JP4485291B2 - Excavator manufacturing method for agricultural machinery and excavator using the same - Google Patents

Description

  The present invention relates to a method for producing an excavator for an agricultural machine used when plowing farmland or the like, and an excavator using the same.

  Conventionally, excavation blades used in agricultural machines such as tractors are made by using a plasma powder method to form a plate-like member made of chromium-rich Fe-Cr-C in a portion where the wear is severe in order to suppress wear due to excavation. A technique for welding has been proposed (see Patent Document 1).

  In general, excavation blades have many single-edged blades, but as described above, they have a three-dimensionally curved shape. Therefore, the wear-resistant material needs to be welded to both blade surfaces.

However, if the wear-resistant material is sequentially welded to both the blade surface and the flat surface, there is a possibility that the degree of welding of the wear-resistant material that has been welded first is lowered due to the heat of welding performed later.
Therefore, in the above publication, a plasma powder method that allows easy thermal control is used in the welding of the wear resistant material to be performed later.
JP 2002-235162 A

  However, when the wear-resistant material as described above is provided by using the welding means, it is a matter of course that the welding is performed one by one, so that the productivity cannot be increased and there is a problem that causes an increase in cost.

  Also, when welding by welding, etc., it must be welded over the entire circumference of the wear-resistant material, and if there are unwelded parts in part, water will enter from there and rust will occur on the drilling blade body. The rust causes a problem that the wear-resistant material is peeled off to reduce the life.

  Of course, if the entire circumference of the wear-resistant material is completely welded, various adverse effects due to such water intrusion can be prevented. However, in order to perform such welding and to ensure that no adverse effects occur, sufficient capital investment is required. And welding time are required, which is also a factor in increasing costs.

  In addition, since the excavating blade is curved three-dimensionally, it is necessary to form a wear-resistant material in accordance with this, and if this effort is included, the cost increases significantly. In this case, it is possible to simplify the shape of the wear-resistant material by covering only the blade surface with the wear-resistant material, but in this case, wear of other parts is inevitable and the blade edge is kept sharp. There is a problem that it is difficult to weld the wear-resistant material as it is.

  Accordingly, an object of the present invention is to provide a method for manufacturing an agricultural machine excavation tool and an excavation tool using the same, which can be provided with an abrasion resistant material easily at low cost.

  In order to solve the above-described problem, a drilling tool manufacturing method according to claim 1 is directed to injecting alumina powder whose particle size and pressure are adjusted to a drilling tool used in an agricultural machine, and attaching the powder to the entire surface of the drilling tool. It is characterized in that a foreign material is removed and a blasting process for polishing the entire surface is performed, and then a hard chromium plating is plated under a predetermined plating condition to form an abrasion resistant material.

  As a result, the smoothness of the plated surface can be easily improved even with a three-dimensionally curved excavator, and the adhesion degree and denseness of the hard chrome plating are improved, and the high hardness Hard chrome plating can be formed, extending the life of the drilling rig.

Drilling tool manufacturing method of the present invention, sandpaper or a metal brush grinding treatment with, puff polishing by pasty oxide chromium, the surface state of the chemical treatment with a chemical reaction with dilute sulfuric acid or Mareshio acid the drilling tool run appropriately selected depending on, followed by performing the blast treatment is a flaw remains on the entire surface of the drilling tool from the 1μm below those characterized in that performing the hard chrome plating.

  Thereby, when performing plating by blasting, it becomes possible to make the depth of scratches remaining on the surface of the drilling tool 1 μm or less, and the adhesion degree and the denseness of the hard chrome plating are improved, It becomes possible to form a hard chrome plating with high hardness, and the life of the drilling tool is extended.

The excavator of the present invention is an excavator formed in a three-dimensional shape used for an agricultural machine, and is manufactured by any one of the manufacturing methods described above .

  This makes it possible to easily provide the wear resistant material at a low cost and extend its life.

