U.S. patent application number 10/363399 was filed with the patent office on 2003-09-11 for method of controlling water base-process type lubricating and processing fluid for cold forging.
Invention is credited to Imai, Yasuo, Yamaguchi, Hidehiro, Yamamoto, Mamoru, Yoshida, Masayuki.
Application Number | 20030167812 10/363399 |
Document ID | / |
Family ID | 18754723 |
Filed Date | 2003-09-11 |
United States Patent
Application |
20030167812 |
Kind Code |
A1 |
Yamamoto, Mamoru ; et
al. |
September 11, 2003 |
Method of controlling water base-process type lubricating and
processing fluid for cold forging
Abstract
An effective and simple controlling process for an aqueous
lubricant of one process type used for cold forging of metallic
material are explained. The process is carried out on an aqueous
lubricant of one process type containing at least one water soluble
inorganic salt. In order to obtain a preferred weight of the
lubricative coating layer by applying this aqueous lubricant, the
electric conductivity of the aqueous lubricant are measured and
controlled in a preferred level by supplementing a constituent to
the aqueous lubricant.
Inventors: |
Yamamoto, Mamoru; (Saitama,
JP) ; Yoshida, Masayuki; (Tokyo, JP) ; Imai,
Yasuo; (Tokyo, JP) ; Yamaguchi, Hidehiro;
(Tokyo, JP) |
Correspondence
Address: |
STEVENS DAVIS MILLER & MOSHER, LLP
1615 L STREET, NW
SUITE 850
WASHINGTON
DC
20036
US
|
Family ID: |
18754723 |
Appl. No.: |
10/363399 |
Filed: |
May 14, 2003 |
PCT Filed: |
September 3, 2001 |
PCT NO: |
PCT/JP01/07590 |
Current U.S.
Class: |
72/42 |
Current CPC
Class: |
C10N 2050/02 20130101;
C10M 2201/084 20130101; C10M 2201/102 20130101; C10M 2201/087
20130101; C10N 2040/243 20200501; C10N 2010/12 20130101; C10N
2040/24 20130101; C10M 173/02 20130101; B21J 3/00 20130101; C10N
2040/22 20130101; C10M 173/00 20130101 |
Class at
Publication: |
72/42 |
International
Class: |
B21B 045/02 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 5, 2000 |
JP |
2000-267883 |
Claims
1. A process for controlling aqueous lubricant of one process type
containing at least one water soluble inorganic salt and is used
for cold forging, wherein concentration of the aqueous lubricant is
controlled by controlling electric conductivity of the aqueous
lubricant at the time of processing, and the electric conductivity
of the aqueous lubricant is controlled by supplementing constituent
to the aqueous lubricant.
2. The process for controlling aqueous lubricant of one process
type used for cold forging according to claim 1, wherein one water
soluble inorganic salt is at least one selected from a group
consisting of sulphate, silicate, borate, molybdate and tungstate.
Description
FIELD OF THE INVENTION
[0001] The present invention is related to a process for
controlling aqueous lubricant of one process type used for cold
forging of metallic material, and is aiming at providing improved
lubricant onto a surface of a metallic material without applying
any previous chemical treatment. Said lubricant is suitable for
cold forging manufacturing of parts to be used for transportation
machineries, etc.
BACKGROUND ART
[0002] Generally, in cod forging of a metallic materials such as
stainless steel, lubricative coating is carried out onto the
surface of a metallic material for aiming at preventing a surface
defects of burning and biting which may be caused from direct
contact of a metallic material to be processed with a mold and a
tool used in the forging process.
[0003] There are two types of the coated layers to be formed onto
the surface of a metallic material, one of which is the type that a
lubricant is being adhered directly onto the surface of the
metallic material and the other is the type that a lubricant is
being used onto the chemical layer being formed previously over the
surface of the metallic material.
[0004] The lubricative coating formed by being adhered directly
onto the surface of a metallic material has less cohesion
performance than the lubricative coating formed by being used
lubricant onto the chemical layer formed previously over the
surface of the metallic material, and therefore, the former type is
generally used for the cold forging with less amount of
deformation.
[0005] In case of the latter type, the chemical layer is firstly
formed on the surface of a metallic material through a chemical
processes such as phosphate layer forming process or oxalate layer
forming process,which generally form the chemical layer suitable as
a carrier of a lubricant, and a lubricant having high lubricative
property is used following to the formation of such chemical layer.
