KR100593100B1 - A bonding material for hard grain - Google Patents

Abstract

The present invention relates to a binder for hard particles, dibutyl phthalate (Dibutyle pthalate) 10-69%, dibenzothiophene (Dibenzothiophene) 0.001-1%, vinyl acetate 10-69%, acetaldehyde 0.05-3% It is composed of 20-60% of water, so it can be easily combined with hard powders when kneading with powders such as metals or ceramics, and can perform other operations within 1 minute after molding. have.

Description

A bonding material for hard grains

The present invention relates to a binder for hard particles, and in particular, a mat having a flexible material that is easy to handle by bonding different metal powders and / or brazing powders to be bonded to each other during brazing for bonding dissimilar metals onto a metal base material. It relates to a binder for hard particles useful for producing a.

In general, parts used in areas requiring wear resistance are bonded to a metal base material by joining a hard metal such as metal carbide powder, metal nitride powder, or metal oxide powder with high hardness, such as tungsten carbide (WC), chromium carbide, and boron carbide. To improve wear resistance.

The conventional brazing method used in the method of joining the high hard metal and the metal base material is to place the powder or paste brazing material between the high hard material and the metal base material and heat it to a temperature at which the brazing material is melted to bond the base material and the metal. To achieve.

However, this brazing method can be easily and easily bonded to a metal base material having a flat surface, but if the metal base material is curved or recessed, the hard material is bent along a curved or recessed shape. As a result, even if the curved surface is formed, the tolerance between the metal base material to be bonded cannot be managed constantly so that a space is formed between the hard material and the metal base material or the braze material is uniformly wetted along the curved surface. Because wetting was not performed, bubbles were generated at the joint surface, resulting in poor bonding.

In this case, when the brazing material is used as powder or paste, the brazing filler is unevenly distributed due to the characteristic of flowing down along the curved surface of the curved object. There was a lot of possibilities.

In order to improve the problems caused by the characteristics of the braze powder, US Patent No. 3876447, filed on June 22, 1973 and registered on April 8, 1975, "Method of applying hard-facing materials." '' Polytetrafluoroethylene (PTFE) is used to fabricate a hard metal and a brazing filler material using a flexible mat, respectively, laminated on a metal base in two stages, and sintered and bonded in a furnace. A method of bending and joining a soluble mat in accordance with a curved state of the present invention is disclosed.

However, the bonding method between the dissimilar materials has a long manufacturing process for manufacturing a flexible mat including hard particles and a flexible mat including polytetrafluoroethylene, and also laminates two mats on a metal substrate. The hard metal mat, the brazing filler mat and the shake while moving there was a problem such as a bad bond occurs.

In addition, the polytetrafluoroethylene used in the manufacture of flexible mats has to be maintained in the furnace for a long time due to the slow pyrolysis rate, which not only accelerates corrosion of the furnace, but also if polytetrafluoroethylene If the residual amount of is left, the bonding strength of the bonding interface or the wear resistance of the hard layer is weakened, and there are problems such as generation of chlorine compounds and strong acid substances harmful to the human body.

Thus, in German Patent DE3801958 entitled "Method of Laminating a Hard Material Layer on a Metal Base", issued on January 23, 1988, ethylene-vinyl acetate is used instead of the method of using polytetrafluoroethylene used in the above-mentioned US Patent 3876447. A method of using a copolymer, an ethyl-propylene copolymer and / or butyl rubber is proposed.

In this method, however, the ethylene-vinyl acetate copolymer, the ethylene-propylene copolymer, and / or butyl rubber, which are used as binders, are not directly combined with dissimilar materials, but are melted and bonded using a separate solvent. After putting the binder and the solvent together, dried for about 16 hours, pre-rolling was performed, and the pre-rolled body was rolled again to prepare a flexible mat having a final thickness of 0.5-3mm.

