Stainless Steel 440B is a high-carbon martensitic stainless steel positioned between 440A and 440C in terms of hardness, wear resistance, and corrosion performance. It delivers higher strength and edge retention than 440A while maintaining better toughness and corrosion resistance than 440C. After proper heat treatment, SS 440B achieves excellent mechanical stability and abrasion resistance, making it suitable for demanding cutting and mechanical applications. Grade 440B is commonly used in industrial knives, valve components, bearings, surgical tools, and precision parts where balanced performance and long service life are required.
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.
