JPS6223986A - Laser beam absorbent for treating surface of laser - Google Patents

Abstract

PURPOSE:To obtain the titled absorbent wherein the scattering and the peeling of a coated film in a period of laser irradiation and both precipitation and flocculation of the absorbent in a soln. are not caused by blending the dispersant and a thickening agent in the laser beam absorbent blended with metallic oxide or the like in a dispersion medium. CONSTITUTION:A laser beam absorbent is obtained by blending the powder for beam absorption consisting of a metallic compd. of one or more kinds of metallic oxide, metallic carbide and metallic nitride, a dispersant and/or a thickening agent in a dispersion medium. Since the powdery grains for beam absorption exist almost individually in this absorbent and each powdery grain is made to a state covered with the soln., the adhesion is remarkably increased after the drying. This effect remains even when it is exposed at high temp. with the laser irradiation. Also since the powdery grains exist individually even when a binder is decomposed, it is melted extremely easily with the laser irradiation and it is considered that this melted phase is penetrated among the nonmelted powdery grains and the adhesion is increased.

Description

Detailed Description of the Invention [Industrial] 17-P-F1 Field The present invention relates to a laser beam used when performing surface heat treatment on metal materials using an infrared laser such as a carbon dioxide laser (length: 10.67 zm). Regarding absorbents.

@Semi-cough surgery Compared to conventional high-frequency heating and carburizing and quenching, laser surface heat treatment of metal materials is: (1) It is rapidly cooled by self-cooling, so it does not require coolants such as oil or water; (2) (3) Since the amount of heat input is small, thermal distortion is small; (4) It has excellent controllability and can be easily automated. ,
It has such excellent characteristics that it is being applied to surface hardening of steel materials and surface heat treatment of various metal materials. However, when carrying out such laser heat treatment, if the laser beam is directly applied to the shiny metal surface, most of the input energy will be lost due to a = +. A method of applying graphite to the surface to be treated or forming phosphoric acid scales or oxide scales to reduce the absorption rate of laser energy has been adopted.

However, it is difficult to say that such a method has a laser beam absorption rate of 1-min.10, and the phosphoric acid treatment and oxidation treatment require a long time, so although it is an efficient method, do not have.

JP-A-56-160943 discloses that 3J-Euna 6 is used as a coating agent containing an oxidizing agent as a main component, and that an oxide is added to the Rubker thinner. A mixed and stirred Nonicorte ink agent is disclosed. This coating agent ('', A (/2
03, S 102, Cr, 0. By utilizing the fact that these metal oxides have a very high absorption rate when exposed to a carbon dioxide laser with a wavelength of 1016μ by χ・1, these metal oxides are applied to the surface of the treated object. By mixing and stirring these beam-absorbing powders in the hookahnon, it is possible to apply them uniformly by spraying, etc. be. .

Solution 1 Retirement - 2 and 4-4 Summary, 1. However, if we use a coachic agent that actually uses such an oxidizing agent as a beam absorber, the following problems may arise and the beam absorber may not be used. 1. I can't say anything about it.

(a) Splashing and peeling of coating during laser irradiation When performing laser heat treatment, it is usually +l- when the surface to be treated is oxidized.
In order to protect optical systems such as condensing lenses and mirrors, which cause .chi.1 to occur at every 100 ms, dregs of Ar, Tle, etc. are often blown onto the surface to be processed. Therefore, if the oxide powder is simply applied to the surface to be treated (J), the film will easily scatter. Even if a binder such as lacquer is used in combination, the amount of powder 1: The oxide powder may be bonded to the surface to be treated, or the adhesion effect may be lost due to heating by laser irradiation.
As in Germany, scattering and peeling occur, making it impossible to maintain stable heat treatment.

(b) Precipitation and aggregation of absorbent in solution In an absorbent solution prepared by mixing and stirring oxide powder in a solvent such as lassocarnonner, the powder is dispersed relatively uniformly in the solvent immediately after stirring, but for a long time. Powder precipitation and agglomeration occur when left for a long time. Once the powder has coagulated, it is difficult to restore it to a homogeneous state even by stirring again, so the absorbent liquid must be newly prepared each time it is used, or it must be continuously stirred for a long time, resulting in poor workability. .

In view of the above-mentioned problems, the present inventors have created an absorbent for laser surface heat treatment that has excellent adhesion to the surface to be treated and is easy to prepare. As a result of various studies, we have completed the present invention.

The present invention provides a beam-absorbing powder comprising one or more metal compounds selected from the group consisting of metal oxides, metal carbides, and metal nitrides in a dispersion medium, as well as a dispersant and/or an additive. The present invention provides a laser light absorbent for laser surface treatment, which is characterized by containing a sticky agent.

