JPS5821489A - Lubricant for cold working or hot-cold working of metallic tube - Google Patents

Abstract

PURPOSE:To provide the titled lubricant composed of an aqueous dispersion containing a bicarbonate as a main component and specific amounts of a dispersant and a surface active agent, giving high reduction ratio, exhibiting excellent lubricating effect in not only cold working but also hot-cold working, and removable easily after working. CONSTITUTION:The objective lubricant oil is composed of an aqueous dispersion containing 5-55(wt)% bicarbonate (e.g. sodium bicarbonate, potassium bicarbonate, etc.) as a main component, 0.1-1.0% dispersant (preferably a linear polysaccharide, silicate, fatty acid metal salt, etc.), 1-2% surface active agent (preferably fatty acid monoethanolamide, etc.) and preferably <=12% metallic soap and/or graphite. EFFECT:The composition is stable to heat, and exhibits excellent lubricating effect even under the working at 400 deg.C. USE:For the rolling and drawing, etc. of metallic sheet, bar, rod, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a lubricant for cold to warm processing of metal pipes, and more specifically, the present invention relates to a lubricant for cold to warm processing of metal pipes, and more specifically, a lubricant containing hydrogen carbonate as a main component and an appropriate amount of a dispersant and a surfactant, or further containing a metal soap or a surfactant. It is used in an aqueous dispersion containing a solid lubricant such as graphite.

When various types of metal pipes, including steel pipes, are subjected to cold or warm processing such as rolling, forging, extrusion, drawing, etc., it is necessary to cover them in order to improve the quality of processed products and suppress tool wear (prevention of seizure). Various lubricants are used. However, the known lubricants cannot be said to satisfy all of the requirements such as lubrication performance, ease of removal after processing, and low pollution of waste fluid.

For example, metal soap, designated vegetable oil, mineral oil, plastic working oil (containing extreme pressure additives), etc. are used as lubricants for relatively light machining, but when the degree of machining increases, the workpiece tube and tool The area of metal contact with the metal increases and damage to the tool and product becomes significant. In order to prevent such troubles, it has been conventional practice to form a chemical conversion film on the surface of the pipe material in advance and to improve lubricity with a chemical metal soap coating agent. The above chemical conversion coating is a phosphate coating (
common steel and low alloy steel), aluminum fluoride coating (IAj
), oxalate wave IE (stainless steel), etc. are known. With this method, a chemical coating is interposed between the pipe to be processed and the chemical metal soap coating, and since these are chemically integrated, the lubricating coating exhibits extremely strong adhesion.
Demonstrates sufficient lubrication function even when machining rates are increased. However, this method has the problem that the lubricating effect decreases as the processing temperature increases. For example, a chemical metal soap coating applied to a phosphate coating loses most of its lubricating effect at around 350°C. Moreover, since it is a chemically reactive lubricant, managing the treatment liquid is troublesome, and its short lifespan requires frequent treatment of waste liquid, which poses economic problems and causes pollution. There is also. In addition, since the above-mentioned lubricating coating has too good adhesion, there is also the problem that it is difficult to remove the coating from the processed product.

Therefore, it has a high machining rate and exhibits an excellent lubrication effect in both cold and warm machining.Moreover, the lubricating fluid is easy to handle and can be easily removed after machining, making it possible to provide lubrication that does not cause waste fluid pollution. Development of new agents is desired.

The present inventors have focused on the above-mentioned circumstances and have conducted research with the aim of developing a lubricant that can satisfy all of the above-mentioned requirements. As a result, as a lubricant component of this type, the main component is hydrogen carbonate, which has never been used before.
We found that an aqueous dispersion containing a small amount of a dispersant and a surfactant, or a suitable amount of a solid lubricant together with these, becomes an excellent lubricant that meets the above objectives, and completed the present invention for strings.

That is, the composition of the lubricant for cold to warm working of metal pipes according to the present invention is hydrogen carbonate: 5 to 55% (weight: the same below), dispersant: 0.1 to 1.0%, and Surfactant: 1~
The gist is that it consists of an aqueous dispersion containing 2% of metal soap and/or graphite, or in addition to these, 12 volumes or less.