  According to the present invention, an alumina powder having a predetermined particle size is sprayed to a drilling tool used in an agricultural machine at a predetermined pressure to remove foreign substances adhering to the surface of the drilling tool and to polish the surface. Blasting is performed, and then hard chrome plating is plated under predetermined plating conditions to form a wear-resistant material, so even a three-dimensional curved excavator can easily improve the smoothness of the plated surface. It becomes possible to improve the adhesion degree and the denseness of the hard chrome plating, and it is possible to form a hard chrome plating with high hardness, thereby extending the life of the excavating tool.

Prior to the description of the embodiments of the present invention, the principle of the present invention will be described. In general, excavating tools such as excavating blades used for agricultural machines such as tractors and tillers, excavating blades, dredges, or excavating blades used when excavating potatoes, satsuma masonry, etc. are made of steel such as SUP6. Forged products having a Vickers hardness Hv of about 215 are often used.
Although the excavator is made of a material having such a high hardness, the excavation tool is thrust into the soil tens of thousands of times, resulting in severe wear and a factor affecting the life.
In the following description, the excavator is a forged product, but the present invention is not limited to this and may be a cast product or a machined product.

  For this reason, conventionally, wear-resistant materials are welded to suppress wear of the excavating tool, but such means such as welding cannot increase productivity, which causes an increase in cost.

  Accordingly, the inventors of the present application have studied various techniques for improving the wear characteristics and improving the productivity, and as a result, have reached a plating technique capable of so-called batch processing. Of course, the plating technology itself is already used in various fields and is not a new technology. However, when this plating technology is used for an excavator for agricultural machinery, it is found that specific considerations and conditions are required. Was completed.

In general, the excavator is a forged product that is three-dimensionally curved as shown in FIG. 1, for example, and is often in an annealed state.
On the other hand, when plating is performed, an etching process using chemicals is performed as a pretreatment to remove oxides on the surface.

  However, since the drilling tool is in an annealed state, the crystal grains are coarsened, and when etching is performed, corrosion along the crystal grain boundaries is likely to proceed, resulting in significant surface roughness.

  In addition, there are various types of excavating tools, but there are cases where there are welded portions or a plurality of members, and there are minute gaps between them. In such welded portions and gaps, etching may occur at a rate different from the etching state in other portions.

For example, if the chemical enters the gap and the subsequent supply decreases and the reaction capacity falls, etching will not be performed from other parts, the metal structure will change due to welding, the etching rate will increase, or unevenness Air or dust may exist in the recess and may not be etched.
These situations become serious when an excavator is positioned as a consumable and an inexpensive material such as iron is used instead of an expensive material such as stainless steel.

  When plating is performed in such a way that the surface is roughened, there are uncorroded parts, or dust or rust remains, voids (voids) are generated between the plating layer and the surface of the drilling tool. It becomes easy to cause plating peeling. When plating peeling occurs, new rust is generated at that portion, and the rust is eroded between the plating layer where the rust is not peeled off and the surface of the excavation tool, causing further peeling.

  Even if the same metal plating layer is formed, the density (density) varies depending on the plating method. So-called decorative plating often requires a glossy plating layer even if the density is somewhat small, but in order to protect the excavator with the plating layer as in the present application, gloss is not required, but hardness Is required to be large. Of course, the hardness and the density are approximately proportional to each other, and it is necessary to increase the density in order to increase the hardness.

  Further, although the chromium metal itself has a high hardness, when it collides with pebbles in the soil during excavation, it is worn or damaged. At this time, if the thickness of the plating layer is thin, the scratch easily reaches the metal, and even a small scratch may start to rust and spread to the entire excavating tool, thereby reducing the sharpness.

  In addition, when electroplating an object with a sharp part such as the edge of a drilling blade, electric field concentration occurs in this sharp part, and the plating thickness of that part becomes thicker than others, such as a blade In this case, there is a problem that it becomes dull and the sharpness is deteriorated, and grass and the like are easily entangled.

  Therefore, in the present invention, the blasting process is a main pre-plating process, and the degree of adhesion and the denseness are improved by performing a grinding process, a polishing process, and a chemical process depending on the situation. Also in the plating process, conditions such as a plating current and a plating temperature are set to improve the hardness by forming a thick plating layer while improving the degree of adhesion and the denseness.

