4340 Steel Supplier
A Trusted Source for High-Performance 4340 Steel Bar
Jade Sterling Steel supplies quality 4340 steel bar supported by nationwide distribution, substantial inventory, and value-added finishing capabilities
For customers sourcing alloy steel for high-stress applications, our team helps deliver the right material with the consistency and responsiveness complex supply chains demand.
With more than 55 years of experience in steel distribution and a broad national network, Jade Sterling Steel is positioned to support both urgent orders and long-term sourcing programs.
What is 4340 Steel?
4340 is an alloy steel widely used in applications that demand high strength, toughness, and deep hardenability. As an AISI 4000-series grade, it is commonly selected for critical components that must perform under heavy loads, repeated stress, or severe service conditions.
Compared with general-purpose carbon steels, 4340 is engineered for more demanding mechanical performance. It is especially well suited for parts that benefit from heat treatment and that must retain strength through larger cross-sections. Common end uses include shafts, gears, landing gear components, axle shafts, trunnion shafts, and other heavily loaded structural parts.
4340 Steel Composition
4340 steel is a medium-carbon alloy steel defined by its combination of nickel, chromium, and molybdenum. This alloy chemistry is designed to provide high strength, toughness, and excellent hardenability for demanding mechanical applications.
4340 steel contains:
Carbon: approximately 0.37–0.43%, providing base strength and supporting heat-treatment response
Nickel: approximately 1.65–2.00%, improving toughness and fatigue resistance
Chromium: approximately 0.70–0.90%, contributing to hardness, strength, and wear resistance
Molybdenum: approximately 0.20–0.30%, enhancing hardenability and high-temperature strength
Manganese: approximately 0.60–0.80%, supporting strength and overall toughness
Silicon: approximately 0.15–0.35%, used as a deoxidizer during steelmaking
Phosphorus and sulfur: controlled at low levels to maintain ductility and toughness
Iron: balance
This alloy structure allows 4340 steel to achieve high mechanical strength and toughness after heat treatment, making it well-suited for critical components such as shafts, gears, and aerospace hardware
4340 Heat Treatment Options
4340 alloy steel responds extremely well to heat treatment, allowing its mechanical properties to be adjusted to meet the needs of demanding applications. By selecting the appropriate heat-treatment process, manufacturers can optimize hardness, strength, toughness, and fatigue resistance.
Common treatment processes include:
Quench and temper
Normalizing
Annealing
Stress relieving
Key Properties of 4340 Steel
4340 Yield and Tensile Strength
4340 steel is valued for its ability to develop high mechanical strength, especially after heat treatment. In the annealed condition, published reference data shows:
Tensile strength around 108,000 psi
Yield strength around 68,200 psi.
Actual properties can vary substantially depending on section size and heat treatment condition, which is one reason 4340 is often chosen for engineered parts with tightly defined performance requirements.
4340 Steel Hardness
4340 offers significantly greater hardness potential than general-purpose carbon steels because it responds well to quench-and-temper processing. In the annealed condition, a typical Brinell hardness value is about 217 HB. Hardened and tempered conditions can be substantially higher depending on the heat treatment used.
This higher hardness capability drives 4340’s suitability for parts that need a stronger combination of wear resistance, fatigue performance, and core strength than lower-alloy alternatives can provide.
4340 Steel Density
4340 steel has a density of approximately 0.284 lb/in3, or 7.85 g/cm3, which is in line with many other alloy and carbon steels
Why Choose Jade Sterling Steel
With more than 55 years in steel distribution, Jade Sterling Steel serves as a dependable supply partner for manufacturers that need consistent material quality and reliable fulfillment.
Our 40,000+ ton inventory across grades and sizes helps customers source 4340 steel bar in the forms and dimensions their applications require, whether for shorter lead-time needs or ongoing supply arrangements.
We support industries where 4340 is commonly used for high-stress components, including:
Aerospace: landing gear and structural components
Industrial manufacturing: shafts, arbors, and power transmission parts
Heavy equipment: axle shafts, trunnion shafts, and wear-critical components
Energy, mining, and transportation: gears, drilling parts, and other demanding mechanical applications
4340 Steel Prices and Availability
4340 steel pricing depends on several variables, including bar size, processing condition, finishing requirements, alloy surcharges, and broader market conditions.
Jade Sterling Steel helps customers navigate those variables with clear pricing, dependable supply, and nationwide reach.
Whether you are planning a long-term purchasing program or sourcing material for an urgent requirement, our team can help you secure the 4340 steel bar your application demands.