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440C Stainless Steel Bright Bar for Industrial Use Hardened & Tempered, Superior Strength

Herkunftsort China
Markenname Delta
Zertifizierung ISO 9001
Modellnummer 440c
Min Bestellmenge 500 kg
Preis 4.5 - 5.5 USD/Kg
Verpackung Informationen Holzkiste oder wasserdichte Papierumhüllung
Lieferzeit 5 - 10 Tage
Zahlungsbedingungen T/T, Western Union
Versorgungsmaterial-Fähigkeit 50 Tonne pro Monat

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Produktdetails
Produktname Stange aus 440C-Edelstahl Durchmesser 10 - 350mm
Länge 6 m oder eine beliebige Länge als Anfrage schneiden Oberfläche Beim Einlegen oder Brennen
Service Schneiden Standard ASTM DIN GB EN
Andere Produkte Runde Bar, Quadratriegel, flache Bar.ETC Technik Heiß gerollt
Hervorheben

440C stainless steel bright bar

,

hardened tempered steel bar

,

industrial stainless steel bar

Hinterlass eine Nachricht
Produkt-Beschreibung

440C Stainless Steel Bright Bar for Industrial Use Hardened & Tempered, Superior Strength

Products Specification

Products Name 440C Stainless Steel Round Bar
Grade

303,303Cu,304,304L,309S,310S,310H,316L,316Ti,316H,317L,321,329,347,410,415,420,

430F,431,440A/B/C,2205,2507,904l,254SMO,253MA,CD4MCU,XM-19,17-4PH,15-5PH,17-7PH,660,C276,600,601,625,718,800,800H,825,926.etc

Products Diameter Range φ3mm - φ350mm
Length 6m/pcs or cutting any length as request
Surface Pickling finishing, bright finishing
Standard ASTM  JIS,GB,DIN EN
Service Cutting
Other Shape Square , Flat, Hexagonal, Round.etc
Loading Port Shanghai Port
MOQ 50 kgs

 

chromium content, which enables it to achieve the highest hardness among all stainless steel grades when subjected to professional hardening and tempering processes . Designed specifically for industrial environments where durability and precision are non-negotiable, 440C bright bar delivers superior mechanical properties that outperform conventional stainless steels like 304 and 316 in high-stress, wear-intensive scenarios . This comprehensive guide explores the composition, properties, applications, and technical advantages of 440C stainless steel bright bar, helping industrial buyers and engineers make informed material selections.

Overview of 440C Stainless Steel Bright Bar

440C stainless steel bright bar is a cold-finished product characterized by its smooth, polished surface (typically No. 4 or BA finish) and consistent dimensional accuracy, making it ideal for precision machining and assembly . As a high-carbon martensitic alloy, its chemical composition is optimized to balance hardness, strength, and corrosion resistance: carbon (0.95-1.20%) enhances hardenability and wear resistance, while chromium (16.0-18.0%) forms a protective oxide layer that guards against rust and oxidation . Unlike austenitic stainless steels (e.g., 304, 316), 440C is magnetic and achieves its peak performance through a controlled hardening and tempering process, reaching a Rockwell C hardness of 58-60 HRC—far exceeding the hardness of standard stainless steel grades . This unique combination of properties makes it a preferred material for components that must withstand heavy loads, repeated friction, and harsh operating conditions.

Chemical Composition of 440C Stainless Steel Bright Bar

The precise chemical composition of 440C stainless steel bright bar adheres to international standards such as ASTM A276-03, JIS G 4303:1998, and DIN EN 10088-3, ensuring consistency and reliability across batches . The table below details the key elemental composition:
 
Element Content Range (%) Function
Carbon (C) 0.95 - 1.20 Primary hardening agent; enhances wear resistance and tensile strength
Chromium (Cr) 16.0 - 18.0 Forms corrosion-resistant oxide layer; improves hardenability
Manganese (Mn) ≤ 1.00 Improves machinability and hot workability
Silicon (Si) ≤ 1.00 Enhances strength and heat resistance
Phosphorus (P) ≤ 0.04 Controlled impurity; minimizes brittleness
Sulfur (S) ≤ 0.03 Controlled impurity; improves machinability in annealed state
Iron (Fe) Balance Base metal; provides structural integrity
 
Trace elements such as molybdenum (Mo) or nickel (Ni) may be added in some formulations to further enhance corrosion resistance or toughness, though they are not required by standard specifications .

