Stainless 303

Annealing Procedure

1850-1950 F (1010-1066 C), followed by rapid cooling is the recommended practice.

Applications

Used in an incredibly wide variety of parts both in screw and general machining industries. Applications include hardware, fasteners, valve parts, nozzles and trim.

Cold Workability

Minor deformation is possible with this alloy, although it is not its strong point. Type 303 Se is superior in this aspect.

Hardening Procedure

This alloy does not respond to hardening by heat treatment. Cold work will raise both the hardness and strength characteristics.

Hot Workability

Forging and upsetting may commence once the workpiece has been thoroughly heated to 2100-2300 F (1149-1260 C). It is not recommended to work this material below 1700 F (927 C). Rapid post-work cooling will optimize corrosion performance.

Machinability

Excellent speeds and feeds are capable with this material. The addition of sulfur causes a very brittle chip. Many companies now offer premium machinability grades, such as CarTech with their Project 70 and 7000 series.

Principle Design Features

303 is one of the most popular of all the free machining stainless steels. It offers good strength, corrosion resistance and great machinability. It will resist scaling at temperatures up to 1600 F(871 C).

Weldability

Although not recommended, welding may be performed if low temperatures are employed. Recommended filler metal is AWS E/ER312. At high temperature, the sulfur in 303 tends to precipitate at the weld boundary resulting in weak and brittle joints.