JPS58213869A - Metal product nitriding process - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to metal heat treatment heroes, and more particularly to a method for nitriding metals in a nitrogen-containing atmosphere.

The invention can be particularly advantageous when locally or selectively nitriding working surfaces of large-sized parts.

Methods for nitriding metal products in glow discharge plasma are known (JlM, Lahtin, J, D, Kog
an' 5teel nitriding', M...
Maahinostroenie, 1976.140
negative reference).

The method involves placing the product to be treated in a sealed container containing a dilute nitrogen-containing atmosphere with a negative pressure of 133.3-1333 N/m2, and then placing the product at the cathode (product) and the anode. This is a method in which full heavy pressure is applied (this applied voltage can be adjusted within the range of 400 to 1,000 OOV) during the (furnace body) period. The voltage applied depends primarily on the shape and dimensions of the product being treated. As a result, gaseous ions impinge on the surface of the article, thereby heating it to a temperature in the range of 450-580<0>C. This nitriding time lasts from less than 1 hour to 24 hours.

By the above method, in the case of steel containing all chromium, molybdenum and aluminum, the surface hardness of 1@250
Q between 0 and 550, a 4 mm thick diffused nitrogen content is formed in 5 hours. By this method, in the same time, in the case of chromium-containing steel, the hardness of the layer surface was reduced to W5500-550.
It is possible to form a diffusion-densified layer with a thickness of (0.45-0.6) x 10 m.

From the above it can be seen that with the prior art method it is possible to control the electrification method to form a diffusion layer having a desired phase composition and structure. [2] However, since this is a time-consuming process (nitriding time is up to an additional hour), and processing of the parts is carried out in a controlled vacuum vessel, this process is a one-shot operation. Furthermore, this method is 133.3 to 1333 Nico,
- It is technically difficult to carry out, since it involves the whole depressurization process, which has to be carried out within a narrow range of negative pressures of tons per square meter (N/m2). The negative pressure of this gas is 1
Above 333 N/m2 there is a tendency towards nuclear glow, arcing which reduces the stability of the discharge and causes overheating 16 and melting of the surface being treated. This negative pressure is 13
Below 3.3 N/m2, the energy of the impinging atoms and ions is insufficient to heat the surface being treated. Furthermore, since the entire product is placed in the heating chamber of the furnace and only part of the surface of the product is treated, special metal-containing pastes, protective All shielding, braces and electroplating must be used.

Applying this prior art method requires a long time (up to 24 hours) to obtain the desired surface strength and hardness. Nevertheless, even with such long-term treatments, the desired strength and hardness are not always achieved.

This nitriding time could have been reduced by employing higher temperatures, but this is not possible due to the operating conditions required in the prior art process.

The object of the present invention is to overcome all of the above disadvantages.

The present invention provides an overall method for nitriding metal products. In the present invention, due to the sharp increase in temperature of the surface of the treated metal product, this treatment time is shortened and the hardness and strength of the surface are simultaneously improved.

(j) The main object of the present invention is to reduce the electrification time of metal products and simultaneously improve the surface hardness and strength of this product. The purpose is to provide a method for converting 14 different products.

Another object of the present invention is to provide a method for electrifying metal products that reliably forms a gold M product surface rTli Im with desired physical and mechanical properties.

Yet another object of the present invention is to provide a method for nitriding metal products that allows selective nitriding of the surface of the product to be treated without protecting surface areas that are not to be treated.

Another object of the present invention is to provide a complete method for nitriding metal products, which allows continuous and automated processing of all metal products.

Yet another object of the invention is to provide an overall method for nitriding metal products that is simple to implement.

The object of the present invention is achieved by the following process method. Namely, a method for nitriding a gold pI4 product, comprising the step of treating said product in a nitrogen-poor plasma, the treatment of said product being (4) at an internal temperature of 6.000 K and (0.03 to 1 )
The process was carried out in a nitrogen-containing plasma stream with a total pressure of the flow on the surface to be treated of It is processed.

