DE2314415A1 - METHOD OF LUBRICATING A WORKPIECE - Google Patents

Description

DR. MÜLLER-BORE DIPL.-PHYS. DR. MANiTZ DIPL-CHEM. DR. DCUFSL D1PL.-ING. FINSTERWALD DIPL INC. GR «.MKOW

PATENT LAWYERS

2: ■ ■ -. '■ ι

11 m ^

K 1092

'Kobe Steel, Ltd., Wakinohama-cho, Eukia-ku, Kobe, Japan

Method for lubricating a workpiece

The invention relates to a method for lubricating a

Workpiece, in particular a wire made of steel, titanium, etc.,

when carrying out a hot forging process, for example dipping in hot s.

In the previously known methods of hot forging wires made of steel, titanium, etc. by heating the wire to a temperature between 450 and 800 ^° C., various problems have arisen with regard to the lubricant and its application.

If a workpiece is heated to a temperature down to below 300 ^° C., then oily materials, such as, for example, oils, fats or lubricating greases, are used as lubricants. Such materials can easily be removed from the workpiece

309842/0831 original inspected

Remove termination of forging. If, however, a workpiece is heated to a temperature above the temperature specified above, in particular to a temperature of more than 450 ⁰ O, then the lubricating capacity of the oily lubricant is practically lost. In these cases, graphite or molybdenum disulfide are used as lubricants. The surface of the workpiece is covered with a film of graphite or molybdenum disulfide, which is very difficult to remove. In order to remove such a film or scale, it is necessary to use a very strong acid, the surface of the workpiece after descaling becomes coarse and the dimensional precision of the workpiece is deteriorated.

When performing a hot forging process, the lubricant is generally dripped onto the workpiece just prior to performing hot forging if the workpiece is a relatively thin wire. However, if the workpiece is a relatively large diameter wire or block, the lubricant is applied to the surfaces in contact with the tool using brushes. However, the oily lubricant mentioned above or other resinous lubricant when performing hot forging process brushed carried out at temperatures of more than 400 ⁰ C, then contact uplifting Liehe difficulties, especially burning, fuming, producing foul-smelling gases occurs etc .

The object of the invention is to solve the above-described Problems with lubrication when performing a Hot forging process occur, which is carried out at a temperature between 450 and 800 ° 0. The invention aims to an improved lubrication method can be made available, when carried out the above-mentioned disadvantages,

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ORIGINAL fNSPEGTED. ■ '·

like burning, smoke formation, the generation of gases etc., can be avoided, with the workpiece after the Forging is very easy to clean, and the surface condition of the workpiece is not impaired.

The invention provides a method of lubricating a V / erkstückes, in particular a wire when carrying out a hot forging process, such as a hot upsetting process, is one such process is carried out at a temperature from 450 to 800 ⁰ G, made available, which is characterized is that an oily lubricant mixed with water is used, and the mixture of lubricant and water is sprayed onto the surfaces of the workpiece which come into contact with the tool.

As for carrying out the inventive method usable oily lubricant come those which are normally used for carrying out hot forging process into consideration, the ⁰ C be carried out at a temperature below 40O. These are, for example, oils, fats, mineral oils and water-soluble resinous synthetic lubricants, which can be used individually or in combination and preferably make up more than 30 % of the lubricating fluid. In addition to the main components, the lubricating fluid may preferably be mixed with other suitable materials for controlling viscosity, suppressing roast, etc. For example, the lubricants given below can be used to carry out the process according to the invention:

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Lubricant, which is composed mainly of oils, fats and Composed of mineral oils:

Sulphide of oils and fats 20 ρ

oils and fats 10 fo

Asphalt ' 8 fo

Anion activator Ί2%

Cation activator 5 fo

Anti-rust agent TO fo '

Mineral oils 30 ^ remainder · .. 5 fo

Lubricant composed mainly of water-soluble synthetic lubricants:

Polyethylene glycol 70 fo

Phosphate 5 fo

Polyacrylic acid 5 fo

Potassium hydroxide 0.5 f °

■ remainder ■. ■. ■ 19.5 fo

To carry out the method according to the invention, the Lubricants such as have been described above, mixed with water or dissolved in water and sprayed onto the surfaces of a workpiece when a hot forging process is carried out with the tool come into contact. It is two-way, the above-described oily lubricants in 5 to 20 times the amount Dissolve water to make a lubricating fluid. Is the amount of lubricant or the degree of thickening of the lubricating fluid too low, then the lubricity of the lubricating fluid is insufficient. On the other hand, the degree of thickening too high, then the fluid becomes too viscous and prone to one

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Burns when sprayed onto the surfaces of a workpiece that come into contact with a tool. The effect of the water is therefore of great importance when carrying out the process according to the invention. The water not only serves as a pluidizing agent for the evenly lubricants to be applied to the surfaces of a workpiece that come into contact with the tool, but also as a coolant to prevent the lubricant from burning and sticking to the hot ones in contact Protect surfaces.

