RU2530600C1 - Two-radius testing roller - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: roller comprises two deforming elements with the profile radius of 0.5-5 mm set with a shift in radial direction in respect to each other by the value of 0.01-0.1 mm both to the roller axis and from it. The distance between the tips of the deforming elements along the roller axis amounts to $$\mathrm{0,6}\dots 1\cdot \left(\frac{R_{pr1}+R_{pr2}}{2}\right),$$

where R_pr1 stands for the profile radius of the first deforming element, R_pr2 - profile radius of the second deforming element.

EFFECT: expanded process functionality.

3 dwg

Description

The invention relates to a technology for the processing of metals by pressure, in particular to hardening processing of machine parts by surface plastic deformation (PPD) by rolling rollers.

Known designs obkatnyh rollers torus form for the implementation of PPD (GOST 16344-70. Rollers obkatnye. Design and dimensions).

All these rollers have a profile of the working surface, made in the form of a radius of constant magnitude - the profile radius of the roller (R _CR ).

GOST 16344-70 torus shaped rollers are manufactured with _straight R value of 1.6 to 16 mm.

In the process of processing the PPD, the roller with the working part is pressed against the surface of the part with some force P (according to the elastic processing scheme) or with some interference h _d (according to the rigid processing scheme). The rotation (n _p ) of the roller is communicated by rotating the part n. The roller moves along the axis of the part with a certain supply S, as a result of which a wave of plastically deformed metal is formed in front of it (Fig. 1).

When introducing a roller in the contact zone, an asymmetric deformation center (OD) ABCDEFG arises, characterized by a front non-contact surface of a plastic wave (ABC), a contact surface (CDE), and a rear non-contact surface (EF). The geometric dimensions and curvature of the surfaces of the OD are determined by the properties of the processed material, as well as the parameters of the processing mode (figure 2).

Due to deformation, the metal particles in the OD move along some streamlines (LT), forming a hardened layer of a certain thickness (figure 2). The initial parameters of the mechanical state of the metal, which the particles had before entering the OD, are transformed into those accumulated by the moment of exit.

In the process of moving along the LT, metal particles experience a continuously changing stress state, which together can be described by the value of hydrostatic pressure (the average normal stress value taken with the opposite sign). In this case, there is a continuous accumulation of deformation and the depletion of the plasticity reserve by metal particles, which are estimated respectively by the degree of shear deformation Λ and the degree of depletion of the plasticity reserve Ψ.

As a result of processing, a surface layer is formed, evaluated by a set of quality parameters, the key of which when processing PPD are:

- degree of hardening, (%);

- hardening depth, (mm);

- gradient hardening, (MPa / mm).

The design of the rollers according to GOST 16344-70 allows, depending on the initial properties of the metal of the part, the conditions and technological modes of processing the PPD, to obtain a surface layer (PS) with certain parameters of the mechanical state of the metal.

The desire to increase the quality parameters of PS leads to the need to intensify the process of PPD through a change in processing modes and thus increase the volume of OD. However, it is known that, for example, the value of the permissible actual introduction of rollers according to GOST 16344-70 for PPD, depending on the properties of the metal being processed, does not exceed 0.05-0.15 mm - in this regard, PPD methods have a limit, primarily due to the plastic properties of the processed metal.

When these values are exceeded, the margin of plasticity is completely exhausted and the metal is destroyed in the region of the apex of the plastic wave (point C in Fig. 2) and, as a result, the treated surface.

Thus, the available range of variation of the parameters of the mechanical state of the substrates achieved during processing of PPD is limited by both the initial properties of the metal of the part and the permissible range of variation of the technological parameters of the processing mode, which also includes the shape of the profile of the rolling roller.

So, for example, for processing the PPD of a billet made of steel 45 in the state of delivery by rollers according to GOST 16344-70, the highest degree of hardening achievable without destruction of the PS is 30-40%, the maximum depth of hardening is 3-4 mm, depending on the processing conditions .

From the presented example it follows that the disadvantage of the obkatnyh rollers of known design is the unattainability of large in size parameters of the mechanical condition of the PS, for example, the degree of hardening of 45-50% without destruction of the PS part.

The technical result of the invention is to expand the processing capabilities of PPD and the range of achievable parameters of the mechanical state of the metal PS through the use of a deforming roller with a special profile profile of the working surface.

The device of the roll-in double-radius roller for surface plastic deformation of the inner and outer cylindrical surfaces is characterized in that:

1. The profile of the working surface consists of two deforming elements made in the form of radii of constant magnitude.

2. The deforming elements are located relative to each other with a shift in the radial direction by a value of 0.01 ... 0.1 mm both to the axis of the roller and from it.