However, the present invention involves adding a specific additive to the dispersion medium that has a dispersing effect and/or thickening effect in addition to a binding effect, and adding metal oxides to the nuclear solution as a beam-absorbing powder. The absorbent made by mixing powders of metal carbide and metal nitride has good laser beam absorption rate, and it also prevents peeling and scattering of the formed film, Jf2, and dispersion after being left for a long time. This method was completed after discovering that there was no precipitation or aggregation of the absorption powder in the liquid.

If a beam-absorbing powder is mixed with a solution that only has a binding effect, such as a lacquernner, aggregates of powder particles are mixed, but based on the present invention, a dispersion effect,
In absorbents containing additives that have a thickening effect, the powder particles exist almost independently, and each individual powder particle is covered with a solution, so the adhesion after drying is poor. <Direction 1- Do.

This effect remains even when exposed to high temperatures due to laser irradiation. Also, the binder decomposes 1. Even in the case where the powder particles exist alone, the laser irradiation makes it easy to melt the powder, and this molten phase penetrates between the unmelted powder particles, directing the density f1 to the direction 1-1. 1” and 4 are given.

Next, each component used in the absorbent of the present invention will be explained.

(1) Beam absorption powder bead 1-. As absorption powder, ΔQ203, S 10
2, T i O9, Cr2O3, F (!203.7.
r Op, V2O3, VO1MgO1CaO1Nb20
．． ,'f''a,,(')5,Y2O,,1,,a,03
Metal oxides such as 2TiC, VC, NbC17, rC,
'l''aC, IlrC1M(hC, MoC1W 2 C
.

we, Cr3C2, Cr7C3, Cr2JCo, F
Metal carbides such as e5C; ZrN, 'f'iN, AIX
N, l(N,'I''aN, MgaN 9.513N
4% CrN, (, r2N.

Metal nitrides such as M 02 N , W , and N are not present in A
1 should also be used. Both of these have a wavelength of 10.611m.
It has a high absorption rate for carbon dioxide lasers and is used as a beam absorption powder. Metal oxides are particularly advantageous in terms of ease of availability, easy solubility during laser irradiation, and chemical stability. Only one type of metal compound may be used, or two types of metal compounds may be used together.

In addition, the particle size of these beam absorbing powders ('', 507zm
It is preferably less than or equal to F, and more preferably less than or equal to 57zm.

The blending amount of these metal compound powders in the total absorbent of the present invention is 20 to 90% by weight, preferably 50 to 90% by weight.
83 weight [1%.

(2) Additives Various additives may be incorporated into the absorbent of the present invention in order to impart dispersion effects, thickening effects, binding effects, etc.

Among these additives, as dispersants, polyacrylic acid,
Examples include compounds such as acrylic acid-acrylic acid ester copolymer, styrene-acrylic acid J (polymer), styrene-maleic acid copolymer, allylsulfonic acid, and dryethylamine. It has the effect of improving the dispersibility of the powder particles by improving the wetting of the powder with the solution and preventing agglomeration of the powder particles F.The distribution of the dispersant is now 0% based on the total weight of the absorbent. □2-3 city mounds%
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Next, as thickeners (J1 polyisobutylene, isophthylene-maleic acid copolymer, polyhinyl butyral, silica sol, alumina sol, etc.) are used.These increase the viscosity of the solution, thereby preventing powder agglomeration. 4" to prevent precipitation and improve the bonding strength of the coating layer.
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The amount of the thickener to be blended is preferably 2 to 10% based on the total weight of the absorbent.

Although either one of these dispersants and thickeners may be blended, it is more preferable to use both in combination.

Further, the bonding effect described in 117 (2) means the effect of bonding the P-11 absorbing powder particles or the powder particles and the surface to be treated after drying. Such a binding effect is achieved by the above-mentioned dispersant and thickener, and there is no need to add a separate binder, or it may be added as desired. Also, during the dispersion process, the absorbent may foam; in this case, add an antifoaming agent such as tributyl phosphate or pine oil, and if necessary, add an i=J plasticizer, etc. It's okay.

(3) Dispersion medium The dispersion medium for mixing and dispersing component h of the absorbent of the present invention includes water, ethanol, methanol, trichloroethylene,
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The absorbent of the present invention can be produced using the above components as follows.

A mixed solution of a dispersant and a dispersion medium is prepared, and this mixed solution and absorbent powder are simultaneously introduced into a blender such as a sand mill and mixed for a predetermined time. Thickeners, binders, etc. were further added to the resulting mixed slurry, and the slurry was treated with Santomil again for several hours to combine with the laser light absorber.

Example 1 Next, the laser beam absorbent of the present invention will be explained in more detail with reference to Examples.

