Alloy 600 is not an age hardening alloy; cold working is the only available means of hardening. Softening by annealing begins at about 1600°F (871°C), and is reasonably complete after 10 to 15 minutes of heating at 1800°F (982°C). Above this temperature, grain growth may be objectionable, although very brief heating at 1900°F will cause complete softening without undue grain growth. Since the rate of cooling has no effect on the softening, the material may be water quenched or air cooled.

Workability

Hot Working/Forging
Low sulfur reducing furnace atmospheres should be used in forging. Major hot working should be done between 2300/1850°F, while light working may be continued as low as 1600°F. No hot working should be attempted between 1600/1200°F due to lower ductility in that range.

Machinability
Alloy 600 is machinable in both the hot worked and annealed conditions. Because considerable heat is generated in machining this alloy, high-speed steel, cast nonferrous or cemented carbide tools should be used. The tools should be kept sharp.
Lathe turning speeds with high-speed and nonferrous tools are 35/45 sfm (0.18/0.23 m/s); speeds with cemented carbide tools are 100/175 sfm (0.51/0.89 m/s). (This data should be used as a guide for initial machine setup only. The figures used are averages. On certain work, the nature of the part may require adjustment of speeds and feeds.)
Sulfur-based oil should be used as a lubricant, but should be completely removed before the machined part is exposed to elevated temperatures, as in welding.

Cold Working
For higher properties, alloy 600 can be cold worked below 1200°F (649°C).

Welding
Alloy 600 can be joined by the usual welding , brazing, and soldering process.