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
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
