Baghouse

An air pollutant control device used to trap particles by filtering gas streams through large cloth or fiberglass bags.

Bake Hardenable Steel

A cold-rolled, low-carbon sheet steel used for automotive body panel applications. Because of special processing, the steel has good stamping and strength characteristics, and, after paint is baked on, improved dent resistance.

Basic Oxygen Furnace (BOF)

What?

A pear-shaped furnace, lined with refractory bricks, that refines molten iron from the blast furnace and scrap into steel. Up to 30% of the charge into the BOF can be scrap, with hot metal accounting for the rest.

Why?

BOFs, which can refine a heat (batch) of steel in less than 45 minutes, replaced open-hearth furnaces in the 1950s; the latter required five to six hours to process the metal. The BOF’s rapid operation, lower cost, and ease of control give it a distinct advantage over previous methods.

How?

Scrap is dumped into the furnace vessel, followed by the hot metal from the blast furnace. A lance is lowered from above, through which blows a high-pressure stream of oxygen to cause chemical reactions that separate impurities as fumes or slag. Once refined, the liquid steel and slag are poured into separate containers.

Bar Turning

Involves machining a metal bar into a smaller diameter.

Bars

Long steel products that are rolled from billets. Merchant bar and reinforcing bar (rebar) are two common categories of bars, where merchants include rounds, flats, angles, squares, and channels that are used by fabricators to manufacture a wide variety of products such as furniture, stair railings, and farm equipment. Rebar is used to strengthen concrete in highways, bridges, and buildings.

Bending 3

The forming of metals into various angles.

Billet

A semi-finished steel form that is used for “long” products: bars, channels or other structural shapes. A billet is different from a slab because of its outer dimensions; billets are normally two to seven inches square, while slabs are 30 inches to 80 inches wide and two inches to ten inches thick. Both shapes are generally continually cast, but they may differ greatly in their chemistry.

Black Plate

Cold-reduced sheet steel, 12 inches to 32 inches wide, that serves as the substrate (raw material) to be coated in the tin mill.

Blast Furnace

A towering cylinder lined with heat-resistant (refractory) bricks, used by integrated steel mills to smelt iron from iron ore. Its name comes from the “blast” of hot air and gases forced up through the iron ore, coke, and limestone that load the furnace.

Blanking

An early step in preparing flat-rolled steel for use by an end user. A blank is a section of sheet that has the same outer dimensions as a specified part (such as a car door or hood), but that has not yet been stamped. Steel processors may offer blanking for their customers to reduce their labor and transportation costs; excess steel can be trimmed prior to shipment.

Bloom

A semi-finished steel form, with a rectangular cross-section that is more than 8”. This large cast steel shape is broken down in the mill to produce the familiar I-beams, H-beams, and sheet piling. Blooms are also part of the high-quality bar manufacturing process: Reduction of a bloom to a much smaller cross-section can improve the quality of the metal.

Breakout

An accident caused by the failure of the walls of the hearth of the blast furnace, resulting in liquid iron or slag (or both) flowing uncontrolled out of the blast furnace.

Brownfield Expansion

A “brownfield” contrasts to a “greenfield” (or a facility new from the ground up). A brownfield expansion means adding on to an existing facility.

Burr

The very subtle ridge on the edge of strip steel left by cutting operations such as slitting, trimming, shearing, or blanking. For example, as a steel processor trims the sides of the sheet steel parallel or cuts a sheet of steel into strips, its edges will bend with the direction of the cut (see Edge Rolling).

Busheling

Scrap consisting of sheet clips and stampings from metal production. This term arose from the practice of collecting the material in bushel baskets through World War II.

Butt-Weld Pipe

The standard pipe used in plumbing. Heated skelp is passed continuously through welding rolls, which form the tube and squeeze the hot edges together to make a solid weld.