JPS61149493A - Surface-hardened plated layer, circular saw and edged tool each coated with said layer - Google Patents

Abstract

PURPOSE:To obtain an edged tool capable of undergoing setting or sharpening and having superior wear resistance, durability, toughness, ductility, adhesion and seizing resistance by forming a surface-hardened plated layer of a composite very-hard Cr alloy on the surface of a circular saw or an edged tool. CONSTITUTION:A surface-hardened plated layer of a composite very-hard Cr alloy contg. Cr, Ca, Na, Al, Mg, Si and Fe as principal elements is formed on the surface of a circular saw in the range of about 3cm from the edge or on the surface of an edged tool to a desired width and a desired thickness from the edge. The height of the peak of each element in the plated layer is as follows: Cr; 400-700, K; 20-250, Ca; 20-250, Na; 40->=150, Al; 10-80, Mg; 5-30, Si; 2-20 and Fe; 0.5-15. The plated layer has 1,000-1,600 hardness Hv, 1,700-1,900 deg.C m.p. and >35kg/mm<2> adhesive strength. An edged tool having superior wear resistance, durability, toughness, ductility, adhesion and seizing resistance is obtd. The tool can be sharpened, and in case of a circular saw, the teeth can be set.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a surface hardened plating layer in which Cr is the main component and several other elements are electrodeposited on the surface of a metal base material by electrolytic plating, and the coating thereof. Concerning circular saws and cutlery made with

[Conventional technology] Due to the recent promotion of unmanned factories including various machining centers, ultra-fine machining, ultra-precision machining, etc., there is a desire to extend the replacement life of tools and cutlery as much as possible to meet the harsh processing conditions. Accordingly, attempts have been made to extend the life of the base material by coating with this type of surface treatment layer, and conventionally hard chrome plating layers and tungsten carbide layers have been adopted, but these have hardnesses of H and V, respectively. 900.120
0, and the pursuit of a coating layer with a higher degree of surface hardening and the tungsten carbide layer require complicated and expensive processing.

Brush cutters, along with chainsaws, are currently the most widely used forestry machines, and are indispensable for the second half of land preparation work. Recently, many lightweight models with low drag and low noise have been manufactured, and various improvements have been made to circular saws, such as the use of special steel for various items and blade materials, and each manufacturer has improved safety, wear resistance, Although efforts are being made to improve cutting performance and other performance, for example, when the blade touches a stone or rock during work, there are many accidents where the blade bursts and scatters, injuring workers. This is impossible, and hard materials such as mugwort have the disadvantage of being too abrasive.

[Problems to be Solved by the Invention] The present invention aims to provide a surface-hardened plating layer made of a composite super-hard chromium alloy that has a higher degree of surface hardening than conventional hard chromium-plated layers.

In addition, the present invention coats the surface with a surface-hardened plating layer made of a composite ultra-hard chromium alloy to improve wear resistance, durability, N properties, viscosity, adhesion, and seizure resistance. The purpose is to provide circular saws and blades that can be sharpened.

[Means for solving problems] Examples of the present invention will be described below.

Table 1 below shows the results of qualitative analysis in the depth direction of the plated layer for each peak height of the detected element distribution of the surface hardened plated layer made of the composite ultra-hard chromium alloy of the present invention.

Table 1 However, "-" is not detected (< 0.01) and the base material is Q.
ll (Daisko).

Note that a spectrum analyzer was used for the measurement.

Here, as an experiment to measure the physical properties of the surface hardened plating layer of the present invention, (1) surface roughness measurement (2) hardness distribution measurement (3) cross-sectional structure observation (4) adhesion test (5) wear resistance And seizure resistance test (6) Each item of fatigue resistance test was conducted.

Each section will be explained in the following sections.

(1) Surface roughness The surface roughness after plating depends on the surface roughness of the base material, and the quality of this roughness greatly affects mechanical properties and corrosion resistance during use. . Therefore, it is necessary to reduce the surface roughness of the base material before plating, or to reduce the roughness by polishing after plating.

