Hot Rolled Squares
About Hot Rolled Squares
Hot rolled steel square bar offers 36,000 PSI yield strength and excellent weldability. Conforms to ASTM A36. Ideal for structural frames, brackets, and general fabrication. Los Angeles stock with custom cutting available.
Quick Facts
- Material: A36 Hot Rolled Steel
- ASTM Standard: A36
- Available Sizes: 1/4" to 5/8" square
- Location: Los Angeles warehouse
- Services: Custom size, same-day pickup
Overview
Hot rolled square steel bar is a cost-effective, general-purpose steel product used widely in construction and fabrication. Produced by rolling steel at high temperatures, it features a characteristic dark, scaled finish and slightly rounded corners. Its manufacturing process makes it more malleable and less expensive than its cold rolled counterpart, though with less precise dimensional tolerances. This makes it a suitable choice for applications where surface finish and exact dimensions are secondary to strength and cost-efficiency.
A36 is the most common grade for hot rolled squares, valued for its structural integrity and superior weldability. It can be easily formed, drilled, and welded using standard fabrication techniques. While its machinability is fair, its primary advantages are its strength, versatility, and economic value. This combination of properties makes hot rolled square bar a foundational material for building frames, supports, braces, and various industrial equipment components where durability is a key requirement.
Technical Specifications
Mechanical Properties (A36 Steel)
| Property | Value | Unit |
|---|---|---|
| Tensile Strength | 58,000 - 80,000 | PSI |
| Yield Strength | 36,000 | PSI |
| Elongation | 20 | % |
| Hardness | 119 - 162 | HB |
Chemical Composition (A36 Steel)
| Element | Percentage (Max) |
|---|---|
| Carbon (C) | 0.26% |
| Manganese (Mn) | 0.75% |
| Phosphorus (P) | 0.04% |
| Sulfur (S) | 0.05% |
| Silicon (Si) | 0.40% |
Applicable Standards
- ASTM A36: Standard Specification for Carbon Structural Steel
Common Applications
- Construction: Structural bracing, support columns, stair railings, and decorative ironwork.
- Fabrication: Equipment frames, trailer components, machinery stands, and heavy-duty shelving.
- Industrial Maintenance: Repair reinforcements, mounting brackets, and custom jigs.
- Automotive: Frame repairs, chassis components, and custom vehicle racks.
- Agriculture: Fence posts, gate construction, and implement repairs.
- General Manufacturing: Axles for carts, support pins, and conveyor system components.
- Architectural: Signage frames, bollards, and ornamental fixtures.
Working with Hot Rolled Squares
Machining
A36 hot rolled steel has fair machinability. Its soft, ductile nature can make it feel "gummy." Use sharp tooling, slower cutting speeds, and higher feed rates compared to harder steels. A cutting fluid is recommended to improve surface finish and extend tool life.
Welding
Weldability is excellent. A36 steel can be welded using all common methods, including MIG, TIG, and stick welding, without requiring pre-heating. For the strongest and cleanest results, the dark mill scale should be ground or sandblasted from the weld area prior to fabrication.
Finishing
The raw mill scale surface will rust if exposed to moisture. For corrosion protection, the surface must be cleaned of scale before applying finishes like paint, powder coating, or galvanizing. Grinding, wire brushing, or abrasive blasting are effective cleaning methods.
Related Products
Frequently Asked Questions
Q: What is the difference between hot rolled and cold rolled square bar?
A: Hot rolled bar is formed at high temperatures, resulting in a rough, scaly surface and looser dimensional tolerances. Cold rolled bar is processed at room temperature, which produces a smooth, clean finish and more precise dimensions, but at a higher cost.
Q: Is A36 square bar good for machining?
A: It is machinable, but its softness can be challenging. For projects requiring significant or precise machining, 1018 Cold Rolled or 1045 steel provide a much better surface finish and machinability.
Q: Do I need to remove the mill scale before welding or painting?
A: Yes. For the strongest welds and proper paint adhesion, the dark, flaky mill scale on the surface must be removed. This can be done with a grinder, wire wheel, or through sandblasting.
Stock & Custom Sizes
Available sizes: 1/4" to 5/8" square. Standard lengths: 12 ft. Custom size available.
Same-day cutting and Los Angeles pickup available.
View Sizes & PricingNeed Hot Rolled Squares? Contact Bobco Metals for availability and Los Angeles pickup.
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