JP3172342B2 - Inspection method and surface modification method for steel material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for inspecting the wear resistance of a steel material and a method for modifying the surface thereof, and more particularly to a method for inspecting the wear resistance of a steel material in which ions are implanted into a surface layer and a method for inspecting the surface of the steel material. The present invention relates to a surface modification method for forming a structure having excellent wear resistance.

[0002]

2. Description of the Related Art It is well known that the injection of titanium ions into a steel material improves the wear resistance of its surface. For example, literature: IL Singer, Appl. Surfa
ce Sci., 18 (1984) p28-p62 shows that titanium ion was added to 52100 steel at 190 keV and 5 × 10 ¹⁷ atoms / cm.
^{When 2 is} injected, carbon is mixed into the surface layer of 52100 steel during the injection to form an iron-titanium-carbon based amorphous phase,
It has been shown that this amorphous phase improves the wear resistance properties of 52100 steel.

[0003] Further, the wear resistance of steel materials is further improved by implanting carbon ions subsequent to the implantation of titanium ions. For example, literature: DM F
ollstaedt, JAKnapp and LEPope, Nucl.Instrum.Meth
ods Phys. Res.B42 (1989) p205-p211; DMFollstaedt, J.
A.Knapp and LEPope, MRS Res.Soc.Symp.Proc.vol140
(1989) In p133-p146, after injecting 3.4 × 10 ¹⁷ atoms / cm ² of titanium ions into SUS304 steel at 180 keV, 2 × 10 ¹⁷ at of carbon ions at 50 keV.
When oms / cm ^{2 is} implanted, the above-described iron-titanium-carbon amorphous phase is formed in the implanted layer. However, the amount of titanium ions implanted was increased to 4.6 × 10 ¹⁷ atoms / cm ² . It is shown that when carbon ions are implanted at 2 × 10 ¹⁷ atoms / cm ² later, an amorphous phase in which fine precipitates having a titanium carbide structure of 20 nm or less are dispersed is formed in the implanted layer.

[0004] Further, a material to be treated in which only an iron-titanium-carbon amorphous phase appeared in the surface layer and a material to be treated in which an amorphous phase in which fine precipitates having a titanium carbide structure were dispersed appeared in the injection layer. The friction properties of the materials were compared for 15-5PH steel. For example, references: DMFollstaedt, JAKnapp, LEPop
e, FGYost and STPicraux, Appl.Phys.Lett., 45 (198
4) For p529-p531, 5 × titanium ion at 180 keV
By implanting 10 ¹⁷ atoms / cm ² , only the iron-titanium-carbon amorphous phase was formed on the surface layer.
5 PH steel and 5 × 10 ¹⁷ titanium ions at 180 keV
30 atoms of carbon ions after atoms / cm ² implantation
By injecting 2 × 10 ¹⁷ atoms / cm ² at V, a comparison is made between a 15-5PH steel in which an amorphous phase in which fine precipitates having a titanium carbide structure are dispersed is formed in an injection layer. It shows that the abrasion resistance is superior to the former.

[0005]

However, even in the case of a steel material in which titanium ions and carbon ions are implanted doubly so that fine precipitates having a titanium carbide structure are dispersed in an amorphous phase. Cannot be said to have sufficient abrasion resistance under a high load, and there is a problem in its durability.

On the other hand, as described above, the inspection of whether or not the steel material into which titanium ions and / or carbon ions have been implanted has obtained the desired wear resistance characteristics has conventionally been carried out by a wear test or the like. Since the inspection work is complicated and nondestructive inspection cannot be performed, the inspection may not be performed depending on the product type and the production amount.

The inventors of the present invention have analyzed the structural change of the implanted layer when ions are implanted into a steel material by transmission electron diffraction. As a result, when only titanium ions are implanted, a lattice constant of 0.210 nm to 0.230 nm is obtained. It was noticed that the maximum diffraction intensity of the diffraction ring from the amorphous phase appeared in between, and when carbon ions were implanted into this, the diffraction ring from the precipitate having the titanium carbide structure further appeared.

In view of the problems of the prior art, a first object of the present invention is to provide a method for inspecting the wear resistance of a steel material into which titanium ions and carbon ions are implanted in a double manner. It is an object of the present invention to provide a method for easily inspecting whether or not abrasion resistance has been improved so as to withstand a sliding environment for a long time. A second object of the present invention is to provide a surface modification method for forming a surface structure having excellent wear resistance on a steel material.

[0009]

According to the present invention, a first object of the present invention is to provide a method for inspecting the wear resistance of a steel material having titanium ions and carbon ions implanted in a surface layer,
The steel material is characterized in that abrasion resistance is obtained from a lattice constant that is a maximum diffraction intensity of a diffraction pattern obtained by performing transmission electron diffraction on an amorphous phase formed in the implanted layer of each ion. This is achieved by providing an inspection method. In particular, the lattice constant is between 0.210 nm and 0.230 nm and between 0.335 nm and 0.3
It is preferable to determine that the desired wear resistance has been obtained when the maximum diffraction intensity of up to 55 nm appears in the diffraction pattern. A second object is a surface modification method for improving the wear resistance of a steel material by double implantation of titanium ions and carbon ions. A surface modification method characterized by performing an implantation treatment so as to obtain a structure in which the maximum diffraction intensity is obtained at a lattice constant between 0.35 nm and 0.330 nm between 0.235 nm and 0.230 nm. It is achieved by doing.

