303

303

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

 CrNiCMnPSSiFe
MIN 17.0 8.0 - - - 0.3 - -
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 5640AMS 5640 Type 1AMS 5640R
ASTM A 262ASTM A314ASTM A484ASTM 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/inch
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