JPS6070136A - Surface treatment of work - Google Patents

Abstract

PURPOSE:To provide high wear resistance to a work by preparing powder of a metallic different from the metallic material of the work or other material as an additive and by introducing the additive to the surface of the work together with plasma arc. CONSTITUTION:A plasma torch 2 is placed above the surface of a work 1 of a metallic material such as cast iron or an Al alloy, and mixing pipe 13 of ceramics or the like are arranged at the tip of the torch 2. A jet of plasma gas is blown on the surface of the work 1 from the torch 2, and at the same time, powder of a metallic material different from the metal of the work 1 or other material is fed as an additive 12 to the arc 10 through the pipes 13 with gaseous Ar as a carrier gas. The additive 12 is introduced into the melted part 11 together with the arc 10, and it is mixed with the metal of the part 11. The part 11 is then cooled to form a layer treated by remelting.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a surface treatment method that is applied to give high wear resistance to the sliding surface of a workpiece, for example, a valve operating cam of an engine.

Conventionally, as a method of this type, a method is known in which a plasma arc generates a molten part on the surface of a workpiece made of cast iron or other metal material, and then the molten part is cooled and solidified to form a remelt treatment layer. In such cases, the treated layer is merely obtained as a hardened layer of the chilled structure by increasing the cooling rate during the cooling and solidification, and thus is not necessarily sufficient for, for example, the above-mentioned lifting platform of the valve train cam. It is accompanied by disadvantages that are difficult to obtain in terms of wear resistance.

The object of the present invention is to provide a method that does not have such disadvantages, that is, a method for obtaining a surface treatment layer that further improves various properties of the remelt treatment layer, such as wear resistance.
In a method in which a plasma arc generates a molten part on the surface of a workpiece made of cast iron, aluminum alloy, or other metal material, and then the molten part is cooled and solidified to form a remelt treatment layer, the metal material of the workpiece is Prepare additives consisting of powders of metal materials and other materials different from the
It is characterized in that it is guided into the molten part along with the plasma arc and forcibly mixed into the molten part.

In this case, the additive is, for example, Ni, Or, M.

Other metals or their alloys, WO, Sin, MO! O
.

0rlO,, B, O and other carbides, BN, TiB and other borides, M o S! p WS2, 1F e
S other sulfides, AltO.

At least one selected from 5iOt and other oxides, etc.
Consisting of different powders.

The method of the present invention will be described in more detail with reference to the attached drawings. (1) shows a valve train cam and other workpieces made of cast iron, aluminum alloy, and other metal materials, and (2) shows a plasma torch opposing this. As clearly shown in Figure 1, (2) has a central electrode (3), a working gas passage (4) on its outer periphery, a nozzle (5), and a shielding gas passage (6) on its outer periphery.
and a plasma gas passage (8) connected to the working gas passage (4) at the tip of the nozzle (5), and a cooling water passage (9) in the nozzle (5).
), through which a jet of plasma gas is blown onto the work (1) through the plasma gas passage (8), and through which the electrode (3) is blown onto the work (13).
), a plasma arc (II) is applied between the workpiece (1) and the workpiece (1) to form a melted part on the surface thereof, and thus the torch (2)
is scanned over the workpiece (1), the melted part (11)
are gradually and continuously formed on the scanning line, and are gradually cooled and solidified from the starting side to obtain a so-called remelt treated layer, which is not particularly different from the conventional method.

According to the present invention, as described above, a powder of a material different from the metal material of the skeleton work (1) is prepared with additive a2,
This is caused by a nuclear plasma arc (which is guided into the molten part along with the IQ and forcibly mixed into the interior of the melted part1). A mixing tube Q31 made of ceramic, for example, is prepared with its tip facing forward, and the above-mentioned additive α2 is conveyed using, for example, argon gas, and the arc a is created inside the mixing tube α9.
In this way, the additive α was introduced into the molten zone (ill) along with the arc α and mixed into the interior of the plasma torch (ill). 2
) the flow velocity of the plasma jet at 20 m/s
ec %The flow velocity of the shielding gas around the outer circumference is 033 m/s
ec, and the conveying speed of the powder is set to 1.5 to 3 times the flow rate of the shielding gas, for example, 7 m/sec, so that the powder overcomes the shielding gas flow and is guided into the plasma jet. I made it.

