Hot Rolled Rounds
About Hot Rolled Rounds
Hot rolled steel rounds provide a minimum yield strength of 36,000 PSI, excellent formability, and superior weldability. Conforms to ASTM A36. Used for axles, shafts, and general fabrication. Custom cutting available.
Quick Facts
- Material: Hot Rolled A36 Steel
- ASTM Standard: A36
- Available Sizes: 1/4" to 1/2" diameter
- Location: Los Angeles warehouse
- Services: Custom size, same-day pickup
Overview
Hot rolled steel round is a cost-effective, general-purpose steel bar produced by rolling steel at high temperatures. This process results in a product with a rougher, scaled surface finish (mill scale) and less precise dimensional tolerances compared to cold rolled steel. Its internal structure is free from stresses, making it easy to form and shape, which is ideal for applications where a pristine surface is not required.
The primary advantage of hot rolled round bar is its combination of good strength, weldability, and ductility at a lower price point. It is the material of choice for structural components, general fabrication, and repairs where dimensional accuracy is secondary to material integrity and cost. While it lacks the clean finish of cold rolled bar, the mill scale can be removed by grinding or pickling for painting.
Technical Specifications
Mechanical Properties (A36 Grade)
| Property | Value | Unit |
|---|---|---|
| Tensile Strength | 58,000-80,000 | PSI |
| Yield Strength | 36,000 | PSI |
| Elongation | 20 | % |
| Hardness | 119-162 | HB |
Applicable Standards
- ASTM A36: Standard Specification for Carbon Structural Steel
Common Applications
- General Fabrication: Brackets, braces, and support elements - valued for its low cost and good weldability.
- Automotive & Trailer: Axles, shafts, and suspension components - chosen for its strength and durability in non-critical applications.
- Construction: Concrete anchors, dowel pins, and decorative railings - provides structural support and can be easily worked.
- Industrial Machinery: Spindles, support rods, and guide pins - where high precision is not required.
- Agriculture: Equipment components, fencing supports, and implement parts - offers a durable and repairable solution.
- Art & Sculpture: Framework, armatures, and structural forms - easily bent and welded into complex shapes.
- Fixtures & Jigs: Support legs, handles, and framework for manufacturing aids.
Working with Hot Rolled Rounds
Machining
A36 hot rolled steel is machinable, but its softness can result in a gummy texture. For best results, use sharp tooling, slow speeds, and high feed rates to prevent material buildup. A proper cutting fluid is highly recommended to improve surface finish and extend tool life. The outer mill scale should be removed before precise machining operations.
Welding
Hot rolled A36 steel offers excellent weldability. It can be easily joined using all common welding processes, including MIG (GMAW), Stick (SMAW), and TIG (GTAW), without the need for pre-heating or post-heating in most applications. Its low carbon content ensures strong, ductile welds that are resistant to cracking.
Finishing
The surface of hot rolled round bar is characterized by a dark, flaky mill scale. For painting or coating, this layer must be removed via grinding, sandblasting, or chemical pickling. Once cleaned, the steel accepts paint, powder coating, and other finishes well. It can also be hot-dip galvanized for long-term corrosion protection.
Related Products
Frequently Asked Questions
Q: What is the difference between hot rolled and cold rolled rounds?
A: Hot rolled steel is processed at high temperatures, resulting in a rough, scaly surface, looser tolerances, and lower cost. Cold rolled steel is further processed at room temperature, giving it a smooth finish, tighter dimensional tolerances, and higher strength, but at a higher cost.
Q: Can I use A36 hot rolled rounds for high-stress axles?
A: For general, low-stress applications like carts or trailers, A36 can be suitable. However, for high-performance or safety-critical axles in vehicles, an alloy steel like 4140 is recommended due to its superior strength, hardness, and fatigue resistance.
Q: Why does hot rolled steel have a dark, scaly surface?
A: The surface is covered in 'mill scale,' an iron oxide layer that forms on the steel when it is exposed to air at high temperatures during the rolling process. This layer offers minimal corrosion resistance and is typically removed before painting or finishing.
Stock & Custom Sizes
Available diameters: 1/4" to 1/2". Standard lengths: 12 ft. Custom size available.
Same-day cutting and Los Angeles pickup available.
View Sizes & PricingNeed Hot Rolled Rounds? Contact Bobco Metals for availability and Los Angeles pickup.
Request a Quote Ask an Expert