Mechanical & Physical Properties (Hardened & Tempered)

The hardening and tempering process is critical to unlocking the full potential of 440C stainless steel bright bar. Typically, the bar is quenched in oil at 1050°C to form a martensitic structure, followed by tempering at 150-200°C to reduce brittleness while retaining high hardness . For applications requiring maximum hardness, a cold treatment at -75°C for 1 hour can increase hardness to 61.5 HRC . The table below outlines the key mechanical and physical properties in the hardened & tempered (H&T) condition:

Mechanical Properties (H&T Condition)

Property Value Standard Reference
Tensile Strength ≥ 560 MPa ASTM A276-03
Yield Strength (σ₀.₂) ≥ 205 MPa ASTM A276-03
Hardness (Rockwell C) 58 - 60 HRC JIS G 4303:1998
Elongation (d5) ≥ 18% ASTM A276-03
Brinell Hardness (HB) ≤ 250 (Annealed) ASTM A276-03

Physical Properties

Property Value Test Condition
Density 7.75 g/cm³ 20°C
Thermal Conductivity 29.3 W/(m·K) 20°C
Coefficient of Linear Expansion 10.5 μm/m·K 20-200°C
  11.7 μm/m·K 20-500°C
Critical Temperatures (Ac1) 815-865°C Austenite formation start
Critical Temperatures (Ms) 145°C Martensite formation start
Magnetic Properties Magnetic H&T Condition
 
These properties make 440C bright bar significantly stronger and more wear-resistant than 304 stainless steel (which has a tensile strength of ~515 MPa and hardness of ≤ 201 HB) and 316 stainless steel (tensile strength ~515 MPa, hardness ≤ 201 HB) . The superior hardness ensures excellent edge retention for cutting tools and minimal wear for bearing components, even under continuous operation .

Heat Treatment Process for 440C Bright Bar

To achieve the "hardened & tempered" condition, 440C stainless steel bright bar undergoes a precise two-step heat treatment process:
  1. Quenching: The bar is heated to 1050-1100°C and held for 30-60 minutes to ensure uniform austenitization, then quenched rapidly in oil or air to form a hard, brittle martensitic structure . This step is critical for maximizing hardness, reaching up to 60 HRC .
  2. Tempering: The quenched bar is reheated to 150-200°C and held for 1-2 hours, then cooled to room temperature. Tempering relieves internal stresses and improves toughness while maintaining high hardness—150°C tempering results in 61 HRC, while 200°C tempering yields 59 HRC . For applications requiring enhanced dimensional stability, a cryogenic treatment (-75°C for 1 hour) can be added after quenching to convert retained austenite to martensite, increasing hardness to 61.5 HRC .
 
It is important to note that 440C has limited weldability due to its high carbon content; welding requires preheating (200-300°C) and post-weld annealing to prevent cracking . Machinability is excellent in the annealed state (≤ 269 HB) but requires carbide or ceramic tools in the hardened condition due to its high hardness .

Industrial Applications of 440C Stainless Steel Bright Bar

The unique combination of superior strength, wear resistance, and moderate corrosion resistance makes 440C bright bar suitable for a wide range of industrial applications across sectors:

1. Bearing & Valve Components

440C is widely used for ball bearings, roller bearings, and valve parts (e.g., stems, seats, nozzles) due to its high hardness, wear resistance, and ability to withstand heavy loads . In marine and industrial pump systems, it resists corrosion from fresh water and mild chemicals while enduring continuous friction .

2. Cutting Tools & Blades

High-end industrial knives, scissors, and surgical/dental instruments rely on 440C for its exceptional edge retention and corrosion resistance . Surgical tools benefit from its ability to withstand repeated sterilization without degrading, while industrial blades maintain sharpness even when cutting abrasive materials .

3. Mold & Die Manufacturing

Plastic injection molds and extrusion dies use 440C bright bar for its hardness, wear resistance, and dimensional stability . The smooth bright surface reduces friction with molten plastic, ensuring high-quality part finishes and extending mold life .