Each operating state of the method of the present invention is, for example, as shown in FIGS. 2 to 6, that is, as shown in FIG. αω is generated to form the melted part (II) on the workpiece (1) side as shown in Figure 5, while the additive (L7J is conveyed by argon gas, for example, through the introduction pipe 0). Thus, as shown in the fourth diagram, the additive a21
is introduced into the upstream side of the plasma arc QO1, heated and accelerated, and guided together with the aluminum al into the molten zone and mixed therein. At this time, the plasma torch (2) is scanned in the lateral direction so that, for example, as shown in FIG.
gradually expands in the lateral direction, and its starting end reaches the workpiece (
The remainder of 1) is rapidly cooled and solidified due to the large specific heat it has, forming the remelt treatment layer (11&) described above.
During this operation, a stirring action is given to each melting part by causing the molten metal to flow vertically and horizontally within the melting part, and the additive a2 introduced therein is stirred by the stirring action. The remelt treatment layer (11a) obtained by dispersing the additive (lz Corresponding properties, such as wear resistance, are improved by this.

The amount of gas in the plasma jet in the plasma arc a is smaller than that in normal plasma melting, for example, 0.3~'s, al7-, and at this time, the additive (I
The conveyance speed of 2 is, for example, 0.5 m/sec or more,
Further, the current and voltage of the arc (10) are, for example, 30 to 2
00 A, 20 to 30 V, and the size of the powder of additive a2 is generally 200 microns or less, for example, about 100 microns.

Note that when the additive a2 is mixed into the melting zone C[1],
It may be dispersed in its original powder state, or at least a portion thereof may be melted or thermally decomposed to form the alloy or compound within the molten zone.

Example 1 A workpiece (11) consisting of F030030 Okoshi specimen was treated using the conditions shown in the first diagram.
, the flow rate of the plasma gas was set to α81/mm, the scanning speed of the plasma torch was set to CL5In/min, a remelt treatment layer was formed on the entire surface, and an additive α2 was added to this.
Or powder was mixed therein.

The size of the Or powder was 5 to 100μ, and the feeding rate was α2 gr 7mlyr. The remelt treated layer was formed at a depth of 1.8 M from the surface, and exhibited a chill composition due to rapid cooling during cooling and solidification. In this layer, Or
were contained approximately evenly distributed over the entire area at a ratio of about 12%.

The resulting product was designated as A and the product with a simple remelt treatment layer was designated as B. The results of the abrasion test are as follows.

01% Specific wear amount A 1.2 a6x1o mrll/to 9B O2,2
X10-? tp The rotor used in the test was made of S()M420 carburized and quenched, and then hard chrome plated to a thickness of 80 μm. The wear rate was 6 m/sec, the final load was 3.1 kg, The friction distance was set to f 200 m.

Example 2 A workpiece (1) consisting of a 5500 Okoshi wear test piece was processed using the apparatus shown in the first figure. Plasma current f: 10
The entire surface of the specimen was treated at a plasma torch scanning speed of 0.0 A, a plasma gas amount f of 0.81/vrin, and a scanning speed of 0.5 m/mm, and Mono powder was added thereto as an additive α. Its size is 2~50μ,
The transport amount was set to 0.697 kaku. The remelt is 1 from the surface
．． It occurred at a depth of 2 mm and exhibited a martensitic structure. Within the remelt treatment layer, MO is approximately 4% over the entire area.
The content was approximately evenly distributed at a ratio of 6%.