Therefore, a long time of 16 hours is required for drying, and there is a problem that there is a risk of explosion due to hydrogen gas because hydrogen gas must be used as a protective gas to thermally decompose the binder.

Accordingly, the present invention is to solve the above problems, and hard particles that can quickly produce a flexible mat without a separate drying process by kneading metal carbide, nitride, oxide, etc. ceramic powder or brazing materials without using a solvent The purpose is to provide a binder for the purpose.

In order to achieve the above object, the binder for hard particles of the present invention is dibutylphthalate (Dibutyle pthalate) 10-69% by weight, dibenzothiophene (Dibenzothiophene) 0.001-1%, vinyl acetate 10-69%, acet Characterized by including 0.05-3% aldehyde, 20-60% water.

According to this configuration of the present invention, the hard material or the brazing material can be kneaded directly without a solvent, and a flexible mat can be produced in a short time without drying.

Hereinafter, preferred embodiments of the present invention will be described in detail.

The present invention comprises 10 to 69% of dibutyle pthalate, 0.001 to 1% of dibenzothiophene, 10 to 69% of vinyl acetate, 0.05 to 3% of acetaldehyde, and 20 to 60% of water. It is configured by.

The reason for limitation of the composition of this invention mentioned above is demonstrated below.

Dibutyl phthalate is bonded with hard particles to give bonding strength. If it is together with water, it stabilizes, and without water, it reacts with metal, forming a bond with Van der Waals, hydrogen bonding, and covalent bond with metal. In the case of too weak to have a sufficient bonding force, the molybdenum itself becomes too large at 69wt% or more because the falling of the wetting falls, the ability to contain hard particles is limited, the composition range is limited to 10-69wt%.

Dibenzothiophene is used to stabilize dibutyl phthalate. Dibenzo phthalate cannot be stabilized at 0.001 wt% or less, and when it is added at 1 wt% or more, it causes a lot of harmful sulfides during incineration of dibenzothiophene. Therefore, the composition range is limited to 0.001-1wt%.

Vinyl acetate is an acidic compound that improves metals and wetting by reducing the overall viscosity due to hydrophilicity. If it is less than 10wt%, the amount is too small to give an acidic effect to the molomer, and more than 69wt% is included with water Since dibutyl phthalate and the like cannot form a stable composition, the composition range is limited to 10-69wt%.

Acetaldehyde is intended to increase binding to hard particles and increase flexibility in the material. If necessary, bisulfite additives of polyaldehydes can be used, for example, polyaldehydes are malonic dialdehydes. , Propanonedial succinic aldehyde, butanone dialal and the like, and the counter ions of bisulfite are mainly composed of lithium, sodium, potassium, magnesium, calcium, aluminum and the like.

If the acetaldehyde is less than 0.05wt%, it may not be able to secure sufficient binding force with the hard particles, and if it is 5wt% or more, the acetaldehyde may not be uniformly dispersed by agglomeration with each other, so the composition range is limited to 0.05-5wt%.

Water is for stabilizing and homogenizing dibutyl phthalate at room temperature. The concentration below 20wt% cannot sufficiently stabilize dibutyl phthalate, and when it is above 60wt%, water is 20-60wt% because dibutyl phthalate is insufficient. Limit the scope.

The binder having the above-described configuration, when mixed with the metal or ceramic powder 30-80 vol%, allows the finished mat to maintain flexible properties.

Example 1

A binder made of 40 wt% water, 55 wt% dibutyl phthalate, 0.5 wt% dibenzothiophene, 2 wt% vinyl acetate, and 2.5 wt% acetaldehyde was mixed with a powder containing tungsten carbide and chromium carbide 2: 1. After sufficiently kneading for more than one minute, the rolls were rolled using a direct roll mill to produce a dissimilar material mat having a thickness of 3 mm.

However, in this case, the viscosity of the binder was large, and more than 30 vol% of hard particles could not be added.