.3. The distance between the vertices of the deforming elements along the axis of the roller is $$0.6...\mathrm{one}\cdot \left(\frac{R_{PR\mathrm{one}}+{\mathrm{<figure-callout\; id="2"\; label="R\; P\; R"\; filenames="00000008.png"\; state="\{\{state\}\}">R\; </figure-callout>}}_{PR}}{2}\right)$$

.

The technical result of the claimed invention is achieved in that the profile shape of the working surface of the roller is a combination of two deforming elements in the form of a radius of a constant value located at a small distance relative to each other with a shift in the radial direction of 0.01 ... 0.1 mm

, The distance between the vertices of the deforming elements along the axis of the roller is $$0.6...\mathrm{one}\cdot \left(\frac{R_{PR\mathrm{one}}+{\mathrm{<figure-callout\; id="2"\; label="R\; P\; R"\; filenames="00000008.png"\; state="\{\{state\}\}">R\; </figure-callout>}}_{PR}}{2}\right)$$

,

where R _CR1 - the profile radius of the first deforming element;

R _CR2 is the profile radius of the second deforming element.

The invention is illustrated by drawings, in which Fig. 1 shows the process of processing PPD by a roller taken as a prototype, Fig. 2 shows the occurrence of a deformation zone when processing a PPD by a roller taken as a prototype, and Fig. 3 shows a construction of a rolling double-radial roller.

A two-radius obkatny roller moves along the axis of the part with a certain feed S.

The deforming element (DE), the first to come into contact with the original (untreated) surface layer 3 of part 2, has a certain profile radius R _pr1 = 0.5 ... 5 mm and moves relative to the surface layer 3 with some interference g _d1 = 0.01 ... 0.1 mm As a result, there arises an OD in the shape and size of a prototype roller typical of RPM.

The second deforming element also has a certain profile radius R _pr2 = 0.5 ... 5 mm and a radial displacement relative to the 1st element in the direction from the axis of the roller by a certain amount within Δ ₁₂ = 0.01 ... 0.1 mm. Thus, the interference of the 2nd element relative to the surface is h _d2 = h _d1 + Δ ₁₂ .

Since the distance between the vertices of the DE is sufficiently small, the first DE completely works in the zone of the OD created by the second DE, which moves relative to the surface with a greater interference fit than the first.

Due to the fact that the dimensions of the OD created by the second DE are larger than the sizes of the OD from the first DE, the deformation centers overlap and merge into one complex OD.

The simulation results show that most of the trajectory of metal particles that they travel in a complex OD along streamlines, the average normal stress is in the negative zone, which corresponds to hydrostatic compression. Under such conditions, the depletion of the plasticity reserve of a metal during plastic deformation is less intense. The destruction of the metal PS when exceeding the critical values of the interference does not occur.

As a result of the above-described design of the profile of the working part of the roll-in of a two-radial rolling metal, the surface layer of the part undergoes plastic deformation with repeated sign changes during processing, which leads to a partial restoration of the ductility margin of the metal in the zones where the sign of deformation changes.

It was established that the most intense increase in Λ and Ψ is observed in the zones of the vertices of the plastic waves in front of both DEs (Fig. 3), however, it is interesting that before the first DE, which has a lower interference, about 60% of the total degree of shear strain accumulates in while before the second DE, in spite of a greater tightness, the fraction of the accumulated degree of shear strain is approximately 40%, and the accumulation of strain itself is less intense. The simulation results show that such an accumulation of deformation and depletion of the plasticity reserve is caused by the fact that the first DE operates in the zone of OD created by the second DE. The resulting picture of the stress-strain state during processing by the roller of the proposed design indicates a significant mutual influence of DE on each other.

The studies show that the above-described profile design of the working part of the rolling roller allows the accumulation of large strain values without destroying the PS and increasing the maximum achievable parameters of the mechanical state of the PS metal during processing.

So, during the experimental processing of billets made of steel 45 in the delivery state with the following processing conditions: D _d = 60 mm; h _d1 = 0.02 mm; h _d2 = 0.05 mm; S = 0.1 mm / rev; n = 200 rpm; roller of the proposed design, having the following geometric parameters: D _p = 60 mm; R _CR1 = R _CR2 = 1 mm; Δ ₁₂ = 0.03 mm; l ₁₂ = 0.7 mm, an increase in the maximum possible degree of hardening of the surface layer to 48-52% was recorded, while with identical treatment with the prototype roller according to GOST 16344-70, the maximum attainable degree of hardening of the surface layer is 40%.

Claims (1)

Two-radius rolling obtuse roller having a working surface profile with a radius of constant value, characterized in that the working surface of the roller contains two deforming elements with a profile radius of 0.5 ... 5 mm, located relative to each other with a radial offset of 0.01 ... 0 , 1 mm both to and from the axis of the roller, and the distance between the vertices of the deforming elements along the axis of the roller is

,
where R _CR1 - the profile radius of the first deforming element;
R _CR2 is the profile radius of the second deforming element.

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