The resulting product is 0, and the product that is simply remelted is D.
The results of the wear test are as follows.

MO% Specific wear amount o 5.2 7.8X1o Fight/Yu6 D Oa5X10 p Example 3 Using the apparatus shown in Fig. 1, a workpiece (1) consisting of a Ni-10%Ou alloy superposition wear test piece was prepared. processed. The entire surface was scanned with a plasma current of 10 OA, a plasma gas of 0.81/min, and a plasma torch scanning speed of a5 m/1 ML, and 'L'iB powder as an additive az was added thereto. This supply amount was defined as 111L49/i. The treated layer is formed to a depth of 1.0 mm, and inside this layer there is TiB.
was approximately evenly distributed over the entire area at a rate of about 2.6%.

The product is E, and the product is simply remelted f, 'I
The results of comparison as P are as follows.

N: TiB% Specific wear amount 'n 2.6 4.0X10 mJ/kli+6 IF Oil 7.2X10 # Example 4 Using the apparatus shown in Figure 1, a workpiece (1) consisting of an FO30 ultra-thread type wear test piece was prepared. was processed. Plasma current 5
The scanning speed of the plasma torch was set to a 5 m/win, and the entire surface of the 0A1 plasma gas was used as remelt and PeS powder was mixed therein. The powder is 5
The size is ~30μ, and the conveyance amount is α3 fl /
It was set as miR. The treated layer was formed at a depth of 1.6 embryos and exhibited a chilled tissue, but FeS was contained within the treated layer at a rate of about 2.0%, distributed approximately evenly over the entire area. .

The results of an abrasion test using the product as G and a simple remelt treated product as f:H are as follows.

Fe8% Specific wear amount G 2.0 6.9X10 nua/kgHD 2.2
X10'''' 〃 Example 5 Using the apparatus shown in the first figure, a workpiece +11f consisting of an A1 alloy AG2B type wear test piece was processed.

Plasma current: 100 A s Plasma gas amount: α81
/mix, the scanning speed of the plasma torch was set to (L8m/i), the entire surface was remelted, and A'l, O was applied to it.

powder was added.

The powder had a size of 0.5 to 10μ, and the amount of transport was 0.69/+m++. The treated layer was formed to a depth of n, am/m, and contained Al, O, and substantially uniformly dispersed over the entire area at a ratio of &0%.

The resulting product is processed, and the product that is simply remelted is called J.
The results of a comparative test are as follows.

A: L, O, % specific wear weight 6.0a5×10-/kg J O6,2X10-'p As seen in the above examples, each workpiece (1) has wear resistance due to the addition of additives. has been significantly improved.

