AMS 6456 is a sub-type specification of Steel 4340 that Tech Steel & Materials offers in the form of welding wire. The material is to be used with every other specification of the alloy, including AMS 6359, AMS 6409, AMS 6414, AMS 6415, AMS 6454, and AMS 6484. However, the welding process is different depending on the heat treatment used on the said material.
For alloy in the annealed condition, a high-strength weld can be easily obtained using traditional methods. Following the weld, additional normalizing, hardening, and tempering processes can produce a finalized part with excellent strength, wear resistance, good abrasion resistance, impact and fatigue resistance, and excellent atmospheric corrosion resistance. Furthermore, additional surface strength can be achieved using flame hardening or nitriding.
Welding is not recommended on parts that were already hardened. However, if necessary, the parts should be preheated to 400-580 °F to (≈200-300 °C), followed by after-welding stress relief at 1020-1200 °F (≈550-650 °F). Whereas, for tempered material, the stress relief should be 60 °F (15 °C) lower than the tempering temperature.
AMS 6456 finds use in various fields, including heavy machinery industry, military industry and ordnance hardware, commercial aircraft industry, automotive industry, etc.