ER 312 is a high-ferrite stainless steel filler metal (like a wire or rod) known for exceptional crack resistance, used primarily for welding dissimilar metals (e.g., stainless to carbon/alloy steels), repairing tools/dies, and joining high-strength steels, creating a strong, ductile, two-phase weld deposit resistant to cracking.
Key Characteristics & Uses:
Dissimilar Metals: Ideal for joining stainless steels to carbon steels or high-nickel alloys, bridging the gap between different metal types.
Crack Resistance: Its high ferrite content (around 30%) in an austenitic matrix provides excellent resistance to hot cracking and fissures.
High Strength & Wear: Offers high tensile strength and good wear resistance, making it suitable for demanding applications.
Applications: Welding cast alloys, armor plate, leaf/coil springs, gears, forged shafts, earth-moving equipment, and general repair.
Limitations: Generally recommended for service temperatures below 420C (790F) to prevent embrittlement from forming a brittle phase.
Welding Processes: Used for GTAW (TIG) and GMAW (MIG).