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Metallic
titanium was first isolated in impure form in 1887 and with
higher purity in 1910; however, it was not until the 1950`s that
it began to come into use as a structural material. This was
initially stimulated by aircraft application .Although the
aerospace industry still provides the major market, titanium and
titanium alloys are finding widespread use in other industries
due to their many desirable properties.
Notable among these is their low densities, which fall between
those of aluminium and iron and give very attractive strength to
weight ratios.
In addition, titanium and titanium alloys really form stable
protective surface layers which give them excellent corrosion
resistance in many environments, including oxidizing acids and
chlorides, and good elevated temperature properties up to about
550 C (1022 F) in some cases.
Titanium metal is abundant in the earth's crust and is extracted
commercially from the ore minerals rutile (titanium dioxide) and
ilmenite (iron-titanium oxide).The commercial extraction process
involves treatment of the ore with chlorine gas to produce
titanium tetrachloride, which is purified and reduced to
metallic titanium sponge by reaction with magnesium or sodium.
The sponge blended with alloying elements as desired, is then
vacuum melted. Several meltings may be necessary to achieve a
homogeneous ingot which is ready for processing into useful
shapes, typically by forging followed by rolling. For many
applications the cost of titanium alloys can be justified on the
basis of desirable properties. Pure titanium, like iron, is
allotropic. At ambient temperature it has a hexagonal close
packed (hcp) crystal structure which is stable during heating up
to 883 C ( 1621 F) where it transforms to the body centred cubic
(bcc) crystal structure. It remains bcc at higher temperatures
until it melts at 1668 C (3034 F). On cooling, the
transformation from bcc to hcp in pure titanium can not be
suppressed by rapid cooling, the transformation occurring by
martensitic type reaction. This is not, however, the case with
titanium alloys, in which the transformation can be suppressed
or modified. Thus the microstructure of titanium alloys
frequently contain particles of the bcc phase of ambient
temperature.
The spectrum of titanium-based materials can be divided into
four classes depending their constituent phases; this in turn
depends on their relative contents of alpha-stabilizing and
beta-stabilizing alloying elements.
The four basic classes are:
unalloyed or commercially pure titanium;
alpha and near alpha alloys;
alpha- plus -beta alloys;
beta-alloys
Products
Titanium mill products vary by forms: titanium bars, titanium
ingots, titanium billets, extrusions, titanium strip, titanium
sheets, titanium plates, titanium wire, titanium pipes (titanium
tubes). All these products available for unalloyed titanium
as well as from titanium alloys. Many grades of titanium and its
alloys are also available as castings and forgings. Some beta
alloys have superior forgeability; sheets can be cold-formed in
the solution-treated condition. Ti 6 Al/ 4V is relatively
difficult to cold form but is readily hot formed or even super
plastically formed.
Titanium
bar. Titanium
sheet, Titanium plate, Titanium tube, titanium wire, titanium
ingot.
Weldability
In general, weldability of titanium and its alloys can be
readily performed but it is necessary to exclude reactive gases,
including oxygen and nitrogen from the air, and to maintain
clearness. Thus weld properties are heavily influenced by
welding procedures, especially by the adequacy of inert gas
shielding. Electron beam welding, gas metal arc welding,
friction welding, laser welding, resistance welding are all used
in some cases. Both alloys composition and microstructure are
important in determining weldability, with the presence of beta
phase having a deleterious effect. Thus unalloyed titanium and
alpha alloys are generally weldable and welded joints generally
have acceptable strength and ductility; postweld stress relief
annealing of weldments is recommended. Some alpha-beta alloys,
especially Ti 6 Al/4 V, are weldable in the annealed condition
as well as in the solution treated and partially aged condition
( aging can be completed during the post-weld heat treatment.
Strongly stabilized alpha-beta alloys can be embrittled by
welding, the result of phase transformation occurring in the
weld metal or the heat affected zone. Some beta alloys are
weldable in the annealed or the solution treated conditions.
Titanium
bar. Titanium
sheet, Titanium plate, Titanium tube, titanium wire, titanium
ingot.
Corrosion Resistance
Unalloyed titanium, the most corrosion-resistant of the titanium
based materials, is resistant to nitric acid and many different
chloride-bearing environments, including hot chloride solutions.
It is also resistant to sulphides. The Pd-bearing unalloyed
grades have improved resistance to corrosion in reducing media,
so that it can be applied in hydrochloric, phosphoric, and
sulphuric acid solutions. Since the corrosion resistance is
based on the formation of a stable adherent protective surface
oxide film, corrosion susceptibility can arise if the
environment is such that the film can not regenerate itself when
damaged; such a situation can arise for example in the case of
crevice corrosion, where oxygen depletion and acidic conditions
can occur in confident space.
