SU1328743A1 - Method of checking the degree of surface hardening of solid bodies - Google Patents

Abstract

The invention relates to non-destructive methods for controlling the degree of surface hardening of solids in statics and dynamics. The aim of the invention is the expansion of technological capabilities, improving the accuracy and productivity of controlling the degree of hardening of solids. For this, the solids are brought into contact; during loading and unloading, the number of acoustic emission pulses or electrical contact resistance of the bodies is recorded; Then, the degree of surface hardening is evaluated by these parameters. 2 tab. 00 1C 00 "4ik SB

Description

1 The invention relates to the field

determine the properties of the surface layers of machine parts.

The purpose of the invention is the expansion of technological capabilities, increasing the accuracy and productivity of control due to non-destructive control of the degree of surface hardening in statics and dynamics by the parameters of contact interaction during plastic deformation of the surface layers of solids.

The method of controlling the degree of surface hardening of solids is carried out as follows.

Solid bodies are brought into contact (static or dynamic). Carrying out loading and unloading of bodies with a given rate of change of load, lying in the range of 5-50 N / s.

During the tests, the Brinell hardness HB and the number of pulses of acoustic emission or electrical resistance of the contact are recorded during loading and unloading of the contact of bodies. The test is repeated 8-10 times. Then find the degree of surface hardening of solids by the formula

10 Nr, - 4N2

- ly

100%

where L NT with the difference of the number of pulses of acoustic emission, respectively, when loading and unloading bodies, or

according to the formula

g

. m., 00%,

 dRci

where jiRc is the difference in electrical resistance of the contact of bodies, respectively, before and after loading.

The value of the contour contact

pressure 7 is chosen from the condition

1328743

0.005.

0.1, where HB - hardness

Brinell is less solid. At PJ, 0.005 HB, the conditions of plastic deformation on the roughness of the surfaces of bodies are not realized, and at Pg 0.1 HB, a volume plastic flow of a less solid body begins.

For samples with a diameter of 10 mm and a height of 50 mm, made of various materials, the test results for the number of acoustic emission pulses are given in Table B. one.

In tab. 2 P1 and the results of determining the hinges of frictional surface hardening of bodies by the electrical resistance of the contact of bodies at a current of 0.1 A.

Formula and. acquisitions

25

thirty

The method of controlling the degree of surface hardening of solids, which consists in bringing the solid bodies into contact, loading and unloading them, and recording the contact interaction parameter of the bodies, which is used to estimate the degree of surface strengthening, characterized in for accuracy and performance, the number of acoustic emission pulses or the electrical resistance of the contact, t, is used as a parameter for contact interaction 1 tel. l, and the value of the loop contact pressure

40, under loading and unloading, selects the following conditions

0.005 0.1,

45 where HB is Brinell hardness less solid.

Steel 45 1.97-103 3.8Y Rolling 7.2 40 4.2105 41 9.85-197 19.1-381 D 16 T. 0.85 10V 1.05-103 Hardening 5.4-10 2.5105 53 4.25-85 5.25-105

50

80

  Hardening can be carried out in the process of friction interaction of solids.

Table 2

Editor P. Geresi

Compiled by V. Danilov

Tehred M. Khodanich Proofreader A. Tsko

Order 3479/47 Circulation 776 Subscription

VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5

Production and printing company, Uzhgorod, st. Project, 4

Table 1

1.2-10 0.8-10 33 0.25-5.0 0.4-8.0

Claims (1)

Claim A method for controlling the degree of surface hardening of solids, 25 ^J which involves contacting solids, loading and unloading them, and registering the contact interaction parameter of the bodies by which a ³ θ degree of surface hardening is estimated, characterized in that, in order to expand technological capabilities, increasing accuracy and productivity, as the parameter of the contact interaction of the bodies, use the number of pulses of acoustic emission or the electrical resistance of the contact t ate, and the magnitude of the contour · contact pressure P _with 40 when loading and unloading is selected. yut of conditions 0.005 4 <0.1, 45 where HB is the Brinell hardness of a less rigid body. Table 1 Material Initial hardness HB, MPa Hardness after hardening HB, MPa Type of hardening * ΔΝ _Σ1 Ψ,% The range of pressure changes P _s , MPa before hardening after hardening Steel 45 1.97’103 3.81-10 ’ Rolling 7.2 C0 ⁵ 4.2 BUT ⁵ 41 9.85-197 19.1-381 D 16 t 0,85'YU ^3. 1.05 · 10 ’ Quenching 5,4-10 ⁵ 2.510 ⁵ 53 4.25-85 5.25-105 Polycaproamide (PKA) fifty 80 1.2 -10 ⁵ 0.8-U ⁵ 33 0.25-5.0 0.4-8.0 * - Hardening can be carried out in the process of friction interaction of solids. table 2 Type of processing 4R _C1 , Ohm dR _C2 , 0m Power hardening φ,% Grinding, R _a = 1.3 μm R ^ 1.54 μm Polishing, I _a = 0.4 μm Sections aHHe, R _a = 1.2 μm 6.4 2.7 58 5.8 4.7 19 5.9 1,2 80 5.3 2,3 • 57 Compiled by B *. Danilov Editor P. Geresh Tehred M. Khodanich Corrector A. Tyasco Order 3479/47 Circulation 776 Subscription VNIIIPI of the USSR State Committee for Inventions and Discoveries 113035, Moscow, Zh-35, Raushskaya nab., 4/5 Production and printing company, Uzhhorod, st. Project, 4.