  Hereinafter, a description will be given with reference to the drawings. FIG. 1 is a perspective view of an excavating blade 2 as an example of an excavating tool according to the present invention, and FIG. 2 is an AA cross-sectional view including the cutting edge portion 5. 1 and 2, reference numeral 3 indicates a drilling tool body to be plated, and reference numeral 4 indicates a plating layer. FIG. 3 is a perspective view of an agricultural machine 6 using the excavating blade 2.

  Note that the agricultural machine 6 shown in FIG. 3 is optionally connected to a tractor or the like, and is used when cultivating land. A plurality of digging blades 2 that push the soil into the soil while rotating and cultivate the soil are provided. It has a power transmission mechanism 7 for rotating, a wheel 8 provided so that the amount of digging blade 2 protruding into the soil can be adjusted.

  As shown in FIG. 4, the plating procedure is roughly divided into pre-plating treatment 10, plating treatment 20, and post-plating treatment 30. The plating pretreatment 10 includes a grinding treatment 11 using sand paper or the like, a chemical treatment 12 using dilute hydrochloric acid or the like, a polishing treatment 13 using puff polishing, and a blast treatment 14 using alumina injection. In these processes, a cleaning process 15 for appropriately cleaning foreign matter, a degreasing process 16 for removing oil, a drying process 17 and a neutralizing process 18 are used in combination.

The cleaning process 15 is a process for cleaning foreign matter such as dust and chemicals adhering to the excavating blade 2 with running water or stored water, and after the cleaning, a drying process 17 for removing water is performed.
The degreasing process 16 is a process for removing various oils adhering to the drilling blade 2, and is a process for dissolving and removing oils with a degreasing agent containing a caustic soda (NaOH) or a surfactant mainly composed thereof. Thus, after the degreasing, a cleaning process 15 is performed.

  If there are small gaps or irregularities in the excavating blade 2, foreign matter, oil, or the like may enter here. In such a situation, even if the washing process 15 and the degreasing process 16 are performed, the washing and degreasing may not be performed sufficiently. In such a case, it is preferable to perform the above treatment using a stirring means such as ultrasonic waves. Of course, not only ultrasonic waves but also other stirring means such as a stirrer may be used.

The neutralization process 18 is a process for neutralizing the remaining chemicals after chemical treatment with acid or alkali chemicals. For example, after degreasing, the cleaning process 15 is performed to remove the remaining degreasing chemicals. However, since caustic soda is alkaline, if the chemicals remain on the drilling blade 2, the subsequent plating is performed. The process 20 is affected and is not preferable in terms of safety management.
Of course, if the washing water becomes alkaline, there is a disadvantage that it cannot be discarded as it is. Therefore, it is preferable to perform neutralization 18 after degreasing.

  The grinding process 11 is a process of scraping with a sandpaper or a metal brush when the digging blade 2 is rusted or foreign matter such as paint or dust adheres, and the cleaning process 15 is appropriately performed before and after. . Although such foreign matters have a great influence on the plating quality, they are not easily removed by the chemical treatment 12, the polishing treatment 13 and the blast treatment 14, and may be omitted when they are removed by the chemical treatment 12 or the like. it can.

  That is, the excavating blade 2 is a forged product mainly composed of iron, and is often not subjected to surface rust prevention treatment. When a long time has passed since the excavating blade 2 was manufactured, May rust. When plating is performed in a rusted state, the adhesion of the plating at the rusted portion is low, so that peeling easily occurs.

  Therefore, rust is scraped off manually or electrically using sand paper or a metal brush. At this time, it is not necessary to completely remove rust. As is well known, since rust erodes and spreads inside the metal, it is intended to avoid the need to scrape away the rusted portion when the rust is completely removed.

  The chemical treatment 12 is a treatment that removes rust and the like by surface etching with, for example, 10 to 30% by volume of dilute sulfuric acid or dilute hydrochloric acid, and a washing treatment 15, a degreasing treatment 16 and a drying treatment 17 are performed before and after. As described above, rust-like oxides erode inside and proceed, and it is difficult to remove recesses such as unevenness due to welding by the grinding process 11. Therefore, chemical treatment 12 is performed for the purpose of removing such oxides.