Titanium bar. Titanium
sheet, Titanium plate, Titanium tube, titanium wire, titanium
ingot.
Creep and oxidation resistance
Unalloyed titanium has good creep resistance below 315 C (599
F).
Alpha alloys are generally stable for periods of 1000 hours up
to 540 C (1004 F),
alpha-beta alloys up to about 370 C(698 F ) in the mill annealed
conditions and as high as 425 C (797 F ) after heat treatment.
Titanium
bar. Titanium
sheet, Titanium plate, Titanium tube, titanium wire, titanium
ingot.
APPLICATION OF TITANIUM AND TITANIUM
ALLOYS
Aircraft Industry
remains the first and the major titanium consumer
Material requirements for aircraft building:
1) small weight
2) high specific strength
3) heat resistance
4) fatigue load resistance
5) crack resistance
6) corrosion resistance
Titanium and its alloys meet this requirement.
Three major trends of titanium application for aircraft
building:
1. Fabrication of items of complex space configuration:
- hatch and door edging where moisture is likely to be
accumulated (high corrosion resistance of titanium is used)
- skins which are affected by engine combustion product flow,
flame preventing fire safety-proof membranes (high temperature
of melting and chemical inactivity of titanium is used)
- thin-walled lead pipes of air system (minimum thermal
titanium extension ratio compared to all other metals is used)
- floor decking of the cargo cabin (high strength and hardness
is used)
2. Fabrication of designated high-loaded assemblies and units
- landing gear
- fastening elements (brackets) of the wing
- hydro cylinders
3. Engine part manufacture (see next section).
The following is manufactured from titanium alloys for aircraft
applications:
ailerons, panel and swivel wing assemblies, spar walls, panels,
brackets, steering wheels, wedge meshes, air intake ducts, lead
pipes, frames, leading edge flaps and flaps, hydraulic systems,
fasteners and a number of other parts.
In aircraft industry the most widely used titanium alloys are
GOST VT1-0, VT22, VT6, VT3-1, VT8, VT9, VT25, ASTM Grade-2,
Grade-3, Grade-4, Grade-5, Ti6Al-4V, Ti6Al2Sn4Zr2Mo,
Ti6Al2Sn4Zr6Mo, IMI318 IMI550, IMI685, IMI829, IMI834.
Titanium bars. Titanium
sheets, Titanium plates, Titanium tubes, titanium wire, titanium
ingots.
Shipbuilding Industry
Titanium metal has many characteristics for use in ships, such
as excellent corrosion resistance against sea-water, light
weight and high tensile strength, good recycle ability, etc. For
the future Ti usage, some basic data on Ti should be studied for
Ti ship-building. Titanium has a big possibility for
ship-material, specially, in some special purpose.
Titanium bar. Titanium
sheet, Titanium plate, Titanium tube, titanium wire, titanium
ingot.
Automotive industry
In the automotive industry, uses for titanium in the
automotive/motorcycle aftermarket and racing market. Engine
parts such as connecting rods, wrist pins, valves, valve
retainers and springs, rocker arms and camshafts, to name a few,
lend themselves to fabrication from titanium, because it is
durable, strong, lightweight and resists heat and corrosion.
While titanium initially may be more expensive for these
applications, designs that exploit its unique characteristics
yield parts that more than pay for themselves with better
performance and a longer life.
Titanium bar. Titanium
sheet, Titanium plate, Titanium tube, titanium wire, titanium
ingot.
Architecture
Titanium has come of age as a competitive building material.
New, more effective production techniques, combined with an
abundance of raw and refined ore, have improved availability.
Titanium's corrosion immunity, strength and physical properties
combine to allow reduced wall thickness, lowering its installed
unit cost. Well-researched designs that capitalize on its unique
attributes and long-term savings from durability and low
maintenance make titanium one of today's most cost effective
building materials on a lifecycle basis. There are architectural
titanium as coil, sheet, composite panel and tube. Sheet is the
most commonly used in constructing of outer walls, roofs,
shields.
Titanium
bar. Titanium
sheet, Titanium plate, Titanium tube, titanium wire, titanium
ingot.
Sports
The sporting goods industry uses the metal in the manufacture of
tennis rackets, golf clubs, lacrosse stick shafts; cricket,
hockey and football helmet grills, bicycle frames and
components. Titanium alloys are also used in spectacle frames.
This results in a rather expensive, but highly durable and long
lasting frame which is light in weight and causes no skin
allergies.
The golf industry has found that lightweight titanium club heads
can be bigger than those made of steel, enlarging the "sweet
spot" of the club and thus increasing distance and accuracy.
