JPH0480387A - How to clean iron sliding parts - Google Patents

Abstract

PURPOSE:To give high rust preventive power to iron-base sliding parts and to improve lubricating property thereof in a real sliding system by cleaning the parts with an inorg. alkali aq. soln. and then repeating cleaning twice with an org. alkali aq. soln. containing ethanolamine and thioacetoamide as coexisting components. CONSTITUTION:A spherical graphite cast iron member is selected as a sliding part to the cleaned. First, this part is subjected to primary cleaning with inorg. alkali aq. soln. This treatment is performed with using 5% sodium hydroxide soln. for 5 minutes. Then the secondary cleaning treatment with org. alkali aq. soln. is performed with using a soln. of 3% triethanolamine + 12% thioacetoamide. Further, the tertiary cleaning treatment with org. alkali aq. soln. is performed at 75 deg.C with using a soln. of 3% triethanolamine + 12% thioacetoamide. Then the cleaned part is dried with hot air at 110-120 deg.C.

Description

[Detailed Description of the Invention] [Purpose of the Invention (Field of Industrial Application) The present invention relates to a method for cleaning iron-based sliding parts, and is particularly suitable for improving the anti-caking effect and sliding characteristics of iron-based sliding parts. Regarding cleaning methods.

(Prior art) Compression mechanism parts, such as compressors for refrigeration cycles, are made of ferrous metal materials such as cast iron and cemented carbide tool steel from the viewpoint of mechanical properties, sliding properties, dimensional accuracy, workability, etc. used.

After these materials are machined into a predetermined part shape, processing oil residue and cutting debris remain on the part surface, so cleaning including degreasing is performed on the part surface.

In this cleaning, conventionally, an organic solvent such as kerosene to which a rust preventive agent has been added has often been used as a cleaning agent.

In this case, since the organic solvent is a flammable substance, it was necessary to take extreme care in cleaning handling and to make the cleaning equipment safer (explosion-proof measures, etc.).

Therefore, instead of using such organic solvents, a method of degreasing and cleaning by alkaline aqueous solution cleaning without using flammable organic solvents has been adopted. This alkaline aqueous solution is
Because of its strong detergency, inorganic alkalis, particularly those containing sodium hydroxide as a main component, are generally used for primary cleaning.

Although inorganic alkali has strong cleaning power, it tends to remain on the iron surface, and if it remains, it may corrode the fitting of sliding parts or adversely affect the cycle, so it is necessary to rinse thoroughly after cleaning with inorganic alkali. There is.

In this rinsing process, if an anti-rust component is not added to the rinsing solution, the iron-based material will rust immediately during the cleaning process, which will impede the dimensional accuracy of assembling the sliding parts.

In order to avoid this problem, conventional methods have been to apply a thin layer of anti-rust oil immediately after rinsing with water only, or to rinse with a rinsing solution containing amine.

However, these methods also include various problems. That is, in the former case, rusting cannot be completely suppressed unless the rinsing time or the drying after rinsing is strictly controlled. Furthermore, controlling the thickness of the anti-rust oil film is difficult due to the high viscosity of the oil, and positioning between parts is often difficult, especially when fitting sliding parts that require dimensional accuracy on the order of microns. Ta.

In the latter method, although the amine rust preventive agent exhibits its effect at low temperatures, if the parts after cleaning are exposed to a high temperature atmosphere such as excessive hot air drying, the anti-caking effect will be significantly reduced.

Furthermore, even if cleaning is performed with sufficient anti-corrosion ability and a thin coating, the material itself may lack lubricity when incorporated into iron-based sliding parts or actual sliding systems after cleaning. Therefore, it was necessary to add a lubricant component to the refrigerating machine oil or to subject the material itself to surface hardening treatment in advance.

(Problems to be Solved by the Invention) As described above, there are various problems in the cleaning method for iron-based sliding parts, and the conventional cleaning method using an alkaline aqueous solution has a difficulty in the rinsing process.