The type of spraying of the lubricating fluid is of minor importance Meaning. However, in order to ensure that the lubricant is evenly applied to the surfaces of a workpiece with the tool come into contact, to apply in the form of a mist, it is advisable to apply the lubricating fluid using a high-pressure nozzle to be sprayed, it being preferable to carry out the spraying in such a way that the lubricant is compressed indirectly by compressed air in an airless pump and not together with under high pressure standing compressed air is compressed. By compressing of the lubricating fluid in an airless pump, it is kept free of bubbles and can be applied evenly to the Surfaces of a workpiece that come into contact with a tool are applied. What the spray pressure in the high pressure nozzle is concerned, it is preferably between

ρ ρ

50 and 150 kg / cm, since if the pressure is below 50 kg / cm it is too low to make the lubricant satisfactory to spray while in case the pressure

2
is higher than 150 kg / cm, it is too high to apply the mist of lubricant in a satisfactory manner to the surfaces of the "workpiece which come into contact with the tool. However, the most favorable spray pressure varies depending on the viscosity of the lubricating fluid, the transit

309842/0831

Original inspected

23-15.

knife, of the wire to be "processed, the distance between the high-pressure nozzle and the wire and the tool as well as-from the relative assignment of these elements.

If a forging process is carried out using a lubricant produced according to the invention, then it adheres the lubricant on the surfaces of the workpiece that come into contact with the tool as a result of the application in the form of a loveIs as a thin film, causing a burn of the workpiece is prevented and the service life of the tool is extended by the cooling effect of the aqueous lubricating fluid will.

Another important advantage of the invention is that compared to the usual method of dripping on the lubricant when carrying out a hot forging process within a relatively high temperature range, for example at a temperature above 50O ⁰ C, the inventive method can be carried out with a very high efficiency can.

A hot-rolled wire is generally poor in terms of its processability and can not be satisfied-; may be processed by means of a cold forging process or by means of a conventional hot forging process at a relatively low temperature, namely because the oily lubricants usually used are limited because there is a risk that cracks will occur during forging. Therefore, a tempered or softened wire has hitherto been used for the usual cold or hot forging. However, when the hot forging performed at a temperature of above 450 ⁰ C under application of the inventive method of lubrication, then a hot-rolled wire can be processed under a load,

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ORIQIfMAL IMSPECTED

_ ₇ _ 23U415

which corresponds to the load that occurs when forging a tempered and softened wire or even is lower, furthermore the problem of hoisting does not arise. There is a very "great" advantage of the invention hence the fact that a cheap hot-rolled wire can be hot-forged without the need for tempering and Softening the wire is required. Becomes a hot rolled one Wire processed directly, then first the scale that has formed on the wire surface is removed, and in a mechanical or chemical way. For descaling, mechanical means are used, for example a peeling device or mechanical descaling device, and relies less on chemical agents, to avoid the dangers of using an acid. The descaled hot-rolled wire is then heated and fed to an arm forging process. The wire turns into screws when a hot forging process is carried out processed, it is preferably subjected to light expansion processing. This is the surface of the wire in terms of its affinity for a lubricant to protect against sparks (the material settles mainly composed of polyethylene glycol) improved. That Lubricant prevents the generation of sparks at the contact points of the electrodes and the wire the heating of the wire by means of electrical resistance heating. It also determines the size of the wire before hot forging made evenly.

It is of great importance in electrical resistance heating to prevent spark generation when a wire is used made of steel, titanium, etc. is continuously heated to carry out a hot forging process, since, if sparks at the Contacting points between the electrodes and the wire are created when the electrical resistance heating is carried out,

309842/0831

ORIGINAL INSPECTED

2-ι. -; Ρ "

defects in the form of small holes often appear on the surface of the wire. These defects worsen the surface condition of the products and often result in cracking during the subsequent processing operations. As a countermeasure to prevent sparking, the wire surface is mechanically scraped off in the usual way or covered with a film of a material with good electrical conductivity before electrical resistance heating is carried out. However, these countermeasures are difficult to perform.

According to a further feature of the invention, the wire before the electrical resistance heating to carry out the hot forging treated in such a way that it is under Application of a lubricant that is mainly composed of polyethylene glycol, is expanded. By Applying the lubricant in the manner described above Way, when performing the expansion of the wire, the wire surface becomes even with a film of lubricant coated, effectively suppressing the generation of sparks in electrical resistance heating.

