354
A. Stetsko
Hμ 100, MPa
L, μm
0
2000
4000
6000
8000
10000
12000
40
80
120 160 200 240 280 320
Fig. 22.8 Microhardness boron hardened layer obtained in steel (0.45%C)
implementation scheme is similar to wear composite material, which is currently
the most promising.
Boron refers to the elements with a small atomic radius (0,91 Å), which
contributes the diffusion of boron in to steel. The small atomic radius (0,91 Å)
of Boron is playing important role in the boron diffusion into steel. Researchers
are inclined to think that the boron solution forms a substitution of α-iron and
appearance solution of γ-iron.
The solubility of boron in α-iron and γ-iron is low. After saturation of iron by
boron, the reaction of diffusion layer zone is seen under microscope (zone borides).
In the system B-Fe reaction diffusion is carried out mainly by diffusion of boron
through the borides layer to the main front of the reaction, which are posted on
the phase boundaries between iron-Fe 2 B borides and boride Fe 2 B-boride FeB.
Obviously, boron diffuses through the lattice borides in the form of positive ions.
Microhardness of the hardened layer (Fig. 22.8), received on steel (0.45%C), is
at least 9000 MPa. The thickness of the diffusion hardened layer is 200 microns.
The roughness is 1,6–1,25 microns.
These figures show hardened layer obtained by boriding from coating and heating
by high-frequency current are sufficient to strengthen the overwhelming amount
of machine details wearing and as a result their, reliability and durability of parts,
reinforced by this way.
The thickness of the resulting hardened layer can be used to the method of repair
sizes significantly which simplifies and reduces the cost of repeated restoration and
repairment.
22.4 Conclusions
1. Use of boriding diffusion in coating with heating by high-frequency current due
to physical and chemical properties of the boron element is a promising method
of surface hardening of machines.
A. Stetsko
Hμ 100, MPa
L, μm
0
2000
4000
6000
8000
10000
12000
40
80
120 160 200 240 280 320
Fig. 22.8 Microhardness boron hardened layer obtained in steel (0.45%C)
implementation scheme is similar to wear composite material, which is currently
the most promising.
Boron refers to the elements with a small atomic radius (0,91 Å), which
contributes the diffusion of boron in to steel. The small atomic radius (0,91 Å)
of Boron is playing important role in the boron diffusion into steel. Researchers
are inclined to think that the boron solution forms a substitution of α-iron and
appearance solution of γ-iron.
The solubility of boron in α-iron and γ-iron is low. After saturation of iron by
boron, the reaction of diffusion layer zone is seen under microscope (zone borides).
In the system B-Fe reaction diffusion is carried out mainly by diffusion of boron
through the borides layer to the main front of the reaction, which are posted on
the phase boundaries between iron-Fe 2 B borides and boride Fe 2 B-boride FeB.
Obviously, boron diffuses through the lattice borides in the form of positive ions.
Microhardness of the hardened layer (Fig. 22.8), received on steel (0.45%C), is
at least 9000 MPa. The thickness of the diffusion hardened layer is 200 microns.
The roughness is 1,6–1,25 microns.
These figures show hardened layer obtained by boriding from coating and heating
by high-frequency current are sufficient to strengthen the overwhelming amount
of machine details wearing and as a result their, reliability and durability of parts,
reinforced by this way.
The thickness of the resulting hardened layer can be used to the method of repair
sizes significantly which simplifies and reduces the cost of repeated restoration and
repairment.
22.4 Conclusions
1. Use of boriding diffusion in coating with heating by high-frequency current due
to physical and chemical properties of the boron element is a promising method
of surface hardening of machines.