The surface roughness after polishing depends on the hardness of the plating layer, and compared to relatively hard surfaces such as nickel and lead plating, those with hard surfaces such as hard chrome plating become mirror-like by polishing. Each property improves easily. The chromium plating layer α of the present invention is also a type of hard chrome plating, and the plating layer α is <H, V8 as described below.
Since it is very hard, it can be easily polished to a mirror surface.

Figure 1 shows the plated layer of the present invention without polishing and with the second plated layer.
The figure shows the results of determining the surface roughness of the plated layer of the present invention subjected to puff polishing. According to this, the plating layer α alone of the present invention is approximately 1.2μlR.
The roughness of a is approximately 0.02 by performing puff polishing.
It can be seen that the value is less than μmRa, resulting in a very good mirror surface.

(2) Ii! Various surface hardening treatments are performed to improve wear resistance or seizure resistance, and hard chrome plating is no exception. It is used in various areas. FIG. 3 shows the results of determining the hardness distribution curve of a sample coated with the plating layer α of the present invention.

According to this result, the HlV is about 20μ from the surface.
A hardness of around 820 is obtained, and it is recognized that the hardness of the inside is closer to that of the base material.

In Fig. 3, the thickness of the hardened layer is affected by the difference in plating processing time according to the present invention, but in any case, the hardness of the hardened layer is a very high value of around 1,200 H,V. I understand what is shown.

Furthermore, the plated layer α of the present invention exhibits excellent characteristics against temperature increases, and has very high softening resistance at each temperature. FIG. 4 shows the plating layer α of the present invention, and FIG. 5 shows the hard chrome plating layer I! ! ! For layer γ, 400°C and 7
This figure shows the indentation β of a diamond indenter in micro-Vickers hardness at room temperature after heating and holding at 00'C for 3 hours.

At each heating temperature, it is recognized that the indentation β of the inventive plating layer α is smaller than that of hard chromium plating. That is,
In the case of hard chrome plating, Cr20 at each heating temperature
3 is generated, whereas in the case of the plated layer, 40
It is thought that chromium carbide of Cr23C6 is produced at heating temperatures up to around 0°C, and that Cr203 is produced on the surface at higher temperatures, resulting in high softening resistance.

(3) Cross-sectional structure When a process that generates a hard surface layer such as industrial hard chrome plating is performed, fine racks η are generated in the hardened layer (plated layer) in the direction perpendicular to the layer thickness during the plating process. The plated layer α of the present invention is no exception, and fine racks η are observed. However, compared to the hard chrome plated layer γ, the occurrence rate is very small and the particles are fine. In the case of the plated layer α of the present invention, a major difference from the hard chrome plated layer γ is that no black layer, which is thought to be an oxide, is observed at the boundary between the plated layer α and the base material δ. The plating layer α of the present invention is characterized by not forming this black layer, and exhibits excellent properties in the adhesion test described below.

(4) Adhesion test A characteristic required of surface-hardened products is that there is no peeling phenomenon between the hardened layer and the base material during use. In this experiment as well, adhesion was tested by the bending method in accordance with JIS H8615. That is, the lower part of a vertically erected specimen was clamped and fixed from both sides, and the upper part was bent from left to right to center to give maximum shear stress to the surface, and its cross section was examined.

The test piece used an SS material with an IM thickness as a base material, and the thickness of the plated layer α was kept constant at 20 μm.

FIGS. 6(a) and 6(b) show the results of examining the peeling phenomenon of the respective cross sections of the plating layer α and FIG. 7 of the hard chrome plating layer γ of the present invention.

According to this result, in both cases, the surface has fine particles and rank η
is observed, and its depth reaches the boundary between the plated layers α, γ and the base material δ, ε, as shown in FIGS. 6 and 7. However, results were obtained in which the plated layer α of the present invention exhibits excellent characteristics in terms of both the number of cracks η and the peeling phenomenon from the base materials δ and ε.

