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A Guide to Choosing the Right Round Bar

What is a round bar?

Round bar refers to solid strip steel with a circular cross-section. Its specifications are expressed in diameter, unit millimeter (mm), such as “50mm”, which means round bar with a diameter of 50mm.

round bar - A Guide to Choosing the Right Round Bar

Classification of round bar

Round bar is divided into three types: hot rolling, forging and cold drawing:

(1) Hot rolled round bar: a variety of specifications to meet the needs

Specification range: 5.5-250 mm

Hot-rolled round bar has a wide range of specifications, from small to 5.5mm to large to 250mm, meeting the needs of different engineering and manufacturing fields. Among them, 5.5-25 mm small round bar is usually supplied in bundles of straight bars and is widely used in the manufacture of steel bars, bolts and various mechanical parts.

The hot-rolled round bar larger than 25 mm is mainly used to manufacture mechanical parts and tube blanks as seamless steel tubes. Its superior mechanical properties and tensile strength make it the preferred material for many important projects.

(2) Forged round bar: precision machining gives strength and toughness

Forged round bar is famous for its precise processing technology, which hammers the raw materials into the desired shape through the forging process. This manufacturing method gives round bar better mechanical properties, strength and toughness.

Forged round bar is widely used in fields that require high reliability and strength, such as aerospace, automobile manufacturing, etc. Its superior fatigue resistance and corrosion resistance make it an ideal choice for some key components.

(3) Cold-drawn round bar: fine and smooth surface quality

Cold-drawn round bar is made by drawing hot rolled raw materials at room temperature. This manufacturing method makes the surface of round bar more delicate and smoother, and the size is more accurate.

In some areas with high surface quality requirements, such as precision instrument manufacturing, optical device manufacturing, etc., cold-drawn round bar is favored for its excellent surface quality and dimensional accuracy.

The material of the round bar

The material used for a round bar can vary widely depending on the specific application and requirements. Common materials for round bars include:

  • Steel: This is one of the most common materials for round bars. Different grades of steel, such as carbon steel, alloy steel, and stainless steel, can be used based on the desired strength, corrosion resistance, and other properties.
  • Aluminum: Round bars made of aluminum are lightweight and corrosion-resistant. They are often used in applications where weight is a critical factor.
  • Brass: Brass round bars are made from a mixture of copper and zinc. They are known for their corrosion resistance and attractive appearance.
  • Copper: Copper round bars are valued for their excellent electrical conductivity and corrosion resistance. They are often used in electrical and electronic applications.
  • Bronze: Bronze is an alloy of copper and other metals, usually tin. Bronze round bars are known for their strength, corrosion resistance, and wear resistance.
  • Stainless Steel: Specifically, stainless steel round bars are corrosion-resistant and have various steel grades with different properties, such as 304 stainless steel (general-purpose), 316 stainless steel (marine applications), and more.
  • Titanium: Titanium round bars are known for their high strength-to-weight ratio, corrosion resistance, and biocompatibility. They are often used in aerospace, medical implants, and other high-performance applications.
  • Nickel Alloys: Alloys like Inconel or Monel, which contain nickel, are known for their high-temperature resistance and corrosion resistance. They are used in harsh environments, such as in chemical processing or aerospace.

When selecting a metal material for a round bar, factors such as mechanical properties (strength, hardness, toughness), corrosion resistance, temperature resistance, and cost need to be considered based on the specific requirements of the application.

Standard for round bars

The standards for round bars depend on the material and the intended application. Different organizations and associations set standards to ensure the quality, consistency, and compatibility of materials used in various industries. Here are some common standards for round bars based on specific materials:


  • ASTM A36/A36M – Standard Specification for Carbon Structural Steel
  • ASTM A108 – Standard Specification for Steel Bar, Carbon and Alloy, Cold-Finished
  • ASTM A276 – Standard Specification for Stainless Steel Bars and Shapes


  • ASTM B211 – Standard Specification for Aluminum and Aluminum-Alloy Bar, Rod, and Wire


  • ASTM B16/B16M – Standard Specification for Free-Cutting Brass Rod, Bar and Shapes for Use in Screw Machines


