JPH0448047A - Fire proof coat on refractory steel for structural use - Google Patents

Abstract

PURPOSE:To permit the fire proof coating on a steel in a good working environment by sticking the noncoated face of a thin metallic sheet in which a thermal expansive refractory film is formed on one side to a refractory steel for structural use having a specified compsn. in a contacting manner. CONSTITUTION:The noncoated face of a formed thin metallic sheet in which a thermal expensive refractory film is formed on one side by the application of a thermal foaming paint or the like is stuck to one side of a refractory steel for structural use in a contacting manner. This sticking is executed via an adhesive or via a screw or a welding pin. The compsn. of the refractory steel for structural use is formed of, by weight, 0.04 to 0.15% C, <=0.6% Si, 0.5 to 1.6% Mn, 0.005 to 0.04% Nb, 0.4 to 0.7% Mo, <=0.1% Al, 0.001 to 0.006% N and the balance Fe with inevitable impurities. In this way, the work of fire proof coat can efficiently be executed to structures such as steel frames at a building site.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to fire-resistant coatings for structural fire-resistant steel materials used in various buildings in the fields of architecture, civil engineering, marine structures and the like.

[Conventional technology]

As is well known, rolled steel for general structures (JIS G 3] 01) and rolled steel for welded structures (J
IS G 3106), weather resistant hot rolled steel for welded structures (JIS G 31) 4), high weather resistant rolled steel (J
IS G3125) and carbon steel pipes for shell structures (JI
SG 3444), square steel pipes for shell structures (JIS G
3466) (hereinafter referred to as well-known steel material) are widely used.

Well-known steel materials are usually produced by removing S and P from hot metal obtained in a blast furnace, then refining it in a converter furnace, turning it into steel billets in a continuous casting or blooming process, and then hot plastic working to obtain the desired properties. However, the structural fire-resistant steel materials targeted by the present invention are also manufactured using similar production means.

By the way, when using well-known steel materials among various buildings, especially those that are closely connected to daily life, such as buildings, offices, and residences, it is mandatory to apply sufficient fireproof coating to ensure safety in the event of a fire. Building-related laws and regulations stipulate that the temperature of steel materials should not rise above 350℃ in the event of a fire. In other words, when well-known steel materials are used in buildings, their yield strength at around 350°C is 60 to 70% of that at room temperature, which may cause the building to collapse. ) In the case of a building whose columns are made of shaped steel stipulated in 2013, in addition to spreading sprayed wood or felt based on slag wool, rock wool, glass wool, asbestos, etc. on the surface, fire prevention Fire-resistant coatings are carefully applied, such as by covering with mortar, or by further protecting the insulation layer with a thin metal plate, such as aluminum or stainless steel plate, to prevent the steel material from absorbing the load due to thermal damage in the event of a fire. Use it without losing it. Therefore, the construction cost for forming the fireproof coating becomes high compared to the cost of the steel materials, and a significant increase in construction cost cannot be avoided.

Therefore, a technology has been proposed that uses round or square steel pipes as structural materials to allow cooling water to circulate, thereby preventing temperature rises and reducing load capacity in the event of a fire. Expansion is being planned. For example, Japanese Utility Model Publication No. 5216021 discloses a fire-resistant building in which a water tank is placed on the top of the building and cooling water is supplied to pillars made of hollow steel pipes.

As mentioned above, when using well-known steel materials in buildings, the price is low, but due to their low high-temperature properties, they cannot be used uncoated or lightly coated, and the construction costs are high because they have to be coated with a fire-resistant coating, which is relatively expensive. At the same time, there are problems in that it narrows the usable space of buildings and reduces economic efficiency.On the other hand, the method of forced cooling using hollow steel materials with the aim of improving fire resistance performance requires design and construction because the structure is complicated. In addition to the cost, equipment costs are high, and maintenance costs are also high. In addition, well-known heat-resistant steel materials such as stainless steel are extremely expensive, and although they have good high-temperature properties, their use as construction materials is limited due to production and construction technology as well as economic considerations. Very difficult.

As buildings have become increasingly high-rise in recent years, fire-resistant design has been reviewed due to improvements in design technology and high reliability, and in 1985, the new Fire-resistant Design Law for Buildings was enacted, and the above-mentioned It is now possible to determine the ability of fireproof coatings based on the high-temperature strength of the steel material and the load actually applied to the building, without being subject to the 350°C temperature limit, and in some cases it has become possible to use steel materials without coating. . However, there is currently no steel material on the market that can be supplied to the market at an economical price as a structural steel material with excellent fire resistance.

