Page 26 - Станочный парк английская версия

INNOVATIVE TECHNOLOGY

Fig. 2. Change in the values of the microhardness "coating - substrate".

steels such as ShX15, 65G. Tests show that the requirement of a dihedral angle.
the resource of crushers increased by 10 The formation of coatings is carried out in
- 12 times in comparison with traditional several stages. Initially, electrical contact
materials from hardened steels. local heating of the sample surface is
Coatings applied to disk cutting tools performed. In the process of feeding the
designed for cutting rocks such as granite, powder, a partial melting of the tungsten
marble and others almost completely carbide binder into the product occurs.
replace diamond tools, but the cost of a At this stage, an adhesive layer is
tool with a coating is 3-4 times lower than partially formed, which further determines
diamond tools. the adhesion strength of the coating to
In the technologies of electrocontact the surface of the part or tool. The tensile
sintering of tool carbide powders, strength at a current of 2 kA is 30 ... 112
compositions based on tungsten carbide MPa in the direction perpendicular to the
and cobalt are mainly used. When an electric surface of the coating. Further layer build-
current is supplied in the sintering stage up is carried out according to the “coating-
following the powder compaction, the final coating” scheme and already depends
formation of the alloy structure occurs.. on the thermophysical properties of the
At this stage, the following processes coating material. Studies show that even
occur: with significant currents of /2...5 kA /, the
● recrystallization of tungsten carbide coating build-up process practically stops
through the liquid phase; when the thickness reaches 2.0 ... 2.5 mm.
● splicing of neighboring grains due Powder is baked in the following modes:
to the predominant growth of one grain at ● voltage 3.0 ... 5.0 V;
the expense of others; ● pressure 40 ... 60 MPa;
● development of contacts between ● current strength 1.5 ... 2.0 kA
grains with the desire to form dihedral depending on the composition of the
angles characteristic of a given system; powder;
● cohesion (adhesion) of grains that ● porosity of the layer 8 ... 12 %;
had contacts and received orientation during ● hardness HRC 80 ... 85.
compaction during compaction, satisfying Recommended powder materials:

26 Stanochniy park