  • ASTM B187/B187M – Standard Specification for Copper, Bus Bar, Rod, and Shapes and General Purpose Rod, Bar, and Shapes


  • ASTM B140/B140M – Standard Specification for Copper-Zinc-Lead (Red Brass or Hardware Bronze) Rod, Bar, and Shapes

Stainless Steel:

  • ASTM A276 – Standard Specification for Stainless Steel Bars and Shapes
  • ASTM A479/A479M – Standard Specification for Stainless Steel Bars and Shapes for Use in Boilers and Other Pressure Vessels


  • ASTM B348 – Standard Specification for Titanium and Titanium Alloy Bars and Billets

Nickel Alloys:

  • ASTM B160 – Standard Specification for Nickel Rod and Bar

These standards provide specifications for dimensions, chemical composition, mechanical properties, testing procedures, and other relevant characteristics of round bars. Manufacturers and users refer to these standards to ensure that materials meet certain criteria and can be used safely and reliably in specific applications. It’s important to check and adhere to the appropriate standards for the material and application in question.

Specifications of round bars

Choosing the right round bar with the appropriate specifications ensures optimal performance and longevity in diverse applications.

  • Diameter: The diameter of a round bar is a critical specification, influencing its strength and application. It is measured across the center and plays a significant role in load-bearing capacities.
  • Length: Round bars are available in various lengths, catering to diverse project requirements. Standard lengths are commonly used, but custom lengths can be manufactured to meet specific needs.
  • Tolerance: Tolerance levels in round bars ensure precision and consistency in their dimensions. Tight tolerances are crucial for applications where exact measurements are imperative.

Sizes & weight of round bars

Calculation of the weight of round bar:

If the round bar has a uniform diameter, you can use the diameter (D) instead of the radius (r) in the formula. The relationship between the radius and diameter is D = 2 × r.

dimensional drawing of round bar - A Guide to Choosing the Right Round BarHere’s the simplified formula when using the diameter:

  • Weight = 4/π × Diameter2 × Length × Density

Make sure to use consistent units for all variables. The density is typically in units like kg/m3, the diameter and length are in meters, and the weight will be in kilograms or other mass units.
Keep in mind that this formula assumes a uniform density throughout the entire length of the round bar. If the density varies, you would need to integrate the density function over the length of the bar to get an accurate weight.

The theoretical weight of the round steel is shown in the table below:

Size in mm Average Weight
10 0.62 0.18
12 0.9 0.3
14 1.2 0.4
16 1.6 0.5
18 2 0.6
20 2.5 0.8
22 3 0.9
24 3.56 1.08
25 3.9 1.2
28 4.8 1.5
30 5.55 1.69
32 6.3 1.9
34 7.14 2.18
36 8 2.44
40 9.9 3
45 12.49 3.81
50 15.4 4.7
56 19.34 5.89
60 22.2 6.8
63 24.47 7.46
63.5 24.86 7.58
65 26.05 7.94
70 30.2 9.2
73 32.86 10
75 34.72 10.58
78 37.51 11.43
80 39.5 12
83 42.47 12.95
85 44.55 13.58
90 50 15.2
92 52.19 15.91
93 53.39 16.27
95 55.65 16.95
100 61.66 18.79
105 67.98 20.72
110 74.6 22.74
115 81.64 24.88
125 96.34 29.36

Rolling Tolerances of round bar

Size Ovality Weight Length
up to 25 mm ± 0.5 mm 25 mm to 35 mm ± 0.6 mm 35 mm to 50 mm ± 0.8 mm 50 mm to 80 mm ± 1 mm 80 mm to 100 mm ± 1.3 mm 100 mm and above ± 1.6 % of diameter. ± 75 % of total tolerance specified on the size. 10 mm to 16 mm ± 5 %
16 mm and above ± 3 %
For fixed length : ± 100 mm

The manufacturing process of round rods

To gain a deeper understanding of the manufacturing process of round rods, we will explore their detailed manufacturing process, including the selection of raw materials, precision machining, and presentation of the final product.

