4140 Cold Finished & Annealed (Rc 19/24) Bar Stock
We stock AISI 4140 steel in squares, flats and hexagons. Call or Email Us for a Free Quote. All material is provided in a cold finished & annealed condition. We offer an extensive inventory of hard-to-find sizes and lengths including (10/12 Ft Random Lengths, 20/24 Ft Random Lengths and Custom Cut-To-Length options). We carry the largest selection of 4140 alloy steel bar stock in North America in one location. Alloy 4140 is widely used for general purpose machine applications.
| 3/8 | 7/8 | 1-1/4 | 2 | 3-1/2 |
| 1/2 | 15/16 | 1-3/8 | 2-1/4 | 4 |
| 5/8 | 1 | 1-1/2 | 2-1/2 | |
| 3/4 | 1-1/8 | 1-3/4 | 2-1/2 |
| 1/4 x 1 | 1/2 x 3 | 1 x 1-1/2 | 1-1/4 x 4 |
| 1/4 x 1-1/2 | 1/2 x 3-1/2 | 1 x 1-3/4 | 1-1/4 x 5 |
| 1/4 x 2 | 1/2 x 4 | 1 x 2 | 1-1/2 x 2 |
| 1/4 x 2-1/2 | 1/2 x 5 | 1 x 2-1/2 | 1-1/2 x 2-1/2 |
| 1/4 x 3 | 1/2 x 6 | 1 x 3 | 1-1/2 x 3 |
| 3/8 x 1 | 5/8 x 2 | 1 x 3-1/2 | 1-1/2 x 3-1/2 |
| 3/8 x 1-1/2 | 5/8 x 3 | 1 x 4 | 1-1/2 x 4 |
| 3/8 x 2 | 3/4 x 1 | 1 x 5 | 1-1/2 x 5 |
| 3/8 x 2-1/2 | 3/4 x 1-1/2 | 1 x 6 | 1-1/2 x 6 |
| 3/8 x 3 | 3/4 x 2 | 1 x 7 | 2 x 3 |
| 3/8 x 4 | 3/4 x 2-1/2 | 1 x 8 | 2 x 4 |
| 3/8 x 6 | 3/4 x 3 | 1-1/4 x 1-1/2 | 2 x 5 |
| 1/2 x 3/4 | 3/4 x 3-1/2 | 1-1/4 x 2 | 2 x 6 |
| 1/2 x 1-1/4 | 1/2 x 1 | 3/4 x 4 | 1-1/4 x 2-1/4 |
| 1/2 x 1-1/2 | 3/4 x 6 | 1-1/4 x 2-1/2 | |
| 1/2 x 2 | 3/4 x 7 | 1-1/4 x 3 | |
| 1/2 x 2-1/2 | 1 x 1-1/4 | 1-1/4 x 3-1/2 |
| 3/16 | ¾ | 1 | 1-1/2 | 2-1/4 | 3 |
| ½ | 13/16 | 1-1/8 | 1-3/4 | 2-3/8 | 3-1/2 |
| 9/16 | 7/8 | 1-1/4 | 1-15/16 | 2-1/2 | 4 |
| 5/8 | 15/16 | 1-3/8 | 2 | 2-5/8 |
4140 Cold Finished & Annealed (Rc 19/24) Bar Stock FAQs
4140 steel is supplied in different conditions to suit various manufacturing needs. The Cold Finished Annealed condition means the steel is supplied in its softest state (RC 19-24 hardness, 197-212 Brinell). This condition is specifically engineered for top-tier machinability, minimizing tool wear and preparation time, and is ideal for parts requiring precise dimensions prior to final thermal treatment.
On the other hand, quenched and tempered (Q&T) or pre-hardened steel, is supplied with maximum hardness and strength, ready for immediate use in demanding applications, but is significantly harder and riskier to machine. If custom hardness or extensive machining is required, annealed stock provides ideal flexibility.
4140 steel is considered moderately weldable, but it is not easily welded due to its higher carbon content compared to grades like 4130. The carbon content increases the risk of cold cracking in the weld zone.
4140 steel is generally recommended over 4340 for applications requiring a balance of strength, toughness, and superior machinability at a reasonable cost. While 4340, due to its nickel content, provides top-tier fracture toughness and extreme fatigue resistance essential for critical aerospace parts, it is significantly more expensive and much more difficult to machine. For the vast majority of machine parts, tooling, and shafting that require robust strength and durability, 4140 provides the necessary performance characteristics while optimizing manufacturing efficiency and material cost.
4. What Are the Key Performance Benefits of the Chromium and Molybdenum Content in 4140 Alloy Steel?
The performance of 4140 steel is defined by its Chromium and Molybdenum (Cr-Mo) content. The Chromium (Cr) component ensures good hardness penetration during the quenching and tempering process, allowing the material to harden uniformly across its thickness and improving wear resistance. The Molybdenum (Mo) content imparts uniformity of strength and significantly aids in creep resistance. This combination allows the steel to resist stress and maintain its mechanical properties under prolonged exposure to high operating temperatures, up to 1000 Degrees (fahrenheit) making it ideal for high-heat and pressure environments.
The best way to keep 4140/4150 from rusting is with proper handling and storage. These items should be stored in dry locations and typically on racks, away from the ground. Additionally, protective coatings can also be utilized like oil or powder coatings to keep rust away.
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