Compare over 50 grades of steel and cast iron to find the right material for you—all with material certificates for traceability.
Low-Carbon Steel Rectangular Tubes

Also known as mild steel, low-carbon steel is easy to machine, form, and weld. These tubes are often fabricated into parts that don’t require high strength, such as frames, supports, and raceways. To increase their wear resistance, you can surface harden them with heat treating. These tubes are manufactured to ASTM or EN standards for quality and performance.
Certificates with a traceable lot number are available for these products. Download certificates from ORDER HISTORY after your order ships.
- Yield Strength: See table
- Hardness: Not Rated
- Heat Treatable: Yes
- Max. Hardness After Heat Treatment: Not Rated
- Fabrication: Welded
- Specifications Met: See table
Outside | Inside | ||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Ht. | Wd. | Ht. | Wd. | Yield Strength, psi | Specifications Met | Straightness Tolerance | 1/2 ft. Lg. | 1 ft. Lg. | 2 ft. Lg. | 3 ft. Lg. | 4 ft. Lg. | 6 ft. Lg. | 8 ft. Lg. | 12 ft. Lg. | |
0.035" Wall Thick. | |||||||||||||||
1/2" | 1/2" | 0.43" | 0.43" | Not Rated | ASTM A513 Type 2 | __ | 00000000 | ||||||||
0.049" Wall Thick. | |||||||||||||||
1/2" | 1/2" | 0.402" | 0.402" | Not Rated | ASTM A513 Type 2 | __ | 0000000 | ||||||||
5/8" | 5/8" | 0.527" | 0.527" | Not Rated | ASTM A513 Type 2 | __ | 0000000 | ||||||||
3/4" | 3/4" | 0.652" | 0.652" | Not Rated | ASTM A513 Type 2 | __ | 0000000 | ||||||||
1/16" Wall Thick. | |||||||||||||||
1/2" | 1/2" | 3/8" | 3/8" | 32,000 | ASTM A513 Type 1 | __ | 0000000 | ||||||||
1/2" | 1" | 3/8" | 7/8" | 32,000 | ASTM A513 Type 1 | __ | 0000000 | ||||||||
3/4" | 3/4" | 5/8" | 5/8" | 32,000 | ASTM A513 Type 1 | __ | 0000000 | ||||||||
1" | 1" | 7/8" | 7/8" | 32,000 | ASTM A513 Type 1 | __ | 0000000 | ||||||||
1" | 2" | 7/8" | 1 7/8" | 32,000 | ASTM A513 Type 1 | __ | 0000000 | ||||||||
1 1/4" | 1 1/4" | 1 1/8" | 1 1/8" | 32,000 | ASTM A513 Type 1 | __ | 0000000 | ||||||||
1 1/2" | 1 1/2" | 1 3/8" | 1 3/8" | 32,000 | ASTM A513 Type 1 | __ | 0000000 | ||||||||
1 3/4" | 1 3/4" | 1 5/8" | 1 5/8" | 32,000 | ASTM A513 Type 1 | __ | 0000000 | ||||||||
2" | 2" | 1 7/8" | 1 7/8" | 32,000 | ASTM A513 Type 1 | __ | 0000000 | ||||||||
0.065" Wall Thick. | |||||||||||||||
1/2" | 1/2" | 0.37" | 0.37" | 32,000 | ASTM A513 Type 1 | __ | 00000000 | ||||||||
1/2" | 1" | 0.37" | 0.87" | Not Rated | ASTM A513 Type 1 | __ | 0000000 | ||||||||
1/2" | 1 1/2" | 0.37" | 1.37" | 32,000 | ASTM A513 Type 1 | __ | 0000000 | ||||||||
5/8" | 5/8" | 0.495" | 0.495" | Not Rated | ASTM A513 | __ | 0000000 | ||||||||
