SS 440C Round Bars & Rods

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Stainless Steel 440C Explained

Stainless Steel 440C is a premium high-carbon martensitic stainless steel. To begin with, it is renowned for its exceptional hardness, outstanding wear resistance, and excellent edge retention after heat treatment. Furthermore, it offers superior strength and abrasion resistance — making it the top choice for high-load and high-wear applications.

Why do engineers and manufacturers choose SS 440C for critical components? First and foremost, it has the highest carbon content among the 440 series, delivering maximum hardness and durability. In addition, it maintains good performance in mildly corrosive environments. Moreover, its dimensional stability after heat treatment ensures precision and reliability in demanding applications.

Consequently, Stainless Steel 440C is widely used in precision bearings, cutting tools, and molds. Furthermore, it is also trusted in valve parts, aerospace components, and high-performance mechanical assemblies. Equally important, its combination of exceptional hardness, superior wear resistance, and excellent edge retention makes it the preferred choice for applications where maximum durability and dimensional stability are critical.

Need high-performance SS 440C round bars for your demanding application? Contact our technical team today — we’ll help you select the right size, heat treatment condition, and finish for your specific requirements, and provide a competitive quote tailored to your needs.

Other Types of Stainless Steel 440C Bars

SS 440C Stainless Steel Square Bar
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SS 440C Square Bar
  • SS 440C square bars developed for extreme hardness and wear resistance
  • Material identification: UNS S44004 high carbon martensitic stainless steel
  • Manufactured in accordance with ASTM A276 and ASME SA276 standards
  • DIN 1.4125 grade ensures metallurgical accuracy and consistency
SS 440C Stainless Steel Hex Bar
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SS 440C Hex Bar
  • ASTM A276 certified SS 440C hex bars for tooling and precision parts
  • DIN 1.4125 / UNS S44004 compliant stainless steel hex profiles
  • High surface hardness suitable for mechanical wear components
  • Available in bright drawn, polished and machined finishes
SS 440C Stainless Steel Rectangular Bar
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SS 440C Rectangular Bar
  • High precision SS 440C rectangular bar sections
  • Produced as per ASTM A276 stainless steel specifications
  • Traceable grade: UNS S44004 / DIN 1.4125
  • Ideal for machining of tooling, guides and wear plates
SS 440C Stainless Steel Flat Bar
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SS 440C Flat Bar
  • DIN 1.4125 flat bars offering superior abrasion resistance
  • UNS S44004 stainless steel grade for consistent chemistry
  • Manufactured in accordance with ASTM A276 / ASME SA276
  • Supplied in hot rolled, ground and polished surface finishes
SS 440C Stainless Steel Bright Bar
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SS 440C Bright Bar
  • Bright finished SS 440C bars with tight dimensional control
  • Excellent surface smoothness for high-precision machining
  • ASTM A276 compliant stainless steel bright rods
  • Uniform straightness across supplied lengths
SS 440C Stainless Steel Forged Bar
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SS 440C Forged Bar
  • Forged SS 440C bars for heavy-duty wear and load conditions
  • UNS S44004 forged stainless steel material traceability
  • ASTM A276 certified forged bar manufacturing
  • Heat treated forgings deliver maximum hardness and durability

440C STAINLESS STEEL ROUND BAR EQUIVALENT GRADES

STANDARD UNS WNR.
SS 440C S44004 1.4125

SPECIFICATION OF STAINLESS STEEL 440C ROUND BAR

Stainless Steel Round Bar Specification ASTM A276 / A479, ASME SA276 / A479
Dimension Standard EN, DIN, JIS, ASTM, BS, ASME, AISI
Size 14 mm – 300 mm
Thickness 50 mm to 6000 mm Long
Length 1 to 6 Meters, Custom Cut Length
Form Round, Square, Hex (A/F), Rectangle, Billet, Ingot, Forging Etc.

