Alloy: 4340 | Material: Alloy Steel | Shape: Round Bar | Diameter: 0.4375 Inches | Item Length: 72 Inches Alloy Steel Round Bar 4340 Normalized Cold Finish has high strength, toughness, wear resistance, and fatigue strength. It can be machined in all states other than hardened and it is easily welded. Additionally, 4340 can be cold worked easily in the annealed state. It is typically used in military aircraft, automotive systems, hydraulic parts, machine tools, and steel crankshafts. Alloy steels are made by combining carbon steel with one or several alloying elements, such as manganese, silicon, nickel, titanium, copper, chromium and aluminum. These metals are added to produce specific properties that are not found in regular carbon steel. The elements are added in varying proportions (or combinations) making the material take on different aspects such as increased hardness, increased corrosion resistance, increased strength, improved formability (ductility); the weldability can also change. UNS G43400, AISI 4340, Alloy Steel This product weighs 3.07 pounds and meets the following specs: ASTM-A29, ASTM-A108, ASTM-A322, AMS-6415, AMS-6484, AMS/MIL-S-5000