Type 303

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SPECIFICATION DATA SHEET: 303 Stainless Steel

BAR	TUBE	PIPE
PSQ SHAFT	WELDING ROD	CASTINGS
FORGINGS	PLATE	FLANGES
TG&P SHAFTS	SHEET	FITTINGS

Type 303

	Austenitic Stainless Steel
	Excellent machining characteristics
	Free machining version of Types 302 and 304 is used for parts requiring extensive machining
	Annealed condition is non-magnetic
	Slightly magnetic when cold worked
	Good corrosion resistance
	Good oxidation resistance up to 1700 degrees F

Type 303 Se

	Basically same as 303
	Obtains free-machining characteristics by the addition of selenium rather than sulfur
	Selenium produces better surface finish
	Selenium improves formability and weldability

Specifications

Types 303 and 303 Se are covered by the following specifications:

Type 303 Se

AMS 5640G
AMS 5641A
AMS 5738
ASTM A314-63
ASTM A230-65
ASTM A581-67
ASTM 582-67

Type 303

AMS 564OG
ASTM A314-63
ASTM A320-65
ASTM 581-67
ASTM 582-67
QQ-S-764A
MIL-S-862B

Composition
	Type 303 %	Type 303 Se %
Carbon	.15 max	.15 max
Manganes	2.00 max	2.00 max
Phosphorus	.20 max	.20 max
Sulfur	.15 min	.06 max
Selenium	NA	.15 min
Silicon	1.00 max	1.00 max
Chromium	17.00 - 19.00	17.00 - 19.00
Nickel	8.00 - 10.00	8.00 - 10.00
Molybdenum	.60 max	NA

Table 1 Typical Mechanical Properties Annealed
Ultimate tensile strength, psi	90,000
.20% Yield strength psi	35,000
Elongation, % in 2”	50
Rockwell hardness	B83
Reduction of area, %	55

Standard Heat Treatments

	Anneal: Heat to 1900 - 2050 F and water quench
	Harden: Types 303 and 303 Se cannot be hardened by heat treatment

Corrosion Resistance

	Excellent corrosion resistance
	Effectively resist attack in atmospheric exposures, sterilizing solutions, most organic and many inorganic chemicals, most dyes nitric acid and foods
	For best corrosion resistance finished parts should be free from scale and foreign particles

Forgeability

	Types 303 and 303Se should be heated slowly to 2000-2150 F
	Soaked for a sufficient time then raised to 2200 - 3250 F
	They should not be forged below 1700 F

Machinability

	Excellent machinability
	Surface finish on parts made of 303 Se is better than that of regular 303

Formability

	Type 303 limited formability because of its sulfur content
	Type 303 Se has better formability but it should be limited to mild forming operations

Weldability

	only fair weldability
	can be welded using proper procedures
	Weldability can be improved by using methods that minimize dilution of the weld metal with the melted base metal
	Reducing the time that weld are in the hot-short temperature range and use of Type 312 (29-9) filler metal helps obtain satisfactory results