CHEMICAL COMPOSITION OF STAINLESS STEEL 440C ROUND BAR

Grade C % Mn % Si % P % S % Cr % Ni %
440C 0.95 – 1.20 1.00 max 1.00 max 0.040 max 0.030 max 16.0 – 18.0 —

MECHANICAL PROPERTIES OF STAINLESS STEEL 440C ROUND BAR

Tempering Temperature (°C) Tensile Strength (MPa) Yield Strength 0.2% Proof (MPa) Elongation (% in 50 mm) Hardness Rockwell C (HRC) Impact Charpy V (J)
Annealed* 758 448 14 269 HB max —
204 2030 1900 4 59 9
260 1960 1830 4 57 9
316 1860 1740 4 56 9
371 1790 1660 4 56 9
* Annealed properties are typical for Condition A of ASTM A276. Brinell hardness shown is the ASTM A276 specified maximum for annealed 440C.

💡 Practical Difference in Use

Use Stainless Steel 440C Round Bars when: extremely high hardness, exceptional wear resistance, superior edge retention, and long service life are required in aggressive mechanical applications. SS 440C is a high-carbon martensitic stainless steel offering the highest hardness among the 400-series stainless grades. After proper heat treatment, it achieves outstanding abrasion resistance and load-bearing capability, making it ideal for precision components exposed to continuous friction and heavy stress. → Example: bearing races, precision bearings, cutting tools, knives, valve seats, mechanical seals, gauge components, aerospace parts, and high-load wear components.


Heat Treated / Ground / Bright Finished Stainless Steel 440C Round Bars when: maximum dimensional accuracy, ultra-smooth surface finish, peak hardness, and superior fatigue resistance are required for critical engineering parts. Ground and polished bars deliver excellent straightness and tight tolerances, while optimized heat treatment ensures consistent hardness and exceptional wear life. → Example: CNC precision shafts, bearing rollers, hardened pins, tooling spindles, aerospace fittings, surgical tools, high-performance seals, and ultra-wear components.

Applications of Stainless Steel 440C Round Bars

Stainless Steel 440C round bars are widely used in aerospace, bearing manufacturing, tooling, medical devices, valve production, and precision engineering where maximum hardness, wear resistance, and dimensional stability are critical.

  • Bearings & Motion Systems: Bearing races, rollers, precision bearings.
  • Tooling & Cutting Equipment: Knives, cutters, punches, dies.
  • Valves & Sealing Systems: Valve seats, stems, mechanical seals.

When to Choose Stainless Steel 440C Round Bars?

The selection mainly depends on required hardness level, wear intensity, operating stress, machining precision, and expected service life.

Choose SS 440C Round Bars when:

  • Maximum achievable hardness is required
  • Components are exposed to extreme abrasion and friction
  • Excellent edge retention and dimensional stability are needed
  • Parts operate under heavy load and repeated cycles
  • Precision grinding and tight tolerances are required
  • Used in bearings, cutters, valves, and high-performance machinery

SS 440C Ground / Bright / Heat Treated Round Bars are preferred when:

  • Ultra-precise dimensional accuracy and surface smoothness are required
  • Low friction and consistent wear performance are critical
  • High-speed CNC machining and precision finishing are involved
  • Critical rotating and sliding components are manufactured
  • Stable hardness and microstructural consistency are essential
  • Used in aerospace, bearing, medical, and sealing applications

Industries That Use Stainless Steel 440C Round Bars

SS 440C is preferred in industries where extreme hardness, wear resistance, precision performance, and long-term reliability are essential.

Bearing Manufacturing

Used in high-precision rolling and sliding bearings.

Uses

Bearing races, rollers, precision balls.

Why SS 440C?

Exceptional hardness and fatigue resistance.

Aerospace & Defense

Used in critical high-load precision components.

Uses

Actuator parts, shafts, locking mechanisms.

Why SS 440C?

High strength with dimensional stability.

Medical & Surgical Equipment

Used in precision surgical and medical tools.

Uses

Surgical instruments, cutting tools, implants.

Why SS 440C?

Sharp edge retention and sterilization durability.

Valve & Seal Industry

Used in abrasion-prone sealing surfaces.

Uses

Valve seats, stems, mechanical seals.

Why SS 440C?

Superior wear resistance and sealing reliability.

Tooling & Precision Engineering

Used in ultra-precision tooling components.

Uses

Dies, punches, gauges, spindles.

Why SS 440C?

Extreme hardness with dimensional accuracy.

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Looking for high-quality Stainless Steel 440C Round Bars & Rods? Fully compliant with ASTM A276, A479 and ASME SA276, SA479. Get in touch with us today.

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