SU1702255A1 - Method of manufacturing compound hollow cylindrical specimen for determining the adhesion force between coating and material - Google Patents

Abstract

This invention relates to tribology. The aim of the invention is to improve the accuracy of determining the adhesion strength of coatings with metal. Two identical hollow cylinders, a cylindrical rod and a base with a hole are used. The first cylinder and the stem located inside it are placed in the hole of the base with ends flush with its surface and are coated on them. The second hollow cylinder is arranged coaxially with the first one and attached end to the surface of the coating. Cut the latter to its thickness along the inner and outer perimeters of the second cylinder, remove the stem and remove the cylinders from the base. The resulting mating of the cylinders is tested for detachment. 3 hp ff, 7 ill.

Description

The invention relates to tribology, in particular, to methods for producing samples for determining the adhesion strength of coatings with a base material.

A known method of making a composite sample for determining the strength of the separation of a coating with a material consists in this. that a hollow cylinder of the material under investigation is used, a cylindrical rod, whose diameter is equal to the inner diameter of the hollow cylinder, a base with a flat surface and a cylindrical bore, whose axis is perpendicular to the flat surface and the depth is not less than the length of the hollow cylinder and rod; the rod into the hole of the base is flush with its flat surface and the test coating is applied onto the flat surface of the base and the ends of the cylinder and rod.

Using such a method of making a composite cylindrical sample

It does not ensure, when testing, complete stress leveling over the contact zone of the coating with the cylinder, and therefore the accuracy of determining the adhesion strength of the coating with the base material remains low. In addition, the top plate is attached to the coating through the holes in the plate from the inside and cannot be attached to the ring, therefore uneven distribution of stresses over the contact area of the coated plate also occurs, which also leads to a decrease in the accuracy of determining the adhesion strength with main material.

The aim of the invention is to improve the accuracy of determining the adhesion strength of the coatings with the material.

This is achieved by using an additional hollow cylinder, similar to the main one, attached by its end to the surface of the coating coaxially with the main cyo

he ate

lindra, cut the coating ng its thickness along the inner and outer perimeters of the additional cylinder and remove the rod from the main cylinder. In addition, the thickness and length of the cylinders are chosen respectively from 0.01 to 0.2 and from 1 to 3 of their outer diameter. The walls of the main and additional cylinders at the places of their attachment to the load device are made thickened, moreover, at the main cylinder by reducing its inner diameter, and additional one by increasing its outer diameter. At the end of the additional cylinder, before fastening it to the coating, they are chamfered at an angle of 20 ... 70 ° to the plane of the end face.

Figure 1 shows a diagram of an apparatus for carrying out this method; Fig. 2 is a diagram of the connected main and additional pins during the test; Fig. 3 is a diagram of connected thin-wall pins in the working part of the pin; figure 4 is a diagram of the relative values of °

but

Opp

f (x), depending on the coordinate of the point being studied, for a sample made by a known method; Fig. 5 is a diagram of relative stresses σ ° f (x) as a function of the coordinate of the test point for a sample made by the proposed method; Fig. 6 shows the dependence of the stress concentration factor as a function of the relative thickness aa - p (- g); Fig. 7 is a diagram of the stress non-uniformity factor Ka V4; r) B dependence on

relative length.

In the drawings, the following designations are given: 1. - base, 2 - hollow cylinder, 3 - additional cylinder, 4 - cover, 5 - cylindrical rod, b - lock, 7 - stops, 8 - working part of the pin, 9 - load part of the pin, 10 - shank of a cylindrical rod. 11 - cylinder head. 12 is a diagram of relative stresses σ ° f (xj for a prototype sample, 13 is a diagram of relative stresses for a sample according to the claimed method, 14 is a graph of stress concentration as a function of relative thickness

sample wall ао р (-г), 15 -diagram of the dependence of the coefficient of non-uniformity of the stresses Ксг V () on the relative working length.

Designations: x - absolute coordinate of the contact point of the coating with the pin; d is the outer diameter of the working part of the cylinder; di is the inner diameter of the working part of the cylinder; d0 is the outer diameter of the loading part of the auxiliary cylinder; d2 is the internal diameter of the loading part of the hollow cylinder; t is the wall thickness of the working part of the cylinder; tn is the coating thickness; I - the length of the working part of the cylinder; H is the length of the loading part of the cylinder; ar voltage at the point under study; (7cr is the average stress over the area of the cylinder end; P is the destructive force; F is the area

cylinder mating with a relative stress;

eat; o ° tg

UCD

t ° t / d is the relative wall thickness of the cylinder; l ° l / d - relative length

the working part of the cylinder; K a - nzib - koefUnaim

voltage irregularity; anaib - the highest voltage in

contact points of the cylinder end with the coating; decay - the lowest voltage: Е - the modulus of elasticity of the material of the cylinder; en is the modulus of elasticity of the mat of the chial coating; Neklon angle. Chamfer.

The method is carried out as follows.

The 3 hole of the base 1 (see Fig. 4) sets the hollow cylinder 2 flush with the plane of the base; the additional cylinder 3 is made so that the dimensions of its working part (outer and inner diameter, wall thickness and length) are respectively equal to the dimensions of the hollow cylinder 2. On base surface 1 and

A coating 4 is applied to the end of cylinder 2, and a cylindrical rod 5 is inserted before the coating into the cylinder, the end of which is set flush with the plane of the end of the cylinder.