In addition, in this experiment, the bending angle was 90'' as per JIS.
However, even at an angle of 45°, the occurrence of fine racks η was observed on the surfaces of both. However, in this case, the cracks η in the plated layer α of the present invention do not reach the boundary with the base material.

As mentioned above, the above results are largely influenced by the presence or absence of oxides generated at the boundary between the base material δ and the plated layer α.

(5) Wear resistance and seizure resistance One of the major features of the surface hardened layer including the hard chromium plating layer γ is that it improves not only corrosion resistance but also abrasion resistance and seizure resistance. FIG. 8 compares the test results in a dry state using an ultra-thin type abrasion tester. As is clear from FIG. 8, the plated layer α of the present invention exhibits superior wear resistance compared to the hard chromium plated layer γ, and the difference tends to increase as the friction distance increases. Furthermore, Figure 9 shows the results of an experiment on seizure resistance, which shows that the coating of the plating layer α of the present invention has a lower coefficient of friction on all types of steel compared to those that have been subjected to other surface treatments. The results were obtained.

The reason why the friction coefficient of the plated layer α of the present invention is 5 to 6 times lower than that of the same hard chromium plated layer γ is that as the temperature increases, hard Cr23C6 double carbides are formed as described above. and further Cr20
This is because 3 occurs at higher temperatures.

Incidentally, a temperature characteristic diagram of Cr23C6 is shown in FIG. 10.

(6) Fatigue resistance It is known that surface hardening heat treatments such as induction hardening or gas nitrocarburizing generate large compressive residual stress during the treatment process, which improves fatigue resistance as well as wear resistance.

All of these processes involve diffusion phenomena, and fatigue cracks occur at surfaces that experience the greatest shear stress. However, in materials that do not involve diffusion and have a boundary between the plated layer and the base material, such as plating, repeated stress causes cracks to occur on the surface of the base material rather than on the outermost plated layer. Therefore, the fatigue resistance is not significantly improved by plating, and depends on the strength of the base material. Figure 11 shows S
This is the result of finding the −N curve. According to these results, the fatigue limit of the sample coated with the plating layer α of the present invention is equivalent to that of the base material δ, and the plated layer α of the present invention is remarkable.
No coating effect was observed. Furthermore, Table 2 shows a comparative study of samples coated with a hard chrome plating layer γ, etc. and a plating layer α of the present invention for each steel type, and even in these results, no differences due to differences in plating treatment were observed. do not have.

2. Obviously, the coating process for the plating layer α of the present invention is substantially the same as the hard chrome plating process, and includes at least 1) cleaning of the base material δ with an organic solvent such as trichlorethylene, 2) alkaline cleaning, and 3) electrolytic polishing. , ■Coating of the present invention, ■Warm bathing, ■Refining, and ■Inspection.

In particular, the coating process of the present invention is carried out in the same manner as the hard chrome plating process, but the plating conditions are, for example, standard in which 250g of chromic anhydride (CrO2) and 2.53g of WA acid (H2S04) are dissolved in 11 parts of water. Liquid (Sarg)
The plating work is usually carried out at a temperature of 60° C. and a current density of 50 A/da2. The solution contains metal elements according to the main element distribution excluding impurities shown in the composition of Table 1 above, for example, main component Q r A8.9 to 7.
8%.

K 4.5-16.3%, Ca 4.5-16.3%
, N87.8-8.2% or more, Al1.3-5.7%,
MQl, 1-2.0%, Si 0.6-1.2%
, Fe0.1-1%.

Dissolve other elements and connect the anode electrode to the liquid.

To perform this plating, it is first necessary to deposit each element at a certain electrical height when used as an electrode, and at a certain plating voltage (decomposition voltage). Various methods have been used to bring the metal ions closer to each other, such as adding additives (organic substances such as gelatin, difunylamine, and gum arabic) to increase the metal ion concentration, adjusting the pH of the liquid, and adjusting the current density.

The characteristics of the plated layer α of the present invention described above are summarized as follows: [Excellent visual abrasion resistance].