As mentioned above, conventional lubricants for processing metal pipes generally do not exhibit sufficient lubrication at high processing rates, even at low processing rates, and furthermore, as the processing temperature increases, the lubricating effect is extremely reduced. However, when the present inventors investigated the lubricating performance of a number of substances under high pressure, they found that hydrogen carbonates such as sodium hydrogen carbonate and potassium hydrogen carbonate form extremely good lubricating films even under high pressure. confirmed. Moreover, this lubricating film is not only applied during cold working, but also
It was found that it is stable even under warm working conditions where temperatures of about 0°C are applied and maintains high lubrication function. As a result, it is possible to prevent seizure during machining, improve the surface and surface properties of the product, and extend the life of the tool. Moreover, it has been confirmed that the above-mentioned lubricating film can be easily removed from the surface of the processed product and hardly causes problems such as waste liquid pollution. However, since hydrogen carbonate is a solid substance, it is difficult to use it directly as a lubricant in terms of workability and the like, so it is necessary to find an appropriate form of use as a lubricant. This point has been easily addressed by dispersing bicarbonate in water with small amounts of dispersants and surfactants. That is, although the preferred content of hydrogen carbonate will be clarified later, its blending ratio with respect to the total amount of the lubricant is quite high, and it is often used in a state exceeding its solubility in water. Therefore, unless special measures are taken, the lubricant must be used in a suspended state, and the lubricant has poor stability, which poses a practical problem. However, when a small amount of a dispersant and a surfactant are coexisting in this suspension system, the mixing and dispersibility during the preparation of the dispersion are improved, the stability of the prepared dispersion is also improved, and furthermore, during processing. The formation of a lubricating film and the lubricity itself are also promoted. In particular, surfactants act on the interface between water and solid components (bicarbonate) to lower the interfacial tension and have the effect of uniformly and rapidly dispersing the solid components.

However, the surfactant promotes foaming of the dispersion, which causes various problems during processing (poor adhesion of II lubricant, uneven adhesion, etc.), so it should be kept to a necessary minimum. Although there are various surfactants that exhibit such an effect, the most preferred surfactants confirmed through preliminary experiments were fatty acid amine soaps such as fatty acid monoethanolamide and fatty acid jetanolamide.

Further, the dispersant has the effect of increasing the stability of the dispersion liquid, and is an essential component as an anti-settling agent for bicarbonate. However, if the amount is too high, the fluidity of the dispersion will decrease and it will be difficult to apply it uniformly to the lubricated surface, so it should be kept to the minimum necessary.There are various dispersants that can have this effect. However, the optimal dispersants confirmed in preliminary experiments were linear polysaccharides, silicates, fatty acid metal salts, etc.

The lubricant of the present invention has the above three components as essential constituents, and achieves its purpose by appropriately adjusting the proportions of each component.Additionally, a small amount of solid lubricant made of metal soap and/or graphite is added to the lubricant of the present invention. If combined, the protection effect during tool regeneration will increase,
The tool life can be further extended.

The reason why the content range of the four essential constituents that are neglected in the present invention was determined will be explained below by following the experimental progress.

First, linear polysaccharide: 0.2% as a dispersant, fatty acid monoethanol as a surfactant: 1. Aqueous dispersions were prepared with various contents of hydrogen carbonate (NaHCOs and ■■S), and the lubrication performance of each was examined.

The machining conditions were as shown in Table 1, and the results are shown in Table 2. An aqueous dispersion containing bicarbonate together with a surfactant and a surfactant exhibits extremely good lubricating performance.In order to effectively exhibit the lubricating effect of bicarbonate, at least 5 liters of bicarbonate should be added to the dispersion.
Preferably, it is necessary to contain 20 or more. However, within the content range used in this experiment, there was no upper limit as far as lubricating performance was concerned. However, among those used in the above experiments, a tendency for the aqueous dispersion to separate was observed in those with a hydrogen carbonate content of over 60%, so the relationship between the stability of the aqueous dispersion and the hydrogen carbonate content was clarified. An experiment was conducted to find out.

That is, an aqueous dispersion (m lubricant) was prepared by using the same dispersant and surfactant as above and adding 5 to 70 hydrogen carbonate (NmHCσ0), and after standing for 200 hours, the liquid We investigated the stability of

The results are shown in Table 3.

Table 3 O: Excellent...uniformly distributed [Figure 1 4] 0: Good
... Although there is some separation in the lower part, there is no practical problem (Figure C111 (c))] Δ: Problem... The solid components are separated into upper and lower parts, and the lower layer tends to solidify [Figure 1, 9] X: Poor ...The solid component precipitates at the bottom and solidifies [Figure 1 (b)] As is clear from the above results, the separation stability of the lubricant is better when the concentration of hydrogen carbonate is lower; rate is 4
It is excellent up to about 5 liters, but if it exceeds 50 liters, it tends to deteriorate, and if it exceeds 55 liters, separation becomes significant and the separated solid components become coagulated, making it impractical. However, if it is less than 55 gallons, there will be a slight tendency for separation, but it will be sufficient to redisperse by natural stirring during use.1.
There is no practical problem.

