ES2203031T3 - MANUFACTURING PROCEDURE OF AN EMBUTITION TOOL IN HYDRAULIC CONCRETE COVERED, AT LEAST PARTIALLY, OF A METAL PLATE. - Google Patents

Abstract

The tool is made from a metal outer shell (9) made to the required shape and acting as a mold for a fiber-reinforced concrete filling, poured in after applying an adhesive compound which has a liquid adhesive phase (13) and a solid phase (14) to anchor the concrete in place. The liquid and solid phases are applied in sequence, so that the solid phase projects partially from the liquid phase to provide an anchoring surface for the concrete. The metal shell is produced by electrodeposition in a polymer mold.

Description

Manufacturing procedure for a tool drawing in hydraulic concrete covered, at least partially, of a metal plate.

The invention relates to tools for drawing of steel sheets made of hydraulic concrete as well as to the manufacturing procedures of these tools.

The drawing consists of manufacturing, from a previously cut sheet of metal of small thickness and that it is called a "starting piece", a piece of form complex and not developable (not capable of being deployed without deformation in a plane), called "drawing piece".

A drawing installation comprises several drawing tools: a "punch", equipped with a "head", a "matrix", endowed with a "background", and a "starting piece jaw"; to the punch head and to the bottom of matrix are conferred a configuration according to the form complex of the drawing piece to be obtained, and of agreement with a complementary form intended to obtain a full drawing of the punch head at the bottom of matrix.

In order to obtain a drawing piece of according to the impression of the matrix bottom (or of the head of punch) from a previously cut starting piece, while maintaining the starting piece in the "piece clamp starting ", with the help of the punch head, the starting piece towards the bottom of the matrix until the coupling and full head socket at the bottom.

For the production of large-scale drawing parts scale, drawing tools are generally used cast iron or steel.

For the manufacture of drawing parts a Small or medium scale, it is possible to use tools less expensive drawing, for example, resin, molded directly or worked according to the shape of the tool, or cast concrete or resin concrete on a "coating of gel "(" gel coat "-in English language) surface.

However, given the weak mechanical characteristics of these materials in regard to the "work surface" of these tools, these tools wear out quickly due to contact with the plates of steel to be embedded, which leads to very short series of drawing.

In order to improve the surface condition and the wear resistance of these tools, is done, by therefore, it is necessary to reinforce these materials on the surfaces of work, and provide them with a metallic "skin" or "shell", as described, for example:

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in document FR 2,669,842 for resin concrete,

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in the US document 1,935,916, for hydraulic concrete,

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or in the article entitled "A functional approach to die and process development: the" composite "die and hydroforming" ( A functional solution for the development of dies or dies and drawing procedures: the "composite" matrix and the hydraulic forming ) - of the authors: G. GALLINARO -in the journal: ATA- Automotive Engineering, November-December 1997, Vol. 50, nº 11/12, p. 635-646.

The metallic "skin" or "shell" serves as this form of support to hydraulic or resin concrete, and form, at least partially, the "work surface" of the tool that comes into contact with the sheet in the course of the drawing

The metal shell can be made by drawing, by projection of metal particles, as described in document FR 2,669,842, by electrodeposition or by vapor deposition, and even using others methods

This metal shell presents, in general, more 1 mm thick.

The invention relates to a tool for Hydraulic concrete drawing equipped with a skin or lining metal.

In order to manufacture a tool hydraulic concrete drawing whose surface intended to enter in contact with the starting part of the sheet to be embedded is covered, at least partially, by a metal shell, know a procedure that includes the consistent stages in:

- prepare a metal shell that has a face called "external", which corresponds to the shape default for the drawing piece, and an opposite face, called "internal".

- prepare a mold for the tool drawing using said shell as a bottom or mold element, in which the inner face is arranged turned towards the inside of the mold, and using, where appropriate, other molding elements,

- cast into said mold a composition of preparing said concrete, and letting said solidify composition,

- demolding said solidified composition lifting the other molding elements that can exist, while keeping the shell in place, joined by glued to solidified concrete.

The metal shell and concrete have very different mechanical characteristics; in the course of a cycle of drawing, and, in particular, at the end of the cycle, the interface between the shell and concrete is subjected to shear stresses very important, especially in areas that have a radius of small curvature; these strong solicitations can cause local ruptures at the junction between the concrete and the shell, which Limit tool performance.

In order to strengthen the union shell-concrete in the case in which it is used resin concrete, according to the document FR-2,669,842, before proceeding to cast the concrete of resin, an intermediate layer of bonding resin is cast compatible with concrete resin (see page 4, lines 27 to 32).

In order to strengthen the union shell-concrete in the case in which it is used hydraulic concrete, in accordance with US 1,935,916, the Inner face of the metal shell is provided with mechanical means of anchoring or fixing the concrete (see page 2, lines 61 to 67); no glue composition is applied previously to the laundry of concrete.

While gluing is a bonding technique that adapts well to resin concrete, adapts with difficulty to hydraulic concrete, since, when casting the hydraulic concrete on a layer of glue, the water of the concrete composition prevent getting a sufficiently strong bond in the interface between the glue and the concrete.

It has been found, in effect, that the union between a glue and a "fresh" or "wet" concrete presents, in overall, remarkably worse behaviors, in regards to shear strength, which the union between the same tail and an "old" concrete, that is, a "set" concrete and dry: Example 1 provided below illustrates this behavioral degradation

It is accepted to avoid, therefore, the use of the technique glued when hydraulic concrete is used.