The cylinder is fixed in the hole of the base with the retainer 6, the base is mounted on the stops 7. The cylinders 2 and 3 have working 8 and load 9 parts. The cylindrical rod is in the form of a shank.

10 threaded and heads 11.

After coating 4 is coaxially attached to the base cylinder, an additional cylinder is attached in a known manner, e.g., using laser welding or

in some other way, then the coating is cut to its thickness along the inner and outer perimeters of the additional cylinder, the cylindrical rod is removed from the main cylinder and

the resulting sample is tested for peeling (figure 2).

In the manufacture of the primary and secondary cylinders, the thickness t and the length I of the working section are respectively equal to 0.01 ... 0.2 and 1 ... 3 of the outer diameter d of the cylinder.

To increase the reliability of mounting the cylinders in the load device for thin-walled cylinders, the walls of the main and additional cylinders are thickened at the points of their attachment to the load device, and at the main cylinder by reducing its internal diameter and additional one by increasing its external diameter.

In addition, in order to improve the processability of attaching an additional cylinder at the end face, before attaching it to the coating, the chamfer is angled (20 ... 70 °) to the face plane (see Fig. 3). Such an end face shape of an additional cylinder provides access for attaching it to a metal coating using, for example, laser welding and other methods.

From a comparison of the diagrams of the relative stresses of Fig. 4 and Fig. B, it follows that in the first case the coefficient of unevenness is Ka 1.64, in the second. 1.09, and the stress concentration factor in the first case is equal to ao 1.38, in the second case to ao 1.06. The original parameters are the same in both cases. In particular, the ratio of the modulus of elasticity of a steel cylinder to the modulus of elasticity by

the roof was taken to be 54; thick nf

on t 3 mm coatings, external cylinder diameter d 20 mm; internal diameter of the cylinder di 17,5 mm; working length I 60 mm.

The coating material is made on the basis of ED-6 epoxy resin, cured with maleic anhydride and plasticized dibutyl phthalate in a proportion of 100: 30: 5 weight parts.

Since the accuracy of determining the adhesion strength is higher, the lower the stress concentration coefficient, i.e. the higher, the closer the maximum voltage in the contact zone to the average voltage, the consequently method provides a higher accuracy of adhesion determination than the prototype and the base object.

The dependence of the concentration ratio on the relative thickness shown in FIG. 6 shows that the thinner the cylinder wall, the closer the value of the concentration coefficients to unity. The choice of limits for changing the thickness of a cylinder 5 t ° 0.01 ... 0.2 was made on the basis of experimentation experience with various coatings. Thus, for working with metal coatings, the optimum thickness value lies closer to the lower limit, and for works with anaerobic, epoxy resins, the optimum value lies closer to the upper limit,

Presented in Fig.7 is a diagram of the coefficient of uneven stresses

5, depending on the size of the working length, shows that the longer the working part of the cylinder, the closer the irregularity coefficient is to one, and therefore the higher the accuracy of determining the strength

0 adhesion of coatings with the material. The choice of limits for changing the length of the working part was made according to the test results. So, at values of I0 1, the accuracy of the test is unacceptably reduced, and at I0

5 3 it is unacceptable to increase the consumption of material for samples while maintaining the same test accuracy.

The choice of chamfer angle is carried out within / 3 20 ... 70 °. When worsens

This means that access to the contact zone of an additional cylinder is coated, while it is difficult to attach this cylinder to the coating. At / 3 70 °, the consumption of the filler (welding) material increases.

The manufacture according to the inventive method of a composite sample for determining the adhesion strength of the coating provides a significant increase in accuracy.

0 determine the adhesion strength of coatings with the base, expanding the functionality of the method by expanding the class of test coatings, because the method allows testing

5 not only adhesive, but also metal coatings, improving the processability of attaching an additional cylinder to metal coatings.

Claims (4)

01. A method of making a composite hollow cylindrical sample to determine the strength of adhesion of a coating to a material, which consists in using a hollow cylinder from the test 5, a cylindrical rod, the diameter of which is equal to the internal diameter of the hollow cylinder, and a base with a flat surface and a cylindrical hole, the axis of which is perpendicular to the flat surface, and a depth not less than the length of the hollow cylinder and stem, place the cylinder and the stem inserted into it a flush with its flat surface and applied to the flat surface of the base and the ends of the cylinder and rod of the test coating, characterized in that, in order to improve the accuracy of determining the adhesion strength, tourists additional hollow cylinder similar to the core, attached to its end face coaxially to the main surface of the coating cylinder is cut at its coating thickness of the inner and outer perimeters of the auxiliary cylinder and the rod is removed from the main cylinder. 0 five 2. The method according to claim 1, wherein the heme is that the thickness and length of the cylinders are respectively selected from 0.01 to 0.2 and from 1 to 3 of their outer diameter. 3. A method according to claims 1 and 2, characterized in that the walls of the main and auxiliary cylinders at their attachment to the loading device are thickened, and at the main cylinder by decreasing its internal diameter, and that of the additional cylinder by increasing its external diameter. 4. A method according to claim 1, characterized in that at the end of the additional cylinder, prior to its attachment to the cover, 1 is chamfered at an angle of 20 ... 70 ° to the plane of the end ™. Kx4 eight FIG. one & Zsnch c / l 9 ± V frtf 9  / by / -B " c / Sh SSZSOil FIG A about 0.05 0.10 0.15 0.20 0.25 t FIG. 6d