The applicant has first developed a steel with excellent high-temperature properties and excellent fire resistance that can be supplied to the market at an economical price, that is, a structural fire-resistant steel material (hereinafter referred to as Invention A), and a method to impart fire-resistant performance to the steel material. A means (hereinafter referred to as the B invention) was developed and filed. Although the fire resistance of steel structures has been significantly improved by inventions A and B, the means for imparting fire resistance are
Further improvements are desirable in terms of fire resistance, workability, and construction costs.

[Problem to be solved by the invention]

That is, the means for imparting the fire-resistant performance include a method of spreading an inorganic fibrous fire-resistant thin layer material on the heat-receiving surface of the structural fire-resistant steel material (hereinafter referred to as method C), and a method of applying a highly heat-resistant paint to the heat-receiving surface of the structural fire-resistant steel material. (hereinafter referred to as the "Method"), a method in which a heat-insulating signboard is attached to the heat-receiving surface of the steel material (hereinafter referred to as "Method E"), or a method in which an ultra-thin metal is spread on the heat-receiving surface of the steel material (hereinafter referred to as "Method F"). However, method C tends to create a poor working environment, which requires expensive protective measures, and the work time tends to be long.The curing process takes a long time, which increases construction costs. There is a problem that cleaning and painting the surface of structural fire-resistant steel materials is costly, and the painted surface is easily damaged during erection, etc., and Methods E and F are not effective in improving fire resistance performance. However, the problem remains that the installation cost is high.

The purpose of the present invention is to use structural fireproof steel materials with excellent fireproofing performance, and to apply a fireproof coating with high fireproofing and heat insulation properties to the structural fireproof steel materials, thereby providing a high guarantee of fireproof performance to steel structures. Another objective is to provide a means by which fire-resistant coating of steel structures at construction sites can be carried out safely and efficiently in a good working environment, has low construction costs, and is fire-resistant. The object of the present invention is to provide a fireproof coating for structural fireproof steel with excellent performance.

[Means to solve the problem]

The gist of the present invention is that the uncoated surface of a formed thin metal plate having a thermally expandable fire-resistant coating on one side has a C0.04 to 0.1 by weight ratio.
5%, Si 0.6% or less, Mn 0.5-1.6%, Nb
0.005-0.04%, Mo0.4-0.7%, Al
o, 1% or less, containing N0.001 to 0.006%,
The weight ratio of the fire-resistant coating of the structural fire-resistant steel material that is in contact with and adhered to the surface of the structural fire-resistant steel material, the remainder of which is Fe and unavoidable impurities, and the uncoated surface of the formed thin metal plate that has a thermally expandable fire-resistant coating on one side. So, C0.04~0.15%, Si
0.6% or less, Mn 0.5-1.6%, Nb 0.00
5-0.04%, Mo 0.4-0.7%, Af0.1
% or less, N 0.001-0.006% plus Tie
, 005~0.10%, Zr0.005~0.03%
, V 0.005-0.10%, Nip, 05-0.
5%, Cu0.05-1.0%, Cry, 05-1.
0%, B0.0O03~0,002%, Cab, 00
05~0.005%, REMo, 001~0.02%
This is a fire-resistant coating of a structural fire-resistant steel material, which contains one or more of these, with the remainder being Fe and unavoidable impurities. It is preferable to abut and fix the formed thin metal plates through an adhesive, a metal screw, and a weld pin. It is also preferable that the thermally expandable fireproof coating is formed of a coating layer of a thermally foamable paint or an adhesive layer of a thermally foamable sheet.

[For production]

As a result of research on the strength of steel materials in the event of a fire, the applicant found that if uncoated use is targeted, the maximum temperature reached in the event of a fire is 1000 degrees Celsius, and therefore, the strength of steel materials at that temperature is 70% or more of the room temperature yield strength. It was learned that in order to provide yield strength, it was necessary to add a large amount of expensive alloying elements, which resulted in a loss of economic efficiency. In other words, the unit price of the steel material becomes higher than the well-known cost of the steel material and, in addition, the cost of installing the fireproof coating, and such steel material cannot be practically used. Therefore, as a result of further research, we found that the most economical steel material is one whose high-temperature yield strength at 600℃ is 70% or more of that at room temperature, as mentioned above. We have developed a structural fire-resistant steel material that allows for thinner coatings and have previously filed an application.