On the other hand, US 1,935,916 describes mechanical anchoring means that are fixed directly to the metal shell (reference 16 in the figures); such way of joining between the shell and the concrete is, consequently, very onerous.

The invention aims to improve economically the union between the shell and the concrete of a Hydraulic concrete drawing tool, as well as improve The performance of this tool.

For this purpose, the invention aims at a manufacturing process of a drawing tool hydraulic concrete intended for the preparation of parts drawing in a predetermined way from starting pieces of sheet metal, tool whose surface intended to come into contact with the sheet metal part to be embedded it is located covered, at least partially, by a metal shell, and the procedure comprising the steps consisting of:

- preparing said metal shell in a way such that it presents a face called "external", which corresponds to the default form for the drawing piece, and an opposite face, called "internal",

- prepare a mold for the tool drawing taking said shell as a bottom or mold element, in which disposes the inner face turned towards the inside of the mold,

- cast into said mold a composition of preparation of said concrete comprising matter in granules or granules,

- solidify said composition,

characterized by that, prior to the casting step, a composition is applied on said inner face of glue comprising a liquid glue phase and a phase solid intended to form mechanical means of anchoring to concrete.

The term "liquid tail phase" designates a classic or conventional glue applicable in liquid form.

The term "solid phase" designates elements anchor or fixation that are scattered so homogeneous in the glue composition.

Thanks to this manufacturing procedure, it it obtains an economic and very resistant union between the shell Metal and concrete.

As mechanical anchoring means, they can be used classic or conventional mineral granules, which is very economic; to further strengthen the union shell-concrete, preferably used granules of the same nature as those of the composition of concrete; the granulometry of the granules of the composition of glue is designed in such a way that the granules emerge partially of the liquid phase of the glue composition After application.

Other advantageous features of procedure according to the invention are set forth in the dependent claims.

In the case that the shell is prepared by electrodeposition, the invention can also present one or more of the following characteristics:

- The shell preparation stage comprises the stages consisting of:

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make a copy or reproduction that presents a surface in correspondence with the default form for the drawing piece,

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become a driver in if necessary, said reproduction surface,

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coat said reproduction surface or, if necessary, said surface conductive, of a metallic layer by electro-deposition to form a shell metallic, then the inner face of the shell corresponding to metallic deposit obtained at the end of the electrodeposition

- Said metallic layer has as basic element nickel, and electrodeposition is carried out in an electrodeposition bath based on nickel sulfamate

- Said metallic layer has as basic element Copper.

- Said copy or reproduction is of material polymer and / or the conductive surface of the reproduction comprises graphite.

The invention also has as its object a hydraulic concrete drawing tool whose surface intended to come into contact with the sheet metal part that it has to be stuffed it is covered, at least partially, with a metal shell attached to the concrete and which is likely to be obtained by the process according to the invention, characterized in that said shell joins the concrete with the help of a glue layer, mechanical anchoring means being inserted into partly in concrete and partly in said glue layer.

Other advantageous features of the drawing tool according to the invention are set forth in the dependent claims.

The invention will be better understood with reading of the description provided in the following, in which the shell is prepared by electro-deposition, having provided this description by way of example no limitative.

The examples that follow this description serve for the purpose of illustrating more accurately, always not limiting and with reference to:

- Figure 1, which is a schematic of the principle of the shear tests of example 1,

- Figures 2 to 4, which correspond to the different stages of manufacturing a drawing tool according to the process according to the invention, as described in example 2: Figure 2: making the copy or reproduction - Figure 3: shell manufacturing - Figure 4: drawing tool according to the invention.

The manufacturing process of a drawing tool according to the invention comprises mainly, therefore, the following stages: preparation of the metal shell, preparation of a concrete casting mold that incorporates this shell, preparation of a concrete composition, preparation and application of a glue composition for the union between concrete and shell, concrete pouring, solidification of concrete and crosslinking or crystallization of the glue, and concrete demoulding.

In order to prepare a metal shell by electrodeposition or electro-shaped, DE 4021384 describes A procedure comprising the steps consisting of:

- make a reproduction that presents a surface corresponding to the predetermined shape of the piece of drawing

- if necessary, make said driver reproduction surface,

- coating said conductive surface with a metal layer formed by electrodeposition, up to form a metal shell,

corresponding therefore the inner face of the shell with the thickness of the metallic layer deposited at the end of the electrodeposition

It is possible to perform a reproduction, by example, by previously trimming a block of soft material and working on it in order to confer with accuracy and Precision desired dimensions.

As a soft material, a organic matrix composite material, prepared, for example, to from a thermosetting resin to which have added charges; if these loads are conductive, it can be obtained a composite material conductive to the electric current.

It is also possible to make a reproduction by molding on a "master model", or pattern, of a resin, a resin concrete or a hydraulic concrete on a "gel coating" ("gel-coat" in English), or any other material compatible with the limitations of electro-shaped; these limitations refer, in particular, at the temperature and chemistry of the bath of electrodeposition, as well as the state of the reproduction surface.

One of the faces of the reproduction must, by therefore, correspond to the default form of the piece of drawing the state of this surface will condition that of the surface of the drawing tool and also the ease of separation between reproduction and shell, carried out usually after concrete pouring; consequently it is particularly important to control this surface state, and certain treatments may prove useful for this purpose surface, such as polishing.

In order to guarantee the geometry of the piece formed by electro-conformation, and, in particular, when the electrolytic deposit is made in a bath at a temperature different from room temperature, should be used for reproduction a material whose expansion coefficient is next to the metal of the shell, or take into account this coefficient in the initial dimensions of reproduction.