The application of titanium in bicycle production started
approximately 25-30 years ago and it was the first time titanium
had been applied in sports. The most commonly used titanium
alloy for bicycle frames is
Òi
3Àl-2.5V
(ASTM Grade 9) / PT3V.
Ti6Al-4V alloy is used in making knives for diving, but this
alloy doesn’t provide the proper durability of blade edge in
compare to other alloys. That’s why some manufacturers prefer to
use GOST VT23 alloy.
Titanium is widely used in tourism and mountaineering – almost
for all articles tourists and alpinists have in their rucksacks:
bottles, cups, other food ware are mostly made from CP titanium
ASTM Grade 1
è
Grade 2 (GOST VT1-0).
Titanium bars. Titanium
sheets, Titanium plates, Titanium tubes, titanium wire, titanium
ingots.
Medicine
Because of its corrosion resistance, titanium and its alloys are
used extensively in prosthetic devices such as artificial heart
pumps, pacemaker cases, heart-valve parts and load bearing bone
or hip-joint replacements or bone splints. Titanium is
completely inert to human body fluids, making it ideal for
medical replacement structures such as hip and knee implants.
Titanium actually allows bone growth to adhere to the implants,
so they last longer than those made of other materials.
Reconstructive titanium plates and mesh that support broken
bones are also commonly used today.
High strength-to-weight ratio and superior ballistic properties
make titanium well suited for armor applications. Used as
protective armor on personnel carriers and tanks, it makes the
vehicles much lighter, increasing mobility of the force.
Personal armor vests and helmets for police made from titanium
are far lighter and more comfortable than those made from
competing materials.
For medical application following titanium grades are common: CP
(commercially pure) GOST VT1-0, VT1-00, ASTM B 348 Grade 1,
Grade 2 Grade 3, Grade 4, alloys VT6 / VT6S, ASTM B 348 Grade 5,
Grade 23, Ti 6Al-4V ASTM F 1472, ASTM, Ti 6Al-4V ELI ASTM F 136.
Titanium bars. Titanium
sheets, Titanium plates, Titanium tubes, titanium wire, titanium
ingots.
Computer industry
Since titanium does not become magnetized, it is used in the
structural parts surrounding computer components such as disk
drives and microchips, which can be ruined by stray magnetism.
In the computer industry, titanium is a promising substrate for
hard disk drives. . Its non-magnetic properties prevent
interference with the data storage process; its ability to
withstand heat allows higher temperatures during the coating
process, which improves manufacturing rates; and the purity of
titanium permits closer read/write head tolerances, increasing
disk capacity.
Food industry
Yet there is a very important sector that still needs to be
analyzed, that is the food industry field. The absolute
biocompatibility and non-toxicity of titanium, its resistance to
the aggression of organic substances, to corrosion and erosion
explain why this material plays a primary role in all food
industry plants.
Titanium has been increasingly used in the manufacture of baking
ovens for hams and sausages that is environment with the
salinity of 10-14% and operation temperatures around 100 0C,
high humidity and continuous operation modes.
All machinery, even if made of the beat stainless steel, has a
useful life not above 2 years, provided that it is subjected
to regular servicing. There is a great demand for titanium for
mincing machines that cut and actually mince the meat and in the
field of sausage production.
Another field where titanium has started to be recently applied,
which is still at an experimental level, not in technical terms
but in terms of global efficiency, is the one related to
pressurized boilers that is in coffee-making machines
distillers.
More update research an studies indicate that there are food
liquid, generally wine products, but also alcoholic beverages
where titanium can be considered an excellent remedy, since it
does not release the elements contains in steels with several
titles.
The success of titanium originates from the excellent behavior
of this material with high temperatures, its lightness,
biocompatibility and resistance.
Titanium
bar. Titanium
sheet, Titanium plate, Titanium tube, titanium wire, titanium
ingot.
Jewelry
Traditionally reserved for industrial uses,
titanium has only recently
been included as a jewelry
material and is increasingly popular. Titanium is a good
material for inlay work as it can be joined to different metals
to make multi-tone pieces. Titanium
is available in pure or alloyed form, but there is no reason to
increase its strength with alloys for the purposes of
jewelry, therefore the purest
grade of titanium is the most
desirable for this application.
The variety of titanium jewelry ware includes: rings, bracelets,
chains, necklaces, pendants, earrings etc.
Titanium jewelry is lightweight and feels warm to the touch; it
is easily adopted by the wearer, and its sober coloring is most
sophisticated. It is far more durable and longer lasting than
gold or platinum.
Titanium bar. Titanium
sheet, Titanium plate, Titanium tube, titanium wire, titanium
ingot.
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