As described above, according to the present invention, when remelting the surface of a workpiece using a plasma arc, powder of an appropriate metal material or other material is introduced into each molten part and mixed therein with the arc. The powder is dispersed and contained in the Mukuremelt treatment layer to improve the wear resistance and other properties of the layer. It has the advantage of being abrasive and relatively easy to work with.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of an example of an apparatus for carrying out the method of the present invention;
2 to 6 are diagrams explaining the principle of each step of the method of the present invention. (1)...War (2)...Plasma torch 0Q...Plasma arc αυ...Melting part (12...Additive procedure amendment 1982) April 6, Patent Office, Palace ], Indication of the case Patent Application No. 168405 filed in 1982 2, Name of the invention Work surface treatment method 3, Person making the amendment Relationship to the case Patent applicant 562 Honda Motor Co., Ltd. 6, Description of the specification subject to the amendment The following has been added between lines 14 and 15 of page 2 of the specification in the Detailed Description of the Invention column, Drawing 7, Contents of Amendment (1) Page 2 of the specification. A member with galling resistance is produced by mixing base metal powder and sulfide powder using powder metallurgy, compacting and sintering, or by adding sulfide powder to molten metal and stirring. There are cast products, but this is disadvantageous in terms of cost because expensive sulfides are mixed into unnecessary parts.In addition, the powder metallurgy method is disadvantageous during sintering, and the casting method is During this period, the sulfides were kept at high temperatures for a relatively long period of time, decomposing them, and the amount remaining as sulfides was significantly reduced, making it difficult to obtain products with sufficient wear resistance and galling resistance. (2) On the 15th line of the second page of the book, the phrase "The present invention..., that is, the advantages" is corrected to "The present invention is effective without the disadvantages of the prior art." (3) Order On page 7, lines 3 and 4, [200μ or less...generally].Ji corrects "200μ or less is normal, and 100μ or less is particularly preferable." (4) Change “supply speed” in line 16 of this book to “supply amount”
I am corrected. (5) Change "12%" in the second line from the bottom of the page to "1.2%"
” he corrected. (6) Add "volume ratio" next to "crossing" on the last line of page 9 and the fifth line from the bottom of page 10. (7) On page 10 of the order, line 4 from the bottom, “FeS is approximately
(FeMn)S generated by the reaction with n is proportional to volume over the entire area.'' (8) “Fea%Ji[)FeS” on page 11, line 2 of the book.
. (FeMn)S%”. (9) The following is added between "Reta" in line 6 of page 12 of the order and "in this way..." in line 7. Example 6 Using the equipment N shown in the first figure, a stator workpiece tlJ consisting of a cast iron FO30 Okoshi type wear test piece was remelted as follows. That is, the plasma arc current is 80A, the plasma gas amount is 0.81/rtμs, the scanning speed of the plasma torch is 0.5m1m1n, the sliding surface is remelted without drawing a trajectory, and 2μ to 10μ of Or, 81 powder is applied to it.
1.29 parts mm of R gas was added to the melting section. Or melted and added to a depth of 1 to 2 mm from the surface,
S reacts with Fe, which is the base material, and Mn, which is its alloying element, to form (Or Fe)! 81 v (O
rF eMn)183 , (Or 'f'e)IS4
A dispersed structure containing a mixture of Or sulfides such as and (OrFsiMn)IS4 was formed. The volume ratio of this Or sulfide is 1
It was 5%. The size of these Or sulfide particles is approximately 1
It was ~8μ. In this case, the cooling after melting was heated by the base material other than the molten layer and solidified rapidly, so leadebrite was precipitated and exhibited a so-called chill structure, in which (OrF'e) 183. (OrFe)IS, , (
OrFeMn)I S3゜(OrFeMn)
)s s, are dispersed. After the treatment, the sliding surface was polished and used as a test piece. For comparison, a chill structure was formed by melting and hardening simply by plasma arc without adding 0rlS3 powder. The sliding surface was polished and used as a test piece. These were subjected to wear tests in the same manner as in Example 1. The results are shown in the table below. Dispersed sulfide volume ratio Specific wear amount K Or sulfide 75% aoxlo mm/9L