In this way, it is usual to make shells of copper in electrodeposition baths at temperature environment, while nickel shells are prepared by electrodeposition at temperatures in general more high, of the order of 55ºC.

If the material used to make the reproduction is not conductive, it should then transform into conductive the face of the reproduction that corresponds to the shape of the drawing piece, so that, when submerging this surface in an electrodeposition bath, either possible to circulate a current of electrodeposition between this surface and a Complementary electrode submerged in the bath.

It is possible to transform the surface into conductive, for example, by applying a layer of conductive paint or by chemical or physical deposition of a material conductor (silver or palladium, for example); preferably the Conductive material comprises graphite.

If the thickness of the deposited layer is too much important in relation to the dimensional tolerances of the tool, it is convenient to carry out a scratch or removal of material from the surface of the reproduction until a depth corresponding to that of the paint layer; the surface quality of the deposited layer is so important such as reproduction, as described previously.

In order to limit the thickness of this layer and to obtain a conductive surface that more faithfully reproduces the of reproduction, it is preferred to proceed by chemical deposition or physics, instead of painted.

The next stage comprises an operation of electrodeposition intended to coat the conductive surface with a metal layer of a suitable thickness to form the metal shell of the drawing tool.

As material of electrodeposition intended to form a shell of drawing tool, nickel or copper can be used, or alloys of these metals, as well as alloys of nickel-cobalt.

The thickness of the metal shell is a function of the shape of the drawing piece, of the characteristics tool concrete and shell metal mechanics, and of the conditions that are foreseen in the use of the tool; so, for example, the complex forms of a drawing piece presenting small radii of curvature are going to cause significant stresses in the shell and require a most important thickness; the thickness that should be given to the shell can be evaluated by methods known to themselves and that will not be described here in detail; this thickness is generally greater than 1 mm

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For electrodeposition, it therefore immerses the conductive surface in a bath of electrodeposition and a current is circulated electrodeposition between this surface and a conjugate or complementary electrode submerged inside the bath.

The conditions of the electrodeposition, such as composition and bath temperature, as well as current density and load electrodeposition, adjust, in a way known by itself, depending on the composition and thickness of the metallic layer to be deposited; this layer deposited form the metal shell of the drawing tool.

Thus, in the case of nickel shells, baths containing mainly are preferably used sulfamate and nickel chloride, as well as boric acid; it's possible add to these baths organic additives intended to improve mechanical properties of the metal shell.

When the deposit of the beginning of the electro-deposition to constitute the surface of Drawing tool work, the conditions of Deposition are particularly important during this phase; in in particular, in the case that the conductivity of the conductive layer of reproduction is small, and / or in order to obtain a homogeneous electrodeposition of good quality and small roughness, it is convenient to apply during this phase a very small current density, well below 1 A / dm 2; to then the current density is increased according to the capacity of authorized work for the bathroom and in accordance with the limits of the permissible internal stresses for the deposited thickness.

Baths containing nickel sulfamate allow to reach high deposition rates, which makes possible decrease in manufacturing costs.

They can be obtained in this way, for densities Average current generally less than 10 A / dm 2, layers Thick nickel metal with a Vickers hardness between 150 and 250 HV, an elastic limit voltage between 250 and 660 MPa, and a breaking limit voltage between 370 and 1,050 MPa.

The addition of cobalt to the bath allows to increase the hardness of the metal obtained; the increase in current density causes, in general, a decrease in hardness.

After electrodeposition, a metal shell is applied on the reproduction by its face called "external", constituting the free surface from the shell the so-called "internal" face of the shell, which corresponds to the thickness of the metallic layer deposited to end of electrodeposition.

In this stage, the shell can be separated from the reproduction; it is preferred, however, to carry out this separation more ahead.

It is then prepared, from elements of molding, a mold for the drawing tool, being used the metal shell as a bottom or mold element, the "internal" face turned into the mold; are arranged other molding elements on the shell contour, in order to form a mold that adapts to the dimensions of the tool drawing to be manufactured; these other elements can look at the reproduction of the shell.

It is then prepared in a way known per se same a hydraulic concrete composition intended for the manufacture of a drawing tool; it's all about of compositions called "BHP", or High Concrete Benefits ("Béton Hautes Performances"), which contain, in addition to the usual components of concrete, to know, a hydraulic binder and granule matter, or granules, pyrolized or calcined silica and a superplasticizer

The granules are constituted, for example, for sand and / or gravel.

For these "BHP" compositions, the kneading water ratio and solidification retraction They are very small.

The complete solidification of these concretes can be obtained by storage at room temperature during minus 28 days; it is also possible to obtain it in an accelerated way by heat treatment.

For these compositions, after complete solidification, concrete whose tension of Breaking limit exceeds 50 MPa at compression and 7 MPa at traction

Preferably, the preparation composition of the concrete used contains reinforcement fibers; these metal fibers allow to limit the propagation of fissures in concrete, which makes it possible to increase its resistance to compression, and, above all, tensile and fatigue, and improve still the capabilities of the drawing tool.

It is prepared and then applied a glue composition on the inner face of the shell metallic, in the bottom or in mold element.

We proceed, for example, in the way described in tests Nos. 4 to 6, or Nos. 13 to 15 of Example 1; according to these tests according to the invention, in order to prepare The glue composition is dispersed in the liquid phase constituted by a conventional tail destined to adhere on concrete, a solid phase intended to form mechanical means of concrete anchor.