In addition, when performing the chemical treatment 12, if oil or the like adheres to the surface of the digging blade 2, the oil or the like may act as a protective film against chemicals, and therefore it is necessary to perform the degreasing treatment 16 in advance. .
Further, since chemicals may remain in the plated product after the chemical treatment 12 (for example, it is assumed that chemicals enter the gap), the cleaning process 15 → the neutralization process 18 → the cleaning process 15 → Each process of the drying process 17 is performed.

  The polishing process 13 is a process for smoothing the plated surface by removing the scratches caused by the grinding process 11 and the scratches attached during the conveyance by puff polishing. Although the density of the plating layer affects the hardness, it is necessary to increase the smoothness of the plated surface in order to increase the density. In the present invention, the blasting process 14 is finally performed to increase the smoothness. However, since the blasting process 14 is difficult to remove irregularities such as large scratches, the polishing process 13 is performed according to the situation.

In particular, since the cutting edge is more worn than other parts, the surface smoothness may be increased by carefully puffing the cutting edge part. That is, the degree of polishing may be changed depending on the part so that the blade edge is polished to a mirror state and the other places are polished to a semi-gloss state.
In puff polishing, paste-like chromium oxide is used to polish to a planar roughness of about 0.5 μm.

The blasting process 14 injects alumina powder (roughness of No. 30 to 120) onto the excavating blade 2 with 4 to 6 (kg / cm ² ) to increase the surface smoothness of the excavating blade 2 and to make it minute. It is the process which removes the foreign material. By this treatment, polishing is performed to the extent that a scratch of about 1 μm remains.

In the grinding process 11 and the polishing process 13, for example, it is very difficult to grind or polish the corner portion of the corner, but in the blasting process 14, alumina powder is sprayed and sprayed. There is an advantage that physical polishing can be performed regardless of the shape of 2.
Further, even when there is no portion that cannot be ground or polished, such as a corner, it is difficult to perform the grinding process 11 and the polishing process 13 with a machine if the excavating blade 2 has a three-dimensionally curved shape. However, as described above, in the blasting process 14 in which the powder is wiped against the drilling blade 2 and polished, it can be polished even if the drilling blade 2 has a complicated shape or has irregularities. There is an advantage that it can be easily automated.

In this way, the pre-plating process 10 is performed, and then the plating process 20 is performed. In the plating process 20, a plurality of excavating blades 2 are plated at once using a plating solution containing hexavalent chromium as a main component (batch method) to plate chromium. As the electrode, a tin-lead alloy (Sn—Pb) or a titanium-platinum alloy (Ti—Pt) is used. Since Ti—Pt is insoluble in the plating solution, there is an advantage that the influence of electrode elution can be eliminated.
By using the batch method, a plurality of excavating blades 2 can be plated at a time, so that the plating cost can be reduced.

  Further, the hard chrome plating is for the purpose of increasing the hardness. That is, the excavation blade 2 is in an annealed state, and the Vickers hardness Hv is about 40. Hard chrome plating is used in order to form a thick plating layer having a hardness greater than this hardness and to function as a wear-resistant material. Since hard chrome plating generally has Hv = about 1000, it is possible to satisfy such a requirement.

Further, since chromium has water repellency, for example, soil adheres to the excavating blade 2 by farm work, and if this is washed with water, the water can be drained naturally without performing a special drying treatment 17, and the occurrence of rust can be suppressed. Is possible.
In addition, when such a metal having no water repellency is plated, it becomes easier to adhere as the soil gets wet, but in the case of a metal having water repellency, it becomes more difficult to attach as the soil gets wet. Therefore, it becomes easy to clean up the farm tools after work.

Plating is started by such pretreatment, and energization at that time is performed in three energization modes. The first energization mode is a reverse current mode 21 in which a current opposite to the current direction during the original plating is passed. By this reverse electricity mode 21, the surface of the excavation blade 2 is reverse-plated to cause minute unevenness. This unevenness (particularly the convex portion) becomes a chromium plating nucleus. When the density of the plating nucleus is high, the density of the plated metal is high.
The plating nucleus means a portion where chromium is first plated due to electric field concentration in a minute uneven portion, and plating is preferentially generated and spreads in this portion to form a dense plating layer.

