DE2109997A1 - Process for metallic cementing animals - Google Patents

Description

2109997 Dipl.-Ing. H. Sauerland · Dr.-lng. R. KoWg -

^{M 5} ^ Olpl.-Ing. Mountains ^ö ^

Patent Attorneys ■ 4ood Düsseldorf ■ Cecilienallee ve · Telephone 432732

Our file: 26,496 March 2nd, 1971

Il / Ro.

Kabushiki Kaisha Eito, 1084, Nakanoshima,

= 3SS = S = S = S == SSSS = SSSSSS3SSSS = SSSC = S == SS

Kawasaki-shi, Kanagawa-ken, Japan S == 3 === S3 ===== SSaSSa = SB3SSSBSSB3S

"Process for metallic cementing"

Common metal products include stainless steel Steels, namely high-alloy steels, if the material is corrosion-free, heat-resistant and wear-resistant target. However, these metals are expensive. From this point of view, the invention is based on the object To create types of material that meet these requirements and are cheap at the same time. In other words, the invention relates to iron or iron products Steel, the surface of which has the properties of a high-alloyed metal, while inside the composition is that of the original material. Acts For example, it is a chain and one takes into account the fact that stainless steel is bad is weldable, this chain is made of a low carbon steel and the invention is applied to this chain. It remains yours internal mechanical strength as it is, and an alloyed layer is formed only on the surface, which is corrosion-resistant, heat-resistant and wear-resistant. In this way, metallic products, especially those made from iron or steel, can

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wrestling costs are produced, the excellent Have properties, such as chains.

-To explain the principles of the invention in more detail reference is made to the following description of typical embodiments of the invention shown in FIG Drawing are shown · Show there

Fig. 1 is a longitudinal section, seen from the side, illustrating an example of a gate direction for metal cementing used to practice the invention.

Fig. 2 is a side view of another example,

3 is a section on an enlarged scale showing part of a product after normal metal cementation;

4 shows a section on an enlarged scale to illustrate the state in which the cemented metals have partially fallen away,

Figures 5 to 9

a second embodiment of the invention, and though

Fig. 5 and 6

enlarged sections showing the surface area of a specimen show whose surface has been treated according to the invention,

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7 shows a section on an enlarged scale to illustrate the surface of a piece, the surface of which has been treated by the usual chrome cementing process,

8 shows a diagram of a method for checking the wear,

9 is a graph showing the result of the wear test;

Figures 10 to 15

a third embodiment of the invention, namely

10 is a diagram showing the distribution of hardness of a chain which has been treated by the usual chrome cementing process;

11 is a diagram showing the distribution of the residual stress in the case of a loaded chain,

12 is a diagram for illustrating the result of a fatigue test and FIG

15 is a diagram to illustrate the result of a wear test.

The invention is described below with reference to the drawings.

First of all, let us consider a device for cementing metal

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according to the invention with reference to FIGS. 1 and 2 described. In this apparatus, a non-oxidizing gas such as nitrogen, argon or a hydrocarbon gas is injected through a large number of blow holes provided on an injection pipe 3 located in the lower part of a front opening 2 of a treatment chamber 1. A gas curtain is formed to prevent the entry of air and a front door 4 at the front opening 2 is opened and then an iron or steel product 5 to be treated by cementing is introduced into the chamber. It is supported by a rail 6, moved through the gas curtain and taken up by the treatment chamber 1, into which a material 7 producing chromium chloride is also introduced. Then, after closing the front door 4, the flow of non-oxidizing gas is interrupted through the injection pipe and, after the air in the treatment chamber 1 has been sucked off through a suction pipe 8, the temperature in the treatment chamber is increased to about 1000 ^° C., whereby the fine particles are removed Chromium chloride, which is in a partially molten state inside the treatment chamber or on its periphery, is floated or held in suspension and held in this state for a period of five hours. During this time, chromium is cemented into the surface of the iron or steel product 5 and a chromium-cemented zone B is formed on the surface of a matrix A.