The manufacturing of a round rod includes several steps:

(1) Hot rolling process of round bars

The hot rolling process is one of the key projects for manufacturing high-quality round bars. Its complexity and technical requirements set high standards for manufacturers while also ensuring the superior performance of the final product. By deeply understanding the various aspects of the hot rolling process, we can better understand the science and technology behind the manufacturing of round bars, providing a more solid foundation for the development of related industries.

  • Preparation of raw materials:

The manufacturing of hot-rolled round bars begins with the selection and preparation of raw materials. Common metal raw materials include steel, aluminum, copper, etc., and their quality directly affects the performance of the final product. The raw materials are first cut into appropriate lengths for subsequent processing.

  • Heating:

The raw materials enter the heating furnace and are heated at high temperatures to reach an appropriate plastic state. This step not only helps to reduce the hardness of the material and improve its ductility but also prepares for subsequent processing.

  • Hot rolling machine processing:

The heated raw materials enter the hot rolling mill, which is a key step in the entire process. The hot rolling mill consists of a series of rollers, which gradually flatten and expand the metal billet into a circular shape through the action of rollers. During this process, the grain structure of the metal will also change, affecting the mechanical properties of the final product.

  • Cooling:

Round bars processed by hot rolling machines need to undergo a cooling process to prevent abnormal grain growth caused by excessive heat treatment. The control of the cooling rate has an important impact on the hardness, toughness, and other properties of products.

  • Cutting and shaping:

The cooled round rod is cut and shaped by a cutting machine to ensure that it meets the predetermined length and shape requirements. The accuracy of this step is directly related to the specifications and geometric shape of the final product.

  • Quality inspection:

The manufactured round rods need to undergo strict quality testing. This includes multiple aspects, such as diameter measurement, surface defect detection, and tensile testing. Only products that have passed the quality inspection can proceed to the next step.

  • Packaging and Delivery:

The round rods that pass the quality inspection are carefully packaged and ready to be delivered to the customer. Packaging not only helps to protect the product but also ensures that the product is not damaged during transportation.

(2) Forging process of round bars

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The forging process is one of the key processes in manufacturing round bars, and its precision and high technical requirements ensure the excellent performance of the final product. By deeply understanding the various aspects of forging technology, we can better understand the complexity and technological content of round bar manufacturing, providing more solid support for the development of engineering and manufacturing industries.

  • Preparation of raw materials:

The forging process begins with material selection. Usually, high-quality metal billets such as steel, aluminum, copper, etc. are used. The raw materials are first pretreated to ensure their appropriate temperature and shape.

  • Preheating:

Raw materials need to be preheated before forging to reach the appropriate forging temperature. This step not only improves the plasticity of the metal but also helps to reduce the deformation resistance during forging.

  • Precision forging:

The raw materials enter the forging press and undergo precise hammering and forming. The strength and direction of hammering directly affect the internal structure and mechanical properties of the final product. The highly technical requirements of this step ensure the high quality of the product.

  • Heat treatment:

The forged round bar may require heat treatment to eliminate internal residual stress and improve its strength and wear resistance. The temperature and time of heat treatment are important parameters that affect product performance.

  • Surface treatment:

Round bars that have undergone forging and heat treatment may require surface treatment, such as polishing or plating, to improve their appearance quality and corrosion resistance.

  • Quality inspection:

The forged round bars produced need to undergo strict quality testing. This includes multiple aspects such as diameter measurement, surface defect detection, and metallographic observation to ensure that the product meets specification requirements.

  • Packaging and Delivery:

The forged round rods that pass the quality inspection are carefully packaged and ready to be delivered to the customer. The quality of packaging is not only related to the safe transportation of products but also to the protection of products.

(3) Cold drawing process of round bars

The cold drawing process is a key process for manufacturing high-precision and high-quality round bars. Its high technicality and complexity ensure the excellent performance of the final product. By deeply understanding the various aspects of cold drawing technology, we can better understand the science and technology of round bar manufacturing, providing a more solid foundation for the development of related industries.

  • Heating:

The beginning of the cold drawing process is moderate heating of the raw materials. This step helps to improve the plasticity of the metal, making it easier to perform drawing processing.

