Fabrication & Finishes

Heat Resistance and Heat Treatment

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3CR12 has shown good oxidation resistance in intermittent service up to 1346°F and in continuous service to 1148°F. If the application will put the metal under stress, the temperature should be limited to 842°F continuous or 1112°F intermittent.

 

For annealing, heat to 1292-1382°F for 90 minutes per 25mm section and follow with air cooling. Controlled atmospheres are recommended and this process should be followed with pickling and passivating.

 

Cold Working

 

3CR12 has excellent formability. Roll forming, bending, and press braking are all suitable with 3CR12, but loadings will be about 30% higher than what is used for mild steel. The minimum inner bend radius is twice the plate thickness. Due to the properties of 3CR12, you should expect greater spring back than mild steel and compensate by over bending.

 

Welding

 

3CR12 has great weldability and can be readily welded using conventional techniques of austenitic stainless steels. A great benefit is that it can be welded to other ferrous metals, as well as mild and stainless steels, quite satisfactorily. The recommended filler wire is grade AWS 309L. Discoloration of the weld should be removed by pickling and passivating to restore maximum corrosion resistance.

 

Machining

 

3CR12 has machining traits similar to that of grade 430 stainless, i.e. 60% compared to mild steel. Slow speeds along with heavy feed rates and sufficient emulsion lubricant will help prevent machining problems.