In practical use, instead of introducing the chromium generating material 7 into the treatment ^{chamber 1, an opening 7 1} for supplying fine particles of a metal halide can be provided in the chamber 1, and it is also possible to use the chamber 1 with the

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to feed fine particles through the opening 7 '.

The next step is In die with one the fine Particles of the mentioned gas containing chromium chloride filled the treatment chamber with a small amount of methane (0.1 to 5 vol. 6 are suitable and propane gas can also be used) introduced through a feed pipe 9, and fine carbon particles are created by thermal decomposition of methane in the treatment chamber * It also becomes a chromium carbide through the reaction of this fine particles are created with the chromium chloride and this chromium carbide gets onto the outer surface of the mentioned chrome-cemented zone B cemented and on this catfish a chrome zone C, in which chrome carbide is distributed, formed on the surface of the Elsen and steel products.

As the next step, non-oxidizing gas, for example nitrogen or argon or hydrocarbon gas, is introduced into the treatment chamber 1 through a feed pipe 9 and the gas containing elsenic chloride (FeCl ₂ ), which has been generated by the chrome cementation, is sucked off through the suction pipe and the atmosphere in the treatment chamber 1 replaced by non-oxidizing gas.

Before the chrome-cemented piece is transferred into a cooling chamber 10, which is connected to the treatment chamber 1, non-oxidizing gas, for example nitrogen, argon, hydrogen or a hydrocarbon gas, is admitted into the cooling chamber 10 through a spill tube 11 and containing _{iron chloride (FeCl 2)} Gas that has penetrated into the cooling chamber 10 from the treatment chamber 1 is sucked off through a suction pipe 12 and the atmosphere in the cooling chamber 10 is replaced by non-oxidizing gas.

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Then an intermediate door 13 between the cooling chamber 10 filled with non-oxidizing gas and the treatment chamber 1 is opened and the chrome-cemented iron or steel product is transferred into the cooling chamber 10 with the support of a rail 6, as indicated by the number. The intermediate door 13 is then closed and the chrome-cemented iron or steel product is cooled. Then non-oxidizing gas is injected from the spray tube 3 at the front opening 2! whereby a gas curtain is formed and the front door 4 is opened and an iron or rod product to be treated by chromium cementing is introduced into the treatment chamber 1 as before, the gas curtain preventing the entry of air into the treatment chamber and the chrome cementing proceeding as before.

When the cemented chrome iron or steel product is cooled in the cooling chamber 10 to about 300 ⁰ C, non-oxidizing gas is blown by means of a spray tube 15, which in the lower region of a rear opening 14 of the cooling chamber 10 is arranged. This creates a gas curtain and takes the chrome-cemented iron or steel product out from inside the cooling chamber 10 to air cool it to room temperature, preventing air from entering the cooling chamber through the gas curtain.

The chrome-cemented iron or steel product thus obtained has a structure as shown in FIG. The chrome-cemented zone B and the chrome zone C, in which chrome carbide is distributed, have been formed one above the other on the surface of the matrix A made of ferrite or pearlite. Since the chrome

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cemented iron or steel product has only been cooled down to a certain temperature in the cooling chamber under conditions under which a harmful influence of the _{atmosphere containing ferric chloride (FeCl 2} ), which was generated in the treatment chamber by the aforementioned chrome cementation, is prevented, so the phenomenon of dechroming does not occur, as would be the case if the cooling were to take place in an atmosphere containing ferric chloride (FeClp). As a result, the chrome-cemented iron or steel product is characterized by high gloss.

According to Fig. 2, a quenching chamber 18 with an oil tank 17 can be provided instead of the cooling chamber, and the atmosphere of non-oxidizing gas is generated in the treatment chamber 1 and the chrome-cemented iron or steel product is brought from the treatment chamber 1 into the quenching chamber 18, in which it is directly in the oil tank 17 is thrown into which oil quenching takes place. The structure in the sectional view of the chromium cemented iron or steel product by sequentially annealing (tempering) within the limits of 180 and 600 ⁰ C is obtained, is such that the chromium cemented zone and the chromium zone is spread in which chromium carbide on the surface of the base material the tempered (tempered) martensite structure appear. The chrome-cemented iron or steel product obtained in this way is characterized by a high gloss and the fact that the phenomenon of dechroming does not occur. In carrying out the invention, a curtain of non-oxidizing gas can also be provided in place of the intermediate door 13, and after the chromium cementing has taken place in the treatment chamber 1, the piece treated by the chromium cementing can be fed directly into the cooling chamber 10 or the quenching chamber.

