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B
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Chemical symbol for Boron. |
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Bainite
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An acicular aggregate of ferrite and carbide particles formed when
austenite is transformed on cooling at temperatures in the
intermediate (200-450°C) range, i.e. above the martensite and below
the pearlite range. |
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Balanced Steel
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Steels in which the deoxidisation is controlled to produce an
intermediate structure between a rimmed and killed steel. Sometimes
referred to as semi- killed steels, they possess uniform properties
throughout the ingot and amongst their applications are boiler plate
and structural sections. |
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Banded Structure
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A layering effect that is sometimes developed during the hot rolling
of steel. |
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Base Metal
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A metal which oxidizes when heated in air, e.g. lead, copper, tin,
zinc, as opposed to noble metals such as gold and platinum. |
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Basic Steel
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Steel produced in a furnace in which the hearth consists of a basic
refractory such as dolomite or magnesite, as opposed to steel melted
in a furnace with an acid lining. The basic process permits the
removal of sulfur and phosphorous and in this respect is superior.
Present day BOS and electric arc furnaces use basic linings. |
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Bark
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An older term used to describe the decarburized skin that develops
on steel bars heated in a non-protective atmosphere. |
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Batch Furnace
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A furnace used to heat-treat a single load at a time. Batch-type
furnaces are necessary for large parts such as heavy forgings and
are preferred for complex alloy grades requiring long cycles. |
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Be
|
Chemical symbol for Beryllium. |
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Belt Furnace
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A continuous-type furnace that uses a mesh-type or cast-link belt to
carry parts through the furnace. |
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Bend Test
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Bending tests are carried out to ensure that a metal has sufficient
ductility to stand bending without fracturing. A standard specimen
is bent through a specified arc and in the case of strip, the
direction of grain flow is noted and whether the bend is with or
across the grain. |
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Bessemer Process
|
A method of producing steel, first introduced in the last century,
where air is blown under pressure through molten iron to remove the
impurities by oxidation. The development of the process has led to
the present day Basic Oxygen Steel-making plants that account for
bulk production of commercial quality steels in the UK. |
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Beta Annealing
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Producing a beta phase by heating certain titanium alloys in the
temperature range of which this phase forms followed by cooling at
an appropriate rate to prevent its decomposition. |
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Bi
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Chemical symbol for Bismuth. |
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Binary Alloy
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An alloy containing only two component elements. |
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Billet
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A section of steel used for rolling into bars, rods and sections. It
can be a product of the ingot route, or increasingly today produced
directly by continuous casting. |
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Black Oxide
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A black finish on a metal produced by immersing it in hot oxidizing
salts or salt solutions. |
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Blast Furnace
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A tall, cylindrical, refractory lined furnace for the production of
pig iron or hot metal for direct conversion into steel. |
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Bloom
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A large square section of steel intermediate in the rolling process
between an ingot and a billet. Blooms are now also being produced by
the continuous casting process eliminating the necessity of first
producing an ingot. |
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Boron Steels
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The addition of boron in the range 0.0005- 0.005% to certain steels
increases the hardenability. A range of boron steels is now listed
in the current BS 970 and are widely used for the production of cold
headed fastenings. |
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Brazing
|
Brazing is a method of joining metal parts together by fusing a
layer of brass between the adjoining surfaces. A red heat is
necessary and a flux is used to protect the metal from oxidation. |
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Breaks
|
Creases or ridges usually in “untempered” or in aged material where
the yield point has been exceeded. Depending on the origin of the
break, it may be termed a cross break, a coil break, an edge break,
or a sticker break. |
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Bright Annealing
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An annealing process that is carried out in a controlled atmosphere
furnace or vacuum in order that oxidation is reduced to a minimum
and the surface remains relatively bright. |
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Bright Drawing
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The process of drawing hot-rolled steel through a die to impart
close dimensional tolerances, a bright, scale-free surface, and
improved mechanical properties. The product is termed bright steel. |
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Brinell Hardness Test
|
The Brinell hardness test for steel, involves impressing a ball 10
mm diameter, of hard steel or tungsten carbide, with a loading of
3000 kilograms into the steel surface. The hardness of the steel
is then determined by measurement of the indentation. For steels
with a hardness over 500 BHN the Vickers test is more reliable. |
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Brittle Tempering Range
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Some hardened steels show an increase in brittleness when tempered
in the range of about 450°F to 700°F even though some tempering
causes some softening. |