3/4" | 3/4" | 0.62" | 0.62" | 32,000 | ASTM A513 Type 1 | __ | 00000000 | ||||||||
3/4" | 1 1/2" | 0.62" | 1.37" | 32,000 | ASTM A513 Type 1 | __ | 0000000 | ||||||||
1" | 1" | 0.87" | 0.87" | 32,000 | ASTM A513 Type 1 | 1/16" per 3 ft. | 00000000 | ||||||||
1" | 1 1/2" | 0.87" | 1.37" | Not Rated | ASTM A513 Type 1 | __ | 0000000 | ||||||||
1" | 2" | 0.87" | 1.87" | Not Rated | ASTM A513 Type 1 | __ | 0000000 | ||||||||
1" | 3" | 0.87" | 2.87" | Not Rated | ASTM A513 Type 1 | __ | 0000000 | ||||||||
1 1/4" | 1 1/4" | 1.12" | 1.12" | 32,000 | ASTM A513 Type 1 | 1/16" per 3 ft. | 00000000 | ||||||||
1 1/2" | 1 1/2" | 1.37" | 1.37" | 32,000 | ASTM A513 Type 1 | 1/16" per 3 ft. | 0000000 | ||||||||
2" | 2" | 1.87" | 1.87" | Not Rated | ASTM A513 Type 1 | __ | 0000000 | ||||||||
2 1/2" | 2 1/2" | 2.37" | 2.37" | 32,000 | ASTM A513 Type 1 | __ | 0000000 | ||||||||
0.083" Wall Thick. | |||||||||||||||
3/4" | 3/4" | 0.584" | 0.584" | 32,000 | ASTM A513 Type 1 | __ | 00000000 | ||||||||
3/4" | 1 1/2" | 0.584" | 1.334" | Not Rated | ASTM A513 Type 1 | __ | 000000 | ||||||||
1" | 1" | 0.834" | 0.834" | 32,000 | ASTM A513 Type 1 | 1/16" per 3 ft. | 00000000 | ||||||||
1" | 1 1/2" | 0.834" | 1.334" | Not Rated | ASTM A513 Type 1 | __ | 0000000 | ||||||||
1" | 2" | 0.834" | 1.834" | Not Rated | ASTM A513 Type 1 | __ | 0000000 | ||||||||
1" | 3" | 0.834" | 2.834" | Not Rated | ASTM A513 Type 1 | __ | 0000000 | ||||||||
1 1/4" | 1 1/4" | 1.084" | 1.084" | Not Rated | ASTM A513 Type 1 | __ | 0000000 | ||||||||
1 1/2" | 1 1/2" | 1.334" | 1.334" | 32,000 | ASTM A513 Type 1 | 1/16" per 3 ft. | 00000000 | ||||||||
2" | 2" | 1.834" | 1.834" | Not Rated | ASTM A513 Type 1 | __ | 00000000 | ||||||||
2" | 4" | 1.834" | 3.834" | Not Rated | ASTM A513 Type 1 | __ | 0000000 | ||||||||
2 1/2" | 2 1/2" | 2.334" | 2.334" | Not Rated | ASTM A513 Type 1 | __ | 0000000 | ||||||||
0.12" Wall Thick. | |||||||||||||||
3/4" | 3/4" | 0.51" | 0.51" | Not Rated | ASTM A513 Type 1 | __ | 0000000 | ||||||||
3/4" | 1 1/2" | 0.51" | 1.26" | 32,000 | ASTM A513 Type 1 | __ | 00000000 | ||||||||
1" | 1" | 0.76" | 0.76" | 46,000 | ASTM A500 | 1/16" per 3 ft. | 00000000 | ||||||||
1" | 1 1/2" | 0.76" | 1.26" | Not Rated | ASTM A513 Type 1 | __ | 0000000 | ||||||||
1" | 2" | 0.76" | 1.76" | Not Rated | ASTM A513 Type 1 | __ | 0000000 | ||||||||
1" | 3" | 0.76" | 2.76" | 32,000 | ASTM A513 Type 1 | __ | 0000000 | ||||||||
1 1/4" | 1 1/4" | 1.01" | 1.01" | Not Rated | ASTM A513 Type 1 | __ | 0000000 | ||||||||
1 1/2" | 1 1/2" | 1.26" | 1.26" | 32,000 | ASTM A513 Type 1 | 1/16" per 3 ft. | 00000000 | ||||||||