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mer 18 are transported, with the supply of methane and non-oxidizing gas in the treatment chamber 1 is omitted. Chromium iodite or chromium fluoride or the like. can besides Chromium fluoride can be used as chromium halide, and the same result can be achieved even when using Titanium halide can be achieved, for example titanium chloride (TiCl ^) or silicon halide (SiCl ^) instead of Chromium halide.

As for the generation of the atmosphere of the above-mentioned halide in the treatment chamber, the halide can generating material are previously introduced into the treatment chamber, as mentioned above, and the fine Particles of halide may or may not be introduced into the treatment chamber through the feed tube 9 both methods can also be used at the same time.

The front part of the device is provided with a gas injection tube 19 for forming a gas curtain and a Preheating chamber 21 provided with a front door 20, and while cementing corrosion-resistant metal in Iron or steel products takes place in the treatment chamber 1, the remaining iron or steel products can be preheated in the preheating chamber 21, which is achieved that the cementing of corrosion-resistant Metal takes place with greater effectiveness.

The implementation of the invention will be described in more detail below:

Version 1 - (A):

Chromium cementation was performed on a gear for a chemical machine under the following conditions

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carried out that of carbon steel the chemical Composition 0.025% C, 0.2596 Si, 0.8% Mn, 0.011% P and 0.025% S consisted.

(1) Treated amount: 150 kg (70 pieces) per work cycle}

(2) Cementing ^{temperature: 1000 0} C |

(3) cementing time: 5 hours;

(4) Cooling time in the cooling chamber: 2 hours.

After cooling in the cooling chamber, cooling took place in atmospheric air.

The chrome-cemented workpiece thus obtained had a chrome zone 18 microns thick and stood out high gloss without occurrence of the phenomenon of dechroming, as illustrated in FIG. The workpiece also showed good properties, indicating the corrosion resistance in a nitric acid solution concerned.

Version 1 - (B):

Under the following conditions a Chromzementierung was performed on a gear wheel which, of chrome-molybdenum steel having a chemical composition of 0.4% C, 0.32% Si, 0.82% Mn, 0.021% P, 0.015% S 1.02% Cr and 0.25% Mo.

(1) Treated quantity: 150 kg (50 pieces) per operation)

(2) Cementing temperature: 1,030 ⁰ C)

(3) cementing time: 5 hours)

(4) Oil quenching took place immediately after cementing.

The chrome-cemented workpiece thus obtained had a

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Chromium zone, 20 microns thick, was characterized by high gloss and the absence of that illustrated in FIG Chromium plating phenomenon and had a Rockwell hardness of 70 on the surface and that of 52 im Core. In addition, this gear exhibited a remarkable improvement in corrosion resistance and wear resistance compared with an ordinary gear.

Version 2 - (A):

(1) An externally smooth round rod of 9.5 mm in diameter and 50 mm in length of the following was examined chemical composition.

Steel type C. Coals
material
stole low man-
ganhalti
ger steel Chrome-
Molybdenum-
stole Si
Mn
P. 0.43 0.23 0.22 Chemical
Together
settlement
(*) S. 0.21
0.68
0.021 0.19
1.35
0.019 0.21
0.72
0.017 Cr 0.016 0.020 0.016 Mon 1.03 0.21

(2) Treatment a:

In the furnace, in which the atmospheric gas can be controlled from the outside, each test piece and a chromium chloride generating material were placed and after removing the air from the furnace, the fine particles of chromium chloride (CrCl ₂ ), which were partly in molten form -

