Transcript Lubrificantes para Matrizes de Prensas de Forja a Quente

FORGING
LUBRICANTS
FOR THE HOT
FORGING OF STEEL
Their impact in the forging quality, the
life of the dies and the manufacturing
of forged parts
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IMPORTANCE OF LUBRICATION
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In a Hot Forging process, DIE LUBRICATION
is the KEY for QUALITY and PRODUCTIVITY.
Lubrication, however, is not an easy job and is
very dependant on the right selection of
parameters such as:
Lubricant and application types.
Team supervision and operator experience, even
when fully automated systems are employed.
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BENEFITS WHEN FORGING
LUBRICANTS ARE USED
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LUBRICATE (reduce the friction metal to metal
thus allowing metal flow to occur in a smooth and
controlled way)
RELEASE (make possible the removal of the forged
part from the die)
COOLING (remove undesirable heat from dies)
PROTECT (protect and as a consequence extend the
die life)
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WHAT IS A FORGING LUBRICANT?
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A lubricant for forging dies is a chemical
compound that has a formulation that makes
possible the forging process to be carried out
within the limits and parameters considered
paramount by the forging industry.
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Usual types of Forging Lubricants
 Graphite
in water dispersions.
 Graphite in oil dispersions.
 Synthetic compounds based on organic
salts.
 Solid lubricants dispersions based on
MoS2, Boron Nitride, Glass.
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What is Graphite?
Graphite is one of
the forms of the
mineral Carbon.
Its origin might
be natural or
artificial.
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Important properties of Graphite
 Geometry
of the particles.
 Particle
size.
 Degree
of purity.
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Structure of Graphite
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Differences between the natural
graphite and the synthetic or
artificial graphite
 Differences
are more in the productive
process rather than in the structure.
Properties are almost identical.
 Natural Graphite: mineral extraction.
 Artificial Graphite: Produced from
petroleum coke.
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Myths and Trues about Graphite I
True
Myth
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All graphites are
equal?
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Only natural or artificial
graphites of hexagonal
and crhystalline
structure properties
are appropriate.
Amorphous graphites
do not possess adequate
lubricating
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Myths and Trues about Graphite II
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Is the particle size the
“differential” among the
different graphites used
by the Forging Lubricant
manufacturers?
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True and false at the
same time. Very small
particles are not always
necessary in a given
formulation. The
combination of particle
size and contained
carbon contain is what
really makes the
difference.
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FORGING DIE
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Inter relation of variables in the
forging process. Their impact in
the adherence.
Degree of dilution of the concentrate.
 Density of the lubricant mist.
 Temperature of the die.
 Pressure of the application of the lubricant over
the die.
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TRENDS IN DIE LUBRICATION
I.
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Applicational aspects
Process automation to make possible the
manufacturing of an increasing number of parts
per hour.
Application of the lubricant in the way of a spray
atomization to make possible to penetrate the
thermal barrier surrounding the dies and
simultaneously lubricate and cool the dies.
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TRENDS IN DIE LUBRICATION II
Applicational aspects
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Use of robotics as main applicational equipment.
Functional lubricating systems-Automatic
refilling of reservoirs.
Dosing systems.
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FACTORS THAT HAVE
INFLUENCE IN THE DIE LIFE
Pressure forces applied to the process
 Speed of the metal flow.
 Type and composition of metals forged.
 Type of metals and treatments employed in the
dies.
 Friction coefficient imparted by the lubricant.
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How must the forging lubricant perform
to promote an extended die life
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In first place forming a bonded film over the
working die surface.
Secondly imparting to the die surface a reduced
friction coefficient able to promote a smooth
metal flow.
In third place imparting cooling properties.
In fourth place not generating build ups on the
die surface.
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Working temperature of the Forging
Lubricant
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To perform within
accepted parameters the
forging lubricant has to
function at temperatures
between 200 and 300
grades centigrades..
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WHAT INFLUENCE THE HEAT
REMOVAL OF THE DIES
Density
of the lubricant.
Pressure of the lubricant
deposition over the dies.
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WHAT INFLUENCE THE
FRICTION COEFFICIENT?
 Adherence
 Type
of the lubricant film to the dies.
and characteristic of the lubricant
used.
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What influences the die temperature?
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Mass and contact time of the billet over the dies.
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FACTOR NOT ALWAYS
OBSERVED IN THE
LUBRICATION
Quality of the water used in the dilution.
 Homogeneity of the diluted lubricant.
 Variation control of the solid content prior to
the application of the lubricant.
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Main ingredients of a Forging Lubricant
Demineralized water.
 Crystalline graphite (natural or sinthetic)
 Binding agents.
 Stabilizers.
 Thickeners.
 Bacteriological inhibitors.
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Die Termography - I
°C
240
220
200
180
160
239ºC
216ºC
240ºC
140
120
100
80
60
40
20
0
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-20
Die Termography-II
°C
240
220
200
180
160
239ºC
216ºC
240ºC
140
120
100
80
60
40
20
0
25-20
DIE LIFE
Important target to achieve:
Keep the total cost of the toolings below the 10%
of the total manufacturing cost.
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Lubrcation -Controls to make-IIn the concentrate product:
Control of the manufactures’s specification
Type of graphite.
Particle size.
Ash content.
Total solid content and graphite content.
Viscosity and Ph of the concentrate.
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Lubrication -Controls to
make-II
 In
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the diluted product:
Chek that the solid content chosen is correct and keep it
constant during the product usage.
Check that the diluted product be under continuous agitation
in the reservoir tank.
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Lubrication -Controls to make-III
In and during its application
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Time,angle,size of the lubricating drop,output and
distance from the lubricating point to the areas to
lubricate.
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Lubricants -Controls to make -IV-
In the lubricating unit (Robot)
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Time of positioning
Time of blow.
Time of retract.
Time of water cooling.
Output of water.
Time of lubrication.
Output of lubricant.
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LUBRICATING SPRAY
ATOMIZATION DROP TYPES
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Interaction between the die
and the billet
Extreme complexity because of:
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Temperature and their control (variation in both).
Transference of heat and its removal(billet cooling and heating
and cooling cycles of the die)
Time of contact billet/die.
Lubrication .
Die composition and treatments.
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Technological barriers to overcome
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Discovery of new ingredients/formulations that
improve lubrication and reduce its incidence in the
factors affecting die life.
Better understanding between the relationship of the
lubricanting film and the die surface during the
forging process.
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The forging techniques-To think
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Despite forging is a technology with high
experimental content, scientific reaserch is gaining
terrain in modern processes.
As per the above concept, the continuous observation
of the process by the operational base (machine
operators, maintennance teams,etc) the accurate
register of the process variables becomes
IMPORTANT.
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Forged automotive parts
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Hot upsetted pipes
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www.forgelube.com
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