SS 440B Round Bars & Rods

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Stainless Steel 440B Explained

Stainless Steel 440B is a high-carbon martensitic stainless steel. To begin with, it is perfectly positioned between 440A and 440C — offering a balanced combination of hardness, wear resistance, and corrosion performance. Furthermore, it delivers higher strength and edge retention than 440A while maintaining better toughness and corrosion resistance than 440C.

Why do engineers and manufacturers choose SS 440B for precision components? First and foremost, it achieves excellent mechanical stability and abrasion resistance after proper heat treatment. In addition, it offers a superior balance of performance characteristics — hardness without sacrificing toughness, and wear resistance without compromising corrosion protection. Moreover, its versatile properties make it suitable for a wide range of demanding applications.

Consequently, Stainless Steel 440B is commonly used in industrial knives, valve components, and bearings. Furthermore, it is also trusted in surgical tools and precision parts. Equally important, its balanced performance and long service life make it the preferred choice for applications where both durability and reliability are critical.

Need high-quality SS 440B round bars for your precision 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 440B Bars

SS 440B Stainless Steel Square Bar
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SS 440B Square Bar
  • SS 440B square bars engineered for high hardness applications
  • Material designation: UNS S44003 martensitic stainless steel
  • Produced in compliance with ASTM A276 and ASME SA276
  • DIN 1.4112 grade ensures reliable metallurgical consistency
SS 440B Stainless Steel Hex Bar
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SS 440B Hex Bar
  • ASTM A276 SS 440B hex bars for tooling and fastening systems
  • DIN 1.4112 and UNS S44003 certified stainless steel hex rods
  • Uniform geometry supports accurate machining performance
  • Available in bright drawn, polished and machined finishes
SS 440B Stainless Steel Rectangular Bar
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SS 440B Rectangular Bar
  • Precision rolled SS 440B rectangular sections
  • Manufactured as per ASTM A276 stainless steel standards
  • UNS S44003 / DIN 1.4112 material traceability
  • Suitable for industrial fabrication and precision assemblies
SS 440B Stainless Steel Flat Bar
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SS 440B Flat Bar
  • DIN 1.4112 stainless steel flat bars for wear-prone components
  • UNS S44003 grade ensures stable chemical composition
  • ASTM A276 / ASME SA276 production standard compliance
  • Supplied in hot rolled, ground and surface-polished condition
SS 440B Stainless Steel Bright Bar
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SS 440B Bright Bar
  • Bright finished SS 440B bars with smooth surface quality
  • Improved straightness for accurate CNC machining
  • ASTM A276 certified stainless bright rod supply
  • Consistent dimensional control across production batches
SS 440B Stainless Steel Forged Bar
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SS 440B Forged Bar
  • Forged SS 440B bars for high-load mechanical components
  • UNS S44003 stainless steel forged material traceability
  • ASTM A276 compliant forged bar manufacturing
  • Heat treated forgings deliver enhanced hardness and durability

440B STAINLESS STEEL ROUND BAR EQUIVALENT GRADES

STANDARD UNS WNR.
SS 440B S44003 1.4112

SPECIFICATION OF STAINLESS STEEL 440B 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 440B ROUND BAR

Grade C % Mn % Si % P % S % Cr % Ni %
440B 0.60 – 0.75 1.00 max 1.00 max 0.040 max 0.030 max 16.0 – 18.0 —

MECHANICAL PROPERTIES OF STAINLESS STEEL 440B 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 440B.

💡 Practical Difference in Use

Use Stainless Steel 440B Round Bars when: higher hardness, improved wear resistance, and good corrosion protection are required for demanding mechanical applications. SS 440B is a high-carbon martensitic stainless steel positioned between 440A and 440C in terms of hardness and corrosion resistance. It delivers stronger edge retention and abrasion resistance than 440A while maintaining better corrosion resistance and toughness than 440C. After heat treatment, it achieves excellent strength and surface durability. → Example: industrial blades, bearings, valve components, pump shafts, cutting tools, rollers, mechanical seals, and high-load machine parts.


Heat Treated / Bright Finished Stainless Steel 440B Round Bars when: maximum dimensional precision, high surface quality, enhanced hardness, and stable mechanical performance are required for precision-engineered components. Bright drawn or ground bars provide superior straightness and finish, while controlled heat treatment improves fatigue resistance and wear life under continuous operation. → Example: CNC machined shafts, bearing races, precision cutters, hardened pins, high-performance rollers, hydraulic components, and tooling parts.

Applications of Stainless Steel 440B Round Bars

Stainless Steel 440B round bars are widely used in tooling, mechanical engineering, power transmission, pump manufacturing, and industrial equipment where strength, wear resistance, and operational stability are essential.

  • Tooling & Cutting Equipment: Industrial knives, cutters, shear parts, hardened pins.
  • Mechanical & Power Transmission: Bearings, rollers, shafts, wear components.
  • Pumps & Valves: Valve stems, pump shafts, mechanical seals.

When to Choose Stainless Steel 440B Round Bars?

The selection mainly depends on required hardness level, wear intensity, corrosion exposure, machining precision, and long-term mechanical reliability.

Choose SS 440B Round Bars when:

  • Higher hardness than 440A is required
  • Better wear resistance and edge retention are needed
  • Moderate corrosion resistance is acceptable
  • Components operate under continuous friction or contact
  • Heat treatment is used to achieve specific hardness targets
  • Used in bearings, cutters, shafts, and industrial machinery

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

  • Tight dimensional tolerance and straightness are critical
  • Superior surface finish improves wear and friction behavior
  • High-speed machining and CNC production are involved
  • Parts operate under heavy mechanical loading
  • Consistent hardness and fatigue performance are required
  • Used in precision tooling and rotating equipment

Industries That Use Stainless Steel 440B Round Bars

SS 440B is preferred in industries where controlled hardness, abrasion resistance, dimensional stability, and dependable service life are required.

Tooling & Cutting Industry

Used in high-wear cutting and shaping tools.

Uses

Industrial knives, cutters, punches, shear parts.

Why SS 440B?

Excellent wear resistance and edge stability.

Bearing & Power Transmission

Used in rotating and load-bearing systems.

Uses

Bearing races, rollers, shafts.

Why SS 440B?

High hardness with stable fatigue strength.

Pump & Valve Manufacturing

Used in wear-prone flow control components.

Uses

Valve stems, pump shafts, seals.

Why SS 440B?

Abrasion resistance and dimensional stability.

Heavy Machinery

Used in industrial equipment components.

Uses

Rollers, hardened pins, wear parts.

Why SS 440B?

Long wear life under load.

Precision Engineering

Used in high-accuracy machined parts.

Uses

CNC shafts, bushings, tooling parts.

Why SS 440B?

Dimensional consistency and surface quality.

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

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