1 1/2" | 2 1/2" | 1.26" | 2.26" | 32,000 | ASTM A513 Type 1 | 1/16" per 3 ft. | 0000000 | ||||||||
1 1/2" | 3" | 1.26" | 2.76" | 32,000 | ASTM A513 Type 1 | __ | 00000000 | ||||||||
2" | 2" | 1.76" | 1.76" | 46,000 | ASTM A500 | 1/16" per 3 ft. | 00000000 | ||||||||
2" | 3" | 1.76" | 2.76" | 39,000 | ASTM A500 | __ | 00000000 | ||||||||
2" | 4" | 1.76" | 3.76" | 39,000 | ASTM A500 | __ | 00000000 | ||||||||
2" | 6" | 1.76" | 5.76" | 39,000 | ASTM A500 | __ | 00000000 | ||||||||
2 1/2" | 2 1/2" | 2.26" | 2.26" | 32,000 | ASTM A513 Type 1 | __ | 00000000 | ||||||||
3" | 3" | 2.76" | 2.76" | 32,000 | ASTM A513 Type 1 | __ | 00000000 | ||||||||
4" | 4" | 3.76" | 3.76" | 39,000 | ASTM A500 | __ | 00000000 | ||||||||
1/8" Wall Thick. | |||||||||||||||
3/4" | 1 1/2" | 1/2" | 1 1/4" | 32,000 | ASTM A513 Type 1 | __ | 00000000 | ||||||||
1" | 1 1/2" | 3/4" | 1 1/4" | 32,000 | ASTM A513 Type 1 | __ | 00000000 | ||||||||
1" | 2" | 3/4" | 1 3/4" | 46,000 | ASTM A500 | 1/16" per 3 ft. | 00000000 | ||||||||
1" | 3" | 3/4" | 2 3/4" | 32,000 | ASTM A500 | __ | 0000000 | ||||||||
1 1/4" | 1 1/4" | 1" | 1" | 32,000 | ASTM A513 Type 1 | __ | 00000000 | ||||||||
1 1/2" | 1 1/2" | 1 1/4" | 1 1/4" | 46,000 | ASTM A500 | 1/16" per 3 ft. | 00000000 | ||||||||
1 1/2" | 2" | 1 1/4" | 1 3/4" | 32,000 | ASTM A513 Type 1 | __ | 00000000 | ||||||||
1 1/2" | 2 1/2" | 1 1/4" | 2 1/4" | 46,000 | ASTM A500 | 1/16" per 3 ft. | 00000000 | ||||||||
1 1/2" | 3" | 1 1/4" | 2 3/4" | 46,000 | ASTM A500 | __ | 0000000 | ||||||||
1 3/4" | 1 3/4" | 1 1/2" | 1 1/2" | 32,000 | ASTM A513 Type 1 | __ | 00000000 | ||||||||
2" | 2" | 1 3/4" | 1 3/4" | 46,000 | ASTM A500 | 1/16" per 3 ft. | 00000000 | ||||||||
2" | 3" | 1 3/4" | 2 3/4" | 46,000 | ASTM A500 | 0.075" per 3 ft. | 00000000 | ||||||||
2" | 4" | 1 3/4" | 3 3/4" | 39,000 | ASTM A500 | __ | 00000000 | ||||||||
2" | 5" | 1 3/4" | 4 3/4" | 39,000 | ASTM A500 | __ | 00000000 | ||||||||
2" | 6" | 1 3/4" | 5 3/4" | 39,000 | ASTM A500 | __ | 00000000 | ||||||||
2 1/2" | 2 1/2" | 2 1/4" | 2 1/4" | 46,000 | ASTM A500 | 1/16" per 3 ft. | 00000000 | ||||||||
3" | 3" | 2 3/4" | 2 3/4" | 46,000 | ASTM A500 | __ | 00000000 | ||||||||
3" | 4" | 2 3/4" | 3 3/4" | 39,000 | ASTM A500 | __ | 00000000 | ||||||||
3 1/2" | 3 1/2" | 3 1/4" | 3 1/4" | 39,000 | ASTM A500 | __ | 00000000 | ||||||||
4" | 4" | 3 3/4" | 3 3/4" | 46,000 | ASTM A500 | __ | 00000000 | ||||||||
0.188" Wall Thick. | |||||||||||||||
1 1/4" | 1 1/4" | 0.874" | 0.874" | 39,000 | ASTM A500 | __ | 0000000 | ||||||||
1 1/2" | 1 1/2" | 1.124" | 1.124" | 39,000 | ASTM A500 | __ | 00000000 | ||||||||
1 1/2" | 3" | 1.124" | 2.624" | 46,000 | ASTM A500 | __ | 0000000 | ||||||||