The coefficient of friction between the present invention and other metals is much smaller than that of general metals, so it has good sliding properties even under high pressure friction, and hardly wears out. Moreover, it also has the effect of reducing the amount of wear on the other machine. [See Table 3] Test conditions Load 0.57Kg/mtn Sliding speed 2°0677
1/SeC oil is approximately 1. Od/min As shown in Table 3, the measurement results for K, carbon steel and wear of carbon steel are 0.55/16hr and 0.44 a9/min, respectively.
By applying the coating of the present invention to one carbon steel, the wear part of the carbon steel on the sliding side was reduced to 0.1.
3jljp/16hr, which is a significant decrease.

[2] Can be easily ground and polished with a general whetstone.

Since the present invention can be easily ground and polished using a general GC or WA grindstone, it is the most suitable coating technology when high dimensional accuracy is required.

Further, since the thickness of the present invention can range from 1 to 1,000 μm, it is also possible to fill up parts of equipment that are insufficient in size or worn parts of jigs and tools.

[31 No seizure occurs even under severe conditions.

Since the plating layer α of the present invention is formed from a special composite alloy mainly composed of chromium, there is no structural change even when exposed to high temperature (500°C) for a long time as shown in Figure 12. Since there is little change in hardness, seizure does not occur even under high temperature, high pressure, and high speed usage conditions.

[41 Excellent adhesion, no cracks or peeling.

The coating of the present invention is a technique in which a plated layer α is electrically deposited while a nonmetallic element is permeated and diffused into a base material.

Therefore, melting point 1800℃, hardness H, V1000~H1
υ1200. The degree of adhesion is high, as shown by the degree of adhesion of 40 Kyld or more, and there is no cracking or peeling, especially when subjected to thermal shocks such as rapid heating and cooling.

[51 There is no change in the base material due to coating.

Since the coating of the present invention requires a low processing temperature as shown in the coating temperature of 60°C, there is no physical change such as distortion to the base material.

◎Base material that can be coated according to the present invention The coating according to the present invention is generally possible on iron-based materials.
In particular, if the base material is selected according to the application, it will show very good effects. A typical example of a material that can be coated is S.
K.

SKS, SKH, SKD, 545C, SCM.

Examples include SUJ, SUS, and FC.

Next, cut-out blades were manufactured from 5KH-9 with a hardness of HRC62 or more, and the present invention blade θ was coated with the plating layer α of the present invention to a thickness of 13μ, and the conventional blade λ was not coated.
A comparative durability test was conducted in which the same hard paper was cut repeatedly for each number of times. We obtained the results shown in the figure.

According to this, in the case of the cutting tool θ of the present invention, although it initially had a sharp cutting shape [see Fig. 13 (a)], it began to cut hard paper, and after that, the cutting vibration that required replacement was detected. Cutting was performed 70,000 times until a current value of 2A was detected electrically, and although the tip of the cutting edge was slightly worn, it still had a pointed shape and was worn out in a step curve shape [No. 13] In contrast, the conventional knife λ had a sharp cutout shape [see Fig. 14 (a)], but after cutting the hard paper, the page was polished. Only 10,000 cutting vibrations were recorded until a current value of 2A was electrically detected, and the tip of the cutting edge was completely arc-shaped [Figure 14 (b)] Reference 1 shows wear and deformation, and simple comparison shows that the cutter θ of the present invention has a durable life seven times longer than that of the conventional cutter λ.

A performance test was carried out on a circular saw for a brush cutter of the present invention coated with the plating layer α of the present invention and a conventional circular saw under the following conditions.

(1) Test circular saw Table 4 Specifications (2) Test procedure and results ■Test method For the second half of the work in the Hinoki 5 ocean plantation, we compared the work performance of both circular saws in normal work under the same conditions. did. For mowing work around the nursery field, it can be efficiently used for one-time sharpening. The durability time of both circular saws was observed, and the cutting performance, photographic performance,
We investigated the degree of damage, operational performance, etc.

■Test results Table 5 Comparison of work performance Table 6 Comparison of work performance that can be used for one sharpening ■ Vibration No particular difference was observed between both circular saws.

