Product Overview
AISI/SAE 4140, 4340, and 8620 hot rolled alloy steel bars are precision-rolled metal stock engineered for high-load and high-stress mechanical applications. By alloying carbon steel with elements such as chromium, molybdenum, nickel, and vanadium, these bars deliver enhanced hardenability, tensile strength, and wear resistance compared to standard carbon grades.
Produced via controlled hot rolling and optional thermal treatments, our bars serve component manufacturers requiring consistent metallurgical properties and predictable machining performance. We supply standard and custom-rolled dimensions backed by mill test certificates conforming to international standards.
Technical Specifications
|
Parameter |
Specification Details |
|
Primary Target Grades |
AISI/SAE 4140, 4340, 8620; 42CrMo4, 34CrNiMo6 (Additional ASTM, EN, DIN, JIS grades available upon request) |
|
Size Range |
Round Bars: Diameter 16mm – 350mm; Square & Flat Bars: Custom profiles available |
|
Length Options |
Standard lengths (3m – 6m) or precision cut-to-length per machining requirements |
|
Execution Standards |
ASTM A29, EN 10083, DIN 17200, JIS G4053 |
|
Delivery Condition |
Hot Rolled (HR), Annealed (A), Quenched & Tempered (Q+T), Peeled/Turned & Polished (PTG) |
|
Surface Finish |
Black, Peeled, Turned, Centerless Ground, or Shot Blasted |
|
Dimensional Tolerances |
Hot rolled tolerances per ASTM A29 / EN 10060; tighter tolerances achievable via secondary peeling |
Product Advantages
Controlled Hardenability:
Strict adherence to restricted chemical composition ranges ensures uniform response during downstream quenching and tempering processes.
Internal Soundness:
Continuous rolling mills paired with strict reduction ratios minimize center porosity and internal micro-voids in heavy cross-sections.
Machinability Consistency:
Microstructure optimization through controlled cooling rates reduces tool wear during turning and CNC milling operations.
Dimensional Stability:
Tight hot-rolling and optional peeling tolerances reduce stock removal allowances during finish machining.
Applications
Automotive Drivetrains: Transmission shafts, axle shafts, and steering components requiring high fatigue strength.
Oil & Gas Equipment: Drill collars, couplings, valve stems, and downhole tool bodies operating under high torsional loads.
Industrial Machinery: Heavy-duty gears, pinions, spindles, hydraulic cylinders, and high-stress structural fasteners.
Power Generation: Turbine shafts and fastening studs exposed to elevated mechanical stress.
Customization & Processing
Manufacturing requirements often extend beyond standard mill lengths and finishes. Our processing capabilities bridge the gap between raw steel bars and immediate component production:
Thermal Treatment: In-house annealing, normalizing, and quenching & tempering to achieve target hardness ranges (e.g., 28–32 HRC or specific Brinell ranges).
Dimensional Processing: Precision centerless grinding, turning, and chamfering to eliminate surface decarburization and scale.
Non-Standard Dimensions: Custom rolling schedules available for specific cross-sections subject to minimum order quantities.
Length Cutting: High-speed band sawing for precise cut-to-length requirements, reducing scrap at the customer's facility.
Quality Control & Inspection
Metallurgical integrity is verified at every stage of production through destructive and non-destructive testing:
Chemical Spectrometry: Direct-reading emission spectrometers verify melt chemistry against grade specifications prior to release.
Mechanical Testing: Tensile testing, Charpy V-notch impact testing, and Brinell/Rockwell hardness testing performed per lot.
Non-Destructive Testing (NDT): 100% ultrasonic testing (UT) available per ASTM A388 or EN 10308 to detect internal discontinuities.
Microstructure Analysis: Grain size determination, inclusion rating, and decarburization depth measurement via optical microscopy.
Traceability: Every bundle is stamped with heat numbers and issued with an EN 10204 3.1 Mill Test Certificate (MTR).
Packaging & Shipping
Bundle Configuration:
Bars are securely bundled with high-strength steel strapping and wooden spacers to prevent shifting during transit.
Rust Prevention:
Application of anti-rust oil or VCI (Vapor Corrosion Inhibitor) wrapping for ocean freight and prolonged outdoor storage.
End Protection:
Plastic caps applied to bar ends upon request to prevent impact damage during handling.
Transport Modes:
Containerized loading for 20GP/40GP maritime shipping or break-bulk vessel chartering for large- tonnage project orders.
FAQ
Q: What is the standard MOQ for non-stock or custom alloy steel bar grades?
A: MOQ typically starts at 5 metric tons per size/grade for direct mill rolling. Smaller quantities may be available if matched with active production schedules or existing stock.
Q: Can you provide third-party inspection (SGS, BV, TUV) prior to shipment?
A: Yes. Third-party inspection is supported, and testing can be witnessed on-site at the mill or processing facility.
Q: How do you control center segregation in larger diameter bars (above 200mm)?
A: Our rolling process utilizes optimized reduction ratios and controlled pouring temperatures to minimize central macro-segregation, verified via macro-etching and ultrasonic testing.
Q: Are Mill Test Certificates (MTR) provided with the shipment?
A: Yes. Every shipment includes an EN 10204 3.1 test report detailing actual chemical analysis, mechanical test results, heat treatment parameters, and heat numbers.
Q: What is the standard delivery lead time for custom cut-to-length orders?
A: Standard stock processing takes 7 to 14 days. Mill production cycles generally require 35 to 45 days depending on the specific grade and cross-section.
Q: Can the bars be supplied in a pre-machined or peeled condition?
A: Yes. Peeled, turned, and ground (PTG) bars are available to remove surface defects, decarburization, and dimensional variance, ready for automated lathe feeding.
Request a Quote
To receive an accurate quotation, please provide the following parameters:
Steel Grade: (e.g., AISI 4140, 4340, 8620)
Dimensions: (Diameter and length)
Delivery Condition: (Hot Rolled, Annealed, Q&T, Peeled)
Quantity: (Tonnage or total length)
Target Destination Port / Delivery Terms: (FOB, CFR, CIF)
Submit your specifications to our engineering sales team for a formal technical and commercial proposal within 24 hours.
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