In appropriate manner, the lubricant contains more than 50 fo polyethylene glycol, further, it may contain other organic and inorganic materials which promote the expansion, further comprising means for suppressing corrosion or roasting etc. Among such materials are phosphates, polyacrylic acids mentioned, potassium hydroxide etc. .

The invention is explained in more detail by means of the accompanying drawings. Show it:

1 shows a schematic view of an apparatus for carrying out the method according to the invention.

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ORIGINAL fNSPECTED

Pig. Figure 2 is a side view of the hot upsetting section of the device by Pig. 1 on a larger scale.

Pig. Figure 3 is a top plan view of the Pig hot upsetting portion. 2 in on an even larger scale.

The Pig. 4 and 5 are graphical representations of examples the relationship between the heating temperature and the workload a tempered and softened steel wire with respect to hot forging with deposition Lubricant and using the inventive Lubrication method.

Pig. 6 is a graph showing the relationship between the heating temperature and the workload shows a hot-rolled steel wire and a tempered and softened steel wire, with both wires below Application of a hot upsetting process as well as application the inventive lubrication method has been processed are.

Pig. 7 is a graph showing the relationship between heating temperature and processability without Ice formation of a hot-rolled steel wire as well as a tempered one and softened steel wire shows, both wires using a hot heading process as well as under Use of the lubrication method according to the invention have been processed.

Pig. 8 is a side view of a portion of the embodiment shown by Pig. 1 reproduced Device, in particular a device which is used for treating the wire for the purpose of preventing the generation of points suitable is.

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ORIGINAL! MSPECTED

FIG. 9 shows an enlarged view of part A from FIG. 8.

Nachf olgend the invention with reference-to "is the accession '-: explained clips drawings.' .-

When carrying out the embodiments described below the processed steel wire has a composition which is summarized in the following table I, being to ICLO screws using a hot upsetting process is processed. '

Table I.

Steel grade G Si Mn P S ■

AISI1027 0.27 "'0.27 1.51 0.010 0.017 - ^;

Example 1 (tempered and softened steel wire)

A steel wire made from AISH 027 with the composition shown in Table I is hot-rolled and then tempered and softened. Using the wire as a raw material, MIO screws are made using a Hot upsetting process produced.

Fig. 1 shows schematically the processing of the wire device used. The tempered and softened steel wire 1 is placed on a spool holder 2 and passed through a mechanical descaling device 3, which has deflection rollers 4 and brush rollers 5, to a descaling perform. That on the surface of the wire adhering scale powder is blown away by air nozzles 6, located at the exit of the mechanical descaling device. This descaling process is used to increase the service life to a drawing nozzle 10 of an expanding device 7

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ORIGINAL INSPECTED

longer. The one descaled in the mechanical descaling device Wire is fed to the expander 7 and passed through a bath of a lubricant that prevents sparking guided and then brought through the drawing nozzle 10 to the desired dimensions.

The expanded wire is wound onto the drum 16 and then passed through a plurality of guide rollers 17 of a straightening device 18, in which the wire is straightened. The straightened steel wire then becomes an electrical one Resistance heater 19 supplied. Since the surface of the the electrical resistance heating device fed wire uniformly with a film of a resinous lubricant is covered with a good electrical conductivity, which has been formed in the previous expansion process, spark formation on the contacting parts of the wire completely avoided with the electrodes 20. The wire heated in the electrical resistance heater is in a hot upsetting device 22, in which a hot upsetting is carried out.

The hot upsetting device 22 is explained in more detail by FIGS. 2 and 3. The wire is attached to a section between the two Electrodes 20 of the electrical resistance heating device 19 and heated by means of a pair of transport rollers 21 of the hot upsetting device 22 supplied. The front end of the wire is first against a valve 26, which the end position of the Wire sets, guided, whereupon a piece of wire with a predetermined length is cut off by means of a cutting tool 24 will. The pieces are hot forged in a predetermined amount by a main tool 25, a first stamp 26 and a second stamp 26 '",