--2,2X10- mm/kg Example 7 Using the apparatus shown in the first figure, an iron-carbon alloy (α50%
) was remelted as follows. That is, plasma arc current 80A1 plasma arc A
r gas amount is 117mln, plasma torch meandering scanning speed f 0.3 m/-, and after meandering, slide @ 1 is remelted, and 2μ to 10μ Or302 f 50
A mixed powder of 50 wt% of 5-60μ MoH'' was contained in Ar gas and supplied to the melting zone, and these mixed powders were mixed together in the melted layer up to 1.4 m/m from the surface. In the reaction of Or, FEB + O
A dispersed structure containing rl s4 chromium sulfide particles was formed. The volume ratio of Or sulfide was approximately Q, 5%, and the particle size was approximately 1 to 9 μm. The treated surface of this product was polished to obtain a test piece M. For comparison, a test piece N which was remelted without any additives was prepared and subjected to the wear test in the same manner as in Example 1. The results are shown in the table below. Test piece Dispersion Volume ratio Abrasion resistance M Or
Sulfide 0.5% 3.6:xlo mnt/kgN
None - asx 1 o mnt/kP Example 8 Using the device shown in Figure 1, the cam lift part of an F030 camshaft to be incorporated into an automobile engine was inspected as a workpiece (1
) was remelted as follows. That is, the plasma arc current is 60A. Ar gas group for arc 0.517ml x, plasma torch scanning speed 1m/+++m, 2p to 10p O
r S3 powder supply JI 0.69/mix,
The powder was fed into the melt bed. Thus (OrF' e)
I SB , (OrFeMn) 183° (Or F
e) Various types of g S4 and (OrFeMn)3s,
A cooled and hardened layer with a thickness of 18 m/m containing sulfurized powder was obtained. The volume ratio of Or sulfide was 2.2%, and the particle size was 1 to 8 μm. The hardness was HRO5B. The cam surface of this camshaft was polished and subjected to practical tests.
This was designated as test material 0. On the other hand, a camshaft made of the same material was subjected to plasma treatment under the same conditions as above without adding the powder, and was subjected to remelting and hardening treatment, and this was designated as camshaft test material P. The thickness of the hardened layer was 1.9 m/m%, and the hardness was HRO51. Practical test conditions: Engine rotation 1ooorpi oil temperature 65℃ test time
As a result of this test for 200 hours, the wear amount of the cam top of test material 0 was 10
It was μ. The wear amount of the cam top of one-way test material P is 12
It was 0μ. Example 9 Using the device shown in the first figure, a valve rocker arm made of 80M420 to be incorporated into an automobile engine was worked (1)
The slipper surface of the persimmon was remelted as follows. That is, arc current 45 A1 Ar gas amount for plasma arc 0
．． 517mm, 2-10μ 0r283 powder supply amount α4
97 ml and a torch sheath of 0.8 m/miq were drawn in a trajectory to melt the slipper surface, and the powder was added to the molten layer. As a result, Or and Sl were generated by the reaction between Fe, which is the main component of the base material, and Mn, which is its alloying element (OrFa).
1 s, s (OrlFeMn) 133 , (Or
Fe)3S4. A chilled hardened layer containing dispersed particles of Or sulfide mixed with (Or Fe M n) B 84 was obtained. The thickness of the layer was 1.0 ml D1, and the volume ratio of the Or sulfide was 54%. This was carburized and quenched and then polished to give a test material Q. On the other hand, a valve rocker arm made of the same material was simply carburized and quenched without being subjected to remelting sand hardening treatment using a plasma arc, and both test materials were subjected to the following practical test. As a result, the wear depth of one surface of the test material Q was 3μ, and the wear depth of the test material R was 3μ.
The wear depth on the entire surface was 50μ. Practical test conditions: Engine rotation: 1000r91 Oil temperature: 65°C Test time: 200 hours Example 10 Using the apparatus shown in Figure 1, a workpiece for a stator (1) consisting of a cast iron FOD55 Okoshi type grinding specimen was prepared as follows. Re-melted. That is, the plasma arc electric current m80 A
N plasma arc Ar gas amount 1817mlx, plasma torch scanning speed o, sm/min, the sliding surface is remelted without drawing a trajectory, and the remelt layer is 5μ to 40μ
FeS powder was supplied in Ar gas for 1.597 min. The depth of the molten layer was 1.2 m/m. On this occasion,
Part of the added amount of FeS is F, which is the main component of the alloy base material.
Reacts with e and part of Mn to generate (FeMn)S,
