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SDP-Tools Technical Description

This volumetric metal nanocomposite material is created on the basis of a steel (HSS) metal matrix. The flow of dust-like particles are used to reinforce the matrix. The creation of a composite material is executed in a dynamic condition through the insertion of a matrix of high-strength fibers. The new material possesses a unique complex of mechanical properties and can be used for cutting metals and in the mining industry.

Introduction

As a basis for deriving many composite materials, for example polymeric, the technique of inserting high-strength fibers is utilized. This type of structure allows the creation of composite materials with anisotropic physical and mechanical properties. The important advantage of such a technique is its productivity and corresponding low cost.

Traditionally, the manufacture of metal volumetric composite materials has been based on other scientific and technological methods such as powder metallurgy. These types of manufacturing, however, involve significant energy expenditures and high processing costs.

The use of techniques which involve the insertion of metals and alloys into a solid state such as a solid metal body has been considered ineffective for a long time. However, the recent rapid development of high density energy and impulse process physics has produced a series of new fundamental results and unusual application possibilities.

For example, based on the physical phenomenon of “superdeep penetration” (SDP) of powder clots in the volume of a solid body, a corresponding reduction of the size of elements within the structure of the material was achieved making it possible to solve engineering questions regarding insertion within metal bodies [1]. On the basis of these physical effects, metal matrix composite materials can be created. Penetration of powder particles in depths of tens to hundreds of millimeters within solid metal bodies occurs within an impulse regime. The conditions involved in manufacturing fibers allows for the synthesis of materials simultaneously with the insertion process – the existence and properties of which were previously very poorly known [2].

Such composite materials can be developed based on the matrixes of known tool steels. The study of structural features and properties of new tool materials represents an important scientific and practical task.

The purpose of the given research activity is the study of new tool materials in the matrix of tool steel (HSS).

New Tool Material Features

The development of volumetric composite materials presents a difficult practical problem. The variance in properties between a metal matrix and reinforcing fibers demands, as a rule, complex and expensive additional processing of composite material. Because of these additional increases in processing costs its use becomes restrictive. In the new approach to creating composite materials the physical phenomenon of superdeep penetration is necessary. The phenomenon of superdeep penetration allows clots of powder particles to enter into the volume of a steel matrix (steel HSS) in current of 10-4-10-5 sec. and within depths of 0,1 - 0,2 m. The resulting structure of the tool material after processing is presented in figure 1.

Particles of powder (Al2O3) have weaved a steel matrix within a depth of 0,15 m. Particles move within steel through the path of least resistance. Therefore the trajectory in which particles are moved does not coincide with the plane of each section. In the cross-section, due to etching, it is possible to determine zones of the insertion (figure 2). The portion of ceramic particles (≤30%) continues onto a lateral area, shaping reinforcement in an orthogonally related direction.


The process of superdeep penetration of ceramic particles in steel occurs with large-scale conditions of energy coherence operating through impulses within narrow zones inside of the steel matrix.

Due to the intensive strain of the material, these zones experience irradiation from flows of high energy ions and simultaneous specific chemical interaction between matrix material and particle material. The process of synthesis for reinforcing material cannot be forecast on known dependences. It is possible to use the fibers for new metastable materials with unusual properties. Such materials are thermally steady within the conditions of the subsequent thermal treatment. The material structure of the fibers and closely located stratums of matrix material (zone of influence) is crushed and possesses high mechanical properties. The volume of newly-built material in the composite material is less than 1 %, but the share of the zones of influence can reach up to 10 volumetric %. Thus composite steel is similar to other typical composite materials.

Depending on the processing conditions of the matrix material, from the composition of the matrix to the substances within the matrix, the heat treatment operation of the tool material will vary. One feature of composite tool steel is its good workability after impulse action within the conditions of superdeep penetration. Strengthening of this material is accomplished only after final heat treatment. The overlapping processes of SDP, mechanical and heat treatment creates wide ranging changes in the mechanical properties of this material. Properties of the SDP tool materials fall between typical tool steels and a hard alloy. They yield to hard alloys on resistance wear. However, they have higher durability at impact and greater durability at curving [1].

Composite Tool Steel Application Areas

Metal composite materials developed through the insertion method have been used for metal-cutting and mining cutting instruments. Composite tool steels can be successfully substituted for matrix analogs in all conditions. Substitution of hard alloy with composite tool steel is expedient when working with instruments in conditions of high dynamic and thermal loadings. In these conditions flaws in the hard alloy causes it to fail whereas  composite steel can successfully withstands the load. At any area of application of a new tool material it is necessary to pay attention to anisotropy. Composite tool steel, as well as other composite materials, have strongly pronounced anisotropic mechanical properties. Depending on processing conditions the anisotropy resulted in the following: resistance wear in 1,5-2 times, impact strength of 20 % and a beam strength of 40-60 %. In order to optimize the operational properties of instruments it is necessary to change the method of constructing the instruments due to the anisotropic mechanical properties of the composite material. For example, hard alloy (on the basis of WC and Co) has been successfully substituted on tool composite steel (matrix HSS) on a mining instrument used for cutting potash ore in Italy. Thus designers were able to diminish the diameter of a cutting insertion by 30 % and  augment its length by two times. The operational resistance of such mining instruments have increased 1,6 times. This substitution of a hard alloy on a composite material is one of very few  successful variants of refusal of this cancerogenic material substituted for matrix analogs in all conditions. Substitution of hard alloy with composite tool steel is expedient when working with instruments in conditions of high dynamic and thermal loadings. In these conditions flaws in the hard alloy causes it to fail whereas composite steel can successfully withstands the load. At any area of application of a new tool material it is necessary to pay attention to anisotropy. Composite tool steel, as well as other composite materials, have strongly pronounced anisotropic mechanical properties.

Dynamic loads created by catastrophic destruction of hard alloy, due to its flaws, lead to the accelerated deterioration of costly equipment and aggravate operating conditions for personnel. The use of a new composite material, however, will allow for essential increases in the operational resistance of instruments and improved equipment efficiency.

Conclusion

Based on the use of new fundamental physical effects, a high-efficiency technique for developing tool composite steel has been created. This new class of composite tool materials utilizes a matrix of steel (HSS). These materials will find wide application for metal-cutting and mining cutting instruments in modern machine and mining industries.

1.S.Usherenko  The phenomenon of superdeep penetration. // Scientific Israel- technological advantages.2006. Vol.8, Issues 1.2 -P.83-94.
2. S.Usherenko  Oleg L. Figovsky, Yu. Usherenko: Receiving of nanomaterials in volume of metals and alloys in a`mode of superdeep penetration. Book of abstracts of First International Conference RAR-2006, Voronezh, Russia, November 9-10, 2006. pp. 73-77.