Merchant Bar — flat, round & square bar for fabrication and repairs

Merchant bar is the day-to-day steel stock used for brackets, frames, supports, repairs and general fabrication. They are the basic building blocks for the metal fabricator (merchants).

Steelmart stocks merchant bar in the common profiles customers ask for:

  • Mild Steel Flat Bar 
  • Round Bar and Square Bar
  • Deformed Bar
  • Duragal Flat Bar (electro-galvanised and hot dip galvanised options)
  • Stainless Steel Flat, Round and Square Bar (priced per metre)

If you’re also building frames or supports, merchant bar is often paired with steel angle, tube (SHS/RHS), and plate to complete the job cleanly.

Flat Bar — the go-to for brackets, straps and general steelwork

Flat bar is exactly what it sounds like: a solid, rectangular bar used for brackets, straps, mounting plates, cleats, repairs and general fabrication. It’s one of the most useful workshop materials because it’s easy to mark out, drill and weld.

Choose the finish that suits the environment:

  • Mild Steel Flat Bar: ideal for general fabrication (paint or coat after fabrication if it’s exposed).
  • Duragal Flat Bar: galvanised protection for outdoor and moisture-prone jobs (electro-gal or hot dip depending on the range).
  • Stainless Flat Bar: for a clean finish and high corrosion resistance — ideal for exposed fabrication and harsh environments (grade selection matters).

Why customers choose flat bar:

  • easy to cut, drill and weld
  • perfect for brackets, straps and mounting points
  • great for gates, frames and repairs
  • galvanised options available for outdoor durability

FAQ's

What is merchant bar?

Merchant bar is a range of solid steel bars used for everyday fabrication, typically supplied as flat bar, round bar, square bar, and deformed bar. It’s popular because it’s easy to cut, drill, weld and fit into brackets, frames, supports and repairs.

What is the difference between merchant bar and rebar?

In simple terms:

  • Merchant bar is used for fabrication (brackets, frames, supports, pins, repairs) and is commonly supplied as flat/round/square.
  • Rebar (reinforcing bar) is designed for reinforced concrete. It’s often deformed to help it bond to concrete.

Steelmart’s deformed bar sits closer to the rebar end of the spectrum, and is typically used where a reinforcing-style bar is required.

Electro galvanised vs hot dip galvanised Duragal flat bar — what’s the difference?

Both are galvanised, but they suit slightly different jobs:

  • Electro galvanised has a smoother, more uniform coating and is often chosen where appearance and a tidy finish matter (and exposure is moderate).
  • Hot dip galvanised has a thicker, tougher coating and is typically preferred for harsher outdoor exposure and long-term durability.

If you tell us whether it’s indoors, outdoors, or coastal-adjacent, we’ll help you choose the best option.

How is merchant bar commonly used?

Merchant bar is used across fabrication, rural, maintenance and DIY work, including:

  • Flat bar: brackets, straps, cleats, fixing plates, repairs
  • Round bar: pins, shafts, handles, spacers, general machining work
  • Square bar: posts, lugs, supports, decorative/architectural details

Deformed bar: reinforcing-style applications where additional grip/bond is needed

What’s the difference between mild steel, Duragal and stainless bar?

  • Mild steel: best value for general fabrication, paint/coat if it’s exposed long term.
  • Duragal (galvanised): added corrosion protection for outdoor and moisture-prone jobs (Steelmart stocks Duragal flat bar options).

Stainless steel: premium corrosion resistance and a clean finish, available in flat/round/square bar (priced per metre).