Abstract

Содержание

1. Theme urgency

Known methods of the analysis of process of deformation of metal on the stages of incomplete crystallization based on results of mathematical modeling by a method of final elements, in most cases demand check of the received results in the conditions of real physical experiment. As carrying out experiments at plants demands big material inputs, there is a need of creation of ways of physical modeling.

2. Goal and tasks of the research

Objective of this research is development of a new way of physical modeling for research of features of formation intense the deformed condition in crystallized a component of a nepreryvnolity ingot (a slab or blum) at deformation at a stage of incomplete crystallization.
Main objectives:
- creation of physical models (slab or blum);
- research of features of formation intense the deformed condition.
Object of research:
- Blum section of 36х34х150 mm;
- slab section of 15х72х150 mm.

3. Review of researches and development

Some methods of physical modeling were considered. Brinza V. V. offered a method in which samples were made of an alloy lead-antimony. In one of samples the core was filled with Wood's alloy, another left hollow (fig. 1).

 

Figure 1 – the Sample models

This method allows to model such parameters:
- metal ushireniye;
- change of thickness of firm layers of a slab;
- change of corners of interface of firm layers of a slab;
- unevenness of a plastic current of metal on width of a firm prikontaktny layer;
- a sign of loss of stability of a slab at deformation.

Other method is offered Smirnovs E.N. The essence of a method consists in manufacturing of physical models from plasticine (fig. 2).

Figure 2 – the Sample from plasticine

 

Full physical similarity of processes on a modeling sample and accuracy of experimental data is thus provided.
One more method is the Bykovo method of the Item of the Lake in which the sample is made of an alloy lead-bismuth (fig. 3), axial porosity was modelled by an opening

 

Figure 3 – the Sample from an alloy lead-bismuth

The obzhatiya and formation of crystallizing metal defined by this method the greatest possible degree shift.
As such experimental methods of an assessment of deformation as are known: a coordinate grid, moire strips, optically - sensitive coverings, the micro and macrostructural analysis, layered models. Each of methods possesses the advantages, shortcomings and restrictions. These methods don't give volume idea of formation intense deform a condition.

Review of researches and development

The hypothesis about possibility of an assessment intense the deformed condition on change of a configuration of spherical grains is put forward. Feature of a method is that transition of an initial spherical form to the deformed ellipsoidny occurs in the directions of the main deformations. In this case diameter of the sphere, owing to equality of volumes of grain before deformation, is defined by a way of direct measurement of the main diagonals ellipse by the equation:

where – diameter of the sphere; – main diagonals ellipse.
In this case deformations pay off on the following formulas:

– the main relative deformations of a material in vicinities ellipse

where: – lengths of axes ellipse; – diameter of the sphere;

– the main logarithmic deformations in vicinities ellipse

Researches of a new way are carried out together with masters and graduate students of chair of processing of metals pressure of Lipetsk state technical university.
For check of this hypothesis physical models were made. They were executed in the form of the closed solid-state squared cover.
The cover simulating crystallized a part of an ingot, represents a composite from spherical fraction (lead) and filler metal (Wood's alloy). For imitation of availability of liquid metal in a cover pumped gelatin. The characteristic of samples is presented in table 1.
Table 1 – the sample Characteristic (Lipetsk)

Sizes of a sample

Core

AF=F0/Fоб

H,mm

B,mm

 L,mm

Wall,mm

16

72

135

4

Gelatin

0,55

 

Rolling of modeling samples carried out on OMD chair of Lipetsk state technical university on a camp 250. Obzhatiye was made by 3 mm. Parameters of rolling are presented in table 2. Cross-section sections of samples after deformation it is shown in drawing 4.

 

Table 2 – Parameters rollings (Lipetsk)

?h,мм

Dв,мм

α,рад

ld,мм

3

250

0,16

19,36

 

Figure 4 - Cross-section sections of samples after deformation

 

On OMD chair of Donetsk national technical university samples with the same sizes, simulating a slab with a liquid core were made. Also made also Blum's model with a liquid core. For manufacturing of slyabovy model forms from glass (drawing 5) were stuck together, for blyumovy model used a steel form (drawing 6).

Figure 5 – the Mould for manufacturing of slyabovy samples

 

Figure 6 – the Mould for manufacturing of blyumovy samples
Appearance of models is presented in figure 7.

 

Figure 7 - Appearance of models

 

For imitation of a liquid core in a slyabovy sample gelatin, blyumovy – paraffin was pumped. Characteristics of samples are presented in table 3.
Table 3 – the Characteristic of samples (Donetsk)

 

Sample

Blum

Slyab

Size, mm

36х34х150

16х72х135

Thickness of a wall, mm

11 и 17

4

Core

Paraffin

Gelatin

AF=F0/Fоб

0,5

0,55

 

Rolling of modeling samples carried out on a laboratory camp 100 and 340. Obzhatiye was made by 2 mm for a blyumovy sample and 2,3 mm for a slyabovy sample. After receiving nedokat became templets which were pickled further. Parameters of rolling of samples are presented in tables 4 and 5.
Table 4 – rolling Parameters Blum (Donetsk)

?h,мм

Dв,мм

α,рад

ld,мм

2

100

0,2

10

 

Table 5 – Parameters of rolling of a slab (Donetsk)

?h,мм

Dв,мм

α,рад

ld,мм

3

100

0,16

19,36

2

100

0,2

10

 

Appearance темплетов after rolling is shown in drawing 8.

a) cross-section section of a slyabovy sample

 

b) cross-section section of a blyumovy sample
Drawing 8 - Appearance темплетов after deformation

Conclusions

Primary researches showed that when manufacturing blyumovy physical models big problems with uniformity of an arrangement of spheres are observed. At the same time their accurate deformation is observed. At an obzhatiya of slyabovy physical models transition of metal to a plastic condition occurs only in the plane, a perpendicular barrel in which there is exclusively firm phase, i.e. at a crust along a narrow side.

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