From these experiments, it is understood that in order to satisfy both lubrication performance and separation stability, the content of hydrogen carbonate should be set in the range of 5 to 55%, more preferably 20 to 45%.

Next〈Based on the above experimental results, the amount of hydrogen carbonate was set at 30 liters, which is thought to be the optimum, and the lubricant was prepared with various surfactant contents while keeping the dispersant content constant at 0.5 liters. The relationship between the amount of surfactant and the dispersibility of solid components was investigated.

Note that sodium hydrogen carbonate was used as the hydrogen carbonate, and fatty acid monoethanolamide was used as the dispersant and linear polysaccharide surfactant.

As a result, it was not possible to uniformly disperse the solid components without adding a surfactant, but when more than 1 liter of surfactant was added, the solid components were easily separated with short stirring, making it possible to obtain a uniform lubricant. Ta. However, if it exceeds 2 gallons, foaming of the lubricant becomes significant, which tends to cause poor adhesion of the lubricant and uneven lubrication during use.

From these results, the amount of surfactant is 1 to 2 in the total lubricant.
Singing is the best.

Next, hydrogen carbonate (NaHCOs) was set at 30%, surfactant (fatty acid monoethanolamide) was set at 1.0%,
The relationship between the amount of dispersant (linear polysaccharide) added and the stability of the lubricant was investigated. As a result, if no dispersant is added, hydrogen carbonate cannot be uniformly dispersed and a uniform and stable lubricant cannot be obtained, but if a dispersant of 0.1- or more is added, extremely stable and uniform dispersion can be achieved. It was found that a liquid was obtained.

However, as the amount of dispersant added increases, the fluidity of the dispersion decreases, and if it exceeds 1.0%, the dispersion solidifies into a gel-like state and cannot be used as a lubricant. From these results,
The content of the dispersant is in the range of 0.1 to 1.0 liters in the total amount of lubricant.
We came to the conclusion that it should be set within the limits.

Through the above experiments, the preferred content ranges of hydrogen carbonate, dispersant, and surfactant, which are the four essential constituents of the lubricant of the present invention, have been clarified. However, the present inventors conducted the following experiment in order to clarify the more preferable content range of hydrogen carbonate, which is the main component, among the above-mentioned essential components.

That is, as shown in Table 4, a large number of lubricants with varying hydrogen carbonate contents were prepared.U. The lubrication performance was measured. This test method uses, for example, 9J
As shown in Figure 2 (A) ~ Illustrated, a short steel tube 1 coated with lubricant on the inside is inserted into the die 2 with a gap, and the steel ball 3 placed above is forcefully pushed in by the ram 4. Short tube 1
to press around.

The performance of the lubricant is judged from the inner surface properties of the short tube 1 and the surface properties of the steel balls 3. Since the conditions are harsher than the actual conditions of the tube, the performance of the lubricant is strictly determined. can be determined.

The performance of each lubricant obtained in the above tests (inner surface flaws of steel pipe 1 and surface flaws of steel ball 3), along with the lubricant adhesion amount and stability, and the actual pressure tube test results (conditions in Table 1 above) Table 4 shows them all.

The performance evaluation criteria in the table are as follows.

0--Excellent 0--Good Δ--Problems (slightly many surface scratches) ×---Poor (unusable due to surface scratches) Based on the results in Table 4, the following can be considered.

■In the above gastric acid rolling test, even when the amount of hydrogen carbonate was added above the specified amount, almost no scratches appeared on the inner surface of the short tube.
This tendency is the same as the results of actual rolling tests, but there is a tendency for surface scratches on the steel balls to become significant when the amount of hydrogen carbonate exceeds 40 liters. The presence or absence of surface scratches on the steel ball has a correlation with the wear of the die during actual rolling tests, and from this experiment it is considered that the more preferable upper limit of the hydrogen carbonate is around 40-40. Observing the occurrence of scratches on the inner surface of the short tube, it changes from "good" to "excellent" when the bicarbonate content increases from 15% to 20'4, indicating that the preferable lower limit of the amount of bicarbonate The value is thought to be around 20%.

■The above tendency can also be seen from the amount of lubricant deposited. In other words, it has been confirmed in preliminary experiments that the lubricant of the present invention tends to seize more severely as the amount of lubricant increases, but when the amount of hydrogen carbonate exceeds 40%, the amount of adhesion decreases. It is rapidly increasing, and from this point of view,
It is considered that the most preferable amount of hydrogen carbonate is 40% or less.

