Black square steel tube is made of high-quality mild steel Q195/Q235B. Cold formed & high frequency welded, with smooth surface, precise dimension and high structural strength. Complete sizes, in large stock, cost-effective. Widely used for steel frames, fencing, scaffolding, furniture and general construction.
Black square steel tube (also known as black square hollow section) is a kind of uncoated carbon steel profile. It is produced by cold rolling steel strip into square shape and high-frequency resistance welding. Without galvanization or painting, it keeps original steel surface, features uniform wall thickness, excellent straightness and stable mechanical property. It is easy to cut, weld, drill and paint on site, an ideal raw material for secondary processing and structural engineering.
Product Features:
● Made of Q195/Q235B mild steel, high tensile strength and good toughness
● Cold formed + ERW welding, firm weld seam, no crack or leakage
● Uniform wall thickness, high straightness, tight tolerance on dimensions
● Original black steel finish, easy for welding, painting and surface treatment
● Wide size range, standard specifications with large inventory
● Light weight but rigid structure, good compression & bending resistance
● Multiple pipe ends: plain end as standard, customized cutting available
● Economical price, fast production and prompt delivery
Frequently Asked Questions (FAQ):
Q: Can you customize size and length?
A：Yes, we customize outer diameter, wall thickness, length and pipe shapes.
Q:What’s your payment term?
A:T/T (30% deposit, 70% balance before shipment) and L/C are acceptable.
Q:What standards do your products comply with?
English: GB/T 6728, ASTM A500, ASTM A123 and other international standards. Inspection reports can be provided.
| Item |
Specification |
| Product Name |
Black Square Steel Tube / Square Hollow Section |
| Material Grade |
Q195, Q235B |
| Production Process |
Cold Formed + High Frequency ERW Welding |
| Executive Standard |
GB/T 6728, ASTM A500 |
| Side Size |
15×15mm – 300×300mm |
| Wall Thickness |
1.0mm – 12.0mm |
| Standard Length |
6m / 12m, custom length acceptable |
| Surface |
Black original steel surface (uncoated) |
| Pipe End |
Plain end |
| MOQ |
100 Ton |
| Delivery Time |
3–8 days |