Preferably, this tail is made of thermosetting polymers, for example, of type epoxy; these types of tails generally have two components, mixing the organic components just before the application; preferably, this tail is designed to completely crystallize under the solidification conditions of the concrete.

It is convenient to avoid the use of queues based on thermoplastic polymers, since the cohesion between the shell and the concrete of the tool would run the risk of degrading by the heating of the tool in the course of its use to a high cadence, which would seriously impair behavior of this tool

The mechanical anchoring means have at least a dimension that extends perpendicular to the surface of the metal shell in such a way that it exceeds the surface of the liquid phase of the glue composition after its application on this shell, so that, once the concrete, these anchoring means are submerged, in one of their parts, in the glue layer and, in the other part, in the concrete.

As mechanical anchoring means, they can be used:

- isolated elements, such as granules minerals or metal nails mentioned in example 1;

- a "two-dimensional" thread of the type of "serrated or barbed iron wire", or a mesh "three-dimensional", which have separate elements regularly and that extend transversely to the direction general, respectively of the thread or mesh, and at least one end of which is destined to be submerged in the concrete.

The use of granules has an advantage economic and an advantage when it comes to anchoring in the concrete, particularly when these granules are the same nature than those of concrete.

To apply the glue composition, it is it begins, in general, by smearing the inner face of the shell metal with a uniform layer of conventional glue in state fluid, and anchoring means are then applied making them penetrate the glue layer in a fluid state; It is very important that these anchoring means are submerged, in one of its parts, in the glue layer, and that the other part emerges from the free surface of the glue layer so that it can be submerged subsequently by concrete; Once the concrete has been cast, anchoring means must be inserted at the same time in the thickness of the glue layer and in the concrete.

Preferably, the dimension of the means of anchor that extends perpendicular to the surface of the shell or to the surface of the glue layer is greater than the thickness of the applied glue layer.

In the case where elements of isolated anchor, these elements are preferably applied distributing them evenly over and within the layer of tail.

The advantage of using a thread or mesh as anchoring means is that the anchoring elements carried by this thread or this mesh are distributed previously of regular form

You can then proceed to the operation of pouring the concrete composition into the mold.

Before laundry:

- depending on the nature of the tail conventional that is used, in a way known to itself, let the tail partially crystallize;

- if necessary, the arrangement of concrete reinforcement frames, as well as metal inserts, which are then arranged within the mold.

Next, the composition of concrete in the mold, the concrete is vibrated in a fluid state of so that it cakes and increases its density, and is allowed to solidify then this concrete in a way known in itself and appropriate to the composition of the concrete used; in the conditions solidification, the glue composition glue is completely crystallized

After solidification, or at least after the beginning of solidification, when the tail of the glue composition is completely crystallized, can proceed to the demoulding raising, if necessary, the others molding elements, with the exception of the metal shell, which remains united jointly by gluing and anchoring in the concrete.

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When the tail is destined to crystallize completely in the solidification conditions of concrete, not it is necessary to provide an independent stage of crystallization after pouring concrete.

The tail guarantees, therefore, a ligature or chemical bond between the shell and concrete, while the mechanical anchoring means essentially ensure a joint mechanical, since they are submerged, at the same time, in the glue layer crystallized and solidified concrete.

The advantage of using granules as a means of anchor is that the distances between the anchor points are very small, particularly when the average diameter of this matter in granules or granules is particularly small, that is, comprised, for example, between 1.5 and 3 times the thickness of the phase liquid of the glue composition, once its application.

It is also possible to use granules not only of the same nature, but also of the same granulometry than those of the concrete composition, which results more economical.

It is equally convenient, if this has not been done still, separate the reproduction of the metal shell, which leaves exposed the outer surface of the shell that corresponds to the work surface of the tool drawing

Advantageously, when the reproduction is of polymeric material and / or when the conductive layer applied on this Reproduction is made with graphite base material, this separation is facilitated.

In this way a tool of Hydraulic concrete drawing intended for the preparation of drawing pieces with a predetermined shape from parts starting sheet, tool whose surface intended to enter in contact with the sheet metal part to be embedded it is covered, at least partially, with a shell metallic

Tool manufacturing can be completed with a slight styling in order to correct in case necessary the dimensions of the tool, and / or with a treatment of the work surface intended to harden and / or adapt its roughness and / or improve the effect of lubrication in the course of drawing

It is possible to perform on the shell tool metal the same surface treatments as those used in conventional drawing tools cast iron; for heat treatments, it should be monitored that temperatures are not reached that carry the risk of deteriorating the crystallized glue of the glue composition that guarantees the union between the shell and the concrete.

Thanks to the invention, the tool of obtained drawing offers a behavior clearly improved with respect to the same type of prior art, since the union between the shell and the concrete is very resistant, especially in the case of shear or shear stresses; the improvement of the strength of this joint in relation to the prior art It is illustrated in Example 1, which is provided below.

Thanks to the invention, it is possible to manufacture with a reduced cost of drawing tools usable in series or most important chains of manufacturing of drawing pieces, and / or for drawing pieces with more complex shapes, that is, shapes that have small radii of curvature.

The following examples complete the description.

Example 1

This example is intended to illustrate the effect of solid anchoring means added to the tail on the bond strength between the shell of a tool drawing and the concrete that sneaks inside said shell.

In order to evaluate this effect, the shear strength of glue joints applied between a concrete block and a metal plate, in accordance with the protocol defined in the \ NAK1 provided below, for several types of glued joints that are defined in the \ NAK2 that are provide later; The results are listed in \ NAK3.