The surface of this product is nitrided by the formation of an active gas phase consisting of dissociated and ionized nitrogen, which has high energy and is chemically active, in a plasma stream with a total internal temperature of at least 6,000 K. Ru.

As the temperature of the plasma stream increases, the amount of monatomic and ionized nitrogen in the plasma stream increases, and the atomic and ion energies increase simultaneously. These atoms and ions impinge on the treated surface and heat the surface at a heating rate of 600-1000°C per second.

Under the action of rapid heating, the high-temperature phase of austenite separates and forms a dispersed state, as a result of which multiple structural defects are generated.

This phenomenon results in the formation of a highly defined surface characterized by increased chemical activity. monatomic σ)
and an active gas phase of ionized nitrogen are brought into contact with this highly developed chemically active metal surface, which is one of the methods of the present invention.
- ensured by the operating conditions of the proposed method,
By nitrogen this surface is intensely saturated and M ; lj) 1, the hardness and strength of the surface of the product treated by kneading is increased.

This proposed method may be implemented in accordance with the present invention.

This method uses 1 air arc J111 contact type plasmatron (plastnatron) VRI Nakagawa I 1
A nitrogen-containing gas is heated to a plasma stream with an internal temperature of at least 6000°C. HF and Vl (F plasmatrons) can be used to heat this gas chamber.

At such temperatures, very sufficient quantities of monatomic and ionized nitrogen will be produced in the plasma stream. This degree of blackness will become history”-! 1, the amount of ionized nitrogen also increases, and kneading accelerates the nitriding process. A stream of monoatomic and ionized nitrogen exits the nozzle of the plasmatron and is directed toward the surface to be treated. Plasma according to the shape and dimensions of the surface to be treated? t is perpendicular to the surface or oriented at an angle of (
For example, in the case of a flat surface, it is convenient for the plasma flow to strike the surface at right angles, and in the case of a cylindrical surface, it is convenient to have the plasma flow strike the surface at right angles. It is effective to orient the object at an angle. ) Plasma M1.) on the surface to be treated. The pressure of is (0,08-1)
It is maintained within the range of Xl05N/m2.

If this selected limit value is not maintained, nitriding of the gold-scented product will not occur.

The surface of the residual product to be treated is lXl0 ~ ΔlXl0
It is scanned by a uniformly passing plasma stream at a velocity of m, p, s.

The scanning speed of the plasma flow is I x 10 m, p, s,
If slower than this surface melts hl and the speed is 20
If X 1 (l m, p, a) is exceeded, nitridation of the surface will not occur.

Depending on the dimensions of the product and the surface area treated, nitriding times can range from a few seconds to several hours.

With this proposed method, the nitriding operation is combined with a subsequent hardening of the heated surface area, resulting in an even greater surface hardness.

(lj) The method of the present invention is particularly advantageous for selectively nitriding the working surfaces of large parts, such as augers, plungers, etc.
It can also be used in the 11 conversion process.

The proposed method makes it possible to form highly energetic and chemically active active I11 nitrogen in the plasma stream and transfer it onto the surface to be treated. The surface of the metal product is rapidly heated to break up all the particles of the metal's initial structure into more uniform dimensions, thereby favoring adsorption, diffusion, and consequent formation of nitrides, and at the same time The strength of the treated product is reduced by 1.5 times, the nitriding time is reduced by 5-10 times, and at the same time the surface hardness is increased by 1.5 times compared to that which can be obtained using conventional methods. , and a pitiful thickness of nitride pIj4
nitriding the entire surface selectively without employing special impurity retention means such as pastes, shields and obscuring materials that align not all surface areas during the process.

(8) Example 1 The working surface of a steel gear was nitrided by the method of the present invention.

The steel used to make this gear has the following components (according to the Gunsei Section):
That is, carbon...0.37, manganese...0.5,
Chromium: 0.8, iron: All remaining amounts were contained.

The nozzle cross section is (I x 2.1) x Hl” m2
Nitrogen-containing gas (i = 6000 to +7
) temperature.