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stood and were inside the whole furnace or in line its inner circumference, whirled up by increasing the temperature in the furnace to about 1000 °. This condition was maintained for about 5 hours during which the chromium was cemented into the surface of each specimen took place. This created a chrome-cemented zone. Then in the Furnace filled with the gas consisting of fine particles of chromium chloride, a small amount of methane (suitable are 0.1 to 5 Vol.96, and propane gas can also are used). Fine carbon particles were produced by the thermal decomposition of methane generated in the furnace. The reaction of these fine particles with chromium chloride produced chromium carbide and by cementing this chromium carbide into the outer surface of the aforementioned chromium-cemented zone a chromium zone with chromium carbide dispersed therein is created on the outer surface of the specimen.

The specimen was then cooled in oil immediately from the furnace temperature, and the quenching was carried out so as to prevent oxidation on the surface of the specimen. This was followed by tempering (tempering) within the limits of 180 and 600 ^° C. in accordance with the mechanical properties required one after the other.

The sectional structure of the surface-treated test piece I obtained in this way, showed a chrome cemented zone B averaging about 15 microns thick and a chrome zone C averaging about 20 microns thick with chromium carbide dispersed in it. These layers were on the outer surface of the Basic mass of tempered or tempered martensite

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structure has been formed as shown in FIG. (5) treatment b.

If, after completion of the chromium carbide cementation described, the specimen was slowly cooled in the furnace and the quenching in the oil was not carried out, then a chromium zone B with an average thickness of 15 microns and a chromium zone C of 20 microns average thickness resulted on the treated surface of sample II, in which chromium carbide was distributed. These layers were produced on the surface of the matrix A ^f made of ferrite or pearlite according to FIG. 6.

(4) Sample treated in the usual way:

After treatment at 1000 ⁰ C for five hours by the usual Chromz erungs method ementi gave the sectional examination of the surface of the treated test piece III after slow cooling inside the furnace a decarburized zone D of ferrite of an average thickness of 10 microns, a zone E, in the chromium had diffused in, of an average thickness of 5 microns and a chromium zone F of an average of 20 microns thickness on the surface of the matrix A * of ferrite and pearlite, as shown in FIG.

(5) Wear test:

In each case two pieces of the specimens I, II, III mentioned are arranged at right angles to one another as shown in FIG Machine oil is used as a lubricant for these pieces, which can then bear a load of 500 kg. and moving forward, whereby a

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» % ·. -jäfä * «** -tätÄ-J = - ,.

- 13 -

Change in the size of the diameter arises, which was measured as wear loss.

As a result, in comparison with the wear on the surface-treated test piece III, that according to the usual Process had been chrome cemented, found that the extent of wear on the surface-treated according to the invention Sample II, slowly cooled in the oven, is excellent, as shown in Fig. 9 |

is, and that a far better result is included for wear was obtained on Sample I that had been quenched and tempered (tempered).

Version 2 - (B):

(1) The examined piece was the same as that of Execution 2 - (A).

(2) Treatment:

After each specimen was treated under the same conditions as in Embodiment 2 - (A) and the chromium ( cemented zone was formed, a small amount of fine particles of very small diameter became carbon powder (about 10 to 200 g per 100 kg and a particle diameter below 1 mm are suitable) is introduced into the furnace, and chromium carbide is generated by the reaction of chromium chloride and carbon. Chroaceation and dispersion of this chromium carbide in the chromium were carried out, and the test piece, quenching and tempering (tempering) thereof were carried out under the same conditions took place as in version 2 - (A), slowly cooled in the oven and processed.

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In the surface-treated test piece thus obtained, a cemented zone and a chrome zone in which Chromium carbide was distributed, formed on the surface of the iron and steel matrix, and said sample - had the same properties as in the case of embodiment 2 - (A) in terms of wear resistance.