In this type, the formed film has a bilayer structure consisting of
a chemical layer as a carrier and a lubricant layer, which has high
resistant property against surface defects. From this reason, this
type has been widely employed in the field such as wire drawing,
tube drawing and cold forging. Particularly, in the cold forging
where severe deformation is required, a process firstly forming the
chemical layer comprising phosphate or oxalate and then using a
lubricant onto the chemical layer is popularly employed.
[0006] The lubricant applied onto the chemical layer may be divided
into major two groups in terms of the usage. The first group
includes a lubricant to be mechanically adhered onto the chemical
layer and the second group were lubricant reacts with the chemical
layer.
[0007] The first group of lubricant includes one prepared by using
mineral oil, vegetable oil,or synthetic oil as a base oil and
containing an extreme pressure additive in the base oil, and one
prepared by dissolving a solid lubricant, such as graphite and
molybdenum disulfide, together with a binder component into the
water. These lubricants have advantage of easy for controlling the
solution since they can be used simply by means of spray coating or
dipping coating, however, as they have just a low lubricative
properties, they tend to be used for a case where less amount of
deformation of metallic material is required.
[0008] On the other hand, in the second group of lubricant, a
reactive soap such as sodium stearate is used for a case where
particularly high lubricative property is required. The reactive
soap reacts with the chemical layer to provide high lubricative
properties.
[0009] However, since the reactive soap gives a chemical reaction,
control of the composition of the reactive soap solution,
temperature control and renewal control of the deteriorated
solution are required during the process.
[0010] On the other hand, it is a big issue to reduce waste
products arising from the industries for global environmental
protection, and therefore, a lubricant and a lubricative process,
those which do not produce waste products, are highly desired.
Further, the conventional process that contains coating layer and
reactive soap, some simplification and improvement is now required,
since it is necessary to have a processing plant of wide area,
greater time and complex control at every steps of the process.
[0011] For example, in the step of forming the coating layer of
phosphate, many complex analysis including free acidity of the
solution, total acidity and concentration of the solution are
carried out manually by means of neutralization titration. Further,
in the step of reactive soap application, complex analysis of free
acidity and concentration of the solution are regularly and
manually carried out, and the supplement of the reduced compounds
has to be carried out.
[0012] A prior art of "Aqueous lubricant applicable for cold
plastic deformation of metallic material" disclosed in JP-10-8085 A
can be cited. This relates to an aqueous lubricant used for cold
plastic deformation processing of metallic materials, which
comprise (A) water soluble inorganic salt, (B) solid lubricant, (C)
oil component selected from a group consisting of mineral oil,
animal oil, vegetable oil and synthetic oil, (D) surface active
agent and (E) water, and in which containing substance and oil are
dispersed and emulsified homogeneously.
[0013] This prior art is related to an aqueous non-reactive type
lubricant, and is aiming at simplifying the conventional three
processes of phosphate layer formation, water rinsing and reactive
soap application into one process. The present invention is also
related to a aqueous lubricant used as a lubricant of one process
type, namely a lubricant without any previous chemical treatment
for making a chemical layer. That is, in the present invention, the
lubricative coating layer is formed directly on the surface of the
metallic material by contacting the metallic material with the
aqueous lubricant by means of dipping or the like, without forming
any chemical layer previously on the surface of the metallic
material. This type of lubricant is generally called as lubricant
of one process type.
[0014] From the knowledge of the inventors of the present
invention, the concentration of the containing substance is
extremely important when using such type of this aqueous
non-reactive lubricant. Because, in case of non-reactive lubricant,
the weight of the lubricative coating layer, namely the amount of
the coating, is decided based on the concentration of the
containing substance in the solution. The weight of the coating
layer is an important factor since it greatly affects the
lubricative performance and resistance to the surface defect. The
weight of the coating layer is calculated as below, based on the
weight difference between before and after the lubrication
treatment and the area of the metallic material.
[0015] Weight of coating layer=(Weight of metallic material after
lubrication treatment-Weight of metallic material before
lubrication treatment)/(Area of metallic material processed).
[0016] Therefore, accurate concentration control of the containing
substance in the lubricant is absolutely important for attaining a
constant weight of the coating layer. However, since much labor is
required for the determination of the concentration, it has been
incovenient to employ the non-reactive lubricant in the
industry.
DISCLOSURE OF THE INVENTION
[0017] Therefore, it is an object of the present invention to solve
the problem of the conventional art as described above and to
provide a new control process of the aqueous lubricant of one
process type used for cold forging wherein all operations are
simplified and is further favorable for the protection of global
environment.