Plasma γ' + tf, having a chamber temperature, exited the nozzle of the plasmatron at an angle onto the surface to be treated, and a pressure of 0.03 x 105 N/m2 was applied onto the surface.

During the nitriding process, the surface to be treated is exposed to a plasma stream 2X
Scanning was performed at a speed of 10-5 m, p, s. The distance from the exit cross section of the nozzle to the surface was 5 x 10-' m.

As a result of the treatment carried out in this way, a nitrided layer 3 x 10-5 m thick with a surface hardness of Hv5o550 was formed on the working surface of the copper-iron gear.

The strength of a product is proportional to the square of its hardness (n, N).

Re5hetov, 'Data mashlne
s/, M, Mashinostroenie.

1974, p. 254).

The nitriding time for the used surface 1 and 2 of the teeth was 5 seconds.

Example 2 All surfaces of an iron gear were nitrided by the method of the present invention.

The composition of the #1 gear made in this gear was as per the queen (depending on the amount of wheels), i.e. 0.45% carbon, 0 manganese.
．． 8% so 17゛ [The remaining amount was iron.

The nitrogen-containing gas was heated to a temperature of 8000 K by means of an indirect air-arc plasmatron with a nozzle exit cross section of (I x 21 ) Xl0-'m2.

A plasma stream containing all nitrogen (nitrogen) is caused to exit the nozzle of the plasmatron at right angles to the surface to be treated, and the pressure created on the surface by the plasma stream is 0.5 x
It was 10 N7m. During the treatment, the surface used to be nitrided was 5×10 m, p, s,
It ran at a speed of -. The distance from the nozzle exit cross section is 1
It was 0xkawa m.

Nitriding (@3,5XIO) is applied to the surface of the gear used.
-811 thickness, and the surface hardness of this 1@ is H′v
It was 5o680.

Nitriding of the used surface IC1n2 of the gear took 2 seconds.

Example 3 By the method proposed by the present invention, 15 X i
A flat test piece made of steel measuring 5 x 10 x 10 was used throughout the building.

The steel from which this test piece was made is (fi product:) 0.4
It contained 2% carbon, 0.3% manganese, 1.05% chromium and the balance iron.

The nitrogen-containing gas was heated to a temperature of k 10,0OOK by an electric arc indirectly acting plasmatron with a nozzle cross section of (lX2,1)XIOm.

For the entire surface to be treated, a plasma stream containing 9 strands (
out of the nozzle of the plasmatron at angle n, and the pressure exerted on the surface by the plasma stream is 0,5 x
It was 10 N7m. The surface of the test piece was scanned by the plasma stream at a speed of 8 x 10 m, p, s. The distance from the exit cross section of the nozzle to the surface to be treated was 10×10 m.

The nitride layer formed on the surface of the test piece was 7× river −4 m
and had a surface hardness of IIV5o1250.

1 cm (1') of the surface of the test piece was nitrided for 2 seconds.

Example 4 The working surface of a 7 x 10-2 m diameter cylindrical auger made of steel was primed by the method of the invention.

This auger was made @ A eye (by IR needle) 0.
It contained 35% charcoal

The nitrogen-containing gas i was heated to a temperature of 10,0OOK by means of an electric arc-operated type 1.11 plasmatron with a nozzle cross-section of (I X2,1 )XIOm.

The plasma stream was directed at the corner 11 of the auger onto the surface to be treated, and the pressure of the plasma stream against the opposite surface was 15 N/m2. by 7 X 1(1-' rn, p
I scanned at Otori's speed. The distance from the nozzle exit point to the surface to be treated was 5 x 1 (1-' m) followed by the auger (13).
,.

Fully cured. The curing operation was carried out by gilding a heated auger with water to a temperature of 100-150°C.

The nitride layer thus produced on the working surface of this auger was 9×10 −2 m thick and its surface hardness was HV501450.

The ICm0) nitriding time of this auger surface was 1.5 seconds.

Example 5 The working surface of a steel cylindrical auger with a diameter of 7×1 (1-2 m) was nitrided by the method of the invention.