As the cutting capacity decreases, the engine speed increases and vibration increases in proportion to the speed. This was the same for both circular saws.

(2) Damage to the blade While using the circular saw of the present invention, the blade hit a stone, which would naturally cause damage with a conventional circular saw, but there was no damage. This is considered to be due to the effect of coating with the plating layer α of the present invention.

■Abrasion Resistance As shown in Table 6, the limit for one sharpening use was that the circular saw of the present invention was superior to the conventional circular saw by 282% in durability time and 341% in processing area.

■Cutting performance Conventional circular saws maintain their sharpness for about 2 hours and rotate at about 4,000 rpm with little vibration, but when used for about 3 hours, the rotation speed decreases to 4.500 - s. If you have to increase the rotation to ooooo, the vibration will increase. At this time, the cutting edge is so rounded and worn that it is not dangerous to touch it with your finger, but if you ignore efficiency, the work is possible. In normal work,
It seems appropriate to alternately use two sheets a day, one in the morning and one in the afternoon.

Circular saw of the present invention: Sharpness is maintained for about 6 hours after sharpening, but after that the rotation speed is reduced to 5,200 to 6.
It has to be increased to 0,000 rpm and the vibration increases. The continuous use limit was 10 hours and 47 minutes in this test, but considering efficiency and cycles, it is considered appropriate to replace the saw every one and a half days, and therefore the durability of the circular saw of the present invention is considered to be approximately three times as long. .

(3) Economical efficiency Regarding the economical efficiency of the circular saw of the present invention, considering the results of this test, the durability of the blade is about 3 times longer, and when considering the lifespan of one blade and the cutting time,
(50 days ÷ 1.5 days) x 25 minutes ÷ 14 hours to prepare for polishing to remove the clams is labor-saving.

(4) General evaluation The circular saw of the present invention has excellent durability, and if the number of moon-shaped teeth is manufactured according to the type of work and the demand is met, it is possible to use an economical and efficient brush cutter. be. Regarding the circular saw of the present invention, for the test, up to 5.4c of debris was processed from the cutting edge, but from the actual usage, it seems that 30 pieces from the cutting edge are sufficient.

To summarize the above-mentioned features of the circular saw of the present invention, (a) The hardness is extremely high due to the carbide surface treatment.

(b) Durability is several times that of conventional circular saws.

(C) Excellent economy.

(d) Grinding and polishing can be done freely.

(e) The waist is surface treated so it won't go out of order.

(f) It is highly durable and will not rust.

(0) It can be used in the same way as a conventional circular saw.

(h) It has intermediate performance between a tipped saw and a conventional circular saw.

(i) It has sufficient stickiness.

(j) Bamboo and bamboo can be cut down, which was previously impossible.

In addition, the circular saw of the present invention has good sharpness, so there is less resistance when cutting the grass, making the work lighter and faster. This reduces worker overwork and saves 25% on gasoline for the brush cutter, which can be done within a unit time. A 21% cutting effect is also required.

In the examples of the present invention, comparative performance tests were carried out using only blades and circular saws as objects coated with the plating layer α, but the scope of application and standard coating thickness shown in the table below are not limited to this. I would like to add that it is applicable.

Table 7 Scope of application of the present invention

[Brief explanation of drawings]