The characteristics of this structural fireproof steel are that it contains a trace amount of Nb in low C-low Mn steel.
The method involves reheating a steel slab with a composition in which a suitable amount of MO is added and then finishing rolling at a relatively high temperature, and the steel produced by this method has an appropriate room temperature yield strength as well as high temperature yield strength. It has the characteristic of high

In other words, the ratio of the proof stress in the temperature range of 600°C to the room temperature proof stress is large (the reason for this is that there are few basic components other than Nb and Mo, and the microstructure is a relatively large ferrite-based structure). On the other hand, fine-grained ferrite, quenched and tempered structures, etc. have a yield strength at room temperature that is higher than the yield strength in the 600°C temperature range, making it difficult to satisfy the specifications at room temperature.The above-mentioned structural fire-resistant steel materials has a low yield ratio and excellent earthquake resistance, but this is also due to the microstructure consisting of relatively large ferrite.

Next, the characteristic constituent elements of the structural fireproof steel material and their additive amounts will be explained.

Nb and Mo form fine carbides, and Mo increases high-temperature strength through solid solution strengthening, but it is difficult to obtain sufficient yield strength in the high-temperature range of 600° C. by adding Mo alone. Therefore, as a result of further research, it was found that adding Nb and Mo in combination is extremely effective in increasing the yield strength in the high temperature range. However, if the Nb and Mo contents are too high, weldability will deteriorate and the toughness of the weld heat affected zone (HAZ') will deteriorate, so the upper limit of the Nb and Mo contents is 0.04 each.
% and 0.7%, and the lower limit is 0.005% and 0.4%, respectively, as the minimum amount to obtain a combined effect.
Contain.

At room temperature, rolled steel materials for welded structures (JIS G310
In order to satisfy the performance stipulated in 6) and maintain high yield strength at a high temperature of 600°C, the conditions for reheating and rolling the steel as well as the steel composition are important.
b. In order to increase the high-temperature yield strength through the combined addition of Mo, it is necessary to sufficiently dissolve these elements during reheating, and the lower limit of the reheating temperature for this purpose is 1) 00°C. Furthermore, if the reheating temperature is too high, the crystal grains will become large and the low temperature toughness will deteriorate, so the upper limit must be set at 1300°C.

Furthermore, the reason why the rolling end temperature is set to a high temperature of 800°C or higher is to prevent carbides of Nb and Mo from precipitating during rolling, and when these elements precipitate in the γ range, the precipitate size becomes large and the high-temperature yield strength is significantly reduced. descend. Well-known low-temperature rolling (controlled rolling) is an essential requirement for steel materials that require low-temperature toughness, such as line pipes, but there is no high requirement for low-temperature toughness like the structural fire-resistant steel materials that are the subject of the present invention, and rather it is necessary for low-temperature strength and low-temperature toughness. If the balance of high temperature strength at 600° C. is important, rolling must be completed at a high temperature. This is also important as a condition for reducing the yield ratio. Further, the upper limit of the rolling end temperature is desirably set to too°C, and the reason for this is to ensure toughness as a building steel material.

The use of Mo to increase high-temperature strength is known in conventional heat-resistant steels, but there is no known steel material with a compound addition of a small amount of Mo and a small amount of Nb as a fire-resistant steel material for use in construction. . However, acicular ferritic steel for line pipes is known as a steel material with a composite addition of Nb and Mo, but acicular ferritic steel is manufactured by controlled rolling for strength in order to achieve its purpose, so it is used as a steel for construction. It is not in accordance with the standard as
It cannot be used in architecture. Furthermore, acicular ferritic steel has a higher Mn content than the structural fire-resistant steel. This is because unlike structural fire-resistant steel materials, it is important to improve low-temperature toughness, and there are significant differences between the two in terms of purpose and function and effect.

Nb in structural fire-resistant steel materials targeted by the present invention.

The reason for limiting components other than Mo will be explained in detail.

C is for ensuring the strength of the base metal and welded part, and Nb.