[0018] The inventors of the present invention have made
investigation for solving the problems described above and have
found on the aqueous lubricant containing at least one water
soluble inorganic salt that the concentration of the containing
substance in the aqueous lubricant can be controlled by controlling
the electric conductivity of the aqueous lubricant.
[0019] That is, the present invention is directed to a process to
control aqueous lubricant of one process type containing at least
one water soluble inorganic salt and is used for cold forging
characterized in that the process comprises a step to control the
concentration of the aqueous lubricant by measuring the electric
conductivity of the aqueous lubricant at the time of coating the
aqueous lubricant on to the surface of the metallic material, and a
step to supplement the constituent to the aqueous lubricant in
order to keep the concentration of the aqueous lubricant at a
prefered level.
[0020] The present invention is also directed to a process to
control the aqueous lubricant of one process type used for cold
forging as explained above, wherein one water soluble inorganic
salt is at least one selected from a group consisting of sulphate,
silicate, borate, molybdate and tungstate. And the main use of said
aqueous lubricant is for manufacturing of parts for
automobiles,motorcycles and other transportation machineries, such
as engines, power trains and chassis.
BRIEF DESCRIPTION OF DRAWINGS
[0021] FIG. 1 shows an embodyment of the apparatus used for
carrying out the control process according to the present
invention;
[0022] FIG. 2 shows an example of the relation between the
concentration and the electric conductivity of the aqueous
lubricant;
[0023] FIG. 3 shows an example of the relation between the electric
conductivity of the aqueous lubricant and the weight of the coating
layer formed on the surface of the metallic material.
MODES FOR CARRYING OUT THE INVENTION
[0024] Now, the present invention is further described in detail.
In the present invention of the process for controlling the aqueous
lubricant of one process type used for cold forging, an aqueous
lubricant, which contains at least one water soluble inorganic salt
may be used. And the present invention may use the electric
conductivity of the aqueous lubricant arisen by the water soluble
inorganic salt contained therein.
[0025] As described before, the weight of the lubricative coating
layer formed on the metallic material is very important when
coating the surface of a metallic material with the aqueous
lubricant of one process type for cold forging. In this case, the
weight of the lubricative coating layer formed on the metallic
material is closely related with the concentration of the aqueous
lubricant. And the concentration of the aqueous lubricant is
closely related with the electric conductivity of the aqueous
lubricant. Therefore, the control of the electric conductivity may
result in the control of the concentration of the aqueous
lubricant, and further, it may result in the control of the weight
of the lubricative coating layer formed on the surface of the
metallic material. That is, the weight of the lubricative coating
layer is reduced by lowering the electric conductivity, namely by
diluting the aqueous liquid with water, while the weight of the
coating layer increases by increasing the electric conductivity by
adding, for example, the concentrated aqueous lubricant solution.
Therefore, the amount of the lubricative coating layer can be
controlled by means of controlling the electric conductivity of the
aqueous lubricant without doing a concentration measurement of the
aqueous lubricant.
[0026] In an industrial operation, it is required to keep the
important operational item to be in a favourable target value. And
in cold forging operation, many items such as a preparation of
suitable cold forging tool, a suitable cold forging speed and the
suitable weight of the lubricative coating layer on the metallic
material must be controlled. The suitable weight of the lubricative
coating layer may be obtained by control the concentration of the
aqueous lubricant. However, the control of the concentration of the
aqueous lubricant by a conventional process may be a complex
operation, since it needs a measurement of the concentration of the
aqueous lubricant frequently. However in the present invention, the
concentration of the aqueous lubricant can be obtained easily and
precisely by simple operation of measurement of electric
conductivity.
[0027] And favorable weight of the lubricative coating layer may
continuously be obtained by controlling the electric conductivity
of the aqueous lubricant to be in the target value by supplementing
the constituent by using, for example, a concentrated aqueous
lubricant solution to the aqueous lubricant in operation.
[0028] The preferred water soluble inorganic salt includes, but is
not specifically limited to, at least one selected from a group
consisting of sulphate, silicate, borate, molybdate and
tungstate.
EMBODYMENT
[0029] Now, the examples for carrying out the present invention are
given below.
[0030] <Aqueous Lubricant>
[0031] Available aqueous lubricant used in the present invention
containing borate as water soluble inorganic salt (Trademark; Fine
Ryube E750HF, manufactured by Nihon Parkerizing Co.,Ltd) is diluted
with pure water so as to be adjusted the concentration respectively
to 50%, 60% and 70% and each aqueous lubricants of 50 liters are
prepared.