1. Protocol for measuring shear strength of glue joints applied between a concrete block and a metal plate

The measurement principle is illustrated in the Figure 1.

1.1- Preparation of the assembly of a concrete block 1 and a metal plate 2, which are joined in solidarity with the aid of a glue joint 3 to be characterized.

The metal plate 2 is constituted by a 1.5 mm thick bare steel plate: the plate has been degreased with the help of trichlorethylene.

Once mixed, if necessary, the different components of the tail, one of the faces of plate 2, having adapted the daub mode to the type of queue that is used (see below).

The following apply, where appropriate, the mechanical anchoring means according to the invention (see more ahead); the glue composition then comprises its own glue and mechanical anchoring means.

Assembly preparation differs, therefore, depending on whether it is an "old" concrete assembly or a assembly on "wet" concrete.

1.1.1- Assembly on "old" concrete

From concrete composition No. 1 (without fibers) described in example 2 (Table III), a concrete block 1 with parallel faces; once maintained for at least 28 days in a conservation room, the block that obtains a compressive strength of the order of 55 MPa.

In order to carry out the assembly, it then apply the glued plate 2 on one of the faces of the block 1.

Once dried in suitable conditions for glue used, junction 3 between block 1 and plate 2 remains then secured by the glue composition.

1.1.2- Assembly on "wet" concrete

On the glued face of plate 2, and then of the beginning of the polymerization of the glue (from 1 to 2 hours according to the type of glue used), a concrete block 1 is molded to from an identical concrete composition to the one described in paragraph 1.1.1 provided above.

Once subjected to vibration the composition in the fluid state, the concrete is allowed to take body and dry in the same conditions as described in paragraph 1.1.1 given in the above, that is, that the assembly or assembly is maintained in a conservation room for at least 28 days.

As in paragraph 1.1.1, union 3 between the block 1 and plate 2 is now guaranteed thanks to the composition of glue

1.2- Measurement of shear strength

The measurement of the shear strength of joint 3 of the following way: while maintaining block 1 between a support 4, located under its lower face, and a support 5, located on its face above, a vertical force F is applied to plate 2 (see arrow in Figure 1) and the breaking force F_ {r} of the joint joint 3.

The request for board 3 is therefore essentially shear.

In order to obtain a more accurate evaluation of the shear strength of a joint 3, perform at least three assemblies with the help of the same board of binding and the breaking strength F_ {r1}, F_ {r2} and F_ {r3} of each assembly; the average of the three measures obtained provides a more accurate assessment of resistance to gasket shear 3.

The choice of a steel sheet metal is He explains as follows: trials of break in those that have been taken, such as metal plate, plates electro-shaped under the same conditions as those of the metal shell of the drawing tool according to the invention; it has been observed then that the breakage of the union of the glue joint always occurred in the interface glue concrete; consequently it has been deduced that some measurements made with the help of steel metal plates would provide the same results as those carried out on electro-shaped plates; with the purpose of simplify the tests, therefore, it has been carried out from this time most of the measurements on plates of steel.

2- Types of concrete-metal joint rehearsed

2.1 Nature of the glues used and mode of application for this purpose

Three tails have been tested:

- "Sikadur 31" ®, of the SIKA Society: se it is a two-component epoxy glue, intended for bonding of metals and fresh concrete on old concrete; this tail It can be considered as a resin mortar; this queue is applied with the help of a 2 mm triangular tooth scraper height.

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- "Sikadur Imprégnation" ® ("Sikadur Impregnation "), of the SIKA Society: it is an epoxy tail of two components, fluid and intended for bonding fresh concrete on old concrete and the resumption of concreting; It is a pure resin that is impregnated well in the concrete; this queue is applied With a brush

- "Mybond Epiphen" ®, of the Society LAMBIOTTE: it is a two component and fluid epoxy resin; I know it is a pure resin that is generally used for manufacture of stratified compounds and resin concretes; This glue is applied by gluing in a thickness between 1 and 2 mm, inside a mold whose bottom is the metal plate; Before your application on the plate, it is allowed to partially crystallize during approximately 2 hours, so that a queue of higher viscosity but still fluid enough to Be cast in the mold.

2.2- Preparation of "composite" joints on "wet" concrete

Three types of composite joints have been tested on "wet" concrete, the last two of which correspond to sizing compositions according to the invention:

- Double layer of glue: "Sikadur 31" + "Sikadur Imprégnation": it is applied on the metal plate in first a layer of "Sikadur 31", it is allowed to crystallize this queue partially for about two hours, and, to then it is applied on this partially crystallized layer a layer of "Sikadur Imprégnation" suitable for a good adhesion on porous materials.

- "Sikadur 31" glue + "mineral" joint: the polymerization of the tail being more difficult in a humid environment, the objective is to complete the union through unions mechanics of the same nature as concrete; after the application of the glue layer on the metal plate, and before beginning of polymerization, matter is dispersed in granules or granules on this layer; the average diameter of the granules is widely greater than the thickness of the applied glue layer; rate or coating ratio of the dispersed granules is choose so that the average space between the granules is the same order of magnitude than the average size of the granules; they are made penetrate the granules in the glue layer.