Further, in the case of Embodiment 2 - (C), the same result was obtained even when carbonitriding treatment was performed instead of cementation. The iron or steel product, the surface treatment of which is carried out by the method according to the invention, forms a chromium zone on its surface, so that rust is not produced by corrosion either in the atmosphere or in fresh water, sea water, nitric acid, organic acids and the like. The corrosion resistance can be remarkably improved, and since super hard crystals of carbides or nitrides of chromium or titanium are dispersed in that chromium zone , the wear resistance can be remarkably improved. In addition, chromium has sufficiently diffused into the iron and has formed a metal phase, so that even if a high load is partially applied to the iron product, the chromium zone is almost certainly prevented from being peeled off Quenching and tempering (tempering) a tempered (tempered) martensite structure. This results in the properties that the iron product with increased breaking strength is sufficiently strong against surface pressure and is characterized by increased wear resistance.

Version 3t

A link chain of 7.1 n »Nornaltbaeeeung and 20.2

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Pitch and a link chain of 9.5 mm normal size and 28.6 mm graduation were made of steel with a low manganese content (chemical composition: 0.23% C, 0.21% Si, 1.45% Mn, 0.012% P, 0.023% S). Such material is characterized by excellent weldability and hardenability. Will treatment on these chains a according to the execution 2 - (A) in connection with a more omchlor iderz eugenden material, see above A chrome-cemented zone B results in the metal structure of the link chains that was examined in the section (Chromium-iron alloy layer) averaging around 17 microns thick and a chromium zone C averaging 24 microns thick in which chromium carbide is distributed. These layers surround a core A of tempered (tempered) Martensite structure by quenching and tempering (Tempering) as shown in Figs. As for the distribution of hardness in the sectional view, this is The hardness of the chromium zone C is greatest, the chromium-cemented zone B has a hardness of an iron-chromium alloy and the core has a tempered (tempered) martensite structure and shows a high degree of hardness as in Fig. 10 is shown.

If - as mentioned above - the quenching and tempering (tempering) takes place, the difference changes accordingly the transformation both in the chrome zone C and in the chrome-cemented zone B and the core A das specific volume of the treated part of the chain, so that, as shown in FIG. 11, a residual tension (pressure) on the outside of the rod and a residual tension (tension) arises within the rod. As a result, there is a preload (Pressure) within the stretched part 5 of the link chain and there became an improvement in fatigue strength the chain observed.

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The following describes the results of tests carried out on a chain according to the invention, a chain usual type, on which no chrome cementation was made, and was obtained on a chain, which after the common procedures of chrome cementing were obtained:

(1) Fatigue test:

First of all, the conventional link chain I of 7.1 mm normal size and 20.2 mm pitch, made of steel, was examined with a low manganese content and a chemical composition of 0.23% C, 0.21 ^ 6 Si, 1.43% Mn, 0.012% P and 0.023% S, as well as link chain II (with about 24 microns average thickness of chrome zone C and approximately 17 microns average thickness of the chrome cemented zone) as in the present invention Execution of the chrome cementation and the heat treatment on such a conventional link chain accordingly obtained by the method according to the above-mentioned embodiment. If the fatigue strength with partial pulsating tensile stress (lowest stress 5 kg / mm) on a Losenhausen machine to test the fatigue strength was investigated, the link chain according to the invention proved to be markedly better than the conventional one Chain I as shown in FIG.

(2) Wear resistance test: A Sample I:

A surface treatment using the usual chrome cementing process was carried out on the link chain of 7.1 mm normal size and 20.2 mm pitch, which consists of Low manganese steel and a chemical

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Composition of 0.23% C, 0.21% Si, 1.43% Mn, 0.012% P and 0.023% S and a decarburization zone of ferrite structure. A chrome diffusion zone and a chrome zone were formed on the outside of the core made of ferrite and pearlite. The average thickness of each zone was 48 microns at 9, 17 microns at 10, and 24 microns at 11.

B Sample II:

The chrome cementation was carried out in accordance with one of the versions described here on the link chain mentioned and, as shown in Figs. 3 and 5, a chrome cemented zone B and a chrome zone C became included therein Chromium carbide contained distributed on the outer surface of the core A of tempered or tempered martensite structure obtained by quenching and tempering (tempering). The average thickness of each zone was 17 microns at 13 and 24 microns at 14.

