Purchased as rolled, pre-Hardened (PH), or in the annealed condition, 4140 steel plate possesses a full range of hardening and wear resistance properties. Due to it’s good hardness penetration and uniformity flame hardening, induction hardening, or oil hardening can considerably increase the wear resistance of 4140 steel.
Common uses of 4140 steel plate: tooling, machine plates, , shafts, sprockets, special machine parts, , metal stamping, tool & die, shredders, couplings, reamer bodies, screws, flywheel components, axles, shafts, bolts, , piston rods and rams.
4140 steel has good machinability when annealed. 4140 steel is not easily welded and post weld treatment should be performed. It can be formed using conventional techniques when annealed and requires more pressure when forming because it is tougher than plain carbon steels.
4140 is a chromium-molybdenun alloy steel that can be oil hardened to relatively high hardenability. The chromium content provides good hardness penetration, and the molybdenum imparts uniformity of hardness and high strength. Through variations in the method of heat treating 4140, an exceptionally wide range of properties can be attained. For this reason, it is often used as stock for forging, as 4140 has self scaling properties. 4140 responds readily to heat treatment and is comparatively easy to machine in the heat treated condition. 4140 resists creep in temperatures up to 1000° F and maintains its properties even after long exposure at these relatively high working temperatures. Other desirable properties include good wear resistance, excellent toughness, and good ductility in the quenched and tempered condition. 4140 cold finished annealed is available in rounds, squares, rectangles, and hexagons. 4140 cold rolled rounds is also available with an addition of .15-.35 lead (41L40), which improves machinability (77% of 1212, surface cutting speed 127 ft/min) without sacrificing other desirable properties, with the exception that the use of 41L40 is not recommended for applications above 400°F, since at elevated temperatures, ductility in 41L40 is low.