Type 303 is a non-magnetic stainless steel, which is not hardenable by heat treatment. It is the free machining modification of the basic 18% chromium - 8% nickel stainless steel.

303 has good resistance to oxidation at temperatures up to 1700°F.  In extreme oxidizing atmospheres, irregular scaling may be encountered, particularly above 1400°F.

Chemistry

	Cr	Ni	C	Mn	P	S	Si	Fe
MIN	17.0	8.0	-	-	-	0.15	-	-
MAX	19.0	10.0	0.15	2.0	0.2	-	1.0	Balance

RAM 303 contains 0.30% minimum sulfur for enhanced machinability, substantially higher than the 0.15% minimum required by ASTM

Specifications

AMS 5640, AMS 5640 Type 1, AMS 5640R
ASTM A 262, ASTM A 484, ASTM A314
ASTM A582, UNS S30300, Werkstoff 1.4305

Inventory

303 Flat Bar, 303 Square Bar

Common Trade Names

303 Stainless

Features

· Melted and processed to maximize machinability

· Improved machinability over 304/304L and 316/316L

Applications

· Automatic screw machines

· Conveyor systems

Physical Properties

Density: 0.290 lb/inch3  
Melting Point: 2552°F 
Thermal Conductivity at 212°F:  113/2 (Btu x in)/(hr x ft2 x °F)

Mechanical Properties

Typical Tensile Properties

Tensile Strength, ksi	75
Yield Strength, ksi	30
% Elongation in 2 inches	35
% Reduction of area	50

Machining

Feeds and Speeds
Starting Feeds and speeds with high speed tooling (Annealed Type 303*)

Tool	Inch	Speed, sfpm**	Feed, inches/revolution
Form Tool (width)	1/4 1/2 3/4	110 105 100	0.0026 0.0022 0.0019
Box Tool (depth)	1 1/8 1/4	115 105 100	0.0065 0.0060 0.0055
Twisting Drill (diameter)	1/4 1/2 3/4	65 70 75	0.0045 0.0050 0.0055
Sizing Reamer	1/2 and under 1/2 and over	90 90	0.0055 0.0085
Finishing Reamer	All	35	0.0035
Tapping (Cut Threads)	-	15/30	-

* As Processed for Best Machinability, **sfpm = Surface feet per minute