Figure 1 is a graph of the non-polishing surface roughness of the plating layer of the present invention.
Figure 2 is a graph of the surface roughness after the same puff polishing.
The figure shows the hardness distribution curve of a sample coated with the plating layer of the present invention.
FIG. 4 shows the state of diamond indentation on the plating layer of the present invention, (a) without heating, (b) with 40%
0℃. (C) shows the case of heating at 700°C for 3 hours, and FIG. ) shows the case of heating at 400°C for 3 hours, (c) shows the case of heating at 700°C for 3 hours, and Figure 6 shows the α cross-sectional structure of the plated layer of the present invention (3% nital) according to the JIS adhesion test method. ), and (a
) is a cross-sectional view enlarged 400 times, (b) is a cross-sectional view enlarged 100 times, FIG. 7 is a cross-sectional structure diagram of the same hard chrome plating layer, enlarged 400 times, and FIG. 8 is a cross-sectional view enlarged 400 times. Figure 9 is a friction characteristic graph of the relationship between the distance between the plated layer α and the hard chrome plated layer γ and the abrasion weight. Fig. 10 is a chromium carbide system diagram, Fig. 11 is an S-N line graph of steel coated according to the present invention, and Fig. 12 is a graph showing the plating layer α of the present invention and hard chromium plating. 13 is a graph comparing the hardness change due to heating with the layer, and FIG. 13 is a longitudinal cross-sectional view of the cutter of the present invention, in which (a) shows the initial shape of the cutting edge, and (b)
14 shows the shape of the cutting edge after cutting hard paper 70,000 times, and Figure 14 shows the shape of the cutting edge of the conventional knife, (a) shows the initial shape of the cutting edge, and (b) shows the shape after cutting hard paper 10,000 times. Figures 15 to 16 show the shape of the cutting edge when
The figure is a graph comparing the correlation between cutting vibration and current between the cutting tool of the present invention and the conventional cutting tool. α...Surface hardened plated layer of the present invention γ...Hard chrome plated layer ε, δ...Base material θ...Cuttle of the present invention λ...Conventional cutler Figure 1, Figure 2, Figure 3 Surface force ° et al. U! , Profile (mm) Fig. 4 Fig. 5 700''03 hours Rishi Fig. 6 (a) Fig. 7 Fig. 8 Fig. 10 Fig. 12 Temperature i ('C) Fig. 13 Fig. 14 (a)
(b) (a) (b) See Figure 15 Invention Effect Figure 16 Procedural Amendment January 30, 1985 Manabu Shiga, Commissioner of the Patent Office 1, Indication of Case 1982 Patent Application No. 271055 2. Title of the invention Surface hardened plating layer and its coating Circular saw and blade 3 Relationship with the case of the person making the amendment Patent applicant address Peninsula Pill 6, 1-12-8 Toranomon, Minato-ku, Tokyo
, Detailed explanation of the invention column of the specification subject to amendment and Drawing 7, Contents of the amendment As stated in the attached sheet 7, Contents of the amendment (1) Specification, page 16, line 8 [4.5 to 16.3% ' was corrected to [4.7-16.3%]. (2) Book I, page 16, lines 8 to 9 r Na 7.8 to 8.2% or more” was replaced with “N
a 7.8 to 8.1% or more.'' (3) On page 16 of the specification, line 18, “Add organic substances such as…” instead of “…”
・Add organic substances such as...'' and correct it. (4) In the 8th line of page 17 of the specification, "...the other party's machine..." is corrected to [...the other party's material...]. (5) Drawing [Figure 5] (a) (b) (c) Correct as shown in the attached sheet.

Claims (1)

[Claims] 1. Main components Cr, K, Ca, Na, Al, Mg, Si
, Fe, and has a hardness of H. V1000～
H. Surface hardened plating layer 2 made of composite super hard chromium alloy with physical properties of V1600, main composition elements are Cr400-700, K20-25
0, Ca20-250, Na40-150 or more, Al1
0~80, Mg5~30, Si2~20, Fe0.5~
The surface hardened plating layer 3 according to claim 1, in which 15 is the peak height of each element distribution, has physical properties such as a melting point of 1700° C. to 1900° C. and an adhesion degree of 35 Kg/mm^2 or more. The surface hardened plating layer 4 according to claim 1 or 2 has main components of Cr, K, Ca, Na, Al, Mg, and Si.
, a circular saw 5 formed by electrodepositing a surface-hardened plating layer of a composite ultra-hard chromium alloy mainly composed of Fe and a desired thickness over a width of at least about 3 cm from the cutting edge, the main components being Cr and K. , Ca, Na, Al, Mg, Si
A cutlery made by electrodepositing a surface-hardened plating layer of a composite ultra-hard chromium alloy mainly composed of Fe and Fe to a desired width and desired thickness.