Industrial Waste Treatment ERT 319 Semester 1 2015/2016 Hanna Ilyani Zulhaimi
Advanced equipment for precise heat treatment of high ... · ing speeds, temperature spread and...
Transcript of Advanced equipment for precise heat treatment of high ... · ing speeds, temperature spread and...
AluReport
Investments 11
Investments for greater security
and flexibility
The extensive investments of recent years
have resulted in one of the most modern
plant pools in the aluminium industry,
which offers maximum production secu-
rity and customer-friendly flexibility with
regard to the realisation of complex, met-
allurgical demands.
The latest simulation tools for
heat treatment
Irrespective of whether final or essential
process-related, intermediate processing
is involved, heat treatment is always tar-
geted on achieving optimum product char-
acteristics. Basically, all heat treatments
have an effect on the microstructure of
the material, whereby properties relating
to customer-processing and use are influ-
enced (mechanical properties, formability,
corrosion behaviour, distortion, etc.). Heat
treatment is a diffusion-determined proc-
ess, which is why temperature and time
are its most important parameters. In the
case of heat treatable alloys, the classic
heat treatment sequence consists of so-
lution annealing, quenching and artificial
ageing. Solution annealing is aimed at
achieving the dissolving of soluble, hetero-
geneous alloying components in solid so-
lution and their homogeneous distribution.
The higher the temperature, the better the
product characteristics, whereby the major
danger is eutectic melting, which can lead
to internal rejects.Therefore AMAG deter-
mines precisely the furnace parameters
(temperature, time, quenching & quench-
delay, heating and cooling curves, etc.) for
the respective alloy composition, not only
in the course of testing, but increasingly
through the use of the latest simulation
tools (e.g. Nougat) and thermal laboratory
analyses (e.g. DSC). The parameters thus
established permit a marked reduction in
large-scale testing in order to verify the
optimum range of parameters and their
fixing for serial production.
Fulfilment of the strictest aviation
industry demands
Not only is a precise knowledge of mate-
rial behaviour needed in order to be able
to near the feasibility limits, but also exact
furnace temperature management. As is
also the case with regard to other char-
acteristics, the aerospace industry places
the highest demands on equipment for
the heat treatment of sheets and plates.
Of these, the main two relate to tem-
perature uniformity within narrow limits
throughout the entire furnace and sub-
sequently, stringent requirements relating
to the entire temperature measurement
chain and furnace control.
All of AMAG rolling’s registered furnaces
fulfil the requirements for the production
of aerospace products according to the
internationally recognised and widely-used
AMS 2750 standard and even stricter
NADCAP (National Aerospace and De-
fence Contractors Accreditation Program)
directive, which in the meantime are re-
quired by many leading aircraft manufac-
turers. However, it should be added that
all other AMAG product groups, e.g. au-
tomotive, mechanical engineering, sport
applications, etc. benefit from the strict
requirements of the aerospace sector.
As a result of intensive teamwork with
furnace producers, AMAG’s heat treat-
ment expertise in both the metallurgical
and engineering sectors flows into the
company’s choice and design of advanced
heat treatment equipment. This results in
optimum furnaces, for AMAG’s product
portfolio, specialized for sheet and plate
production.
Advanced equipment for precise
heat treatment of high-strength
aluminium alloys
AMAG rolling specialises in the pro-
duction of high-strength aluminium
sheets and plates and disposes over
enormous competence with regard to
the heat treatment of age-hardening
aluminium products. Moreover, new
advanced heat treatment equipment
and new technologies open the way
to previously untapped potential.
▼
Please read the article concerning
the latest investments relating to the
operational furnaces.
Investments12
Horizontal annealing furnace for
solution annealing of plates
As a result of the systematic expansion of
high-quality aerospace plate production
capacity, two virtually identical horizontal
annealing furnaces have been purchased
for the batch solution annealing of heat
treatable plates in the 2xxx (AlCu), 6xxx
(AlMgSi) and 7xxx (AlZn) alloy groups.
Both annealing furnaces are heated
electrically and attain a temperature ac-
curacy of +/-2°C, which surpasses
even the strictest aerospace demands.
This precision is due to the latest con-
trol technology and a specially optimised
heat register. All heating and quenching
parameters are stored in a database, for
correct presetting of the furnace with the
optimum parameter sets and prevents
individual errors during the input of heat
treatment data.
Following heating and the annealing
soaking time, which is necessary from
a metallurgical standpoint, the plates
are quenched. During this process the
plates are cooled from the annealing
temperature to room temperature by
means of individually controllable rows
of high-pressure water jets. In the high-
pressure section well over 1,000 m3/h of
water are sprayed onto the hot plates by
several thousand jets. Subsequently, the
Al plates are air-dried in order to prevent
surface corrosion and water-stains.
Owing to the fact that both horizontal an-
nealing furnaces are of identical system
design, it is possible to use a spare part
pool, which simplifies repairs and thus
facilitates reduced downtimes. Both fur-
naces were “Made in Austria” and were
designed in conjunction with EBNER
Industrieofenbau in a far-sighted move,
which has ensured that the systems of-
fer expansion possibilities to deal with
future increases in the need for heat
treatment.
Artificial ageing furnace for plates
Apart from solution annealing, a major
step in the production of heat treatable
aluminium alloys is artificial ageing to a
defined temper, whereby the alloying el-
ements precipitate out of the quenched
and “frozen” supersaturated solid solu-
tion.
In addition to tempers in line with speci-
fications, AMAG has also developed
customised tempers, which permit spe-
cial combinations of characteristics and
mirror the company’s special expertise
in this field. The express and systematic
response to customer requests, which
extends to small batches, is also par-
ticularly clear within the context of the
installed heat treatment equipment.
