JPH01268772A - Coating composition for friction grip joining of stainless steel - Google Patents

Abstract

PURPOSE:To obtain the subject composition, containing a compound containing Si-O bind or Ti-O bond in the molecule and further specified stainless steel powder having a specific average particle diameter and capable of imparting excellent adhesion, corrosion resistance and friction grip joining characteristics, etc., to friction grip joining surfaces of buildings, etc. CONSTITUTION:The objective composition, obtained by blending (A) 100pts.wt. stainless steel powder (e.g., SUS 304) having 0.1-50mum average particle diameter with (B) 5-50pts.wt. (expressed in terms of solids) solution or suspension containing one or two or more high polymers having Si-O bonds or Ti-O bonds in the molecule and capable of imparting an excellent slip factor to stainless steel joining members and further long-period durability to friction grip joining parts of buildings, etc.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a coating composition for stainless steel friction bonding, and more specifically, it relates to a coating composition for friction bonding of stainless steel, and more specifically, it provides excellent coating compositions for friction bonding surfaces of buildings using stainless steel. The present invention relates to a coating composition that provides adhesion, corrosion resistance, friction bonding properties, etc.

[Conventional technology]! On-site joining methods used in the field of a-products include riveting, high-strength bolt friction welding that uses high-strength bolts that are two to three times stronger than ordinary bolts, and arc welding. Welding methods have been used, and recently, high-strength bolt friction welding has become the mainstream method because it is easy to work on-site and at the same time provides a highly rigid joint.

This high-strength bolt friction welding is performed by tightening the joining members 1a, 1b, and 1C with high-strength bolts 2, nuts 3, and washers 4, as shown in FIGS. This is a joining method in which stress is transmitted by frictional force generated between members 1a, 1b, and 10. In such a high-strength bolted joint, the magnitude S of the frictional force between the joined members is determined by the compressive force C between the joined members and the coefficient of friction Cf.
It is expressed as the product of Therefore, if there is one friction surface as shown in FIG. 1, 3=Cf-C, and if there are two friction surfaces as shown in FIG. 2, 5=2Cf-C.

By the way, the sliding strength F, which is the objective of this high-strength bolt friction welding, has the same concept as the magnitude S of the frictional force, and this sliding strength F is calculated by the bolt axial force B corresponding to the compressive force C between joining members and the friction coefficient. The product of Cf and the corresponding slip coefficient μ (F=
expressed in μB).

Friction bonding using such high-strength bolts is often employed in large buildings, bridges, etc., and efforts have been made to increase the slip coefficient μ in order to improve the slip resistance F.

For example, in high-strength bolt friction welding using joining members made of steel, the slip coefficient μ is set to a value of 0.45 or more by intentionally rusting the joint surfaces, and this is the commonly used method. I'll go. In addition, as a method of surface treatment, a method of forming a coating film on the joint is known, and when an inorganic zinc coating is applied, the slip coefficient μ
is approximately 0°5, the slip coefficient μ for organic zinc coatings is approximately 0.3, and the slip coefficient μ for thermal spraying of zinc, aluminum, etc. is in the range of 0.5 to 0.7.

Incidentally, in recent years, the high corrosion resistance and design properties of stainless steel have attracted attention in various building industries, and ideas have begun to emerge to use this stainless steel for building structures. However, this stainless steel is not commonly used for building structures, and no suitable and efficient on-site joining method has been developed. Therefore, we are considering forming each joint surface of the stainless steel joint members to be joined to each other into a rough surface, or applying the same surface treatment as steel materials, that is, applying an inorganic zinc paint, or thermally spraying zinc, aluminum, etc. It will be done.

However, in the case of stainless steel friction welding, the slip coefficient μ is around 0.2 just by making the welding surface rough, and since it is made of stainless steel, it is not prone to rust like steel materials. Can not.

In addition, when an inorganic zinc paint is applied as described above, the slip coefficient μ reaches approximately 0.5, but the zinc powder in the coating film obtained by applying this inorganic zinc paint is higher than that of stainless steel. Since it is a base metal, there is a problem in that it causes contact corrosion and elution over a long period of time, causing a change in the slip coefficient μ. Roughly, even when zinc or aluminum is sprayed, the value of the slip coefficient μ is 0.5 to 0.7.
, and almost the same results as with inorganic zinc paints can be obtained, but in this case as well, there are problems similar to those of inorganic zinc paints because zinc and aluminum are metals that are less noble than stainless steel. In practice, the thermal spraying process is complicated.

[Problems to be Solved by the Invention] Therefore, an object of the present invention is to provide a means for imparting a stable and high slip coefficient over a long period of time by a simple method in stainless steel friction welding using high-strength bolts. It is about providing.

