Product Description

Stainless steel **4 has excellent corrosion resistance in a wide variety of environments and when in contact with different corrosive media. Pitting and crevice corrosion can occur in environments containing chlorides. Stress corrosion cracking can occur at temperatures over *0°C.

Heat Resistance of Stainless Steel **4

Stainless steel **4 has good resistance to oxidation in intermittent service up to **0°C and in continuous service to **5°C. However, continuous use at ******0°C is not recommended if corrosion resistance in water is required. In this instance **4L is recommended due to its resistance to carbide precipitation.

Where high strength is required at temperatures above **0°C and up to **0°C, grade **4H is recommended. This material will retain aqueous corrosion resistance.

Fabrication of Stainless Steel **4

Fabrication of all stainless steels should be done only with tools dedicated to stainless steel materials. Tooling and work surfaces must be thoroughly cleaned before use. These precautions are necessary to avoid cross contamination of stainless steel by easily corroded metals that may discolour the surface of the fabricated product.

Cold Working of Stainless Steel **4

Stainless steel **4 readily work hardens. Fabrication methods involving cold working may require an intermediate annealing stage to alleviate work hardening and avoid tearing or cracking. At the completion of fabrication a full annealing operation should be employed to reduce internal stresses and optimise corrosion resistance.

Hot Working of Stainless Steel **4

Fabrication methods, like forging, that involve hot working should occur after uniform heating to ********0°C. The fabricated components should then be rapidly cooled to ensure maximum corrosion resistance.

Heat Treatment of Stainless Steel **4

Stainless steel **4 cannot be hardened by heat treatment.

Solution treatment or annealing can be done by rapid cooling after heating to ********0°C.

Machinability

Stainless steel **4 has good machinability. Machining can be enhanced by using the following rules:

• Cutting edges must be kept sharp. Dull edges cause excess work hardening.
• Cuts should be light but deep enough to prevent work hardening by riding on the surface of the material.
• Chip breakers should be employed to assist in ensuring swarf remains clear of the work
• Low thermal conductivity of austenitic alloys results in heat concentrating at the cutting edges. This means coolants and lubricants are necessary and must be used in large quantities.

Welding of Stainless Steel **4

Fusion welding performance for Stainless steel **4 is excellent both with and without fillers. Recommended filler rods and electrodes for stainless steel **4 is grade **8 stainless steel. For **4L the recommended filler is **8L. Heavy welded sections may require post-weld annealing.This step is not required for **4L. Grade **1 may be used if post-weld heat treatment is not possible.