4. Mechanical & Automotive Components

Shafts, gears, and fasteners in heavy machinery and automotive applications utilize 440C for its tensile strength and fatigue resistance . It is particularly suitable for components in high-temperature environments (up to 300°C) where standard stainless steels may soften .

5. Marine & Defense Applications

In marine atmospheres and coastal industrial settings, 440C resists corrosion from salt spray and humidity better than carbon steel and some low-chromium stainless steels . It is used in shipbuilding (e.g., propeller shafts, valve stems) and defense equipment requiring durability in harsh conditions .

Product Specifications & Customization Options

440C stainless steel bright bar is available in a range of sizes and configurations to meet diverse industrial needs, with compliance to international standards (ASTM, AISI, JIS, GB, DIN) . The table below lists standard specifications:
 
Product Type Dimensions Surface Finish Length Tolerance
Round Bar 4 mm - 500 mm (OD) Bright Polished (No. 4), BA, Matt 1-6 meters (customizable) ±0.05 mm
Hexagon Bar 18 mm - 57 mm (11/16″ to 2-3/4″) Bright Polished 1-6 meters (customizable) ±0.10 mm
Square Bar 18 mm - 47 mm (11/16″ to 1-3/4″) Bright Polished 1-6 meters (customizable) ±0.10 mm
Flat Bar 2 mm - 150 mm (thickness); 12.7 mm - 254 mm (width) Bright Polished 1-6 meters (customizable) ±0.08 mm
 
Customization options include:
  • Non-standard diameters/lengths (up to 12 meters)
  • Special surface finishes (8K mirror polish, HL hairline)
  • Precision machining (threading, grooving, grinding)
  • Certifications (ISO, SGS, BV) for quality assurance

440C vs. Common Stainless Steel Grades: Key Advantages

When compared to widely used grades like 304 and 316, 440C stainless steel bright bar offers distinct advantages for industrial applications requiring superior strength and wear resistance:
 
Property 440C Stainless Steel 304 Stainless Steel 316 Stainless Steel
Hardness (HRC) 58-60 (H&T) ≤ 22 ≤ 22
Tensile Strength ≥ 560 MPa ~515 MPa ~515 MPa
Wear Resistance Excellent Moderate Moderate
Corrosion Resistance Good (dry/mild environments) Excellent (general use) Superior (corrosive environments)
Machinability (H&T) Moderate (requires carbide tools) Excellent Good
Cost Higher Lower Higher than 304, lower than 440C
Ideal Applications Bearings, blades, molds Food processing, construction Chemical processing, marine (high chloride)
 
While 304 and 316 excel in corrosion resistance for general and chemical applications, 440C is unmatched in hardness and wear resistance, making it the preferred choice for high-stress, precision industrial components .

Quality Assurance & Compliance

Our 440C stainless steel bright bar is manufactured in ISO 9001-certified facilities, with strict quality control throughout the production process—from raw material selection to final inspection . Each batch undergoes:
  • Chemical composition analysis (spectrometry)
  • Mechanical property testing (tensile, hardness, elongation)
  • Dimensional accuracy checks (laser measurement)
  • Surface finish inspection (visual and roughness testing)
  • Corrosion resistance testing (salt spray, immersion)
 
Compliance with international standards (ASTM A276, JIS G 4303, DIN EN 10088-3) ensures compatibility with global industrial requirements, while SGS/BV third-party certifications provide additional quality assurance .

Conclusion

440C stainless steel bright bar—hardened and tempered for superior strength—stands as a premium material for industrial applications demanding exceptional hardness, wear resistance, and precision. Its unique chemical composition, optimized heat treatment, and versatile specifications make it indispensable in bearings, cutting tools, molds, and mechanical components across automotive, marine, defense, and manufacturing sectors. By outperforming conventional stainless steel grades in high-stress environments, 440C bright bar delivers long-term reliability, reduced maintenance costs, and enhanced performance for critical industrial systems. Whether you require standard sizes or custom-engineered solutions, our 440C stainless steel bright bar meets the most stringent quality standards, backed by comprehensive testing and compliance. Choose 440C for your next project to experience the difference in strength, durability, and precision.
 
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