As a whole, a remelt hardened layer in which dispersed particles of iron sulfide mixed with FeS and (FeMn)S were dispersed was formed. The size of the dispersed particles was 1-9μ. The volume ratio of Fee and (FeMn)S was 15%. The sliding pattern of the thus obtained treated product was polished to obtain a test piece S. For comparison, a test piece T was prepared by semi-solid remelt hardening of workpiece (1) of the same material without adding iron sulfide under the same conditions as above. All of these were subjected to wear tests in the same manner as in Example 1 above. The test results were as follows. Test piece Dispersed sulfide Volume ratio Ratio Wear amount Example 1
1 Using the apparatus shown in the first figure, a wear test piece made of 5500 was used as a workpiece (1) for a stator, and this was remelted as follows. That is, the plasma arc current is 80A, the plasma arc Ar gas amount is 11/min, and the torch meandering scanning speed is 0.
3m/m, remelt the sliding surface without meandering, and add 10μ to 40μ to the molten layer at a depth of 1.4m to 7m.
MoS was supplied in an amount of 0.15p/- in Ar gas. As a result, MoS and the alloy base material Fe
FeS and (FeMn) react with Mn in the molten layer.
) A hardened layer in which S is produced and dispersed is obtained by subsequent cooling. The size of these produced particles was about 1 to 7 microns, and their volume ratio was about 0.8%. The treated surface was polished to obtain a test piece U. For comparison, a workpiece of the same material (one piece was simply remelt hardened in the same manner as above, without adding any additives, and this was used as test piece V).
And so. These test pieces were subjected to all abrasion resistance tests in the same manner as described above, and the following results were obtained. Test piece Dispersed sulfide Volume ratio Ratio Abrasion resistance U (F
eMn)S α8% 4.2×10- mtfl/k
gV --a, 5 x 10 mnl/kg Example 12 Using the device shown in Figure 1, the cam lift part of an F030 camshaft to be incorporated into an automobile engine was fabricated as a workpiece (1
) was remelted as follows. That is, the plasma arc current is 60A1, the arc Ar gas amount αB/=, the scanning speed of the plasma torch is 1m/-, the surface of the cam lift part is melted while drawing a trajectory, and the supply amount of WS and powder of 2 to 10μ in the gas is α6fl/mix was supplied to the melting section. The depth of the melt layer was 1.8 m/m. As a result of that addition, WS! and the compositional elements of the base material Fe, M
A hardened layer of a molten layer in which FeS and (FeMn)S, which were generated by reacting with n, were mixed and dispersed was obtained. The size of the dispersed particles was about 1-10μ, and the volume ratio was 2.8%. The hardness of the hardened layer was HRO53. This cam shirt was polished to obtain a test material W. For comparison,
Test material X was obtained by simply remelting the same camshaft. The hardness of the hardened layer was HRG51. These test materials all engine revolutions 100 QrpH, oil temperature 6
A practical test was conducted under test conditions of 5°C and 200 hours of test time. As a result, the wear amount of test material U was 30 μ, test material ■
The amount of wear was 120μ. Example 13 Using the apparatus shown in the first figure, a valve rocker arm made of S 0M420 to be incorporated into an automobile engine was worked (1
) The slipper face metal was remelted as follows. That is, the plasma arc current is 45 A, and the plasma Ar gas amount is 0.5 l/min. Using a plasma torch speed [L8 m/miy+, scan and melt the slipper surface, and add PeS to the melted part.
It was transported with r gas and supplied with a 0.497+m++ supply lid. A part of the supplied amount of FeS is M, which is a constituent element of the alloy base material.
A molten hardened layer was obtained by cooling, in which (FeMn)S, which was generated in opposition to u, was mixed and dispersed together with FeS. Fe
The size of S and (FeMn)S was about 1 to 8 μ, and the volume ratio thereof was about 5.2%. Next, in order to improve the strength of the slipper of the workpiece (1) treated in this way, carburizing and quenching is performed to form a carburized layer of about 1.2 on the hardened layer. A wear-resistant structure layer containing the aforementioned sulfides was obtained.This surface was polished and used as test material W.For comparison, the same workpiece (tl) was simply remelted and then carburized and quenched in the same manner as above. The material with the applied wear-resistant structure layer was designated as test material X. For these test materials,