It is also an object of the present invention to provide a paint for stainless steel friction welding that can stably obtain high sliding strength over a long period of time by applying it to the joint surface during friction welding of structures using the above-mentioned stainless steel. An object of the present invention is to provide a composition.

[Means for Solving the Problems] That is, the present invention provides Si-0 bonds or T
A coating composition for friction bonding of stainless steel, which contains one or more polymer compounds having an i-0 bond, and stainless steel powder with an average particle size of 0.1 to 50 Ijx. is.

First, in the present invention, a solution or suspension containing one or more types of polymer compounds having S 1-Oa or 11-0 bonds in the molecule is used as a vehicle for the coating composition. .

That is, in order to improve the frictional force in friction bonding, it is effective to use various pigments as fillers together with a vehicle in the bonding coating composition in order to prevent like-kind contact between bonding members.

However, organic polymers commonly used as vehicles,
For products that use so-called resin, when the stress is increased in an experiment to determine the slip coefficient, the temperature locally rises to several hundred degrees at the joint surface, causing the resin used to soften and, in some cases, melt. For this reason, metal oxides or their acid salts are used, including stainless steel powder, which will be described later. Even if silica, titania, zirconia, alumina, etc. are used as pigments, a slip coefficient of 0.4 or more cannot be obtained.

Therefore, it is necessary for the vehicle to not soften or melt even if the temperature locally rises to several hundred degrees, and to harden even at room temperature. Therefore, in the present invention, as such substances, polymer compounds having Si-0 or Ti-0 bonds in the molecule, such as water glass, alkyl silicate or its partial hydrolyzate, alkyl titanate or its A solution or suspension of one or more kinds of partial hydrolysates and the like is used as a vehicle. In this case, the solvent used to prepare the solution or suspension has the effect of spreading the pigment, etc. during application, and evaporates under natural or heated conditions to form a coating film. It is fine as long as it is
Water, organic solvents such as alcohol, or mixed solvents thereof can be used, but water, alcohol, or a mixed solvent thereof is preferable. The use of such a vehicle overcomes the drawbacks of conventional vehicles, and upon drying, a glass-like film with a high softening and melting point is formed on the joint surface. The alkyl silicates and alkyl titanates themselves are monomers and are not polymeric compounds, but when they react with a trace amount of water, they partially hydrolyze and polymerize to become polymeric compounds. When a substance is used as a paint composition and coexists with a solvent such as water or alcohol, it is considered to be substantially polymerized in the paint composition, and it is necessary to use a substance that has been polymerized to some extent. Curing is faster and a coating film with superior mechanical performance can be obtained.

Therefore, in the present invention, these alkyl silicates and alkyl titanates also contain "Si-0 or Ti in the molecule."
-0 bond.

In this case, especially in the present invention, Si-0 or T
The material with i-0 bond was selected because it has the ability to act as a vehicle to bind pigment powder, and is liquid at room temperature when dissolved or suspended in water, etc., and has a softening melting point of several hundred degrees when hardened. This is because it is most suitable as the above.

Next, in the present invention, the pigment has an average particle size of 0.1 to
Use 50m stainless steel powder.

That is, as mentioned above, it is effective to add various pigments as fillers to the coating composition for bonding in order to prevent contact between the bonded members during friction bonding.
In this case, the pigments are generally various metal powders, metal oxide powders, or powders of their acid salts. However, when it comes to metals, when stainless steel is used as a bonding member, metals that are baser than stainless steel will elute the metal itself, and conversely, if stainless steel is a true metal, stainless steel However, the purpose of using a stainless steel joint member is lost due to corrosion. In this case, if the metal is stainless steel, the degree of corrosion will be small, but it is preferable to use the same type of metal.

In addition, regarding metal oxides, etc., when stress is applied between the joining members, powders of ordinary materials will be crushed before they reach sufficient strength, whereas silica, titania, etc.
Powders such as zirconia and alumina have high crushing strength and a slip coefficient of about 0.4 to 0.8, but this
oxide as a pigment, Si-0 or T is added in the above molecule.
When a solution or suspension containing a polymeric compound having an i-0 bond is used as a vehicle, after the vehicle dries, the vitreous nature of these powders causes a drop in the particles between the particles and the solidified vehicle component. The stress is not relaxed and cracks are likely to occur, and sufficient adhesion cannot be obtained, causing practical problems. On the other hand, when stainless steel powder with an average particle size of 0.1 to 50 is added to the vehicle, excellent adhesion between the particles is obtained, and a high slip coefficient of about 0.6 is obtained. Furthermore, a friction bonding coating composition that does not cause corrosion problems and that satisfies various required properties can be obtained.