2" | 2" | 1.624" | 1.624" | 46,000 | ASTM A500 | 1/16" per 3 ft. | 00000000 | ||||||||
2" | 4" | 1.624" | 3.624" | 46,000 | ASTM A500 | 0.075" per 3 ft. | 00000000 | ||||||||
2" | 6" | 1.624" | 5.624" | 39,000 | ASTM A500 | __ | 00000000 | ||||||||
2 1/2" | 2 1/2" | 2.124" | 2.124" | 46,000 | ASTM A500 | __ | 0000000 | ||||||||
3" | 3" | 2.624" | 2.624" | 46,000 | ASTM A500 | __ | 00000000 | ||||||||
3" | 4" | 2.624" | 3.624" | 46,000 | ASTM A500 | 0.075" per 3 ft. | 00000000 | ||||||||
3" | 6" | 2.624" | 5.624" | 39,000 | ASTM A500 | __ | 00000000 | ||||||||
4" | 4" | 3.624" | 3.624" | 46,000 | ASTM A500 | __ | 00000000 | ||||||||
4" | 6" | 3.624" | 5.624" | 46,000 | ASTM A500 | 0.075" per 3 ft. | 00000000 | ||||||||
5" | 5" | 4.624" | 4.624" | 46,000 | ASTM A500 | 0.075" per 3 ft. | 00000000 | ||||||||
6" | 6" | 5.624" | 5.624" | 46,000 | ASTM A500 | 0.075" per 3 ft. | 00000000 | ||||||||
1/4" Wall Thick. | |||||||||||||||
1 1/2" | 1 1/2" | 1" | 1" | 39,000 | ASTM A500 | __ | 00000000 | ||||||||
1 1/2" | 3" | 1" | 2 1/2" | 46,000 | ASTM A500 | __ | 0000000 | ||||||||
2" | 2" | 1 1/2" | 1 1/2" | 46,000 | ASTM A500 | 1/16" per 3 ft. | 00000000 | ||||||||
2" | 3" | 1 1/2" | 2 1/2" | 46,000 | ASTM A500 | 0.075" per 3 ft. | 00000000 | ||||||||
2" | 4" | 1 1/2" | 3 1/2" | 46,000 | ASTM A500 | 0.075" per 3 ft. | 00000000 | ||||||||
2" | 6" | 1 1/2" | 5 1/2" | 46,000 | ASTM A500 | 0.075" per 3 ft. | 00000000 | ||||||||
2" | 8" | 1 1/2" | 7 1/2" | 39,000 | ASTM A500 | __ | 00000000 | ||||||||
2 1/2" | 2 1/2" | 2" | 2" | 46,000 | ASTM A500 | __ | 0000000 | ||||||||
3" | 3" | 2 1/2" | 2 1/2" | 46,000 | ASTM A500 | __ | 00000000 | ||||||||
3" | 4" | 2 1/2" | 3 1/2" | 46,000 | ASTM A500 | 0.075" per 3 ft. | 00000000 | ||||||||
3 1/2" | 3 1/2" | 3" | 3" | 39,000 | ASTM A500 | __ | 00000000 | ||||||||
4" | 4" | 3 1/2" | 3 1/2" | 46,000 | ASTM A500 | __ | 00000000 | ||||||||
4" | 6" | 3 1/2" | 5 1/2" | 46,000 | ASTM A500 | 0.075" per 3 ft. | 00000000 | ||||||||
4" | 8" | 3 1/2" | 7 1/2" | 39,000 | ASTM A500 | __ | 00000000 | ||||||||
5" | 5" | 4 1/2" | 4 1/2" | 39,000 | ASTM A500 | __ | 00000000 | ||||||||
6" | 6" | 5 1/2" | 5 1/2" | 46,000 | ASTM A500 | __ | 00000000 | ||||||||
5/16" Wall Thick. | |||||||||||||||
4" | 4" | 3 3/8" | 3 3/8" | 39,000 | ASTM A500 | __ | 00000000 | ||||||||
6" | 6" | 5 3/8" | 5 3/8" | 39,000 | ASTM A500 | __ | 00000000 | ||||||||
3/8" Wall Thick. | |||||||||||||||
3" | 3" | 2 1/4" | 2 1/4" | 39,000 | ASTM A500 | __ | 00000000 | ||||||||
4" | 4" | 3 1/4" | 3 1/4" | 39,000 | ASTM A500 | __ | 00000000 | ||||||||
6" | 6" | 5 1/4" | 5 1/4" | 46,000 | ASTM A500 | 0.075" per 3 ft. | 00000000 | ||||||||