Necessary to exhibit the effect of adding Mo, and 0.0
If it is less than 4%, the effect will be weakened, so the lower limit is set to 0.04%. Furthermore, if the amount of C is too large, it not only adversely affects the low-temperature toughness of the weld heat affected zone but also deteriorates the toughness and weldability of the base metal, so 0.15% is the upper limit.

Si is an element contained in deoxidized steel, and as Si increases, weldability and HAZ toughness deteriorate, so the upper limit was set at 0.6%. For the structural fire-resistant steel materials targeted by the present invention, Ai7 deoxidation is sufficient, and Ti deoxidation may also be used. From the viewpoint of HAZ toughness, it is desirable that the Si content be approximately 0.15%.

Mn is an essential element for ensuring strength and toughness.
Its lower limit is 0.5%. However, if the amount of Mn is too large, not only will hardenability increase and weldability and HAZ toughness deteriorate, but also it will not be possible to obtain base metal strength that meets the target standards. Therefore, the upper limit of the Mn content was set to 1.6%.

Al is generally an element contained in deoxidized steel, but since deoxidation is also performed by Si and Ti, there is no lower limit for Al in the structural fire-resistant steel material targeted by the present invention. However, if the amount of Al increases, the cleanliness of the steel will deteriorate and the toughness of the weld will deteriorate, so the upper limit was set at 0.1%.

N is generally contained in steel as an unavoidable impurity, but it combines with Nb to form carbonitride Nb (CN), which is effective in improving high-temperature strength. For this reason, 0.001% is required as the minimum amount, but if the amount of N increases, 1(A
Since it promotes deterioration of Z toughness and occurrence of surface flaws in continuously cast slabs, the upper limit is set at 0.006%.

Note that the structural fireproof steel material to which the present invention is directed contains P and S as unavoidable impurities. P.

Since S has a small effect on high-temperature strength, its amount is not particularly limited, but in general, the properties of steel materials such as toughness and strength in the thickness direction are determined by these P.

The smaller the amount of S element, the better. Desirable amounts of P and B are 0.02% and 0.005% or less, respectively.

The basic components of the structural fire-resistant steel material targeted by the present invention are as described above, and the purpose can be fully achieved. However, in order to further improve the characteristics for the purpose, the following elements, namely Ti
, Zr, V, Ni, Cu, Cr, B.

When Ca and REM are selectively added, more favorable results can be obtained in terms of improvement in strength and toughness. Next, the additive elements and their amounts will be explained.

Ti is an element that has almost the same effect as Nb mentioned above, and 0
,005 to 0.02%, when the amount of Al is small, Ti
oxides and carbonitrides are formed to improve HAZ toughness, but if it is less than 0.005%, there is no effect, and if it exceeds o or i%, it will have an adverse effect on weldability etc., which is not preferable.

V is also an element that has almost the same effect as Nb and Ti, and although its effect on high-temperature yield strength is smaller than that of Nb and Ti, it improves HAZ toughness in the range of 0.005 to 0.10%. However, if it is less than 0.005%, there is no effect;
．． If it exceeds 10%, it will have an unfavorable effect on HAZ toughness.

Next, Ni improves the strength and toughness of the base metal without adversely affecting weldability and HAZ toughness, but 0.05
If less than 0.5%, the effect is weak, and if it is added more than 0.5%, it becomes extremely expensive for the purpose of building steel and loses economic efficiency, so the upper limit was set at 0.5%.

Cu has almost the same effect as Ni, and also has the effect of increasing high temperature strength and improving corrosion resistance and weather resistance due to Cu precipitates. However, if the Cu amount exceeds 1.0%, Cu cracking occurs during hot rolling, making manufacturing difficult.
There is no effect if it is less than 5%, so the amount of Cu is 0.05 to 1.0.
%.

C is an element that increases the strength of the base metal and welded joint, and is also effective in improving weather resistance, but if it exceeds 1.0%, it deteriorates weldability and t (AZ toughness), and if it exceeds 0.05% If it is less than that, the effect is weak. Therefore, the amount of Cr should be 0.05 to 1.0%. Like Mo, C is an element that increases high temperature strength, but unlike Mo, it does not increase the strength at room temperature. ,600℃
The effect of increasing high temperature strength is relatively small.