[0032] <Measurement>
[0033] The electric conductivity of the aqueous lubricant is
measured by using a commercially available electric conductivity
measuring meter. A cleaned steel specimen (cylindrical shape,
diameter 50 mm length 150 mm) is treated with the aqueous lubricant
to form a lubricative coating layer onto the surface of the steel
specimen, and the weight of the lubricative coating layer (the
amount of the coating) is determined by detracting the weight of
the steel before coating from the weight of the steel after
coating.
[0034] Continuous Processing Test
[0035] A apparatus shown in FIG. 1 was prepared. The volume of a
aqueous lubricant tank (1) for the aqueous lubricant (2) is 50
liters and the temperature of the aqueous lubricant (2) is set at
60.degree. C. A meniscus sensor (3) was set at the meniscus level
of the aqueous lubricant, and the meniscus controller (4) is set to
work when the meniscus level of the aqueous lubricant comes 1 cm
down from the initial meniscus level automatically by opening the
electromagnetic valve (5), thereby pure water from a water supply
tank (6) flow into the aqueous lubricant (2). Said electromagnetic
valve was set to be closed when the meniscus level reaches to the
initial level. The meniscus level of the aqueous lubricant is
usually coming down in operation as it is consumed by adhering to
the steel material and by evaporation owing to be heated at
60.degree. C.
[0036] Whereas, the electric conductivity of the aqueous lubricant
measured by the electric conductivity sensor (7) is displayed on
the electric conductivity controller (8). The electromagnetic valve
(9) opens when the electric conductivity is decreased to an extent
of 2% from the initial value, and flow the condensed aqueous
lubricant (Fine Ryube E750HF (100%)) from a condensed aqueous
lubricant tank (10) for supplementing the constituent of the
aqueous lubricant, and the electromagnetic valve (9) is set to
automatically close when the electric conductivity has recovered to
the initial value in order to discontinue the supplement of the
condensed aqueous lubricant. Under the condition as described
above, 6,000 pieces the steel specimen were continuously treated
with the aqueous lubricant of the respective concentration. The
weight of the lubricative coating layer (the amount of the coating)
of each steel specimen was checked in extractive manner, and the
steel specimen having a lubricative coating layer were subjected to
cold forging to evaluate the lubricative performance.
[0037] The relation between the concentration of the aqueous
lubricant and the electric conductivity are shown in FIG. 2, and
good relation can be recognized between these two. The relation
between the electric conductivity and the weight of the lubricative
coating layer are shown in FIG. 3, and good relation can be
recognized between these two. Therefore,it is understood that the
weight of the coating layer may decrease along with the reduction
of the electric conductivity being resulted by diluting the aqueous
lubricant. Consequently, it shows that the control of the weight of
the coating layer can be achieved by controlling the electric
conductivity of the aqueous lubricant.
[0038] The results of the continuous processing test are shown in
Table 1. It shows that the weight of the lubricative coating layer
may be controlled at a constant level by controlling the electric
conductivity of the aqueous lubricant, and that good cold forging
can be done by this process without arising any problem.
1 [TABLE 11] 50% 60% 70% Electric Electric Electric Conductivity
Conductivity Coductivity 27 mS/cm 30 mS/cm 33 mS/cm Treatment order
Lubricative Cold Lubricative Cold Lubricative Cold of specimen in
Coating forging Coating forgong Coating forging continuos layer
perform- layer perform- layer perform- process mg/m.sup.2 ance
mg/m.sup.2 ance mg/m.sup.2 ance First 8. 8 Good 9. 8 Good 10. 5
Good 1000.sup.t h 8. 9 Good 9. 7 Good 10. 6 Good 2000.sup.t h 8. 7
Good 9. 7 Good 10. 6 Good 3000.sup.t h 8. 8 Good 9. 8 Good 10. 6
Good 4000.sup.t h 8. 8 Good 9. 7 Good 10. 5 Good 5000.sup.t h 8. 7
Good 9. 7 Good 10. 6 Good 6000.sup.t h 8. 8 Good 9. 8 Good 10. 6
Good
ADVANTAGE OF THE INVENTION
[0039] As clearly understood in the explanation above, the present
invention provides advantageous effect in cold forging process by
using aqueous lubricant of one process type, wherein the simple and
precise control of the weight of the lubricative coating layer can
be obtained by controlling the electric conductivity of the aqueous
lubricant and by supplementing the constituent to the aqueous
lubricant in the operation.
* * * * *