8" | 8" | 7 1/4" | 7 1/4" | 46,000 | ASTM A500 | 0.075" per 3 ft. | 00000000 | ||||||||
1/2" Wall Thick. | |||||||||||||||
4" | 4" | 3" | 3" | 39,000 | ASTM A500 | __ | 00000000 | ||||||||
4" | 6" | 3" | 5" | 39,000 | ASTM A500 | __ | 00000000 | ||||||||
4" | 8" | 3" | 7" | 39,000 | ASTM A500 | __ | 00000000 | ||||||||
6" | 6" | 5" | 5" | 46,000 | ASTM A500 | 0.075" per 3 ft. | 00000000 | ||||||||
8" | 8" | 7" | 7" | 39,000 | ASTM A500 | __ | 00000000 |
- Yield Strength: 34,000 psi
- Hardness: Rockwell B65 (Medium)
- Heat Treatable: Yes
- Max. Hardness After Heat Treatment: Not Rated
- Fabrication: Welded
- Specifications Met: EN 10305-5
Easy-to-Weld 4130 Alloy Steel Rectangular Tubes

- Yield Strength: 75,000 psi
- Hardness: Rockwell C20 (Hard)
- Heat Treatable: Yes
- Max. Hardness After Heat Treatment: Rockwell C49
- Fabrication: Seamless
- Specifications Met: MIL-T-6736, SAE AMS-T-6736
Made from 4130 alloy steel, also known as chrome-moly steel, these tubes have low carbon content for good weldability. They’re often used for building frames and supports, since their flat sides make them easier to bolt than round tubes. To increase their wear resistance, you can harden them with heat treating. These tubes have been manufactured to SAE and military standards for quality and performance.
For technical drawings and 3-D models, click on a part number.
Certificates with a traceable lot number are available for these products. Download certificates from ORDER HISTORY after your order ships.
Outside | Inside | ||||||||
---|---|---|---|---|---|---|---|---|---|
Ht. | Wd. | Ht. | Wd. | 1/2 ft. Lg. | 1 ft. Lg. | 2 ft. Lg. | 3 ft. Lg. | 6 ft. Lg. | |
0.035" Wall Thick. | |||||||||
3/8" | 3/8" | 0.305" | 0.305" | 0000000 | |||||
1/2" | 1/2" | 0.43" | 0.43" | 0000000 | |||||
1/2" | 1" | 0.43" | 0.93" | 0000000 | |||||
5/8" | 5/8" | 0.555" | 0.555" | 0000000 | |||||
3/4" | 3/4" | 0.68" | 0.68" | 0000000 | |||||
1" | 1" | 0.93" | 0.93" | 0000000 | |||||
0.049" Wall Thick. | |||||||||
1/2" | 1" | 0.402" | 0.902" | 0000000 | |||||
5/8" | 5/8" | 0.527" | 0.527" | 0000000 | |||||
3/4" | 3/4" | 0.652" | 0.652" | 0000000 | |||||
3/4" | 1 1/2" | 0.652" | 1.402" | 0000000 | |||||
1" | 1" | 0.902" | 0.902" | 0000000 | |||||
1" | 1 1/2" | 0.902" | 1.402" | 0000000 | |||||
0.065" Wall Thick. | |||||||||
1/2" | 1" | 0.37" | 0.87" | 0000000 | |||||
5/8" | 5/8" | 0.495" | 0.495" | 0000000 | |||||
3/4" | 3/4" | 0.62" | 0.62" | 0000000 | |||||
1" | 1" | 0.87" | 0.87" | 0000000 | |||||
1" | 1 1/2" | 0.87" | 1.37" | 0000000 | |||||
1" | 1 3/4" | 0.87" | 1.62" | 0000000 | |||||
1" | 2" | 0.87" | 1.87" | 0000000 |