The second quarter of 2009 saw the
successful commissioning of a new,
HOFMANN artificial ageing furnace. As
a result, a total of nine ageing furnaces
of the same design are available for the
artificial ageing of plates in the 2xxx, 6xxx
and 7xxx alloy groups.
The furnaces are electrically heated
and due to the use of the latest control
technology and optimised air flow, which
was specially optimised for AMAG roll-
ing, offer temperature precision and uni-
formity that is far above the norm. The
optimisation of air flow was based on the
teamwork between Linz University and
AMAG’s experts, which in addition to
testing with new measurement methods,
also involved the use of simulation tools.
Three new artificial ageing furnaces are
of overhead design, the Al plates being
fed into the furnace from below. This de-
sign saves a great deal of energy, as the
hot air remains in the furnace and does
not escape, which facilitates very high
levels of temperature uniformity in the
furnace chamber.
All three furnaces are filled and emptied
via a single charging station. Following
heat treatment the material is cooled
and the residual heat employed for hall
heating. Therefore, when the material is
removed from the charging station it is
already cool, which is also important from
a safety standpoint (danger of burns).
Furnace control is fully automatic and
The most advanced furnace technology for plates,
strips, coils and sheet bundles
Artificial ageing furnace Horizontal annealing furnace
AluReport
Investments 13
goes so far that the furnace personnel
can be supplied with defect and status
reports directly from the furnace per e-
mail and SMS. The entire artificial ageing
furnace group was also manufactured in
Austria.
Continuous heat treatment line for
strip solution annealing
In order to expand its heat treatment
capacity with regard to heat-treatable
sheets and strips, AMAG rolling recent-
ly invested in another continuous heat
treatment (CHT) line. With this two-digit
million investment, AMAG has strength-
ened its competence and capacity in the
continuous, largely non-contact, strip
heat treatment segment. AMAG rolling
is the world’s only supplier to offer solu-
tion annealing of this type for strips in the
0.3-6.0 mm thickness range.
The CHT line, which went into operation
in mid-2008, was primarily designed for
the continuous annealing of heat treat-
able strips in the 2xxx, 6xxx and 7xxx al-
loy groups.
Strip guidance in the furnace takes place
without any rolls, the strip moving through
the furnace on an air cushion. The lat-
est burner and furnace controls provide
a precisely controllable heating regime,
which extends to very high temperature
gradients. With different furnace zones
the necessary metal temperature can be
controlled very precisely, which is metal-
lurgically essential, prior to quenching
of the material with water and/or air to
room temperature following the appropri-
ate soaking time. When water is used as
a quenching medium, quenching speeds
reach several 100°C/sec.
A great deal of AMAG expertise has
been utilised for the design and layout
of the quenching section and the trans-
fer from the furnace. The experience of
the company’s technology specialists has
been systematically implemented in or-
der to ensure that the highest quality
demands relating to heat treatable sheet
and strip products can continue to be
met in future.
As flatness deviations always occur in the
strip during quenching, the new CHT line
was designed with an integrated, continu-
ous stretcher. This allows the fulfilment of
strict requirements relating to strip flat-
ness for a wide range of thicknesses. In
addition, integrated trimming shears can
be set to tailor the strip to its end width di-
rectly in the line, which means that some
products can be produced on a ready-to-
pack basis.
Single-chamber, hood-type
annealing furnace for coils
and sheet bundles
From 2006-2008, four JUNKER hood-
type annealing furnaces were commis-
sioned for the artificial ageing and an-
nealing of coils and sheet bundles. The
strengths of this furnace concept lies in
its flexibility as compared to conventional
multiple coil furnaces, as it offers the pos-
sibility for the completion of urgent orders
with optimum use of capacity levels. The
heat treatment systems, which allow en-
largement on a modular basis, can be ex-
tended beyond their current status through
the addition of further independent, single
hood-type coil annealing furnaces.
The main heat-treated products consist of
coils, although rings (slit coils) and sheet
bundles can also be charged. Loading
and unloading takes place by means of
a hall stacking crane, whereby the entire
charging process from coil handover to a
shuttle is fully automated. Automatic fan
speed regulation, and the latest gas burn-
er technology with special control charac-
teristics ensures maximum furnace tem-
perature fluctuations of +/-2°C through-
out a temperature range of 100-600°C.
This allows the fulfilment of all demands
regarding precision heat treatment such
as artificial ageing, annealing and stress-
relieving.
High air flow volumes and speeds with
the appropriately dimensioned circulation
capacity in combination with a patented
air flow system, which was optimised in
teamwork with AMAG, guarantees high-
precision temperature management. As
opposed to previous concepts, this sys-
tem permits a marked reduction in heat-
ing speeds, temperature spread and heat
treatment process times.
All furnaces can be operated using a in-
ert gas atmosphere. It is also possible to
cool the furnace by means of nitrogen
and thus achieve high cooling gradients,
which can be varied in line with process
requirements. The regulation and con-
trol of the holding times and tempera-
tures takes place automatically, whereby
throughout the heat treatment process
all that is required is on-the-spot surveil-
lance, or monitoring via a client station.
By means of the optimisation of the pro-
cess parameters of all the heat treatment
steps along the process chain, AMAG’s
specialists have been able to create previ-
ously unattainable property characteritics
for various alloys to the advantage of cus-
tomers worldwide.
Special results from work on 6xxx
alloys will be presented in AluReport
3/2009.
Hood-type annealing furnaceContinuous heat treatment line