In other words, the rust prevention effect after cleaning may be insufficient, or conversely, if a rust prevention oil is used to exert its rust prevention ability, it is difficult to control the thickness of the rust prevention film that is formed.
There was a problem with the film becoming too thick.

Therefore, the cleaning method can easily control the thickness of the anti-rust film, form a thin film, provide high anti-corrosive power, and improve lubricity in actual sliding systems. is strongly desired.

The present invention has been made in response to such conventional circumstances, and it is possible to maintain the rust prevention effect of the parts during and after the cleaning process in cleaning iron-based sliding parts with an alkaline aqueous solution, and to The purpose of the present invention is to provide a cleaning method that can ensure the sliding properties of the sliding system of iron-based sliding parts, especially the initial conformability, by surface hardening the material or adding a 111 lubricating component to the refrigerating machine oil. .

[Structure of the Invention] (Means for Solving the Problems) The method for cleaning iron-based sliding parts of the present invention includes an inorganic alkaline cleaning step of cleaning the iron-based sliding parts with an inorganic alkaline aqueous solution;
This inorganic alkali washing step is followed by an organic alkali washing step of washing with an organic alkali aqueous solution containing ethanolamine and thioacetamide as co-components, and the organic alkali washing step is repeated at least twice. It is said that

In the present invention, as the inorganic alkali aqueous solution, for example, a sodium hydroxide aqueous solution, a silicate aqueous solution, a phosphate aqueous solution, etc. are used, and cleaning is performed by a dipping method or a spray method.

The organic alkaline aqueous solution used in the present invention contains ethanolamine and thioacetamide as co-components.

It is preferable that at least one of triethanolamine and jetanolamine is contained as ethanolamine in an amount of 1 to 5% as a total ethanolamine concentration.

In addition, the concentration of the thioacetamide is preferably 5 to 10% with respect to the organic alkali aqueous solution, and if the concentration of thioacetamide is less than 5%, the sliding properties cannot be improved;
If it exceeds 0%, the cleaning effect will be impaired.

Furthermore, in the present invention, the organic alkali cleaning step is repeated two or more times, and the temperature of the organic alkali aqueous solution from the second time onwards is set to 70°C or higher, thereby further improving the rust prevention effect and sliding properties. I can do it. This is because the 18 atoms in thioacetamide form a strong bond with iron at a temperature of 70°C or higher, so when this iron-based sliding part is applied to an actual sliding system, it will re-9 at the initial stage of sliding. This is because a skin-like lubricating film is formed by the compound and improves initial familiarity.

(Function) In the actual cleaning process, the temperature of the object to be cleaned varies greatly depending on the air temperature at that time, but according to the present invention, by co-adding ethanolamine and thioacetamide, ethanolamine is added in the low temperature range, and thioacetamide is added in the high temperature range. Due to the action of thioacetamide, a stable rust prevention effect can always be obtained even if the temperature of the parts to be cleaned changes.

In addition, the sulfur (S) atoms in thioacetamide react with the iron base material to form a re-8 compound on the iron base during the run-in process at the initial stage of sliding, and this compound improves the sliding properties.

Furthermore, in the present invention, all treatments are performed using an aqueous solution system, which facilitates work and liquid management.

(Example) Next, embodiments of the present invention will be described using the drawings.

Embodiment 1 FIG. 1 is a flowchart showing a cleaning process for iron-based sliding parts according to an embodiment of the present invention.

FCD-55 (spheroidal graphite cast iron) material is selected as the sliding part to be cleaned, and the FCD-55 material is first subjected to primary inorganic alkaline aqueous solution cleaning. A 5% aqueous sodium hydroxide solution was used as the inorganic alkali aqueous solution, and the treatment was performed for 5 minutes (step 11).

Next, secondary organic alkaline aqueous solution cleaning was performed at room temperature using an aqueous solution of 3% triethanolamine + 12% thioacetamide for 2 minutes (step 12).

Furthermore, tertiary organic alkaline aqueous solution cleaning was carried out at 75°C.
A washing process was performed for 2 minutes using an aqueous solution of 3% triethanolamine + 12% thioacetamide (
Step 13).