In this case, the stainless steel powder referred to in the present invention is 5US3
04.5tJS430, 5US316, etc., and may be the same or different from the stainless steel that constitutes the joining member, but preferably the same type of stainless steel. Such stainless steel powder is produced using stainless steel, for example, by a mechanical pulverization method, an underwater atomization method, or the like. The average particle size is usually 0.1~
50ust, preferably 1-15Jj! 1, and if this average particle size is less than 0.14, a sufficient slip coefficient cannot be obtained, and if it exceeds 50, the surface becomes too rough, which impairs the adhesion of the paint film, and large particles become difficult to bond. It may roll on the surface and gradually become loose.

The amount of the vehicle to be blended is 5 to 50 parts by weight in terms of solid content, preferably 1 part by weight, based on 100 parts by weight of the stainless steel powder.
If the amount is less than 5 parts by weight, it will be difficult to achieve sufficient adhesion of the coating film, and if it is more than 50 parts by weight, cracks may occur due to the solidified vehicle being produced in glass trade. becomes easier to enter.

In addition to the above-mentioned basic composition, the paint of the present invention also contains dispersants, reactive diluents, anti-settling agents, etc. that are added to ordinary paints, for example, for the purpose of quickly curing a paint film with excellent uniformity. One or more of these may be added as necessary.

Further, as a method for producing the paint, a commonly used method such as mixing and stirring a vehicle and a pigment can be used.

Next, as a means for applying the paint of the present invention to the joint members,
Conventionally known means such as brush coating and spray coating can be used, and the film thickness after drying is 20 to 200 mm.
Preferably, 50 to 1001 U is appropriate. Film thickness is 20
*If it is thinner, you will not be able to obtain a sufficient slip coefficient;
If it is thicker than 0*, the coating film tends to collapse when stress is applied, and sufficient sliding strength cannot be obtained.

[Examples] The present invention will be specifically described below based on Examples and Comparative Examples.

Examples 1 to 4 and Comparative Examples 1 to 8 5US304 stainless steel powder 10 with the particle size shown in Table 1
The vehicle aqueous solution shown in Table 1 was added to 0 parts by weight in the ratio (solid content) shown in Table 1, and the mixture was thoroughly mixed to prepare a bonding coating composition of each Example and Comparative Example.

5US304 joint member (main plates 1a and l) shown in Figure 3.
b: 100sX 400sX 16m, side plates 5a and 5b: 100sX 400sX 9#) Grind the surface as a base for painting, and reduce the roughness to Ra1.
5 to 25 EI and Rmax 40 g, the bonding coating compositions of the above-mentioned Examples and Comparative Examples were applied and left to dry at room temperature for 48 hours to form coating films 6a and 6 with the film thickness shown in Table 1.
b was formed.

Regarding the coating films 6a and 6b obtained in this way, 2
A total of 25 scratches were made by making scratches that reached the base at M intervals, and a peel test was performed using tape. . The results are shown in Table 1.

In addition, the main plates 1a and 1b and the side plates 5a and 5b of the 5US304 bonding member on which the above coating film was formed were used, and the third
A high-strength bolt friction joint as shown in the figure was fabricated. Regarding this high-strength bolt friction joint, the slip coefficient was measured according to the test method described in "High-strength bolt joint, design and construction guidelines" published by the Architectural Institute of Japan, page 54. The results are shown in Table 1.

[Effects of the Invention] The coating composition for friction bonding of the present invention imparts an excellent heel coefficient to stainless steel bonding members coated with the composition, and is particularly suitable for use in highly corrosive environments that require stainless steel. It is used for large structures, buildings, equipment plants, bridges, expressways, etc. in high-temperature and corrosive environments, etc., and provides excellent friction joints, and is applicable to applications that conventionally required maintenance such as repainting. It also has long-term durability and can be maintenance-free.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of a high-strength bolt friction joint with one friction surface, Fig. 2 is an explanatory diagram of a high-strength bolt friction joint with two friction surfaces, and Fig. 3 is an explanatory diagram of a high-strength bolt friction joint with two friction surfaces. FIG. 3 is an explanatory diagram of a high-strength bolt friction joint used to measure coefficients. Patent applicant: Nippon Steel Chemical Co., Ltd.

Claims (1)

[Claims] Contains one or more types of polymer compounds having Si-O bonds or Ti-O bonds in the molecule, and has an average particle size of 0
．． A coating composition for friction bonding of stainless steel, characterized in that it contains stainless steel powder of 1 to 50 μm.