SU1613307A1 - Method of mechanical working of parts by several steps - Google Patents

Abstract

The invention relates to the technology of cold treatment of metals by surface plastic deformation and can be used for machining flat parts. The purpose of the invention is to improve the accuracy and productivity of the process. In the process, a layer of metal is removed from one surface of the flat part, then the part is turned over and the opposite surface is rolled up to compensate for internal residual stresses and eliminate distortion. The knurling is done with a force determined by the magnitude of the internal residual stresses in the part after removing the metal layer. This sequence of operations allows to improve the accuracy of parts and productivity of the process. 1 tab., 3 Il.

Description

The invention relates to the technology of cold treatment of metals by surface plastic deformation.

The purpose of the invention is to expand the technological capabilities of the method and improve the accuracy and productivity of processing.

FIG. 1-3 schematically shows the processing sequence.

The machining part 2 is fixed on the machine table 1 and the allowance I is removed by the tool 3. The signals from the sensor 4 of the device 5 fix the redistribution of residual stresses in the part, which leads to its distortion (figure 2). Then, the turning of the part 2 and the rolling of the surface B of the opposite treated surface A with the tool 6 with a rolling force equal to

PH

Obsy

where Oo is the internal residual stresses in the parts;

Sy is the static moment of the area of the remote allowance;

L-length details.

Example. Detail 2 of steel 40X is installed and fixed on the table 1 of a milling machine model 6PH12 i2f01. Detail 2 is machined with a face milling cutter 3 with T5K10 hard-alloy plates with removal of i 5 mm allowance. After processing, the internal residual stresses of part 2 are measured by a sensor 4 of a device 5 ION-4 (residual stress meter). After removing an allowance of I 5 mm in detail 3, a moment of unbalanced internal forces MI occurs, which is equal to

Mi CToSy, (1)

where 00 is the internal residual stress of the part;

Sy is the static moment of the stock allowance.

The moment MI, due to the redistribution of residual stresses, causes the component 2 to warp, and the surface being machined and the opposite surfaces become concave.

Warping value is

, Mi iF

iKop

(2)

8EI

where LI is the length of the part;

E is the modulus of elasticity;

I is the moment of inertia.

To compensate for the warping value after removing the allowance of 1 to 5 mm, i.e. to bring the part into balance, it is necessary to add stresses equal in magnitude and sign to the stresses that went with an allowance, and it follows from this that the magnitude is redundant. the potential energy doing the work of warping the machined part 2 is equal to the energy taken from part 2 when removing the allowance I

Eisb - Epr, Iw

where Epr. the energy that had with allowance removed from the surface A.

The value of EPR depends on the moment Mi, the rigidity of the part and its length. Knurling the opposite surface B, creating a moment M2, equal, but opposite in sign to the moment Mi, i.e. condition must be met

Mi M2, and)

where Mg is the moment from the force RN of the run-up (ani of the surface B.

Thus, the moment M creates programmed parts.

M2 PH L, (5)

, f, ..

T2 - Reproach

Roll up the surface B of the part 2 with the knurled-roller 6 (fmg.Z) with the force of the knurling found from equality (3)

0

five

0

aoSy PH I (7)

PH 4 .. (8)

The force of knurling PH and the main characteristics of the method and details are given in the table.

Improves machining accuracy by compensating for internal residual stresses lost due to removal of allowance, applied stresses from surface knurling, which reduces component buckling, reduces fitting operations.

Claims (1)

Invention Formula A method of machining parts with several transitions, in which the part is fixed on the table, a preliminary deflection of the part at the first transition is performed by removing the metal layer from the surface of the part, the stress state parameter in the workpiece is measured, and surface plastic deformation is produced by rolling a roll on one of the surfaces. details, characterized in that, in order to improve the accuracy and productivity of processing, after removing the metal layer from the surface of the part, it is freed from being fixed, turning They put the treated surface on the table and fix it; internal residual stresses are measured as a parameter of the stress state; they are measured after removing the metal layer and releasing the part from fixing, and the surface of the part opposite to the surface with the removed surface is subjected to plastic deformation. layer, and the force is determined from the expression ОУ оу Рн- L where Hundred - internal residual stresses, MPa; Sy is the static moment of the removed layer, m; 0 five 0 five L - part length, m. ///////// fpuz.l //////// w /////// f I Cor. I SchigZ