303 Polished Stainless Steel Round Bar

303 stainless steel belongs to austenitictype stainless steel. It contains sulfur and selenium which makes it easy to be cut and wear resisitant. 303 stainless steel is widely used at the occasions that requires easy cutting and high surface finish

The sulphur addition which is responsible for the improved machining and galling characteristics of Grade 303 lowers its corrosion resistance to below that of Grade 304. As for other austenitic grades the structure gives 303 excellent toughness, although the sulphur in 303 reduces its toughness slightly.

Grade 303Se (UNS S30323) has a selenium rather than sulphur addition, improving the hot and cold forming characteristics over those of 303 and providing a smoother machined surface finish. The machinability rate is also slightly reduced.

Key Properties 

These properties are specified for long product (bar) in ASTM A582. Similar but not necessarily identical properties are specified for other products such as wire and forgings in their respective specifications. Grade 303 is not produced in flat rolled products.

Corrosion Resistance

Good resistance to mildly corrosive atmospheres, but significantly less than Grade 304 due to the sulphur addition; the sulphide inclusions act as pit initiation sites. Grade 303 should not be exposed to marine or other similar environments, as these will result in rapid pitting corrosion. Because the sulphide inclusions in 303 are primarily aligned along the rolling direction the corrosion resistance is particularly reduced in cross-sections. Grade 303, like other common austenitic stainless steels, is subject to stress corrosion cracking in chloride containing environments above about 60°C.

Heat Resistance

Good oxidation resistance in intermittent service to 760°C and in continuous service to 870°C. Continuous use in 425-860°C range not usually recommended due to carbide precipitation - 303 usually does not have a low carbon content so is susceptible to sensitisation.

Fabrication

As well as reducing the corrosion resistance, the sulphur additions in 303 also result in poor weldability and reduced formability compared to Grade 304. Sharp bends should not be attempted in 303. A practical compromise alternative may be a 304 Ugima Improved Machinability grade - this does not machine as readily as 303, but does offer better formability (as well as better weldability and corrosion resistance).

Heat Treatment

Solution Treatment (Annealing) - Heat to 1010-1120°C and cool rapidly. This grade cannot be hardened by thermal treatment.

Welding

Not generally recommended but, if unavoidable and a lower strength can be tolerated, use Grade 308L or 309 electrodes. AS 1554.6 does not pre-qualify welding of 303. Welds must be annealed for maximum corrosion resistance.

Machining

A "Ugima" improved machinability version of grade 303 is available in round bar products. This machines significantly better even than standard 303, giving very high machining rates and lower tool wear in many operations.

Applications

Typical applications include:

Nuts and Bolts

Bushings

Shafts

Aircraft Fittings

Electrical Switchgear Components

Gears

In general any component that is heavily machined and where the corrosion resistance and fabrication properties of 303 are viable.

Chemical composition(WT%)

(C) :≤0.15

(Si) :≤1.00

(Mn) :≤2.00

(Cr) :18.0 to 19.0%

(P) :≤0.20

(S) :≥0.15

(Ni) : 8 to 10.5%

(Mo) :≤0.6

physical property

tensile strength:≥520MPa

Yield strength:≥205MPa

Elongation:≥40%

The normal OD of 303 stainless steel bar is from 4mm to 100mm, the usual length is 6m.

Usually, it only takes 3 working days for us to make delivery if the products are ready in stock.

Of course, unusual size can also be customized according your request.

FAQ: Whats the difference between 304 stainless steel and 303 satinless steel ?

303 stainless steel has more sulfur than 304 stainless steel so it is mostly used in occasions that requires easy cutting and high surface finish, for example, automatic lathe,bolts and nults. Whats more , 303 stainless steel  has lower chrom than 304 stainless steel so its rust resistance is not as good as 304 stainless steel.

303 polished stainless steel round bar 

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