ISO Standard Anti Corrosion Galvanized Square Pipe for Construction Works

1) Surface: Hot-dip galvanized square pipe has silver-white zinc layer, black square pipe surface is black scale; 2) Anti-corrosion: Hot-dip galvanized square pipe 20-30 year life, black square pipe no anti-corrosion (outdoor 1-2 years rust); 3) Price: Hot-dip galvanized square pipe RMB 800-1200/tonne more expensive than black (galvanizing fee);

Yes, but neednote. Welding damages zinc layer in welding area, produces zinc fumes (toxic), and welded area prone to rust. Welding notes: 1) Remove zinc layer in welding area before welding (grinding); 2) Strengthen ventilation during welding, avoid inhaling zinc fumes; 3) Clean welding area after welding, apply zinc-rich primer or hot-dip galvanizing repair paint.

Hot-dip galvanized square pipe zinc coating thickness tested with magnetic thickness gauge (non-destructive), test multiple points on four surfaces and take average. GB/T 13912 specifies: square pipe thickness >=6mm, average zinc coating >=85um, local >=70um; thickness <6mm, average >=65um, local >=55um.

1) Welded connection: Square pipes or with other members directly welded, good sealing, high strength, but damages zinc layer; 2) Bolted connection: Drill holes on square pipe, bolted connection, detachable, does not damage zinc layer (need touch up paint at holes); 3) Flanged connection: Welded flange then bolted, detachable; 4) Socket connection: Insert small pipe into large pipe, drill holes then pin or bolt fix, convenient construction;

Stock from 1 pipe 3-7 days, common sizes same-day pickup; special sizes and custom lengths from 5 tonnes 7-15 days. Cutting, drilling, bending, welding etc. fabrication services available.