Bola de acero inoxidable
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Bola de acero inoxidable
Bola de acero inoxidable AISI 440C
AISI 440C stainless steel balls provide maximum hardness, toughness and dimensional stability. They are highly resistant to rolling-contact fatigue and perform similarly to tool steels, making them ideal for antifriction bearings. After heat treatment, 440C achieves HRC 57-65 — the highest hardness among stainless steel balls.As a 30-year 440C ball manufacturer in China, Jiaxin supplies precision 440C balls from 0.3 mm to 250 mm in grades G3 to G60 — a wider size range and tighter precision than most competitors. Trusted by Fortune 500 companies across four continents.
ISO 9001
Certified
30+ Years
Experience
0.3–250mm
Size Range
G3–G60
Precision
Four advantages over typical 440C ball suppliers.
Widest Size Range
0.3 mm miniature to 250 mm large balls — far exceeding the typical 50.8 mm limit of most suppliers.
Bearing-Grade Precision
Grades G3 to G60, significantly tighter than industry-standard G20 or grade 1000, ideal for precision bearings
30 Years, Fortune 500
Three decades of manufacturing experience, trusted by Fortune 500 oil, gas and chemical companies worldwide.
ISO Certified Quality
Every batch ships with material certificate and inspection report. Passivation and custom packaging available.
Why Jiaxin 440C Balls
Chemistry
Reference chemical composition of AISI 440C stainless steel.
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Carbon (C): 0.95 – 1.20% — high carbon enables maximum hardness
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Chromium (Cr): 16.00 – 18.00% — provides corrosion resistance
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Molybdenum (Mo): 0.75 max — enhances pitting resistance
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Manganese (Mn): 1.00 max
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Silicon (Si): 1.00 max
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Phosphorus (P): 0.040 max
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Sulfur (S): 0.030 max
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Iron (Fe): Balance
Micrographs of 440 steel balls tempered at 150°C.
Characteristics
Key material properties that make 440C the hardest stainless steel ball available.
Maximum Hardness
Heat treated to HRC 57–65, providing exceptional wear resistance and making 440C the hardest stainless steel ball grade.
Excellent Corrosion Resistance
High chromium martensitic stainless steel delivers excellent resistance to moisture, chemicals, and mildly corrosive environments.
Precision Manufacturing
Available in precision grades G10–G1000 with outstanding roundness, surface finish, and tight dimensional tolerances.
Magnetic
440C balls are magnetic, facilitating automated sorting and assembly.
Corrosion Resistance
440C stainless steel balls offer generally good resistance to mild acids, alkalis, foods, fresh water and air. They outperform chrome steel (52100) balls in mildly corrosive environments.
However, 440C is not recommended for: seawater, chloride environments, strong acids, or marine applications. For these conditions, consider 316/316L stainless steel balls or ceramic balls.
Technical Specifications
Standard 440C ball specifications. Custom dimensions available on request.
Material Grade
AISI 440C / UNS S44004
Precision Grades
G3, G5, G10, G16, G20, G28, G40, G60
Young's Modulus
~210 GPa
Surface Finish
Polished, passivated, oiled, or custom
Equivalent Names
SUS440C, 1.4125, 9Cr18Mo
Hardness
HRC 57-65 after heat treatment
Tensile
Strength~1900-2000 MPa
Supply Condition
Hardened, polished, passivated or oiled
Diameter Range
0.3 mm – 250 mm
Density
~7.70 g/cm³
Magnetism
Magnetic
Certification
ISO 9001, material certificate, inspection report
International Grade Equivalents
440C is known by different designations worldwide.
AISI / ASTM (USA): 440CUNS (USA): S44004JIS (Japan): SUS440CEN / DIN (Europe): X105CrMo17 / 1.4125GB (China): 9Cr18Mo
9Cr18Mo
SUS440C
440C
Z100CD17
SUS440C
din 1.4125
95x18
X 105CrMo17
Material Selection Guide
Compare 440C with other common ball materials to choose the right one.
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440C — HRC 57-65, good corrosion resistance in mild environments. Best for bearings, pumps and valves. → 440C product page
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420C — HRC 48-56, moderate corrosion resistance. Lower-cost martensitic option. → 420C product page
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304 — ~HRC 25, good corrosion resistance. General-purpose non-magnetic. → 304 product page
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316 / 316L — ~HRC 25, excellent corrosion resistance. Best for marine and chemical. → 316 product page
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52100 Chrome Steel — HRC 60-67, low corrosion resistance. Highest wear resistance at lower cost. → Chrome steel page
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Silicon Nitride (Ceramic) — Extremely hard, corrosion-proof, lightweight. For extreme environments. → Ceramic ball page
Industries Using 440C Balls
440C balls are specified where maximum hardness, wear resistance and rolling-contact fatigue life are critical.
Precision Bearings
Rolling element bearings, antifriction bearings, high-load bearing applications requiring maximum hardness and dimensional stability. 440C performs similarly to tool steels in these demanding rolling-contact applications.
Pumps and Valves
Check valves, pump seats, ball valves, actuators, quick-disconnect couplings, plug balls for oil, gas and chemical service. The HRC 57-65 hardness ensures long service life in fluid handling systems.
Industrial
Couplings, grinding media, conveyors, casters, industrial equipment, medical instruments, surgical tools, dental handpieces, and oil refining equipment requiring high-load, wear-resistant performance.
Lead Times & Ordering
Flexible supply for both standard and custom requirements.
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Standard sizes: Popular diameters in stock — typically 3-7 days for shipment.
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Custom orders: Lead time 15-30 days, based on diameter, grade and quantity.
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MOQ: Standard sizes have low MOQ. Custom sizes quoted per requirement.
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Packaging: Standard export packaging, or custom VCI bags, vacuum packing, bulk drums.
Technical Resources
Learn more about precision ball selection and applications.
Frequently asked questions
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