- Queue "Sikadur 31" + "metallic" junction: the polymerization of the tail being more difficult in a humid environment, the objective is to complete the union through unions Metals comparable to concrete reinforcements; once applied the glue layer on the metal plate, and before the start of the polymerization, nails are dispersed on this layer approximately 40 mm in length, such that the head of these nails are submerged in the glue layer, the direction being general of the nails transverse to the surface of the plate; the Coating ratio of the dispersed nails is chosen from such that the minimum space between each nail is greater than minimum diameter of concrete gravel particles.

3. Results of resistance measurements shear of the different joints concrete-metal

The results obtained, as well as the type and location of the break after the test, are presented in the table I that is provided below.

TABLE I Shear strength of the different concrete-metal joints

Type of Union essay nº Breakage stress (kN) Type and location of breakage Sikadur 31 in the interface glue / concrete on concrete 25 11.5 old "old" 26 14.4 idem 27 17.2 idem Sikadur 31 progressive - in the Interface on concrete one 7.9 glue / concrete "damp" two 9.2 idem 3 6.5 idem Sikadur Imprégnation on concrete 22 8.6 in the interface glue / steel "damp" 2. 3 6.3 idem 24 10.1 idem

TABLE I (continued)

Type of Union essay nº Breakage stress (kN) Type and location of breakage Lambiotte Resin on concrete 16 9.4 in the interface glue / steel "damp" 17 13.5 idem 18 10.2 idem Sikadur 31 + Print on concrete "damp" progressive - in the Interface 19 10.6 tail / tail twenty 15.5 idem twenty-one 14.3 idem Sikadur 31 + "mineral" joints on "wet" concrete in the interface glue / steel Y 4 19.2 glue / concrete 5 18.2 in the interface glue / concrete 6 19.4 in the glue / steel interface Sikadur 31 + unions "metallic" on concrete "damp" 13 20.3 in the interface glue / steel 14 22.6 idem fifteen 22.6 idem

The comparison of test results Nos. 1, 2 and 3 with those of tests Nos. 25, 26 and 27 show clearly that a glue applied on “fresh” or “wet” concrete in general it shows a remarkably poorer behavior in terms of shear strength, than the same glue applied on “old” concrete, that is to say “concrete” “set” and dry.

It is precisely an essential purpose of the invention avoid or compensate for this deterioration of qualities.

The behaviors obtained with other queues applied on wet concrete (tests no. 16 to 18 and no. 22 to 24) they may be slightly higher, although they are still insufficient to withstand the strong solicitations between the concrete and the metal shell that are produced in a tool drawing

It is also an object of the invention to propose a concrete-metal joint that resists the shear.

Thus, tests Nos. 4 to 6 and Nos. 13 to 15, of in accordance with the invention, show that the joints composed of according to the invention they resist shear much better than "tail" joints according to the prior art on wet concrete (tests no. 1 to 3 and no. 16 to 24); the invention therefore entails the use of a glue composition that includes mechanical anchoring means, such as granules (tests no. 4 to 6) or metal nails (tests no. 13 to 15).

By using this type of composite joint for manufacture of a concrete drawing tool equipped with a metallic shell, cohesion between the shell and concrete, and, as a consequence, the behavior of the tool.

An advantage of the composite joint according to the invention lies in the reliability of the resistance of this union: the dispersion of the results of the tests carried out on the composite union is indeed much smaller than that of the results of the tests carried out on the glued joint conventional (see Table I); this advantage therefore improves the reliability of drawing tools manufactured according with the invention

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Example 2

This example is intended to illustrate the manufacture of a hydraulic concrete mold according to the invention, referring to Figures 2 to 4.

1.- Making reproduction 6 referring to Figure 2.

A block of material is previously trimmed soft, which is then worked on to give it a way exact and precise of the desired dimensions, and in such a way that a of faces 7 correspond to the default form for drawing piece.

As a soft material, one of the polymeric materials set forth in Table II provided to continuation.

TABLE II Examples of polymeric materials for copying or reproduction

Base polymer: cop- carbonate epoxy -urethane Reference commercial: Lexan® LAB 900 Ren Shape® 540 Characteristics: Society: Axson CIBA Mass per unit volume (g / cm3) 1.2 1.6 1.65 Water absorption at 24h: 0.3% 0.2% 0 Compressive strength (Mpa) 77 120 73 Breaking Elongation (%) 60-100 fifty 90 Flexural elasticity modulus (Gpa) 2.24 4,5 5 Hardness M70-R118 88 Shore D 90 Shore D Temperature of heat resistance (ºC) (Tg: transition vitreous) 120 123 (Tg) 110 (Tg) Thermic dilatation coefficient (/ ºC) 70 • 10-6 55 • 10-6 45 • 10-6 Acid Action weak null - resistant Strong acid action attack slow - attack

The materials described in this Table II they have the following characteristics:

- higher expansion coefficient, but relatively close to nickel (approximately 17 · 10-6) in the temperature range between 20 and 100 ° C,

- density greater than 1 kg / dm 3, in order to facilitate immersion in the bathroom electrodeposition, glass transition temperature Widely higher than the temperature of bathroom use, good resistance to the acidic chemical action of the bath and swelling in Water,

- good malleability or ability to be carved, as a consequence of its mechanical properties (resistance to compression, elongation of breakage, hardness),

- excellent surface condition after styled, particularly with regard to roughness and porosity, which facilitates the separation between the shell and the reproduction.

Once clean of fat, the face is transformed 7 in conductive by application of a very thin layer of a paint conductor containing silver particles: reproduction 6 se it then provides a conductive film 8 on its surface 7; the thickness of the conductive film 8 is of the order of the micrometer.

It is also possible to use a paint that It contains graphite particles, which facilitates the separation between The shell and reproduction.

