440C (UNS S44004) Martensitic Stainless Forgings — Quench-and-Temper Hardened Bearing, Valve & Cutlery-Grade Components
Shivam Forge manufactures forgings in 440C martensitic stainless steel — a high-carbon grade hardenable to 58-60 HRC through conventional quench-and-temper heat treatment, used for bearing races and balls, valve components, and cutlery-grade applications demanding both high hardness and corrosion resistance. Distinct hardening mechanism from precipitation-hardening grades like 17-4PH. Rajkot, India. Call +91-9265772827.
440C occupies a distinct position within the stainless steel family relative to the precipitation-hardening (PH) grades like 17-4PH and 15-5PH that this same alloy category is often discussed alongside: while both 440C and the PH grades are martensitic stainless steels capable of reaching high strength and hardness, they get there through genuinely different hardening mechanisms, and understanding this distinction matters directly to selecting the correct grade for a given application. 440C hardens through the same conventional quench-and-temper mechanism that carbon and low-alloy tool steels use — its high carbon content (0.95-1.20%) enables martensitic transformation on rapid quenching from austenitizing temperature, followed by tempering to relieve brittleness while retaining high hardness, reaching a hardness ceiling (58-60 HRC) that precipitation-hardening grades, whose strengthening comes instead from a much lower-carbon martensitic base subsequently aged to precipitate fine strengthening compounds, simply cannot approach — 17-4PH and 15-5PH typically top out in the low-to-mid 40s HRC even in their highest-strength aging condition. This higher achievable hardness makes 440C the preferred stainless choice specifically where rolling contact fatigue resistance, wear resistance, and edge retention are the governing requirements — bearing races and balls, valve seats and trim, cutlery and surgical instrument edges — applications where the PH grades' more moderate hardness ceiling, however useful their toughness and stress-corrosion cracking resistance are for structural applications, simply isn't competitive.
Forged 440C blanks for bearing race and rolling element applications requiring corrosion resistance alongside the rolling contact fatigue resistance high hardness provides, for service environments where standard bearing steel's lack of corrosion resistance is a genuine limitation.
Forged 440C valve seat, ball, and trim component blanks for valve applications requiring hard, wear-resistant sealing surfaces combined with stainless corrosion resistance.
Forged 440C blanks for cutlery-grade and surgical instrument applications, where the grade's high achievable hardness supports sustained edge retention through repeated use and sharpening.
Forged 440C blanks for precision mechanical components requiring maximum hardness and dimensional stability in a stainless material, such as gauge blocks, precision shafts, and wear plates.
Austenitizing, quench, and temper heat treatment developing 440C's characteristic high hardness, with tempering temperature adjusted to the specific hardness and toughness balance the application requires.
Heat treatment capability to 440C's full hardness ceiling of 58-60 HRC for maximum wear resistance applications, or to a lower tempered hardness where additional toughness margin is preferred.
Material verification confirming 440C's stainless corrosion resistance meets application requirements, noting that maximum-hardness tempering conditions can moderately reduce corrosion resistance compared to lower-hardness tempers.
Material test certificates per EN 10204 3.1 as standard, with 3.2 third-party witnessed certification available for bearing, valve, and precision component documentation requirements.
440C's position within the martensitic stainless steel family is often discussed alongside precipitation-hardening grades like 17-4PH and 15-5PH, since all three share the broad martensitic stainless classification and can be forged and heat-treated to develop high strength — but the hardening mechanism each grade actually relies on, and the resulting hardness ceiling each can achieve, differ in ways that matter considerably to correct application-specific grade selection. 440C's high carbon content, at 0.95-1.20%, enables conventional martensitic transformation through rapid quenching from austenitizing temperature, the same fundamental hardening mechanism carbon and alloy tool steels rely on, followed by a tempering step that relieves as-quenched brittleness while retaining the bulk of the achieved hardness.
Precipitation-hardening grades take a genuinely different metallurgical path to reach high strength: 17-4PH and 15-5PH start from a much lower-carbon martensitic base — already relatively soft as-quenched compared to 440C's higher-carbon martensite — and then develop their working strength through a controlled aging heat treatment that precipitates fine copper-rich or other strengthening compounds throughout the microstructure. This aging mechanism delivers a genuinely useful strength-toughness combination and, notably, better stress-corrosion cracking resistance than a high-carbon martensitic grade typically offers, but it simply cannot reach the hardness ceiling 440C's carbon-driven martensitic hardening achieves — PH grades generally top out in the low-to-mid 40s HRC even in their highest-strength aging condition, while 440C readily reaches 58-60 HRC.
This hardness gap is precisely why application selection between 440C and the PH grades tends to sort along fairly clear lines: applications where rolling contact fatigue resistance, sliding wear resistance, or sustained cutting-edge retention is the governing requirement — bearing races and balls, valve seats and trim, cutlery and surgical instrument edges — consistently favor 440C, since no amount of toughness or stress-corrosion resistance from a PH grade compensates for a hardness ceiling roughly 15-18 HRC points below what these wear-dominated applications actually need. Conversely, structural components where fracture toughness, weldability, or resistance to stress-corrosion cracking under sustained load matter more than maximum surface hardness generally favor the PH grades' more moderate but tougher property profile — a distinction genuinely worth clarifying at the specification stage rather than treating all high-strength martensitic stainless grades as broadly interchangeable.
For bearing, valve, and precision component manufacturers requiring forged 440C blanks hardened to their specific wear-resistance target, Shivam Forge provides quench-and-temper heat treatment across 440C's full hardness range with corrosion resistance verification available. Contact our engineering team at +91-9265772827 or sales@shivamforge.com with your drawing and target hardness specification for a manufacturability review and quotation.
440C is a high-carbon martensitic stainless steel that hardens through conventional quench-and-temper heat treatment, reaching up to 58-60 HRC. 17-4PH and 15-5PH are precipitation-hardening (PH) grades that harden through a much lower-carbon martensitic base subsequently aged to precipitate strengthening compounds, typically reaching only the low-to-mid 40s HRC even at maximum strength condition. 440C's higher achievable hardness makes it the preferred choice for bearing, valve seat, and cutlery applications where wear resistance and edge retention are the governing requirement, while the PH grades are generally preferred for structural applications valuing toughness and stress-corrosion cracking resistance over maximum hardness.
Bearing races and balls, valve seats and trim components, cutlery and surgical instrument blanks, and precision wear-critical components — anywhere the combination of high hardness (for rolling contact fatigue resistance, wear resistance, or edge retention) and stainless corrosion resistance is the governing material requirement.
440C can be heat-treated to 58-60 HRC, comparable to the hardness range standard through-hardened bearing steel (like 52100) achieves, but with the added benefit of stainless corrosion resistance that 52100 lacks — making 440C the preferred choice specifically for bearing applications in corrosive service environments where standard bearing steel would be inadequate.
Yes, moderately. Tempering conditions that maximize hardness can somewhat reduce 440C's corrosion resistance compared to lower-hardness tempering conditions, since the tempering process affects chromium carbide distribution. We can advise on the appropriate hardness/corrosion-resistance balance for your specific application and service environment.
Send your drawing, dimensions, quantity, and required condition (annealed or heat-treated to target HRC) to sales@shivamforge.com or call +91-9265772827. We confirm material availability and provide a quotation within 24-48 hours.
Why Choose Shivam Forge
Shivam Forge delivers precision hot-forged components from our integrated Shapar, Rajkot facility — covering forging, CNC machining, heat treatment, and quality inspection under one roof.