[0010] The inventors of the present invention concluded that the structural change of the surface due to the double implantation of titanium ions and carbon ions is a change in wear resistance, that is, the surface of a steel material which can withstand a severe sliding environment by transmission electron diffraction. Was inspected.

As a result, it has been found that an amorphous phase having a different structure is formed on the surface layer depending on the amount of titanium ions and carbon ions implanted. Also, from 0.210 nm to 0.2
Titanium ions are implanted under the condition that a diffraction ring from the amorphous phase having the maximum diffraction intensity does not appear at a lattice constant of 30 nm, and when carbon ions are further implanted and when carbon ions are implanted without titanium ions, When only ions are implanted, no matter how much the carbon ion implantation amount is increased, only iron carbide is formed on the surface layer of the material to be treated, and 0.335 n
It was found that no diffraction ring from the amorphous phase having the maximum diffraction intensity appeared at a lattice constant between m and 0.355 nm.

When these sliding properties were evaluated, it was found that
Between 335 nm and 0.355 nm and 0.210 nm
The wear resistance of the surface layer, which has a structure that allows the maximum diffraction intensity of the diffraction ring from the amorphous phase to be obtained at a lattice constant of from 0.230 nm to 0.230 nm, is very excellent, and it can be used in a severe sliding environment for a long time. I found it to be tolerable.

[0013]

In this manner, transmission electron diffraction is performed on the amorphous phase formed in the ion-implanted layer to determine whether the desired abrasion resistance has been obtained in the steel material subjected to the ion implantation. Only can be inspected.

Here, 0.335 nm to 0.3
Between 55 nm and from 0.210 nm to 0.230 n
A method of double implantation of titanium ions and carbon ions for forming a surface layer having a structure in which the maximum diffraction intensity of a diffraction ring from an amorphous phase is obtained at a lattice constant of up to m will be described. .

In general, the energy of titanium used for implantation is desirably 50 keV or more and 400 keV or less.
This is because at 50 keV or less, since the implantation depth is shallow and the sputtering accompanying the implantation increases, the surface is saturated while the titanium concentration is low, so that a sufficient modifying effect cannot be obtained. Further, the reason why the energy is set to 400 keV or less is that if the energy is equal to or more than 400 keV, the size of the ion implanter becomes large, and the industrial process cannot be realized. That is, in the case of ion implantation, the penetration depth of ions into the material to be processed varies depending on the energy of the ions. When the energy of ions is low, the ions are concentrated at a shallow position from the surface. It can be used to improve the quality and effect. When the energy of the ions is high, the ions penetrate deeply from the surface, so that the distribution of the ions is widened, and a large amount of implantation is required to make the ions amorphous.

Next, 0.210 n by electron diffraction is applied to the injection layer.
The injection amount of titanium for forming a phase in which the maximum diffraction intensity of the diffraction ring from the amorphous phase appears at a lattice constant between m and 0.230 nm is divided according to the energy range of titanium. Show.

When the energy of titanium ions is not less than 50 keV and not more than 100 keV, the implantation amount of titanium ions is
× 10 ¹⁷ atoms / cm ² or more and then, when the energy of the titanium ions is less than 200keV least 100 keV, the implantation dose of titanium ions 3 × 10 ¹⁷ atoms / c
m ² or more. In addition, the energy of titanium ions is 20
When the energy is 0 keV or more and 300 keV or less, the implantation amount of titanium ions is 4 × 10 ¹⁷ atoms / cm ² or more. When the energy of the titanium ions is 300 keV or more, the implantation amount of titanium ions is 6 × 10 ¹⁷ atoms / cm ^2. Above.

Next, the energy and implantation amount of carbon ions are also shown separately according to the energy range of titanium ions.

Regarding the implantation of carbon ions, a phase where the maximum diffraction intensity of the diffraction ring from the amorphous phase appears at a lattice constant between 0.335 nm and 0.355 nm by electron diffraction in the implanted layer is efficiently formed. In order to achieve this, it is most effective to perform the implantation so as to overlap the distribution of the titanium ions implanted in advance. Therefore, since carbon has a smaller mass number than titanium, it is implanted with less energy than at the time of titanium ion implantation. Further, the amount of implantation depends on the energy of carbon ions as at the time of titanium ion implantation. Determined according to the energy of the carbon ions to be formed.

