STAINLESS

303
Chromium-nickel stainless steel with added sulfur or selenium and phosphorus to improve machinability and non-seizing properties. It is the most free machining of the chromium-nickel grades. Non-magnetic in the annealed condition.
Applications: Aircraft parts and parts requiring machining, grinding or polishing
with good corrosion resistance. Excellent for moving parts and where low magnetic permeability is required.
Analysis:
303S 303Se
C .15 Max. .15 Max.
Mn 2.00 Max. 2.00 Max.
P .15 Max. .17 Max.
S .15 Max. .04 Max.
Se --- .15/.40
Si 1.00 Max. 1.00 Max.
Cr 17.00/19.00 17.00/19.00
Ni 8.00/10.00 8.00/10.00
Cu .75 Max. .75 Max.
Mo .75 Max. .75 Max.
Mechanical Properties: (following values are average and are representative)
(1/2” and under)
Tensile Strength (psi) 100,000
Brinell Hardness 228
Surface Cutting Speed: 130 ft/min. Weldability: Fair. Hardening: Not hardenable
by heat treatment. Cold working increases tensile strength and hardness.
Corrosion Resistance: Maximum corrosion resistance in the annealed condition. Free machining elements reduce overall corrosion resistance. Resistance to Scaling: Excellent up to 1600º F in continuous service. In design, beware of high coefficient of expansion.
304
Similar to Type 302 with excellent mechanical properties, resistance to many corrosive agents. Useful where sanitation and cleanliness are important. Non magnetic in the
annealed condition. Hardness and tensile strength can be increased by cold working,
but modified by lowered carbon content providing good resistance to corrosion in welded construction where subsequent heat treatment is not practical.
Applications: Dairy, beverage and food product handling/processing equipment. Used for handling acetic, nitric, and citric acids; organic and inorganic chemicals, dye stuff, crude and refined oils; instruments; hospital equipment; applications requiring welding.
Analysis: C - .08 Max. Mn - 2.00 Max. P - .04 Max. S - .03 Max. Si - 1.0 Max.
Cr - 18.00/20.00 Ni - 8.00/10.50 Cu - .75 Max. Mo - .75 Max.
Mechanical Properties: (following values are average and are representative)
Tensile Strength (psi) 90,000
Yield Point (psi) 40,000
Elongation (% in 2”) 50
Brinell Hardness 163
Weldability: Excellent. Surface Cutting Speed: 75 ft/Min. Corrosion Resistance:
Maximum resistance in annealed condition shows good resistance to strong oxidizing
acids such as nitric acid, and resists attack by a wide variety of organic and inorganic chemicals. Intergranular corrosion may occur if heated within or cooled through the range of 800º F - 1500º F. Resistance to Scaling: Excellent at temperatures up to
1600º F in continuous service. In design, beware of high coefficient of expansion.
304L
As per above except: 304L is an extra-low-carbon analysis, the advantage of which is that it precludes any harmful precipitation in the 800º F - 1500º F range, such as might otherwise occur in welding heavier sections.
309
This alloy is known for good strength and oxidation resistance in continuous service temperatures up to 2000º F (1093º C). It is superior to 304 stainless in both strength and corrosion resistance.
Applications: Oven linings, boiler baffles, fire box sheets, furnace components and other high temperature containers.
Analysis: C - .2 Max. Cr - 22.00/24.00 Fe - Balance Mn - 2.00 Max.
Ni - 12.00/15.00 P - .045 Max. S - .03 Max. Si – 1.0 Max.
Mechanical Properties: (following values are average and are representative)
Tensile Strength (psi)
Yield Point (psi)
Elongation (% in 2”)
Brinell Hardness
Machinability: This alloy machines similarly to type 304 stainless. Its chips are stringy and it will work-harden rapidly. It is necessary to keep the tool cutting at all times and use chip breakers. Weldability: Most of the austenitic stainless steels can be readily welded using fusion or resistance methods. Oxyacetylene welding is not recommended.
Hot Working: Working temperatures are 2150º F (1177º C), with reheating necessary at 1800º F (982º C). Rapid quenching is recommended. Full post-work annealing is required to reattain maximum corrosion resistance. Cold Working: Although this alloy has a high work hardening rate, it can be drawn, headed, upset, and stamped. Full annealing is
required after cold work to remove internal stress. Cold work will cause an increase in both hardness and strength. Annealing: 1900º - 2050º F (1038º - 1121º C), water quench. Hardening: This alloy does not respond to heat treatment.