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2.- Manufacture by electro-deposition of a nickel shell 9 of an approximate thickness of 0.8 mm, referring to Figure 3.

It is then covered by electro-deposition in a bath the conductive film 8 with a layer of nickel, which will constitute the metal shell 9 of the drawing tool.

Bathroom composition of electrodeposition: - boric acid, H_ {BO} {3}: 80 g / l - chloride nickel, NiCl2, 6H2 O: from 5 to 10 g / l - nickel sulfamate, Ni (NH2 SO 3) 2 200 g / l ... from way that is obtained | Ni2 + | = 40 g / l - wetting agent: <1% in weight Conditions of the electrodeposition: - Bath: 4.2 <pH <4.8, and temperature between 50 and 55 ° C, - current density: 0.1 A / dm 2 at the beginning, which is progressively taken to 5 A / dm 2. Mechanical characteristics of nickel obtained: - elastic limit tension (for 0.2%): 485 MPa, - module elastic: 182.5 GPa, - limit voltage of breakage: 840 MPa, - lengthening of break: 8.3% - surface hardness external (in the direction of film 8): 210 Hv - hardness on the inner surface (bottom of mold): 238 HV

The value of tensions has also been evaluated residuals in the thickness of the nickel layer making measurements in layers deposited under the same conditions, but on a sheet of steel.

On this substrate, and contrary to what occurs with the conductive film 8 or with the surface of the reproduction 7, it is known that nickel is strongly adherent; a Once the nickel is deposited, it adheres by gluing on the face without cover a deformation gauge of the sheet, and measure it, with the help of this gauge, the relaxation that appears when they get up by electro-erosion the successive layers of the deposit of nickel.

These measures allow estimating that tensions residuals are between 90 and 150 MPa in traction.

The low magnitude of residual stresses allows to limit the risks of "detachment" or detachment of certain areas of the shell with respect to reproduction in the electrodeposition course or before casting the concrete, which guarantees even better respect for geometric tolerances of the work surface of the tool.

After electrodeposition, a metal shell is thus obtained on reproduction 6 9 presenting a face called "external", in contact with the conductive film 8, and an opposite face, called "internal."

Taking into account the shape of the shell 9 represented in Figure 3, no element has to be added here molding to form the concrete casting mold.

3.- Preparation of the concrete composition

Compositions are prepared with the following constituents:

- hydraulic cement type binder and sand: mortar called Clavex® Lanko 701, from the LAFARGE Society; This mortar has already been formulated with additives that limit the retraction, such as pyrolyzed or calcined silica,

- gravel of granulometry between 3 and 8 mm,

- reinforcing fibers: amorphous foundry fibers which are presented in the form of flexible and very thin strips of dimensions 15 x 1 x 0.03 mm approximately, called Fibralex, of the SEVA Society,

- fluidizer or agent super-plasticizer: called Sikament FF86, from the SIKA Society,

- kneading water.

The granules are formed here, therefore, to from the mortar and gravel sand.

Three different types of composition are prepared by the proportions of these constituents, as indicated in Table III

TABLE III Concrete compositions for a tool drawing

Concrete Fibers Mortar Gravel Water E / C Fluidizer nº one 0 1270 1250 200 0.41 1.35 (0.3%) nº2 36 (0.5%) 1250 1133 200 0.42 4.75 (one%) nº 3 72 (one%) 1500 480 240 0.42 5.7 (one%)

In this Table III, the proportions are identical in mass per unit volume (kg / m 3), and the figures between parentheses indicate:

- in the "Fibers" column, the volume of fibers with respect to the volume of concrete,

- in the "Fluidifier" column, the volume of fluidizer with respect to the cement volume.

The E / C ratio designates the weight of water divided by the weight of cement.

4.- Preparation and application of the glue composition on the inner face of the metal shell 9

In example 1, two types of glue composition: the first one corresponds to the essays 4 to 6, and the second corresponds to essays 13 to fifteen; the glue composition is prepared and applied on the plate metallic 2.

They are used here in the same way, either the first glue composition, either the second, on the metal shell 9, always supported by reproduction 6.

5.- Casting and solidification of the concrete in relation to Figure 4, in the case of using the first glue composition (mineral joints).

Before casting, inserts are placed metallic 10 and 11.

The composition of concrete in the mold formed by the shell 9 supported by the reproduction 6, and then the concrete is vibrated in state fluid with the help of a vibrating rod intended for such effect.

How the shell 9 forms the corresponding mold to the shape of the tool to be manufactured, there is no here other molding elements and there is therefore no subsequent stage of unmolding

Then the concrete is allowed experience the following conditions: storage for 28 days in a constant temperature atmosphere (\21 ° C) and with a constant humidity rate (approximately 95%), while protect fresh concrete surfaces from drying out exposed to the atmosphere.

Specimens or samples thereof are prepared concrete in identical conditions, in order to evaluate the properties mechanical

It is found that the retraction at 30 days is of the order of 0.05 mm / m for the three concrete compositions.

The mechanical properties of the Following way:

- compressive strength \ sigma_ {max.c}: on these specimens of 110 mm in diameter and 220 mm in length;

- tensile strength \ sigma_ {max.t1}: by means of flexural tests (of the "three point" type), with displacement imposed on specimens of dimensions: 70 x 70 x 280 mm;

- tensile strength \ sigma_ {max.t2}: by means of flexural tests (of the "three point" type), with the force imposed on specimens in which it has been practiced previously a notch, and of dimensions: 47 x 70 x 280 mm; these Trials are carried out in one year.

- compression elastic modulus, E_ {c}, and to flexure, E_ {f}.

The results obtained are presented in the Table IV for each concrete composition (according to \ NAK3 previous).

TABLE IV Mechanical properties of Table concretes III

Concrete S_ {max.c} (MPa) S_ {max.t1} (Mpa) S_ {max.t2} (MPa) E_ {c} (GPa) E_ {t} (GPa) nº one 55.5 8.5 9.4 33.6 43.4 nº two 67.5 10.6 11.1 34.5 46.7 nº 3 62.7 17.1 16.4 37.3 45.6

This Table illustrates the reinforcing effect of fibers introduced into the concrete composition.

After casting and solidification, it separates the reproduction 6 of the metallic shell 9 integral with the solidified concrete piece 12, and the tool is obtained from drawing as depicted in Figure 4.

Figure 4 illustrates the joint between the piece of concrete 12 and shell 9, which is guaranteed by the composition of glue comprising crystallized glue 13 and granules 14.

The combination of the chemical bonding effect guaranteed by glue 13 and the mechanical bonding effect guaranteed by granules 14 it allows to achieve a very strong cohesion between the shell 9 and the concrete piece.

The inserts and the surface part of the tool that is concrete are worked in order to get the dimensions and centering desired; the shell 9 electro-shaped does not need any treatment particular before using the tool under the press of drawing

In this way a tool of drawing with a particularly good behavior, which resists very good wear and allows large series of parts of quality drawing.

A complete study on friction in the drawing and, in particular, on the effect of nickel as tool surface material showed that they were obtained particularly equivalent friction conditions with a surface material of the steel tool and with a material nickel tool surface electro-shaped; on a sheet of steel that it was simply coated with a lubrication film of Temporary corrosion protection, the coefficient of Friction was estimated at approximately 0.22.

The drawing tools obtained were tested in an industrial press and have proved satisfactory in conventional drawing conditions; the essays have revealed that the same tool is capable of performing several Hundreds of thousands of stuffings.

Claims (16)

1. A manufacturing procedure for a hydraulic concrete drawing tool (12) intended for preparation of drawing pieces with a predetermined way to starting from sheet metal parts, the surface of the tool intended to come into contact with the starting piece of sheet metal to be embedded covered, at least partially, with a metal shell (9), and the process comprising the stages consisting of: - preparing said metal shell (9) of such so that it presents a face called "external", which corresponds to the default form of the drawing piece, and an opposite face, called "internal", - prepare a mold for the tool drawing taking said shell (9) as a bottom or mold element, arranging the inner face turned towards the inside of the mold, - cast into said mold a composition of preparation of said concrete comprising matter in granules or granules, - solidify said composition, characterized in that, prior to the casting stage, a glue composition comprising a liquid glue phase and a solid phase intended to constitute mechanical anchoring means (14) is applied to the concrete on said inner face. 2. A method according to claim 1, characterized in that said solid phase of the glue composition is constituted by granules or granules. 3. A process according to claim 2, characterized in that the granules of the glue composition are of the same nature as those of the concrete composition. 4. A method according to any one of the preceding claims, characterized in that the dimension of said anchoring means (14) extending perpendicularly to the surface of the shell (9) is greater than the thickness of the liquid phase ( 13) of the glue composition applied. 5. A method according to any one of the preceding claims, characterized in that, in order to apply said glue composition, the liquid phase (13) of the glue composition is applied first, and said means of application are then applied anchor (14) causing them to partially penetrate said liquid phase (13). A method according to claim 5, characterized in that the anchoring means (14) are applied such that they partially emerge from the free surface of said liquid phase (13). 7. A process according to any one of the preceding claims, characterized in that the liquid phase (13) of the glue composition is thermosetting under the solidification conditions of said concrete composition. A method according to any one of the preceding claims, characterized in that said concrete preparation composition contains reinforcing fibers. 9. A manufacturing process according to any one of the preceding claims, characterized in that said shell (9) is prepared by electrodeposition. 10. A method according to claim 9, characterized in that said shell preparation comprises the steps consisting of: - make a copy or reproduction (6) that it has a surface (7) that corresponds to the shape default for the drawing piece, - if necessary, make said driver surface (7) of reproduction (6), - covering said surface (7) or, in case necessary, said conductive surface (8), with a metallic layer deposited by electrodeposition, until forming a metal shell (9), corresponding then the inner face of the shell (9) to the metal deposit at the end of the electrodeposition 11. A method according to any one of claims 9 to 10, characterized in that said metal layer is made of nickel base material and that said electrodeposition is performed in an electrodeposition bath containing essentially sulfamate of nickel. 12. A process according to any one of claims 9 to 10, characterized in that said metal layer is made of copper base material. 13. A process according to any one of claims 9 to 12, characterized in that said reproduction (6) is made of polymeric material. 14. A hydraulic concrete drawing tool whose surface intended to come into contact with the sheet metal part to be embedded is coated, at least partially, with a metal shell (9) that joins the concrete (12) and that it is capable of being obtained by the method according to any one of the preceding claims, characterized in that said shell (9) is joined to the concrete (12) with the help of a glue layer, and mechanical anchoring means are inserted (14) partly in concrete (12) and partly in said glue layer. 15. A tool according to claim 14, characterized in that the mechanical anchoring means (14) consist of material in granules or granules. 16. A tool according to claim 15, characterized in that said granules are of the same nature as those of concrete.