Example 2

A binder prepared by adding 65 wt% water, 15 wt% dibutyl phthalate, 0.5 wt% dibenzothiophene, 17 wt% vinyl acetate, and 2.5 wt% acetaldehyde together with a mixed powder of tungsten carbide and chromium carbide 2: 1 After sufficiently kneading for more than one minute, the rolls were rolled using a direct roll mill to produce a dissimilar material mat having a thickness of 3 mm.

However, due to the excessive amount of water did not have a sufficient bonding force with the hard particles, hard particles fall off the mat could not produce a flexible mat.

Example 3

A binder prepared by adding 45 wt% water, 20 wt% dibutyl phthalate, 0.5 wt% dibenzothiophene, 32 wt% vinyl acetate, and 2.5 wt% acetaldehyde together with a mixed powder of tungsten carbide and chromium carbide 2: 1 After sufficiently kneading for more than one minute, the rolls were rolled using a direct roll mill to produce a dissimilar material mat having a thickness of 3 mm.

At this time, 70 vol% of the mixed powder was added to obtain an excellent flexible hard mat. The manufactured hard mat is laminated up and down with BNi-2 brazing mat manufactured using the same binder as above, placed on a metal base material of SM45C (see KSD 3752 of the Industrial Standard-Mechanical Structural Carbon Steel) and argon atmosphere. It was heated to 1100 ℃, the temperature at which the brazing material was melted and maintained for 10 minutes to form a hard layer of about 3mm having a hardness of HRA (see Korean Industrial Standard KSB 0806) 85-86 on the metal base material.

The components of BiN-2 were 7 wt% chromium, 3 wt% boron, 4.5 wt% silicon, 3.0 wt% iron, 0.1 wt% carbon, and 82.4 wt% nickel.

The binder of the present invention having such a configuration includes water and a binder such as dibutyl phthalate, dibenzothiophene (DBT), vinyl acetate, and acetaldehyde when mixed with a powder such as metal or ceramic. It is easily combined with the hard powder, and can be performed within 1 minute after molding, and has the property of easily evaporating when heated.

Therefore, it is possible to make a single mat by mixing hard powder and brazing powder together and placing it on a metal base material and brazing without having to place two pieces of a mat containing a hard powder and a brazing mat on a metal base. This will be.

In addition, the polymer binder of the present invention does not require hydrogen gas to thermally decompose the polymer material, and can be manufactured very well in an atmosphere of non-oxidizing atmospheres such as arcon gas, nitrogen gas, and helium gas, thereby improving stability without risk of explosion. There is.

As described above, when the binder of the present invention is kneaded with a powder such as metal or ceramic, the binder including dibutyl phthalate, dibenzothiophene (DBT), vinyl acetate and acetaldehyde, including water, Easily combined with hard powders such as, and other operations can be performed within one minute after molding, there is a property that easily evaporates when heat is applied.

Therefore, it is possible to make a single mat by mixing hard powder and brazing powder together and placing it on a metal base material and brazing without having to place two pieces of a mat containing a hard powder and a brazing mat on a metal base. This will be.

In addition, the polymer binder of the present invention does not require hydrogen gas to thermally decompose the polymer material, and can be manufactured very well in an atmosphere of non-oxidizing atmospheres such as arcon gas, nitrogen gas, and helium gas. It is effective to increase.

Claims (2)

In order to bond the dissimilar material to the metal base material by the brazing method, the binder which forms the flexible mat by combining with the dissimilar material or the powder of the brazing material, A binder comprising dibutyl phthalate (Dibutyle pthalate), dibenzothiophene (dibenzothiophene), vinyl acetate, acetaldehyde, water According to claim 1, Dibutyle pthalate (dibutyle pthalate) 10-69%, Dibenzothiophene (Dibenzothiophene) 0.001-1%, vinyl acetate 10-69%, acetaldehyde 0.05-3%, water 20-60 A binder comprising a composition of%.