That is, 0.335 nm by electron diffraction is applied to the injection layer.
In order to form a phase in which the maximum diffraction intensity of the diffraction ring from the amorphous phase appears at a lattice constant of from 0.355 nm to 0.355 nm, the energy of the carbon ions and the implantation amount are such that the energy of the titanium ions is not less than 50 keV and not more than 100 keV. In the following cases, the energy of carbon ions should be 30 keV or more and 40 keV
V or less, and the injection amount is 4 × 10 ¹⁷ atoms / cm ² or more. Also, the energy of the titanium ions is 100 ke
When V is not less than 200 keV, the energy of carbon ions is not less than 40 keV and not more than 60 keV, and the implantation amount is 6 keV.
× 10 ¹⁷ atoms / cm ² or more. When the energy of the titanium ions is 200 keV or more and 300 keV or less, the energy of the carbon ions is 60 keV or more and 80 keV or more.
keV or less and the injection amount is 8 × 10 ¹⁷ atoms / cm
² or more. Further, the energy of titanium ions is 300
When the energy is more than keV, the energy of carbon ions is reduced to 80 keV.
V or more, and the injection amount is 1 × 10 ¹⁸ atoms / cm ² or more.

Here, the method of implanting carbon ions after implanting titanium ions has been described. However, titanium ions may be implanted after implanting carbon ions, or two ion sources may be simultaneously implanted. Needless to say, the processing efficiency is further improved.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail.

Titanium only / titanium ion and carbon ion are implanted into bearing steel (SUJ2) under the conditions shown in Table 1.
The structure of the injection layer was analyzed with a transmission electron microscope, and the wear amount and the change in friction coefficient of the injection material were evaluated by a linear reciprocating sliding test.

[0024]

[Table 1]

The test conditions were as follows: load: 1 kgf, sliding speed:
10 mm / sec, number of slides: 2000, mating pin: SU
Performed at S440C. For the evaluation of the wear amount, the maximum depth of the wear mark was measured with a precision roughness meter. FIG. 1 shows a change in friction coefficient of a sample processed under the conditions shown in Table 1 in a linear reciprocating sliding test. In the samples of Condition 1, Condition 3, Condition 4, Condition 7, Condition 8, and Condition 11, the number of times of sliding at which the friction coefficient is 0.3 or less does not reach 2000 times, whereas the condition 2, Condition 5,
In the samples under the condition 6, condition 9, condition 10 and condition 12, the friction coefficient is 0.3 or less up to 2000 times of sliding. Table 1 shows the number of sliding times at which the friction coefficient is 0.3 or less and the wear depth after 2000 reciprocations as a result of the structural analysis of the injection layer. As a result, the lattice constant that is the maximum diffraction intensity of the diffraction pattern obtained by performing transmission electron diffraction on the amorphous phase formed in the ion-implanted layer is 0.210 n.
It can be seen that the desired wear resistance is obtained when the maximum diffraction intensity between m and 0.230 nm and between 0.335 nm and 0.355 nm appears in the diffraction pattern.

[0026]

As described above, according to the present invention, in order to inspect the wear resistance of a steel material in which titanium ions and carbon ions have been implanted into the surface layer, the amorphous phase formed in the implanted layer of each ion is examined. Judging from the lattice constant that is the maximum diffraction intensity of the diffraction pattern obtained by performing transmission electron diffraction on
In particular, it is determined that the desired wear resistance has been obtained when the maximum diffraction intensity having a lattice constant between 0.210 nm and 0.230 nm and between 0.335 nm and 0.355 nm appears in the diffraction pattern. Thereby, the wear resistance of a steel material into which titanium ions and carbon ions are double-implanted can be easily inspected, and a steel material having a surface that can withstand a severe sliding environment can be easily and reliably obtained.

[Brief description of the drawings]

FIG. 1 is a graph showing a change in friction coefficient of a sample processed under the conditions shown in Table 1 in a linear reciprocating sliding test.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-6-322535 (JP, A) JP-B-52-10397 (JP, B2) Hiroshi Furuichi et al., “Metal and metal oxides subjected to repeated friction Organization ”, Proceedings of the 70th Annual Conference of the Japan Society of Mechanical Engineers (Vol.B), (1992), P637-P639 Kazunori Hayashi et al.,“ Development of Wear-Resistant Members by Ion Implantation and Ion Beam Mixing ” , No.336, P34-P39 (58) Fields investigated (Int. Cl. ⁷ , DB name) G01N 23/20-23/207 C23C 14/48 JICST file (JOIS)

Claims (3)

(57) [Claims] 1. A method for inspecting the wear resistance of a steel material in which titanium ions and carbon ions have been implanted into a surface layer, wherein transmission electron diffraction is performed on an amorphous phase formed in the implanted layer of each ion. A method for inspecting a steel material, wherein wear resistance is obtained from a lattice constant that is a maximum diffraction intensity of a diffraction pattern obtained by performing the above. 2. The method according to claim 1, wherein said lattice constant is between 0.210 nm and 0.230 nm and between 0.335 nm and 0.3 nm.
The method for inspecting a steel material according to claim 1, wherein it is determined that desired wear resistance has been obtained when a maximum diffraction intensity of up to 55 nm appears in the diffraction pattern. 3. A surface modification method for improving wear resistance of a steel material by double implantation of titanium ions and carbon ions, wherein the transmission electron diffraction of the implanted layer is from 0.210 nm to 0%. 0.230 nm and 0.335 nm to 0.2 nm.
A surface modification method characterized by performing an implantation treatment so as to obtain a structure in which the maximum diffraction intensity is obtained at a lattice constant of up to 355 nm.