue, black, charcoal, gold, purple and green. As this is a chemically induced coloring it does not flake or peel when the material is formed or drawn for example. The oxide layer is harder which makes it better pitting resistant and does repel water and dirt.

303 stainless steel machinability

To avoid excess work hardening keep the cutting edges sharp. Lubricants and coolants should be used liberally to avoid the heat concentration at the cutting edges. Chip breakers should be employed to keep the workpiece clear. 

Forging 303 stainless steel

This steel grade is not easily forged due to the risk of overheating with the high forging temperatures needed. Forging is usually performed at a temperature range of 2102 - 1742°F (1150 - 950°C) with subsequent cooling in air. To minimize the risk of hot cracking, low forging temperatures are preferred.

A post forging heat treatment can be done to restore properties, reduce internal stresses and to restore the corrosion resistance for the 303.

Welding 303 stainless steel

It is not recommended to weld this steel grade.

303 stainless steel fabrication

To avoid cross contamination while fabricating, only tools dedicated to stainless steel materials should be used to avoid surface discoloration of the fabricated products. Clean all tooling and work surfaces thoroughly against cross contamination as well.

303 stainless steel wear resistance

The wear resistance for the 303 is 2 on a scale where 1 is low and 6 is high.

Tensile strength for the 303 stainless steel

The tensile strength for the stainless steel 303 is approx. 116.0 KSI (0.145KSI = 1MPa). This value is the result from a tensile test to show how much force is needed before the material starts to stretch or elongate before it breaks.

Working hardness for the 303 stainless steel

The working hardness for the 303 stainless is at delivery 215 - 250 BHN.

303  stainless steel specific heat capacity

The specific heat capacity of stainless steel 303 at room temperature is ~ 0.5 J/(g*K). This value shows how much heat is needed to heat 1lb of material by 1 Fahrenheit.

303 stainless steel specific heat capacity chart303 stainless steel specific heat capacity chart

303 stainless steel steel properties

303 stainless steel hot work

Uniformly heat the material to 2100 - 2300°F (1149 - 1260°C) for hot working, when finished, rapidly cool the work piece to ensure the maximum corrosion resistance.

303 stainless steel cold work

303 cannot readily be cold worked, some cold work is possible but sharp bending should not be applied.

303 stainless steel density

Typically the density of stainless steel 303 is 0.285 lb/in3 (7.9g/cm3) at room temperature.

303 Stainless steel thermal conductivity

The heat conductivity for stainless steel 303 is at 15 W/(m*K) (104 BTU/(h-ft*°F)) at room temperature.

303 stainless steel thermal conductivity diagram chart303 stainless steel thermal conductivity diagram chart

303 stainless steel thermal expansion coefficient

This diagram shows how much the 303 might expand or contract when the temperatures change which can be very important when working with high temperatures or strong temperature changes.

Medium thermal expansion coefficient
10-6m/(m • K) At a temperature of
16 68 - 212°F
16.5 68 - 392°F
17 68 - 572°F
17.5 668 - 752°F
18 68 - 932°F
18.5 68 - 1112°F
18.5 68 - 1292°F
19 68 - 1472°F
303 stainless steel thermal expansion coefficient diagram chart303 stainless steel thermal expansion coefficient diagram chart

303 stainless steel specific electrical resistivity

You can find the temperature dependent material constant (Resistivity) in the following table. The electrical conductivity is the reciprocal value of the specific resistance.

Table of the specific electrical resistivity
Value At a temperature of
~0.73 (Ohm*mm²)/m 20°C

303 stainless steel modulus of elasticity (Young’s Modulus)

The stress and strain modulus or modulus of elasticity (Young’s modulus) for 303 stainless steel is at 27.992 KSI (193 GPa). 

Is stainless steel 303 a knife steel?

303 is not a classic knife steel as it does not have the right balance of hardness and toughness for good edge retention, sharpness and chipping resistance.

Conclusion

Stainless steel 303 is chosen when machinability is the focus, its good machinability enables the production of high precision components which are often used in the automotive or electronics industry. Though it has a lower corrosion resistance than some other stainless steels, it is resistant to atmospheric corrosion and mild chemical exposure.

303 stainless steel datasheet

As a 303 steel supplier we provide you with the datasheet for stainless steel 303 in PDF format.

Stainless Steel alternatives or equivalent

Search for an alternative Stainless Steel with the ABRAMS STEEL GUIDE®

It is possible with just one click to find an alternative or an equivalent steel grade!

We have the solution! (Registration is not needed).

Try it now - find an alternative steel grade and its properties in no time.

Steel comparison - 303 Stainless Steel - Alternative Equivalent - Steel GuideSteel comparison - 303 Stainless Steel - Alternative Equivalent - Steel Guide

Disclaimer

The data shown here has been compiled with the greatest diligence and is regularly updated with regard to the correctness and completeness of its content. The content is indicative only and should not be taken as a warranty of specific properties of the product described or a warranty of suitability for a particular purpose. All information presented is given in good faith and no liability will be accepted for actions taken by third parties in reliance on this information. ABRAMS Industries reserves the right to change or amend the information given here in full or parts without prior notice.