The steel used to make this auger is 0.35% (depending on the amount of vehicles)
of carbon, 0.3% manganese, 1.3F1% chromium,
It had a composition of 0.15% molybdenum, 0.7% aluminum and the balance iron.

(I X 2.1) Electric arc indirect action plasmatron with a nozzle cross section of XIO' m2? make use of,
The nitrogen gas was heated to a temperature of 10,0 OOK.

At the corner of the nitrogen-containing plasma stream? The pressure directed onto the surface to be treated and exerted by the plasma stream on the surface was 1×1 O 5 N/m 2 .

7A (14) The surface to be nitrided is 5 x 10-3 m by plasma flow.
The measurement was conducted at a speed of p, s. The distance from the exit cross section of the nozzle in front of the surface to be treated was approximately 10 m.

The nitride 1- thus produced on the surface-1- of this auger had a thickness of 1"" m and a hardness of the surface HVIlo 750.

The nitriding time of this auger table 1-1σ mesh m2 is 2
It was a second.

Example 6 The FJ group 1 curved surface of a steel gear was nitrided by the method of the invention.

The steel produced in this southern part contained (by M) 0.45% carbon, 0.8% manganese, 1.1'fi chromium, and residual iron.

A nitrogen-containing gas i fl (heated to a temperature of 100 K) was used using an electric arc indirect action plasmatron gold with a nozzle cross section of (I

The nitrogen-containing plasma (rlt) was directed onto the surface to be treated at a right angle and the pressure of the plasma flow below the surface was 1 x 111'' N/m2. O, l X m' m
, p, s. The distance from the exit cross-section of the nozzle to the surface to be treated was 5 x 10-' m. The nitrided layer thus produced on the working surface of this gear had a thickness of I x 10 -5 m and a surface hardness of HV5 (.550).

The nitriding time for each surface of this gear used was 10 seconds.

Example 7 The working surface of a steel gear was nitrided by the method of the invention.

The steel from which this gear was made had a composition (from one stitch) of 0.45% carbon, 0.8% manganese, 1.1% chromium, and residual iron.

The wood-containing gas was heated to a temperature of 'klo,0OOK' by an electric arc indirectly acting plasmatron with a nozzle cross section of (I x 2,1 ) x 10-' m2.

The nitrogen-containing plasma stream was directed at all normal angles onto the surface to be treated, and the pressure exerted by the plasma stream on the surface was 0.1 x 105 N/m2.

(It) treatment)] surface by 6X10-'m by plasma flow
, p, s. The distance from the exit cross section of the nozzle to the surface to be treated was 5×10 m.

After that, the gear was completely hardened. Therefore, the heated gear was rapidly cooled with water to a temperature of 100 to 150°C σ).

The nitrided layer thus produced on the working surface of this gear was 65×1 (l m) thick and the hardness of the surface was IIV5o960.

The time required for 9ization of the used surface of this gear was 2 seconds.

While specific implementations of the invention have been shown and described, various modifications will be apparent to those skilled in the art. Therefore, the invention is not limited to the embodiments or details disclosed, as modifications within the spirit of the invention may be possible.

Applicant's agent Kiyoshi Inomata (16) N'Darenko Soviet Union Kiev U-IJ Sotsya Industrialianaya 22 Bay Carver 48 0 Inventor Evgeny Ivanovich Yakoulev Soviet Union Kiev Purvar Regi Ukraine 2 forces 1 bar 25 0 Inventor Lev Zakharovich Neymark Soviet Union Fastov Kievskaya Oblast Uritsa Plautoy 17

Claims (1)

[Claims] In the process of nitriding gold@products, which involves treating the metal product in a nitrogen-containing plasma, the internal temperature of the stream is low (both 6,0 OOK and the pressure of the flow on the surface of the metal product being treated is (0,03 to 1 )XIO"N/m2 in a nitrogen-containing plasma flow with a pressure of 0-3 to 10-2m, p
A method for nitriding metal products, characterized in that the treatment is carried out by scanning the surface with the plasma flow at a speed of , s.