  • Cold drawn machining:

After heating, the raw materials enter the cold drawing machine and gradually decrease in diameter through a series of die heads and traction rollers. This process can not only improve the surface quality of the round bar but also ensure that its size is more accurate.

  • Cooling:

The drawn round rod needs to be cooled to solidify its internal structure. The control of the cooling rate has an important impact on the hardness and strength of products.

  • Reheating:

The cold-drawn round rod may need to be reheated to reach the appropriate temperature, providing conditions for subsequent processing and treatment.

  • Surface treatment:

The surface of cold-drawn round bars is usually smoother, but further surface treatments, such as polishing, may still be required to improve their appearance quality and corrosion resistance.

  • Quality inspection:

The cold-drawn round bars produced need to undergo strict quality testing, including diameter measurement, surface defect detection, and other aspects to ensure that the product meets the specifications.

  • Packaging and Delivery:

The cold-drawn round rods that pass the quality inspection are carefully packaged and ready to be delivered to the customer. Good packaging not only helps with the safe transportation of products but also protects their surface quality.

Various Industries Benefit from Round Bars and Rods

  • Round bars find applications in roofing industries for their structural support.
  • The switchgear industry utilizes hex bars for specific engineering purposes.
  • Bright bars play a crucial role in the construction of heat exchangers.
  • Round bars are commonly employed in instrumentation for their versatility and strength.
  • The metallurgical industry relies on stainless steel bars and rods for diverse applications.
  • In the oil and gas sectors, black bars are widely used for their durability and resilience.
  • Pharmaceutical-grade nickel alloy bars and rods meet the stringent requirements of the pharmaceutical industry.
  • Power plants incorporate round bars and rods for various structural and functional purposes.

The difference between round steel and rebar

  • The shape is not the same, round steel shape is round, no grain without ribs, rebar surface appearance has ribbed or ribbed, so that the bonding force between round steel and concrete is small, and the bonding force between rebar and concrete is large.
  • The composition is different, round steel belongs to alloy steel, rebar is mostly ordinary low carbon steel.
  • The strength of round steel is different. The strength of round steel is low and the strength of steel is high. That is to say, compared with rebar, round steel with the same diameter can bear less tensile force than rebar, but the plasticity of round steel is stronger than rebar. That is to say, round steel has a large deformation before being broken, while rebar has a much smaller deformation before being broken.

How to choose the right round bar for your project?

Selecting the ideal round bar for your project involves careful consideration of various factors to guarantee optimal performance and long-term durability. Here are some recommendations to help you make informed decisions:

Surface Quality
Prioritize inspecting the surface quality of the round bar during the purchasing process. A qualified round bar should be free from significant defects such as faults, nodules, and cracks. Ensure that the surface shape adheres to allowable tolerances.

Material Selection
Consider the diverse materials available for round bars, including ordinary carbon structural steel, low alloy high-strength steel, and steel plate bending forming. Choose materials based on the specific usage environment and project requirements.

Strength Requirements
Calculate the bending and tensile strength of the round bar to determine the appropriate specification for your project. Familiarize yourself with the material and hardness of the round bar, selecting specifications that align with project requirements and load considerations.

Dimensional Considerations
Understand standard dimensions and production processes for round bars. Choose specifications based on project requirements, taking into account the required size, ease of assembly, and usage convenience.

Surface Treatment
Recognize the significance of surface treatment for durability and appearance. Common methods like hot dip galvanizing prevent rust and extend the round bar’s lifespan. Consider sand rolling pickling for improved appearance and steel protection.

Application Scenario
Tailor your choice of round bar specifications and materials to the specific application scenarios in your project. Consider the stress and usage environment of the round bar, ensuring it aligns with safety and quality standards.

Economic Factors
Balance considerations of price, weight, and specifications to select an economically practical round bar. Collaborate with industry stakeholders to understand market prices and policies. Choose specifications that meet both budget constraints and project requirements, ensuring cost-effectiveness.

By methodically considering these factors, you can confidently select the appropriate round bar, ensuring the quality, safety, and economic viability of your project.