Thereafter, the parts to be cleaned were dried by hot air drying at about 110 to 120°C (step 14).

After the cleaning process is completed in this way, the temperature is 901°C at 40°C. l
When the sliding parts were left in an I% atmosphere and the time until rusting was measured, a result of 9.5 hours was obtained.

In addition, as a result of investigating the time required for rust to occur on the surface of the component while it is still immersed in the final cleaning solution, it was found that in this example,
It did not rust over time. These results are shown in Table 1.

Furthermore, PCD-55 (spheroidal graphite cast iron) material was processed into a pin shape for Falex sliding test, and washed and dried using the method according to this example.

Then, a Falex sliding test of 501bs (while contacting with a load of 50 pounds) for 1 minute was conducted under non-lubricated conditions, facing a block made of SMF4 type sintered alloy. The measurement results of the dynamic friction coefficient at this time are shown in Table 2.

Example 2 1. According to the flowchart shown in FIG. As in Example 1, a PCD-55 (spheroidal graphite cast iron) material processed into a predetermined shape as a sliding part was cleaned.

However, in step 12, an organic alkaline aqueous solution of 3% triethanolamine + 2% thioacetamide was used, and in step 13, 3% triethanolamine + 2% thioacetamide was used.
A 2% organic alkaline aqueous solution of thioacetamide was used.

Other conditions were the same as in Example 1. In addition, the time required for rust to develop after the completion of the cleaning process and the time required for rust to occur on the surface of the component while immersed in the final cleaning solution were measured under the same conditions as in Example 1, and the results were reported in the first example. Shown in the table.

Further, Table 2 shows the results of the Farex sliding test under non-lubricated conditions.

Example 3 According to the flowchart shown in FIG. 1, FCC-55 (spheroidal graphite cast iron) material processed into a predetermined shape as a sliding part was cleaned in the same manner as in Example 1.

However, in step 13, the cleaning treatment was performed at room temperature for 2 minutes.

Other conditions are the same as in Example 1. In addition, the time required for rust to develop after the completion of the cleaning process and the time required for rust to appear on the surface of the component while immersed in the final cleaning solution were determined under the same conditions as in Example 1, and the results were reported in Section 7111j. It is shown in Table 1.

Further, Table 2 shows the results of the Farex sliding test under non-lubricated conditions.

Example 4 According to the flowchart shown in FIG. 1, POD-55 (spheroidal graphite cast iron) material processed into a predetermined shape as a sliding part was cleaned in the same manner as in Example 1.

However, in Step 12, an organic alkaline aqueous solution of 0.5% triethanolamine + 12% thioacetamide was used, and in Step 13, an organic alkaline aqueous solution of 0.5% triethanolamine + 12% thioacetamide was used.

Other conditions were the same as in Example 1. In addition, the time until rust appears after the completion of the cleaning process and the time until rust appears on the surface of the part while immersed in the final cleaning solution were measured under the same conditions as in Example 1, and the results are shown in Table 1. Shown below.

Further, Table 2 shows the results of the Farex sliding test under non-lubricated conditions.

Comparative Example 1 FIG. 2 is a flowchart showing a conventional cleaning process for iron-based sliding parts.

The same PCD-55 as in the example was used as the sliding part for cleaning.
Spheroidal graphite cast iron) material is selected, and this FCD-55 material is subjected to primary inorganic alkaline aqueous solution cleaning. A 5% aqueous sodium hydroxide solution was used as the inorganic alkali aqueous solution, and treatment was performed for 5 minutes (step 21).

Next, a secondary organic alkaline aqueous solution cleaning was performed at room temperature using a 3% alkaline aqueous solution of triethanolamine.
A washing process was performed for 2 minutes (step 22).

Thereafter, the parts to be cleaned were dried by hot air drying at about 110 to 120°C (step 23).

After the cleaning process is completed in this way, 40
When the sliding parts were left in an atmosphere of 90RH% at ℃ and the time until rusting was measured, the result was 4.0 hours.
Further, the time required for rust to appear on the surface of the part while it was immersed in the final cleaning solution was investigated and the result was 40 minutes.

