SAE 4340 Alloy Steel Bar, also known as 4340 Alloy Rod, is a premium-grade nickel-chromium-molybdenum alloy steel widely recognized for its outstanding strength, toughness, and fatigue resistance. With balanced mechanical properties and good through-hardening capability, it is an ideal choice for critical engineering components.
At Jiangsu Cunrui Metal Products Co., Ltd., our 4340 Alloy Steel Bars are produced according to international standards such as ASTM A29, SAE J404, and EN 10083. Every batch is supported with mill test certificates, chemical composition reports, and third-party inspection if required. The material ensures reliable performance under heat treatment and offers excellent wear resistance and durability in demanding environments.
Features & Advantages
High tensile and yield strength even under heavy loads
Excellent toughness and fatigue resistance for long service life
Good hardenability with uniform mechanical properties across sections
Heat-treatable for various hardness and strength levels
Supplied with test reports and third-party certifications
Applications
Aerospace: landing gear components, shafts, fasteners
Automotive: gears, crankshafts, connecting rods
Oil & Gas: drill collars, pipeline fittings, downhole tools
Power Generation: turbine shafts, bolts, pressure vessel components
Heavy Machinery: axles, structural parts, and high-stress equipment
Product Specifications & Technical Parameters
Basic Information
|
Specification |
Details |
|
Material |
SAE 4340 / AISI 4340 |
|
Diameter Range |
8mm – 500mm (customized sizes available) |
|
Length |
1m – 12m, or as per request |
|
Surface Finish |
Black, Bright, Peeled, Polished, or Turned |
|
Heat Treatment |
Annealed, Quenched & Tempered, Normalized |
|
Hardness (HB) |
197 – 255 HB (annealed); up to 470 HB (quenched & tempered) |
|
Yield Strength |
835 MPa (min) |
|
Tensile Strength |
1080 – 1230 MPa |
|
Elongation |
12 – 15% |
|
Impact Toughness |
≥ 60 J |
|
Standards |
ASTM A29, AISI, SAE |
Chemical Composition (Typical %)
|
Element |
Content (%) |
|
Carbon (C) |
0.38 – 0.43 |
|
Silicon (Si) |
0.15 – 0.30 |
|
Manganese (Mn) |
0.60 – 0.80 |
|
Nickel (Ni) |
1.65 – 2.00 |
|
Chromium (Cr) |
0.70 – 0.90 |
|
Molybdenum (Mo) |
0.20 – 0.30 |
|
Phosphorus (P) |
≤ 0.035 |
|
Sulfur (S) |
≤ 0.040 |
Customization Services
Tailor-made sizes, tolerances, and machining options
CNC cutting, drilling, threading, and forging services
Surface treatment: anti-rust oil, phosphating, galvanizing, polishing
Production according to technical drawings or special requests
Flexible MOQ to support both trial and bulk orders
Price & Delivery
Competitive pricing with attractive bulk order discounts
Ready stock in popular dimensions
Reliable lead time with fast production cycles
Multiple delivery options (FOB, CIF, DDP) to suit global clients
Our Strength
Advanced production lines for forging, rolling, and heat treatment
Strong R&D capability and professional technical team
Export experience to Europe, Middle East, Asia, and America
Certified with ISO, SGS, BV, and other international standards
Large annual output ensuring stable supply for long-term projects
Service & Support
Prompt inquiry response within 12 hours
Technical consultation and material selection guidance
Export-standard packaging (bundles, wooden cases, or pallets)
Full after-sales support with refund or replacement for defective goods
Professional logistics coordination for safe and fast delivery
FAQ
Q1: What is the difference between 4340 Alloy Rod and SAE 4340 Alloy Steel Bar?
They are the same material; the term "rod" usually refers to smaller diameters, while "bar" applies to larger sections.
Q2: Can 4340 Alloy Steel Bar be heat-treated?
Yes, it is highly heat-treatable and can achieve a wide range of mechanical properties.
Q3: Do you offer machining services?
Yes, CNC machining, drilling, threading, and custom cutting are available.
Q4: What certificates do you provide?
Mill Test Certificate (EN 10204 3.1/3.2), chemical and mechanical property reports, third-party inspection if requested.
Q5: What is your minimum order quantity (MOQ)?
We accept flexible MOQs, supporting both small trial orders and bulk production.
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