How to find a suitable round bar manufacturer?

When seeking a suitable round bar manufacturer, the following guidelines can help ensure the best choice for your project:

Professional Experience and Qualifications:

Choose a manufacturer with extensive professional experience and necessary qualifications.
Look for manufacturers with years of experience, meeting industry standards, and possessing relevant certifications and qualification documents.
Technical Strength and Production Equipment:

Opt for a manufacturer with advanced technical strength and high-end production equipment.
Assess their production equipment and technical capabilities to ensure they can meet the specific needs of your project.
Product Quality and Standards:

Prioritize product quality by ensuring that the manufacturer’s products comply with national and industry standards.
Confirm that strict quality control procedures are in place, ensuring products have high strength, corrosion resistance, and stable performance for long-term use.
Customer Reputation and Evaluation:

Utilize digital platforms to check customer reputation and reviews for the manufacturer.
Seek feedback on the manufacturer’s performance in areas such as delivery, service, and after-sales support to gauge their reliability.
Customized Services and Flexibility:

Choose a manufacturer that provides customized services to meet the specific requirements of your project.
Assess their flexibility in adapting to changes in the project, as this will impact the smooth progression of the work.
Reasonable Price and Transparency:

Ensure that the selected manufacturer offers reasonable and transparent pricing.
Clearly understand the various costs included in the product quotation, avoiding hidden costs to stay within budget and prevent future disputes.
By following these suggestions, you increase the likelihood of choosing a reputable round bar manufacturer that aligns with your project’s needs. Conduct thorough research, gather feedback, and assess their capabilities to make an informed decision for a successful project outcome.

Why opt for YAANG as your round bar manufacturer?

Ensuring top-notch quality is paramount when selecting round bar manufacturers. YAANG Company stands out for its unwavering commitment to delivering superior round bar products. Rigorous quality control and testing procedures guarantee the reliability and durability of our products, instilling confidence in customers who can use them worry-free, free from concerns about additional costs or troubles arising from quality issues. Each product undergoes meticulous testing to ensure alignment with industry standards and requirements.

Cutting-edge production processes

YAANG boasts advanced production equipment and a skilled technical team, allowing us to flexibly meet diverse customer needs. Our dedication to efficient and precise production processes drives ongoing industry development and innovation. Whether customers require solutions for varied or specific needs, YAANG offers customized options to ensure product quality and performance align with customer expectations.

A team of seasoned experts

Our experienced team of experts possesses extensive knowledge in round bar manufacturing. They not only offer professional advice but also provide customized solutions based on specific customer requirements. Whether it’s product design specifications or unique application needs, our expert team can deliver tailored advice and support, providing comprehensive services and solutions.

Flexible production capacity and on-time delivery

YAANG maintains a flexible production capacity, adjusting to customer order volume and time constraints. This commitment ensures timely product delivery and allows customers to make informed adjustments based on project schedules. We prioritize customer needs and continuously optimize production processes to guarantee on-time product delivery, offering robust assurances and support for seamless project progression.

Outstanding customer service

YAANG Company prides itself on delivering excellent customer service. Prioritizing customer needs and concerns, our customer service team provides timely and effective solutions. Whether it’s product inquiries or post-sales support, our team maintains a professional, efficient, and friendly approach to ensure customers receive the best experience and service.

Competitive pricing strategy

YAANG’s competitive pricing aims to provide customers with cost-effective products and services. Our focus extends beyond product quality to cost savings for customers, enhancing market competitiveness. Choosing YAANG as your round bar manufacturer not only secures high-quality products and service support but also reduces procurement costs, strengthening your market position.

Stringent quality assurance and certification

YAANG Company’s products undergo strict quality control and certification processes, meeting international standards and industry requirements. We prioritize product quality, ensuring that our products meet customer expectations and requirements through rigorous testing and certification standards. Customers can confidently choose YAANG’s products, free from concerns about quality and performance issues.

The above highlights the advantages and characteristics of YAANG Company. We are committed to providing you with the highest quality round bar products and services, aspiring to be your reliable partner.



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