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ORIGINAL INSPECTED

23UM5

During this hot stagnation process, the above-mentioned Apply lubricant to the surfaces of the wire that are connected to the Processing tools come into contact, sprayed on in the form of an airless spray. The lubricant is from a Bath 27 in a lubricant vessel 28 is pumped upwards by means of an airless pump 29. After it's under a relatively high pressure has been applied, it becomes through the Filter 30 sent to remove impurities, and then fed to a manifold 32 through a high pressure hose 31. In the embodiment shown, the lubricant divided into three parts by the manifold 32. However, if the compression device is larger, the distributor can have several branches own. Each of the split streams of lubricant is passed through a stopcock, through which the pressure is regulated can be sent and the nozzles 34.1 and 34.2 or 34.3 fed. The spray pressure in the high-pressure nozzles 34.1 to 34.3 is set to 50 to 150 kg / cm depending on the material and the dimensions of the wire. The high pressure nozzle 34.1 is used mainly for cooling and lubricating the main tool as well for blowing away contaminants from the "main tool. The position or arrangement of the high-pressure nozzle 34.1 is determined mainly after the on the main tool and the wire amount to be applied as well as after the spray pressure. For example, the high pressure nozzle 34.1 can preferably be approximately 300 mm above of the main tool 25 at an angle of inclination between 35 and 45 °. In this case, a relatively high spray pressure of 100 kg / cm is favorable. The high pressure nozzle 34.2 usually not used, but the high pressure nozzle can 34.1 replace or add to this nozzle if its capacity subsides. Even if the high pressure nozzle 34.1 fails, the productivity of the upsetting device is increased in this way fully maintained. The high pressure nozzle 34.3 is used to Lubricant on the cut surface of the material as well

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JNSPECTED

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to be applied to the surfaces of the punches 26 and 26 'so that the piece of wire lubricated on all its surfaces is and also removed impurities that are on the surfaces of the cutting tool 24 and the punch 26 and 26 'can adhere. The lubricant applied through the high pressure nozzle 34.3 increases the service life of the Sehneidewerkzeuges and the stamp considerably extended. In ordinary lubrication by dripping drops of lubricant the cut surface of the piece of wire is not lubricated, thereby reducing the life of the punches relatively is short. In order to let the high pressure nozzle 34.3 come into full effect, it is advantageous to use it. Nozzle at a distance of 300 mm above the cutting tool 24 at an angle of inclination between 34 and 45 °. The spray pressure should preferably be relatively low and between 50 and 70 kg / cm. A safety cover 35 is used to protect the nozzles to protect against an adjustment and to prevent the lubricant mist from blowing, so that its effect is increased will. The workpieces hot forged in this way using the lubrication method according to the invention fall onto a chute 36 and pass to a lubricant recovery facility 37, in which the lubricant is separated. Since the lubricant contains a lot of impurities, it is filtered by means of a filter 38 before it is fed to the lubricant bath 37 again.

Using the by the Pig. 1 to 3 reproduced Device can be the steel wire AISI1027 (tempered and softened wire) hot-forged into M10 screws, where the results are shown by Figs. Fig. 4 shows the relationship between the heating temperature and the workload of hot forging using a lubricant made from oils, fats and mineral oils according to

3 0 9842/0831

ORIGINAL INSPECTED

The inventive method using a luf ± -. loose pump, and while maintaining a pressure of 100 kg / cm in a first EaIl and according to the method of dripping -üblichen enlassens of lubricant in a second EaIl. The working ratio on the screw head portion is $ 75.0. As is apparent from Fig * 4, the workload at a heating temperature below 250 ⁰ C 'is the same as in the implementation of the known drop method, however, it assumes at a heating temperature above 300 ⁰ C according to the invention quickly, so that a smooth in the inventive case Hot forging is possible, while in the case of the usual drip method, the workload tends to increase due to the burning and sticking of the lubricant. It had been assumed that lubricants from oil, grease and mineral oils can only be used in a temperature range up to 300 ⁰ C. It has now been found that these lubricants can be used in the application of erf indungsgemässen process also up to a temperature of 700 to 800 ⁰ C.

Fig. 5 shows the relationship between the heating temperature and the workload in hot forging MCIO screws, the hot forging once using a Lubricant made from oils, fats and mineral oils according to the present invention with spraying of the lubricant under a spray pressure of 100 kg / cm and the other time below Use of a graphite lubricant according to the usual Drip method was performed. As can be seen from Fig. 5, the workload according to the invention is lower than when carrying out the usual method and amounts to 4 to 8 tons over the entire heating temperature range, from which it can be seen that the lubrication method according to the invention the known Procedure is superior. If a lubricant made from oils, greases or mineral oils or water-soluble resinous lubricants is

309842/0831

iQfNAL INSPECTED

23 u vi 5

standing lubricant used according to the invention, then leave the lubricants can be removed very easily by pickling with a weak acid, without the risk of that the surface of the products becomes coarser than it was before. In contrast, the usual high-temperature hot upsetting process has hitherto been used with the application of graphite or MbIybdenum disulfide carried out. These two components are very difficult to remove.