  If the density of such plating nuclei is small, unevenness may occur in the overall plating thickness and density. Conversely, if the density of plating nuclei is large, the size of each plating nuclei is reduced, and efficient electric field concentration does not occur (even if electric field concentration occurs, the electric field concentration state is such that plating is preferentially performed). However, it is difficult to obtain a desired effect.

Therefore, it is important to control the density of such plating nuclei. In the present invention, for example, by applying a current of −30 (Adm ² ) for 2 to 5 seconds, a plating with good density can be obtained. I found what I could do.

The second energization mode is an electrodeposition mode, which is a deposition mode 22 in which chromium is deposited in the plating solution. In the present invention, the current is set to 35 A (Adm ² ) and energization is performed for 2 to 5 seconds. When chromium is deposited, a uniform chromium film is plated on the surface of the excavating blade 2 in a short time when plating is started. Thereby, coupled with the first energization mode, a dense chromium film is plated, and the electrical state of the surface can be made substantially uniform.

The third energization mode is the original plating mode 23. In the present invention, the current was 30 (Adm ² ) and energization was performed for 24 hours to plate about 0.5 mm of chromium.

Although the temperature of the plating solution during plating rises, the denseness of the plated chromium decreases as the plating temperature rises, so the temperature should be in the range of about 40-60 ° C. while cooling with cooling water. Management is performed.
Further, since the state of the plating solution changes as the plating progresses, the solution management is performed while appropriately measuring the specific gravity of the plating solution.
Furthermore, since the plating current becomes difficult to flow as the plating progresses, the plating current is kept constant by adjusting the voltage.

  Although plating is performed in this manner, the excavation blade 2 has various portions having different curvatures. For example, the cutting edge is acute but the blade is flat. When the geometrical shape is different, the electric distribution is also different, and electric field concentration occurs at an acute angle portion such as a blade edge, and plating may proceed preferentially over others.

  Therefore, in the present invention, in order to suppress the electric field concentration in the sharp part, the electric field concentration in the sharp part is relaxed by connecting the part and the electrode with a high resistance electric wire or the like.

  Thus, the plating process 20 is completed, and then a post-plating process 30 including a water washing process 15 and a drying process 17 for the purpose of cleaning the plating solution is performed.

The chromium layer thus formed had a very high Vickers hardness Hv of 900 to 1300 and was able to achieve good wear resistance.
For example, when the excavating blade 2 is plated, the wear life is 2 to 4 times that of the unplated state, and an excavating tool having sufficient resistance for use in one season can be manufactured. .

It is a perspective view of an excavation blade applied to explanation of the present invention. It is AA arrow sectional drawing in FIG. It is a perspective view of the agricultural machine 6 provided with the excavation blade which concerns on this invention. It is a figure which shows a plating process process.

Explanation of symbols

DESCRIPTION OF SYMBOLS 2 Excavation blade 3 Excavation tool main body 4 Plating layer 5 Cutting edge part 6 Agricultural machine 10 Pre-plating process 11 Grinding process 12 Chemical process 13 Polishing process 14 Blasting process 20 Plating process 21 Reverse electric mode 22 Deposition mode 23 Plating mode 30 Post-plating process

Claims (3)

  Alumina powder adjusted in particle size and pressure is sprayed on a drilling tool used in an agricultural machine to remove foreign substances adhering to the entire surface of the drilling tool and perform a blasting process to polish the entire surface. A method for producing an excavator for an agricultural machine, characterized in that a hard chrome plating is then plated under predetermined plating conditions to form an abrasion resistant material. Grinding process by sandpaper or a metal brush, puff polishing by pasty oxide chromium, running appropriately selected depending on the surface state of the chemical treatment the drilling tool with a chemical reaction with dilute sulfuric acid or Mareshio acid The method for producing an excavator for an agricultural machine according to claim 1, wherein the hard chrome plating is performed after the blast treatment is performed to reduce the scratches remaining on the entire surface of the excavator to 1 μm or less. . An excavator for an agricultural machine, which is an excavator formed in a three-dimensional shape used in an agricultural machine, wherein the excavator is manufactured by the manufacturing method according to claim 1 or 2.

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