These results are shown in Table 1 together with the results of Examples.

Furthermore, a Farex sliding test was conducted under non-lubricated conditions, facing a block made of SMP type 4 sintered alloy. The coefficient of dynamic friction at this time was 0.56, indicating low lubricity. This measurement result is combined with the results of the example and the second
Shown in the table.

Comparative Example 2 FIG. 3 is a flowchart showing a cleaning process in another conventional method for iron-based sliding parts.

The same FCD-55 (
Spheroidal graphite cast iron) material is selected, and this PCD-55 material is first subjected to primary inorganic alkaline aqueous solution cleaning. A treatment was performed for 5 minutes using a 5% aqueous sodium hydroxide solution as an inorganic alkali aqueous solution (step 31).

Next, rinsing with pure water was performed for 2 minutes at room temperature (step 32).

After rinsing, fender oil was applied to the surface of the part by dipping (step 33).

Thereafter, the parts to be cleaned were dried by hot air drying at about 110 to 120°C (step 34).

After the cleaning process was completed, we measured the time for rust to develop in the same manner as in the example, and found that the time to rust after cleaning and drying was 9.0 hours, which was not that fast. However, when it was immersed in the final cleaning solution, rust developed within one minute. These results are shown in Table 1 together with the results of Examples.

Furthermore, when a Falex sliding test was conducted under non-lubricated conditions, the coefficient of dynamic friction was 0.55, indicating low lubricity. The i'1llJ determination results are shown in Table 2 together with the results of Examples.

Comparative Example 3 The same FCD-55 (
Spheroidal graphite cast iron) material was selected, and this PCD-55 material was cleaned with only acetone.

Then, the time until rusting and the Farex sliding test were conducted in the same manner as in the examples. The results are shown in Tables 1 and 2.

(Left space below) Table 1 As is clear from these results, all the sliding parts to which the cleaning method of the example was applied did not develop rust for more than 7 hours after drying and had good corrosion resistance. In all comparative examples using the conventional cleaning method, except for comparative example 2 where anti-rust oil was applied, all of the comparative examples were 4.
Rust occurs in less than an hour, and in the case of Comparative Example 2, rust was observed within 1 minute while immersed in the final cleaning solution, suggesting that the probability of rusting is extremely high if the cleaning solution is not carefully removed. be done.

In addition, the results of the Farex sliding test showed that the comparative example using the conventional cleaning method showed a dynamic friction coefficient exceeding 0.5 and lacked lubricity, whereas the sliding test using the cleaning method of the example The parts had improved lubricity with a dynamic friction coefficient of 0.4 or less.

[Effects of the Invention] As explained above, according to the method for cleaning iron-based sliding parts of the present invention, there is a high rust prevention effect on iron-based sliding parts, and the sliding parts are assembled after cleaning. The sliding characteristics of iron-based sliding parts in the compression mechanism can be improved.

[Brief explanation of drawings]

Figure 1 is a flowchart showing the cleaning method for iron-based sliding parts according to the present invention in order of process, Figure 2 is a flowchart showing the conventional cleaning method for iron-based sliding parts in order of process, and Figure 3 is a flowchart showing the conventional cleaning method for iron-based sliding parts in order of process. It is a flowchart which shows the cleaning method of system sliding parts in order of steps. Applicant: Toshiba Corporation

Claims (2)

[Claims] (1) An inorganic alkali cleaning process in which iron-based sliding parts are cleaned with an inorganic alkali aqueous solution, and an organic alkali cleaning process following this inorganic alkali cleaning process in which they are cleaned with an organic alkali aqueous solution containing ethanolamine and thioacetamide as coexisting components. A method for cleaning iron-based sliding parts, comprising: the organic alkali cleaning step being repeated at least twice. (2) The method for cleaning iron-based sliding parts according to claim 1, wherein in the organic alkaline cleaning step, the temperature of the organic alkaline aqueous solution is set to 70° C. or higher.