Example 2 (hot rolled steel wire)

The AISI1O27 steel wire defined in Table I is hot-rolled into MiO discs using a hot upsetting process and using the S ¹ Ig. 1 to 3 reproduced device processed. Fig. 6 shows the relationship between the heating temperature and the workload in two cases, one case being the hot forging of a hot-rolled steel wire using the lubricating method according to the invention using a lubricant made of oils, fats and mineral oils, which is sprayed under a pressure of 100 kg / cm, while the other case is hot forging a tempered and softened steel wire using a conventionally dripped lubricant, but the same lubricant as mentioned above. The labor ratio on the screw head section is $ 75.0. As is apparent from Fig. 6, · processed at a heating temperature above 400 ⁰ G during hot forging of the hot-rolled steel wire with a work load corresponding to the workload of the annealed and softened steel wire, which has been processed using conventional lubricating method, or less than Burden is. This shows that smooth hot forging is possible according to the invention.

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23 ίΐ: 15

The J ¹ Ig. 7 shows that when the Pig. 6 described hot forging process no crack formation occurs. When hot forging using the method according to the invention, ^{the machinability is reduced in a heating temperature range from 300 to 40O 0} C due to the blue brittleness of the steel. Since the machinability in this area is in the G-size order of $ 72.5 and is below the expected working ratio (75 °) of the screw head section, there is a risk that cracks will occur in the section of the screw head. However, the HEAT achieved wetness temperature 45Q ⁰ C, then the i / is recovered erarbeitbarkeit quickly. At a heating temperature above 500 ° ö, the machinability without crack formation reaches a value of 80 ° . No cracking is found in such a high temperature range.

Example 3 (lubricant to prevent sparking)

A tempered and softened AISI1O27 steel wire (cf. Table I) is first pickled and then treated with lime, or first pickled and then treated with Bondelite (not shown) and then fed to the processing chamber 8. In the processing chamber 8, the wire is coated with the screening agent 9 and then drawn through the drawing nozzle 10 to adjust the desired dimensions. The lubricant 9 is composed of 70 ° i PoTyäthylenglykol, 5% phosphate, 5 fi of a polyacrylic acid, 0.5 f "potassium hydroxide and the balance of water, the surface of the expanded through the die wire is uniformly coated with a film 11 of lubricant having a good electrical conductivity. The lubricant is stored in a vessel 12 and fed by a circulation pump 13 to the processing chamber 8, from which it is fed back to the vessel 12 via a reversing line 14. Since the lubricant coming from the processing chamber 8

309S42 / 0S31

■ · ORIGINAL! MSPECTED

_ ₁₇ . 23 U ^ 15

comes, contains impurities, it is filtered by means of a piper 15. The expanded wire is wound onto the drum, passed around a plurality of guide rollers 17 and then fed to the straightening device 18. The straightened steel wire is then passed through the electrical resistance heater 19. During the electrical resistance heating carried out in this device, the generation of points at the electrodes 20 is completely avoided because the wire is coated with the PiIm with good electrical conductivity. The wire heated by the electrical resistance heating is fed to the upsetting device 22, where it is thermally upset. The lubricant film composed essentially of polyethylene glycol, also prevents rusting of the wire and is easily from the surface of the products prepared by washing with an appropriate degreasing agent, such as a weak acid, for example a 10 follow aqueous hydrochloric acid and / or nitric acid , removed.

309842/0831

ORIGINAL INSPECTED

Claims (6)

23 U - 15 - 18 claims (1.! Method for lubricating a workpiece of that an oily. Lubricant is mixed with water, used a Warmsehmiedeverfahren, for example a hot upsetting process, is subjected, at temperatures from 450 to 800 ⁰ C, characterized in that in particular a wire, and the Mixture of lubricant and water is sprayed airlessly onto the surfaces of the workpiece that come into contact with the machining tool. 2. The method according to claim 1, characterized in that the oily lubricant used consists of oils, fats, mineral oils and / or polyethylene glycol. 3. The method according to claim 1, characterized in that the oily lubricant used is mixed with 5 to 20 times the amount of water. 4. The method according to claim 1, characterized in that the mixture below:
is sprayed on. the mixture under a spray pressure between 50 and 150 kg / cm 5. The method according to claim 1, characterized in that the wire used with a lubricating film of polyethylene glycol during the heating stage for hot forging by electrical Resistance heating is coated. 6. The method according to claim 5, characterized in that the lubricating film formed from polyethylene glycol at the time on which the wire is expanded through a nozzle. 7 "The method according to claim 1, characterized in - that the mixture is sprayed in a compressed state using an airless pump. 309842/0831 Blank page, te