The group ``Lubricant ^■'' is an example in which carbonate is used in combination with hydrogen carbonate, and even in this case, a lubricant with excellent performance can be obtained. However, it has been confirmed that when all of the hydrogen carbonate is replaced with carbonate, the separation stability and lubricating function of the lubricant are far inferior.

In addition, according to preliminary experiments conducted separately, it was found that adding a small amount of solid lubricant made of metal soap and/or graphite to the above-mentioned lubricant further improved the lubrication performance, and in particular, there was a tendency to reduce die seizure. Therefore, an experiment was conducted to clarify the preferred content of the solid lubricant.

That is, as shown in Table 5, lubricants were prepared in which the contents of the Na□S1 dispersant and surfactant were kept constant and only the amount of the solid lubricant (calcium stearate or graphite) was changed.
Separation stability and lubrication performance were investigated using the same test methods as shown in the table.

The results are summarized in Table 5.

As is clear from Table 6, an appropriate amount of metal soap and/or
Or, if graphite is used in combination, the lubrication performance will be further improved. The allowable addition amount of these solid lubricants is 1 from the viewpoint of lubricant stability.
Although the content is 2% or less, a range of 2 to 8-8 is optimal in order to effectively exhibit the effect of improving lubrication performance.

However, it is desired that the lubricant not only have good separation stability and lubrication performance as described above, but also not impair the corrosion resistance of the pipe to be processed. Therefore, we conducted an experiment to clearly confirm this point.

[Corrosiveness to metal materials]

Prepare the following three types of lubricants, and dip-coat each lubricant on iron, steel, or plate (60mj x 80W) #c polished with emery paper φ240. After this was left at 110° C. for 2 hours, the state of corrosion on the surface was observed.

The results are shown in Table 6.

Lubricant A, NaHω@: 36%, dispersant: 0
．． 2%, surfactant: 1-Lubricant B, NaHOOs: 30%, dispersant: 0.2%, surfactant: 1%, stearin Cm: 4, lubricant C-N output ω$: 30 liters, dispersant: 0.2 liters, surfactant: 1 liter, graphite: 4- Table 6 O: No corrosion observed at all.

0: No corrosion was observed in the noodles.

As is clear from the above results, the lubricant of the present invention has no fear of corroding the materials to be aged.

The outline of the present invention is constructed as described above, but the key point is that hydrogen carbonate is used as the main component, and this is uniformly dispersed in water with an appropriate amount of a dispersant and a surfactant, or an appropriate amount of solid is added to this. By adding a lubricant, it became possible to provide a lubricant having various excellent properties as listed below.

■It forms a lubricating film with excellent performance even under severe machining conditions, so it can be used effectively over a wide range of machining rates.

In addition, the number of printing tables and the like during processing is drastically reduced, improving the quality of processed products and significantly extending the life of the processed parts.

■It is stable against heat and exhibits excellent lubrication even under processing conditions of about 400 tons, so it can be used not only for cold working but also for warm working.

■Since no adhesive is used and the main component, hydrogen carbonate, is easily soluble in water, it is extremely easy to remove after processing.

- Carbonated water bulk salt is economical because it is cheaper than general lubricants, and since it is harmless, there is no risk of causing waste liquid pollution.

■The lubricant is stable and has a long service life with little deterioration, making it highly suitable for continuous processing.

■This lubricant is most effective when used for metal pipes and processing (especially rolling), but it is also used as a lubricant for rolling and wire drawing of metal plates, bars, wires, etc. also exhibits excellent functionality.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a separation state observed in a lubricant separation stability test, and FIG. 2 is a schematic cross-sectional explanatory diagram showing a lubricant performance test method. 1... Short metal tube, 2... Dice, 3... Steel ball, 4...
...Rum. Applicant Kobe Steel, Ltd.

Claims (2)

[Claims] (1) Hydrogen salt: 5 to 55 weight - 1 dispersant 80.1 to
1. A lubricant for cold to warm working of metal pipes, comprising an aqueous dispersion containing 1 to 2 parts by weight of a surfactant. (2) Hydrogen carbonate = S~55 weight, weight agent: 0.1~
For cold to warm processing of metal pipes, comprising an aqueous dispersion containing 1.0 kg by weight, surfactant = 1 to 2 kg by weight, and metal soap and/or graphite: 12 kg by weight or less. lubricant.