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Choose Better 4340 Steel Round Bar

AISI 4340 steel round bar is a commonly used alloy steel with a circular shape, which is more widely used and in greater demand than 4340 steel plate. Factors such as composition, properties, processing, and application of 4340 steel, it may affect the success of your project. Therefore, the correct material selection is crucial for ensuring the success of the project when selecting 4340 steel round bar. So how to choose a good 4340 steel round bar? This article will provide you with a detailed analysis to meet your needs.

4340 Steel Round Bar Chemical Composition

STAND C(%) Mn(%) P(%) S(%) Si(%) Cr(%) Mo(%) Ni(%)
ASTM A29 / A29M-05 0.38-0.43 0.60-0.80 ≤0.035 ≤0.040 0.15-0.35 0.70-0.90 0.20-0.30 1.65-2.00
EN 10263/4-2001 0.38-0.44 0.60-0.90 ≤0.025 ≤0.025 ≤0.30 0.70-0.90 0.15-0.30 1.65-2.00
JIS G4053-2008 0.36-0.43 0.60-0.90 ≤0.030 ≤0.030 0.15-0.35 0.60-1.00 0.15-0.30 1.60-2.00
ISO 683/18-1996 0.32-0.40 0.50-0.80 ≤0.035 ≤0.035 0.10-0.40 0.90-1.20 0.15-0.30 0.90-1.20

If you need to import SAE 4340 steel round bars from other countries, the corresponding steel grades in each country are different, and the corresponding chemical compositions are very similar, but also different. 4340 steel round bars correspond to the ASTM A29 standard, similar to China’s GB 40CrNiMoA / 34CrNi3Mo, Germany’s DIN 36NiCrMo4 / 1.6511, Japan’s JIS SNCM439, etc. From the above table, we can see the similarities and differences in the chemical composition between different standards. The different additions of element content will also give different properties. So if your project requires some alloy elements, Songshun can add alloys that meet your needs when manufacturing 4340 steel, so that you can purchase steel that is more suitable for you.

Mechanical Properties Of ASTM 4340 Steel Round Bars

Properties Metric Imperial
Tensile strength 745 MPa 108000 psi
Yield strength 470 MPa 68200 psi
Bulk modulus(typical for steel) 140 GPa 20300 ksi
Shear modulus(typical for steel) 80 GPa 11600 ksi
Elastic modulus 190-210 GPa 27557-30458 ksi
Poisson's ratio 0.27-0.30 0.27-0.30
Elongation at break 22% 22%
Reduction of area 50% 50%
Hardness, Brinell 217 217
Hardness, Knoop(converted from Brinell hardness) 240 240
Hardness, Rockwell B(converted from Brinell hardness) 95 95
Hardness, Rockwell C (converted from Brinell hardness. Value below normal HRC range, for comparison purposes only) 17 17
Hardness, Vickers(converted from Brinell hardness) 228 228
Machinability(annealed and cold drawn. Based on 100 machinability for AISI 1212 steel.) 50 50

Different projects and application scenarios have different performance requirements for 4340 round bar steel. The above is the range of mechanical properties that 4340 steel round bars usually have in the annealed state. Therefore, before choosing 4340 material, you must first clearly know your usage requirements. If your application needs to withstand greater tension and pressure, then tensile strength and yield strength are very important indicators. If your application requires good ductility and deformation ability, then elongation and cross-sectional shrinkage are the key factors to focus on. Only in this way can better steel be selected.

Steel Round Bar 4340 Manufacturing and Processing

The cost and performance of 4340 steel round bars produced by electric furnace plus vacuum degassing or electroslag remelting will be different. The manufacturing and processing technology used for 4340 round bars and steel plates will also be different, and the processes used for steels of different specifications will also be different. Therefore, if you need to purchase better 4340 alloy round bars, you must meet your needs through appropriate and precise manufacturing and processing technology to ensure that the steel has no cracks, a smooth surface, bubbles or other defects.

SAE 4340 Steel Round Bar Application

This steel is widely used in many fields, and different fields have different requirements for 4340 steel round bars. The following are application examples of companies that have long cooperated with Songshun:

(1) XXA automobile manufacturers rely on Songshun to meet their 4340 steel needs. They mainly use it to manufacture high-load transmission parts. The 4340 we supply not only ensures the reliability and durability of these parts under high stress conditions, but also improves production efficiency.

(2) ESXX mechanical equipment manufacturers require that the manufactured 350mm diameter turbine shafts be efficient and high-strength. According to their needs, Songshun optimizes the heat treatment process of 4340 steel round bars to improve its strength and quality, thereby completing their manufactured products very well, and thus establishing a good cooperative relationship for many years.

In addition to the above applications, 4340 steel round bars are also commonly used to manufacture various shafts, gears, bolts, fasteners, etc.

4340 Steel Round Bar Supplier

If you want to choose a better 4340 round bar, it is very important to investigate the supplier. Songshun will be your best choice to meet all your needs for 4340 steel round bar.

  • Quality assurance and reliability: At Songshun, we have rich experience, reliable production technology, perfect quality control system, etc. We can provide various testing items to ensure that the 4340 steel round bars you purchase meet the quality standards and requirements. This is the main factor for you to choose better materials.
  • Sufficient inventory and support customization: At Songshun, we have 4340 steel round bars of various sizes in stock, ready to meet your specific project needs at any time. And we support customized services, whether it requires cutting or other processing, we can meet it.
  • Good service and rich experience: We have more than 10 years of experience in providing alloy steel, and we have a good understanding of the steel industry and 4340 steel round bars. We can effectively provide technical support and comprehensive solutions. And we are committed to providing various services to meet the needs of specific projects.

In summary, selecting a better 4340 steel round bar requires comprehensive consideration from multiple aspects such as understanding its composition, properties, manufacturing, processing, quality testing, suppliers, and reference to practical applications. Only in this way can we ensure that the selected steel performs best in practical applications and meets the needs of various complex working conditions. And Songshun can meet your various requirements for 4340 steel, and pay special attention to optimizing the manufacturing process of 4340 round bar, so as to provide customers with the best steel and maximize its excellent performance.


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