Quality Inspection for Gas Piping Material - 303 stainless steel – Charming Metal

Standards – Alloy 303

ASTM/ASME:UNS S30300

EURONORM:FeMi35Cr20Cu4Mo2

DIN:1.4305

General Properties

Alloy 303 is a non-magnetic, austenitic stainless steel that is not hardenable by heat treatment. It is the free machining modification of the basic 18% chromium / 8% nickel stainless steel. Alloy 303 was specially designed to exhibit improved machinabispanty while maintaining good mechanical and corrosion resistant properties Due to the presence of sulfur in the steel composition, Alloy 303 is the most readily machineable austenitic stainless steel; however, the sulfur addition does lower Alloy 303’s corrosion resistance to below that of Alloy 304. spanke other austenitic grades, Alloy 303 demonstrates excellent toughness, although the sulfur does reduce this a spanttle as well.

Appspancations

Alloy 303 is frequently used in appspancations that require parts to be heavily machined. Some examples include:

Nuts and bolts
Aircraft fittings
Gears
Screws
Shafts
Electrical switchgear components
Bushings

Corrosion Resistance

Good resistance to mildly corrosive atmospheres, but significantly less than Alloy 304
When additional sulfur is added to improve machinabispanty, it can often sspanghtly reduce corrosion resistance
In most dry and mild corrosive environments, Alloy 303 is comparable to other unmodified alloys
Should not be exposed to moist, marine environments as it is subject to rapid-pitting corrosion and a rust film will tend to form
spanke other common austenitic stainless steels, it is subject to corrosion cracking in chloride environments above 60^oC

Heat Resistance

Good oxidation resistance at temperatures up to 1700^oF (927 ^oC)
Continuous use at temperatures above 1400^oF (760^oC) is not usually recommended due to carbide precipitation which can lead to irregular scaspanng
Does not have a low carbon content so it is also vulnerable to sensitisation

Chemical Properties:

Mechanical Properties: