EP1651389B1 - Composite tool for percussive and/or abrasive strains - Google Patents

Abstract

The main body (2) is a highly-ductile impact-hardened steel alloy. Cast into it, held by interlocking only, the molding (3) is located in the impact region. It is a prefabricated, solid, highly wear-resistant metal alloy differing from that of the body.

Description

The invention relates to a composite tool for beating loads. Such tools are used for example for crushing metal, rock or demolition materials. The tools are subjected to extreme loads both in the area of their surfaces which come into direct contact with the material to be comminuted and in the area in which they are held in the respective comminution machine.

Known from practice and in the DE 28 29 847 A1 are described in use beating and / or abrasive loaded tools that are designed as a so-called "monoblock". Simple embodiments of these block-like tools consisting of a single metal material generally have a uniform hardness over their cross section and their length. On the other hand, monoblock tools better adapted to the loads occurring in each case usually have at least two zones of different hardness, of which the harder is subjected to the direct impact load, while in the region of the tougher, less hard zone the clamping of the tool is carried out in the respective machine ,

A disadvantage of the above-explained monobloc simple tools is that they have a consistently low base hardness or are made of impact-hardening materials. They point in usually a too low wear resistance. In contrast, still differentiated, over several sections differently hardened monobloc tools, however, there is often the risk of breakage in the zones, which have a particularly high hardness and, consequently, a low ductility.

Attempts have been made to eliminate the disadvantages of monobloc tools by using tools made of materials with different mechanical and technological properties. The wear-resistant, the high mechanical impact loads receiving molded parts are clamped by mechanical aids in the respective body. In practical use, however, it can be seen that the mechanical connections between the elements coupled to one another are susceptible to fatigue as a result of the high loads occurring during operation.

Also tools for impact loads are known, which have been produced by composite casting. In these tools, the seal-resistant molded body is usually held by a material connection in the material of the body. A disadvantage of these tools, however, the high cost of their production, resulting from a high cost of material and complex process control. In addition, there is a constant risk of breakage of the metallic connection between the wear-resistant molded element and the base body during operation. Tools of this kind are for example from the DE-PS 592 580 known.

There are also known composite tools in which a sponge-like, porous trained insert made of metal or a ceramic can be cast in the material of the body. In the course of pouring the main body material penetrates into the opening and cavities of the insert, so that there is an intensive clamping of the base body with the inlay. However, a problem with the use of tools produced in this way is that the brittleness of the metal oxides used as the material for the inlay material has a disadvantageous effect on the application behavior of the tools in certain applications.

Finally, out of the US 5,238,046 a composite tool according to the preamble of claim 1, in which the base body is connected to the molded body via substantially exclusively positively, in that the molded body has a constriction. However, such constrictions are weak points that adversely affect the durability of the composite tool.

Based on the above-described prior art, the present invention seeks to provide a composite tool of the type described above, which has a high wear resistance while minimizing the risk of tool breakage and in which the molded body is securely held in the body over a long period of operation ,

This object is achieved according to the invention by a composite tool for impacting and / or abrasive loads, which is cast by a base body made of a highly ductile, schlaghärtenden iron-based alloy and at least one cast into the body, with the greatest possible exclusion of a cohesive connection form-fitting held shaped body is formed, which is arranged in the beating load directly exposed area of the composite tool and prefabricated from a deviating from the iron material of the body, highly wear-resistant metal material as a solid body, wherein the molded body starting from a base surface in the direction of his the base surface opposite end face has tapered shape and wherein the end face is assigned to the beating load directly exposed area of the composite tool.

Such a shape is given, for example, when the shaped body has the basic shape of a truncated pyramid. In such a substantially conically tapering from the base to the end face shape is ensured in a simple manner that the molded body is held securely in the base body even after a long period of operation.

The composite tool according to the invention essentially consists of a base body which is produced from a cast, highly ductile material. In the striking during operation and / or abrasive zone of this body a molded body is placed, which is made of a high-strength, also metallic, preferably iron-based alloy. The shape of the shaped body is chosen such that the shaped body is securely held positively in the surrounding material of the base body. At the same time, the materials of the base body and the molded body are matched to one another in such a way that there is no significant cohesive connection between the molded body and the base body. Nor is it according to the invention intended; that the shaped body is held by additional mechanically acting aids in the base body.

With the invention, a universally usable in crushing machines, particularly easy to produce composite tool is available, which has a high wear resistance in its exposed primary wear work zone by the molded body arranged there and at the same time has a significantly reduced fracture sensitivity. Since the high impact or abrasive loads are absorbed by the body made of hard, wear-resistant material, the material of the body and applied during its processing heat treatments can be aligned regardless of the loads occurring in practical operation to the highest possible ductility of the body.

The heat treatment used in the production of composite tools according to the invention provides that the heat transfer during the manufacturing process takes into account the necessary parameters for the two materials to be combined. The aim is to produce the highest possible ductility in the main body and the highest possible hardness in the molded body. This is achieved by a treatment in the high temperature range of 950 - 1100 ° C. Then there is a broken liquid hardening in the range of 350-600 ° C, which in turn followed by a cooling in air and a subsequent relaxation at temperatures of 300 - 400 ° C.

Another essential advantage of the invention is that the molding can be prefabricated in any desired, cost-effective manner. Thus, for example, the molded body cast into the composite tool according to the invention can be a forged part, a stamped part, a cut part, a fired part, a sintered part or a cast piece. In this case, the stamped part, fired or cut part can be made of a flat material.

According to the invention, the selection of the materials used for the main body and the molded body ensures that the specific mechanical-technological properties of both materials, namely on the one hand high-sealing strength for the molding and the other highly ductile for the body, both during the manufacturing process itself and in practical use stay. As a material suitable for the production of the basic body, which fulfills these requirements, an iron alloy which (in wt .-%) 8.0 - 22.0% Mn, 0.2 - 2.8% Cr, 0.5 1.5% C and balance Fe and unavoidable impurities. In contrast, an iron alloy which enables a high hardness of the molding contains (in% by weight) 6.0-16.0% Cr, 0.3-1.5% Mo, 0.3-1.4% W, 0.6 - 2.2% C and balance Fe and unavoidable impurities. Supported by a heat treatment adapted to the respective material compositions, these alloys can be used to produce particularly durable, robust composite tools which withstand even the toughest loads over the respective required service life. In this case, the materials of the base body and the molded body can be coordinated with one another within the alloy specified according to the invention be that the shaped body during and as a result of the use stress is permanently clamped in the composite tool.

Another embodiment of the invention which is particularly favorable in terms of increasing the wear resistance and minimizing the risk of tool breakage is characterized in that in the region in which the iron material of the base material laterally surrounds the shaped body, the ratio of the mean measured in a first axis Strength of the base material for measured on the same axis average thickness of the cast molded body is 0.2 to 1.0. Taking into account this range of strength ratios, a high degree of safety against breakage is ensured even in the case of heavily varying loads in the area of the clamping and bearing zone of the composite tool.

The production of a composite tool according to the invention is carried out deliberately so that there is no significant metallic bond between the molding and the body surrounding it at least partially. In order to ensure the permanent connection between the base body and the molded body, the molded body is rather designed so that the molded body is embedded in a form-fitting manner in the material of the base body.

The form-fitting hold of the shaped body can also be achieved by forming depressions in the side surfaces of the shaped body. Alternatively or additionally, elevations may be formed on the side surfaces of the molded body for the same purpose.

The invention will be explained in more detail with reference to an exemplary embodiments illustrative drawing. Fig. 1 to 4 each show a composite tool in perspective view.

The composite tools 1, 11, 21, 31 shown in the figures each have a cuboid base body 2, which is cast from a highly ductile iron material. The base body 2 is starting from its one narrow end face 2a in a practical use the direct contact with the material to be crushed, extending over about one third of the total length L of the base body 2 working section 2b, a subsequent to the working section 2b clamping section 2c, on which mounted composite tool 1, 11, 21, 31, the clamping device, not shown, a crusher also not shown, and a subsequent to the chucking section 2c bearing portion 2d divided, on which the composite tool 1 in the mounted position in the crusher is supported.

When in Fig. 1 shown composite tool 1 is poured into the working portion of the base body 2 of a high-strength, hard iron material mass-produced molded body 3. The molded body 3 has a hexagonal base 3a with two opposite long sides, which are connected at their ends in each case by two under a blunt, open in the direction of the inner surface open angle meeting each other short sides. Starting from the base surface 3a shaped in this way, the molded body 3 tapers in the direction of the end face 2a of the main body 2.

In this way, a shape of the molded body 3 tapering from the base 3 a in the direction of the end face 2 a of the base body 2 3 is associated. The thus shaped molded body 3 is completely surrounded in the new state of the composite tool 1 laterally and in the region of its base 3a of the material of the base body 2. The average thickness d _G1 of the body 2 laterally surrounding the shaped body 3 in the thickness direction in a direction parallel to the end face 2 a in the direction of the wider side faces of the base body 2 and perpendicular to the measuring axis X is selected such that the ratio the average thickness d _G1 for measured in the same measuring axis X mean thickness d _{F1 of} the molded body 3 is about 0.3. Similarly, the spectrum measured in a transversely oriented to the measurement axis X measuring axis Y thickness d _G2 is the 3 laterally surrounding widthwise wall 2e of the body 2 are chosen the shaped body so that the ratio of the mean thickness d of _G2 to the measured in the same measurement axis Y average thickness d _{F2 of} the molding 3 is about 0.2.

By this dimensioning of the mold body 3 laterally surrounding walls 2e, 2f of the base body 2 in combination with the conically tapering in the direction of its end face 3b shape of the molded body 3 ensures that the molded body 3 safely even under high impact loads occurring in practice the composite tool 1 is held. The coordination of the materials of the molded body 3 and body 2 not only supports the firm grip of the molded body 3 in the base body 2, but above all ensures that the risk of breakage of the composite tool 1 in the region of the clamping section 2c or the bearing section 2d is reduced to a minimum.

In the working section 2b of the main body 2 of the in Fig. 2 Composite tool 11 shown is also molded from a high-hardness iron material massively manufactured molded body 13. Unlike the composite tool 1, the material of the main body 2 completely surrounds the shaped body 3 in the new state of the composite tool 11.

Again, according to the in Fig. 1 Shaped body 3 shown, the molded body 13 of the composite tool 11 has a starting from its base 13a in the direction of its end face 2a of the body 2 associated end face 13b tapered shape. The base surface 13a and accordingly the end face 13b of the molded body 13 are also hexagonal, wherein the surfaces 13a, 13b are bounded in this case by two short, mutually parallel opposite sides, each blunt by two, to the respective surface 13a, 13b , open angles are juxtaposed on longer sides.

In the case of the composite tool 11 as well, the substantially conical shape starting from the base surface 13a, the shaping of the solid shaped body 13 and the embedding of the molded body 13 in the material of the base body 12 ensure that the molded body 13 is safe even after a long service life held in the base body 2 and capable of acting on the composite tool 11 directly striking beating load just as safely record.

When in Fig. 3 shown composite tool 21 is in turn cast in the working section 2 b of the base body 2, a generated from a hard metal material, solidly formed moldings 23. As with the composite tool 11, the material of the main body 2 completely surrounds the shaped body 23 when new.

The molded body 23 has a truncated pyramid-shaped, four side surfaces 23c, 23d, 23e, 23f having basic shape whose base 23a is greater than its the end face 2a of the base body 2 associated end face 23b. In two of the opposite side surfaces 23c, 23d of the molded body 23 are formed at regular intervals, extending over the length of the molded body 23 channel-like recesses 23g formed while on the other two opposite side surfaces 23e, 23f in an irregular arrangement knob-like projections 23h are formed , The recesses 23g and the projections 23h, in combination with the conically tapering shape of the molded body 23 starting from the base surface 23a in the direction of the end face 23b, support its secure, form-fitting hold in the material of the base body 2. The composition of the iron material of the base body 2 is the same tuned to the composition of the iron material from which the molded body 23 is made, that the molded body 23 is additionally retained in the base body 2 in a force-locking manner after the completion of the composite tool 21 as a result of the different thermal expansion behavior of the two materials.

When in Fig. 4 Finally, three composite molds 31 ', 33 "and 33''each made of a wear-resistant, hard iron material are produced as massive bodies. The shaped bodies 33 ', 33 ", 33"' are each designed in the shape of a truncated pyramid and, starting from their rectangular base 33a in the direction of the end face 2a of the base body 2 of the composite tool 31, taper conically and in the new state flush with this aligned end face 33b. The length of the molded body 33 "disposed between the two outer molded bodies 33 ', 33"' is about half the length of the two other molded bodies 33 'and 33 "'. The molded bodies 33 ', 33" and 33 "' are included arranged at a distance such that both the ratio of the measured in the direction of the measuring axis X average thickness d _G1 of the mold bodies 33 ', 33 "and 33"' in the thickness direction surrounding material of the base body 2 measured in the same measuring axis X average thickness d _F1 the shape of the body 33 ', 33 ", 33"' and the ratio of measured in the direction of the measuring axis Y average thickness d _G2 of the mold body 33 ', 33 "and 33"' respectively in the width direction surrounding material of the base body 2 in the same measuring axis Y measured average thickness d _{F2 of} the shaped bodies 33 ', 33 ", 33"' is in the range of 0.2 to 1.0. As already mentioned in connection with FIG Fig. 1 illustrated composite tool 1 illustrated, is through this to the thickness d _F1, d _F2 of the molding 33 ', 33 ", 33"' related adjustment of the wall thickness d _G1 or d _G2 ensures that hard under the occurring in practical use Loads of the molded body 33 ', 333', 33 "'' are held in a ductile iron material of the base body 2 in the composite tool 31 in a manner that is sufficiently elastic for a permanently secure grip.

An important advantage of in Fig. 4 shown composite tool 31 is that with the introduction of a plurality of harder molded body 33 ', 33 ", 33"' in the highly ductile base body 2 by the present between the individual moldings 33 ', 33 ", 33"' ductile base material fracture risk in practical use is substantially minimized. The different length of the molded bodies 33 ', 33 ", 33"' takes into account the limitation of the desired increased wear resistance on zones of the main wear stress.

REFERENCE NUMBERS

1,11,21,31

Composite Tools

2

body

2a

narrow face of the body 2

L

Total length of the main body 2

2 B

Working section of the main body 2

2c

Clamping section of the main body 2

2d

Bearing portion of the body 2

3,13,23,33 ', 33 ", 33"'

moldings

3a, 13a, 33a

Base surface of the respective molded body 3, 13, 23, 33 ', 33 ", 33"'

3b, 13b, 33b

End face of the respective shaped body 3, 13

d _G1 , d _G2 , d _F1 , d _F2

average thickness of the mold body 3 laterally surrounding wall 2e

2e

Walls 2e of the main body 2

23c, 23d, 23e, 23f

Side surfaces of the molded body 23

23g

channel-like depressions

23h

projections

X, Y

measuring axes

Claims (7)

1. Composite tool for percussive and/or abrasive strains, having a base body (2) made of a highly ductile impact-hardening iron-based alloy, and at least one shaped body (3, 13, 23, 33', 33", 33"'), cast into the base body (2) and retained in the base body (2) by positive fit, excluding metallurgical joining as far as possible, which shaped body (3, 13, 23, 33', 33", 33"') is arranged in the area of the composite tool (1, 11, 21, 31) which is directly subjected to the percussive strain, and is prefabricated as a solid body from a highly wear-resistant metal material which deviates from the iron material of the base body (2), characterised in that the shaped body (3, 13, 23, 33', 33", 33"') has a shape which tapers from a base surface (3a, 13a, 33a) in the direction of its face surface (3b, 13b, 33b) located opposite the base surface (3a, 13a, 33a), and in that the face surface (3b, 13b, 33b) is allocated to the area (2a) of the composite tool (1, 11, 21, 31) which is directly subjected to the percussive strain.
2. Composite tool according to Claim 1, characterised in that the iron alloy of the base body (2) contains (as % by weight): Mn: 8.0 - 22.0 % Cr: 0.2 - 2.8 % C: 0.5 - 1.5 % and the remainder being Fe and unavoidable impurities.
3. Composite tool according to one of the preceding claims, characterised in that the metal material of the shaped body (3, 13, 23, 33', 33", 33"') contains (as % by weight) : Cr: 6.0 - 16.0 % Mo: 0.3 - 1.5 % W: 0.3 - 1.4 % C: 0.6 - 2.2 % and the remainder being Fe and unavoidable impurities.
4. Composite tool according to one of the preceding claims, characterised in that, in the area in which the iron material of the base body (2) surrounds the shaped body (3, 13, 23, 33', 33", 33"') laterally, the ratio of the mean thickness (d_G1, d_G2) of the basic material, measured in a measurement axis (X, Y), to the respective mean thickness (d_F1, d_F2) of the shaped body (3, 13, 23, 33', 33", 33"'), measured in the same measurement axis (X, Y), amounts to 0.2 to 1.0.
5. Composite tool according to one of the preceding claims, characterised in that the shaped body (3, 13, 23, 33', 33", 33"') has the shape of a truncated pyramid.
6. Composite tool according to one of the preceding claims, characterised in that indentations are formed into the side surfaces (23c, 23d, 23e, 23f) of the shaped body (23).
7. Composite tool according to one of the preceding claims, characterised in that elevations (23h) are formed into the side surfaces (23e, 23f) of the shaped body (23h).

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