Practical tests were conducted under the conditions of engine rotation of 1000rI1m, oil temperature 65°C, and test time of 200 hours. As a result, the wear depth of test material W was 10μ, and the wear depth of test material X was 50μ. As is clear from Examples 1 to 13 above, Or. By dispersing Mo, TiB, A110g, FeS, and other various sulfides in the remelt layer of the workpiece, the wear resistance can be significantly improved compared to those without such treatment. can. In particular, Or
Sulfide has higher stability at high temperatures than other sulfides, and unlike other Or sulfides, it does not decompose even at high temperatures of 1000°C or higher, providing an extremely stable frictional sliding surface and being effective as a lubricant. It is advantageous to have both. The particles to be added generally have a particle size of 200 μm or less, and preferably 100 μm or less. When this is added to the molten layer on the surface of the workpiece, it becomes liquid particles,
As it is scanned by the plasma arc in this state, a fluid agitation phenomenon occurs in the melt, and the liquid phase particles are fragmented from the traps, and as a result of being cooled and solidified in this state, the fragmented in-phase particles enter the hardened layer. A surface treatment layer in which the particles are dispersed is obtained. For example, in the case of a cured product, the diameter of the dispersed particles is about 1 to 20
A range of .mu. is preferable, since it reduces the internal stress concentration rate, resulting in excellent pitting resistance, galling resistance, etc., and the lubricating effect of sulfide on the worn surface tends to act uniformly on the sliding surface. Further, by repeating the friction, the particles are stretched and a coating of tens to hundreds of sulfides is easily formed on the surface, which is preferable. Further, according to the present invention, the remelt time is generally only about 1 second or less, which is advantageous because there is almost no loss due to thermal decomposition of sulfides, for example. FIG. 7 shows the results of investigating the relationship between the volume % of Or sulfide and the amount of wear of the treated product for a camshaft made of an automobile engine FO30. As is clear from this, approximately 0.2%
From the above, it exhibits a wear-resistant effect, and its effect is remarkable even when added in small amounts. However, if it exceeds about 12%, the toughness tends to decrease, so it is advantageous to limit the content to about 12% from the viewpoint that the improvement in effect is small and it becomes economically expensive. Figure 8 shows the relationship between the volume percent of iron sulfide (FeEI + (PeMn)S) and the wear amount of the treated product.
The results of the investigation on the 30-made camshaft showed gold. In this case, the effect is exhibited at 0.5% or more. As the amount increases, the improvement in effectiveness decreases, and from an economical point of view, it is about 20%! It is advantageous to Q: In the fourth line from the bottom of page 12 of the manual, ``It is simple, etc.'' is corrected to ``It is simple, and there is no thermal decomposition loss of effective dispersed particles, etc.''. αυ Book, page 13, line 1, ``...Explanatory diagram.'' was changed to ``...Explanatory diagram, Figures 7 and 8 are the volume percent of sulfide. It is a curve diagram showing the relationship between the amount of wear and the amount of wear.'' (121 Figures 7 and 8 are all attached as shown in the accompanying paper.

Claims (1)

[Claims] 1. A method of forming a remelt treatment layer on the surface of a workpiece made of cast iron, aluminum alloy, or other metal material by generating a molten part by plasma arc and then cooling and solidifying the molten part. In this method, an additive consisting of a powder of a metal material or other material different from the metal material of the workpiece is prepared, and the additive is guided into the molten part along with the plasma arc and forced into the interior of the molten part. A method for surface treatment of a workpiece, characterized by mixing the surface of the workpiece. 2 The additives include lJi, Or, Mo and other metals or their alloys, To, Sin, Mo), 0. Or,
O! , B40 and other carbides, BN, TiB and other borides, Mob, , WSI, F'eS and other sulfides, Al, O,. Sin! At least one selected from other oxides, etc.
A method for surface treating a workpiece according to claim 1, comprising powder of various types.