BLACK FLAT BAR

Steel stockholders & suppliers

Black flat steel bar

A black flat steel bar is typically a hot-rolled mild steel bar with its original dark oxide layer (hence the name) still on the surface. Because it hasn’t been machined it has a rougher finish and slightly rounded edges compared to a bright drawn steel bar. For precision and subcontract engineers, this means:

  • A cost-effective raw material
  • Reliable mechanical properties
  • Ideal starting point for machining operations

As such, black bar steel is used where strength is required but a polished finish or a tight tolerance are not required. As you might expect, black bar is a cheaper alternative to bright bar steel.

Available in a range of carbon and alloy grades including EN9, EN19 and EN24, black flat steel bar allows engineers to select the right balance of strength, machinability and performance for the job.

High Peak Steels typically supply flat black bar steel in lengths of 3m and 6m, although we can deliver bespoke lengths to suit your exact requirements. Please get in touch to discuss an order.

Black flat engineering steel bar

Why engineers choose black flat steel

Black flat is widely used across precision engineering due to its balance of cost, availability and performance. Key advantages include:

  • Excellent base material for machining
  • Suitable for batch and repeat production
  • Wide size availability for flexible sourcing
  • Strong mechanical properties across multiple grades

Milled black flat

While black flat is supplied as hot rolled, many engineers choose milled flat bar to improve machining performance. Light milling enhances:

  • Flatness and dimensional consistency
  • Surface condition for improved tool contact
  • Reduced scale, leading to less tool wear
  • Faster setup times for repeat work

This makes milled black flat particularly beneficial in high-volume or tight-tolerance environments.

We supply black flat steel bar in a range of engineering grades, each suited to different performance requirements. Each grade is available to suit machining, repetition work and subcontract manufacturing environments.

EN9 | 070M55

Medium carbon steel for general engineering and wear-resistant components

GRADE E9

EN19 | 709M40T

Alloy steel with improved strength, toughness and fatigue resistance

GRADE E19

EN24 | 817M40T

High strength alloy steel for demanding, high load applications

GRADE E24

For prices and stock availability of flat black steel bar, talk to one of our advisors on 01457 866911 Or get in touch via our enquiry page