4140 Steel Heat Treatment: Material Properties, Hardness, Strength & In-Stock Options
4140 steel (AISI 4140) is a versatile chromium-molybdenum alloy steel prized for its balance of strength, toughness, and fatigue resistance after proper heat treatment. Engineers use it for shafts, gears, axles, and tooling where customizable hardness (28-55 HRC) via quenching and tempering is essential for performance. Heat Treatment Process Annealing softens 4140 for machining at 815-870°C (1500-1600°F), holding 1 hour per inch thickness, then furnace cooling to ~200 HB. For hardening, austenitize at 840-875°C (1550-1600°F), oil quench, then temper at 200-650°C (400-1200°F) to balance hardness and ductility—lower temps yield 50-55 HRC for wear parts, higher for tougher applications. Key Properties by Condition In-Stock Options Nifty Alloys LLC stocks 4140 in rounds (10-500mm), plates (up to 400mm thick), and bars, available annealed or pre-quenched&tempered with MTC 3.1 certification for UAE/GCC pro...