Example 1 Comparative absorbents A-C and inventive absorbent D-8 were manufactured using the components and formulations shown in Table 1 below. In Table 1, % means weight %, r) A A is acrylic acid-acrylic acid j-ster copolymer (7fl:30) PStAij styrene-acrylic acid copolymer (2080), PSLM is styrene-acrylic acid copolymer (2080), Ren-maleic acid copolymer (50:50), PiB
uM is isobutylene-maleic acid copolymer (30 nia)
n), PVB means polyvinyl butyral.

These absorbents were manufactured as described above.

The results of tests conducted on the properties of the various absorbents obtained, the properties of steel sheets when laser heat treatment was performed using these absorbents, and the surface condition after treatment are shown below.

(1) Sedimentation and aggregation of absorbent powder after being left for a long time The absorbents shown in Table 1 (excluding A) were placed in a sealed container and left to stand for 72 hours, and the degree of precipitation and aggregation after leaving was determined. A comparative absorbent (BS
In C), the beam-absorbing powder almost completely settled on the bottom 17 after being left to stand, and it was impossible to uniformly disperse it even by stirring. In contrast, the absorbent of the present invention did not cause precipitation or aggregation and exhibited the same performance as the new preparation even when used after being left for a long period of time.

(2) Shape of hardened layer after laser heat treatment
・The shape (width, depth) of the quenched layer was examined by spray coating it on a No. 1 plate and scanning it once with a laser under the following conditions, and compared it with the case where a conventional absorbent was used.

Laser scanning condition output: 5KW Workpiece movement speed: 2m/min Beam cross-sectional shape: I Omm S 420.12 (
llv178) Shape of material to be treated: 50 mm x 5
0 mm x 5 mm" Figure 1 compares the depth (D) and width (W) of the hardened layer on the outermost surface of the treated surface. Here, the hardened layer is -1- means the area hardened to -1-.The area to which the present invention absorbent CD-5) is applied is manganese phosphate (CD-5), which is commonly used in the past.
A) It can be seen that both the depth and width of the hardened layer are significantly improved compared to those subjected to coating treatment, and the absorption rate is extremely high.

In addition, in the cases where comparative absorbents (B, C) not containing additives having a dispersing effect or thickening effect were applied, the shape of the hardened layer varied greatly depending on the measurement location.

On the other hand, when the absorbent of the present invention is applied, a hardened layer with a width of 7.0 mm or more and a depth of 0.6 mm or more is reliably formed, with small variations and extremely excellent stability. .

(3) Surface hardness and peeling after laser heat treatment Table 2 below shows the measurement results of the outermost surface hardness of the 5US420J 2 flat plate after laser irradiation and the presence or absence of peeling of the absorbent near the irradiated surface.

The absorbent of the present invention (D-S) is coated with a phosphate (A) coating, has high hardness, and does not contain additives that have a dispersing or thickening effect. When (B, C) is used, the variation in hardness is extremely small.

In addition, absorbents that do not contain the above additives tend to peel off near the laser irradiated surface. When the absorbent of the present invention was applied, there was no peeling.

1. Application of the laser light absorbent of the present invention to the surface to be treated. If
Since a sufficient improvement in the absorption rate of laser light is achieved, the properties of the heat-treated portion are as follows: L, and the stability of the quality of the object to be treated is also significantly improved.

Therefore, performance equivalent to that of the conventional method can be achieved even at higher processing speeds, the heat treatment time can be shortened, and distortion due to heat is also small.

Further, the absorbent of the present invention does not cause precipitation or aggregation even after being left for a long period of time, and can maintain the desired performance for a long period of time.

Table 2

[Brief explanation of the drawing]

Figure 1 shows S LJ 54 coated with various absorbents and quenched.
It is a graph showing the depth and width of the hardened layer of 20J2.

Claims (4)

[Claims] (1) A beam-absorbing powder containing one or more metal compounds selected from the group consisting of metal oxides, metal carbides, and metal nitrides in a dispersion medium, and a dispersant and/or
Or a laser light absorbent for laser surface treatment, which is characterized by containing a thickener. (2) The beam absorbing powder is a metal oxide.
) Laser light absorbent. (3) The dispersant is polyacrylic acid, acrylic acid-acrylic acid ester copolymer, styrene-acrylic acid copolymer,
The laser light absorber according to item (1) above, which is one or more compounds selected from the group consisting of styrene-maleic acid copolymer, allylsulfonic acid, or triethylamine. (4) The thickener is polyisobutylene, isobutylene-maleic acid copolymer, polyvinyl butyral, silica sol,
The laser light absorbent according to item (1) above, which is an alumina sol.