If a wear test was carried out on the specimens I and II mentioned, this resulted in { Result shown in Fig. 13.

In the wear test, machine oil was also applied to the link chain, and the chain was loaded with 1 to and its upward and downward movement was repeated so that the loss of damage (difference between the pitch of the door and the pitch after the test) could be measured.

Since a chain according to the invention has on its surface a Chroaschicht so ktin rust caused by corrosion

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rosion in the atmosphere in fresh water, sea water, nitric acid, organic acids, etc. and the resistance against corrosion can be improved in a remarkable manner. The fact that the chrome zone is super hard Crystals of carbides or nitrides of chromium and titanium contains, in the state of distribution, gives a remarkable improvement in wear resistance. The core has a tempered (tempered) martensite structure obtained by the quenching and tempering (tempering), so that the breaking strength is thereby increased. When the chain was loaded, there was sufficient resistance to stress through Surface pressure on the mutual contact surfaces of the links. Then it corresponds to the metal structure and the hardness distribution according to Fig. 10 chromium in sufficient Diffuses to a large extent, and the hardness of this zone in which chromium is diffused does not change to an extreme Dimensions so that even when the link chain is subjected to a heavy load, there is an effect that the Chromium zone is certainly prevented from peeling off.

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Claims (8)

Kabushiki Kaisha Kito, 1084, Nakanoshima, Kawasaki-shi, Kanagawa-ken, Japan Claims: 1.; Method for cementing metallic objects, characterized in that the object to be cemented is cemented in a treatment chamber in which the fine particles of a halide (e.g., chromium, titanium, or silicon) in suspension and essentially partially molten state and having at least one of the following properties term means: Corrosion Resistanceι Heat Resistancej Wear Resistance. 2. The method according to claim 1, characterized in that after the actual metallic cementing the cemented object is cooled in a cooling chamber, which contains non-oxidizing gas, and from which by-products, e.g. iron halide, are removed have been. 3. The method according to claim 1 or 2, characterized in that the metallic cemented object after the actual cementing using the cementing treatment generated heat in a quenching chamber, 1/113 which contains a non-oxidizing gas and from which by-products such as iron halide etc. have been removed are quenched to a suitable temperature. 4. The method according to any one of claims 1 to 3, in particular for treating objects made of iron or Steel, on the base of which a metal diffusion zone is created by means of the metal halides and then fine particles of carbon, which metal carbides are attached to the atmosphere, are added to the atmosphere Generate the surface of the diffusion zone. 5. The method according to any one of claims 1 to 4, characterized in that before the action of the metal halides a carborated zone or a carbonitrided zone on the Surface of the basic mass of the object made of iron or steel is produced. 6. Device for metal cementing, in particular for performing the method according to one of the claims 1 to 5, characterized by a cementing chamber with an opening to let out gas, which prevents the metal cementing, an opening for the supply of non-oxidizing Gas, an opening for the supply of fine particles of metal halides and a heating source, wherein a cooling chamber with an opening to the outlet of the metal cementing preventive Gas and an opening for the inlet of non-oxidizing Gas arranged side by side and separated by a wall and means are provided in the wall, 1 09841/1133 through which the chamber in which the metal cementing takes place, and the cooling chamber can be connected to one another. 7. Apparatus according to claim 6, characterized in that that the cooling chamber is provided with means for quenching the cemented object. 8. Object made of steel, thereby characterized in that it according to one of the methods according to claims 1 to 5 or in a device according to claim 6 or 7 and made of a by tempering (tempering) the base material consists of martensite structure, which is surrounded by a layer, which is cemented underneath Use of metal halides is made, this layer in turn surrounded by a layer which contains carbides or nitrides of chromium, titanium or silicon in a distributed form. 9 »Link chain, characterized in that it is made according to one of the methods according to claim 1 to 5 and / or in one of the devices according to claim 6 or 7 is produced. 109841/1133