B is an element that increases the hardenability of steel and increases its strength. BN combined with N acts as a ferrite generation nucleus,
Refine the HAZ structure. In order to obtain this kind of effect, a minimum amount of B of 0.0003% is required; less than that will have no effect, and too much B will cause coarseness.
nstituent precipitates at the grain boundaries of the HAZ and deteriorates low-temperature toughness. Therefore, the upper limit of the amount of B is limited to 0.002%.

Ca and REM control the morphology of sulfide (MnS), increase Charpy absorbed energy, improve low-temperature toughness, and are also effective in improving hydrogen-induced cracking resistance.

However, if the Ca content is less than 0.0005%, it has no practical effect, and if it exceeds 0.005%, a large amount of Cab and CaS will be generated, forming large inclusions that will harm not only the toughness of the steel but also its cleanliness. Furthermore, C has a negative effect on weldability.
The range of the amount of a added is 0.0005 to 0.005%.

In addition, REM has the same effect as Ca, and increasing the amount added causes the same problems as Ca and is also less economical, so the lower limit of REM amount is set at 0.001%, and the upper limit is set at 0.02%. %.

In addition, after manufacturing the structural fireproof steel material targeted by the present invention, A is used for purposes such as dehydrogenation. Even if it is reheated to a temperature below the 1 transformation point, its characteristics will not be impaired in any way. In addition, as is well known, a product is produced by reheating a steel billet and then subjecting it to hot plastic working.After that, in order to produce a steel material with a desired shape, the product is further subjected to hot plastic working. Good too.

For example, in addition to forming blooms or billets into shaped steel, the product may be used as a raw material and cold-worked to produce desired steel materials such as shaped steel or steel pipes. At that time, heat treatment is appropriately performed as necessary.

Next, the mechanical properties of the structural fire-resistant steel material targeted by the present invention will be explained in detail in comparison with well-known steel materials.

Table 1 shows a composition comparison between structural fire-resistant steel and JIS G 3106 welded structural rolled steel (3M50A).
The figure shows the results of comparing the fire resistance of both types. Table 1 Figure 1 shows the YP ratio on the vertical axis and the temperature (°C) on the horizontal axis, where the solid line 1 indicates the structural fire-resistant steel material targeted by the present invention, and the broken line 2+ indicates the structural fireproof steel material targeted by the present invention. is SS old, broken line 2 shown by dotted chain line. shows the change in 5M50A.

As is clear from Fig. 1, the difference disappears at temperatures exceeding 800°C, but the structural fire-resistant steel material targeted by the present invention is
It can be seen that it maintains twice the yield strength of 5M50A at 00°C to 700°C, and has excellent properties as a construction steel. From this, it is clear that the structural fireproof steel material targeted by the present invention requires a thinner fireproof coating when the fire load is equal compared to 5M50A and 3341.

Next, when fire-resistant coating is applied to the structural fire-resistant steel material targeted by the present invention by the C-F method, the fire-resistant performance is significantly improved, but there are problems as described above.

In the present invention, unlike the above-mentioned C-F method, a formed thin metal plate having a heat-expandable fire-resistant coating on one side, which has been manufactured in advance at a factory, is transported to the construction site, and the uncoated side of the formed thin metal plate is transported to the construction site. Since the fireproof coating can be formed by contacting and fixing the fireproof coating to the surface of the structural fireproof steel material, the fireproof coating can be easily applied and can be carried out with high efficiency, and the working environment will not be deteriorated. Furthermore, since it is easy to handle during transportation and installation, there is extremely little damage to the fireproof coating and less manpower is required.

In addition, since the structure exposes a thermally expandable fireproof coating on the outer surface,
In the event of a fire, the flames directly hit the thermally expandable fireproof coating,
The fireproof coating reliably thermally expands and the foaming carbonization process proceeds smoothly, achieving effective heat insulation.

Furthermore, when the formed thin metal plates are abutted and fixed together via an adhesive, there is no need for skilled workers, and the fireproof coating can be formed in a short period of time. If the metal screws or weld pins are used for contact and fixation, the construction time will be shorter, and the bond between the formed thin metal plate and the steel structure will be mechanically very strong, and there is a risk of the fireproof coating peeling off, etc. Since the amount of damage is extremely small, high reliability of the protection function can be obtained.

When the thermally expandable fireproof coating is formed from a coating layer of thermally foamable paint, the molded thin metal plates are manufactured in a fully equipped factory, so cleaning treatment of the surface to be painted, temperature, humidity, Since mass production is possible in a well-controlled atmosphere in terms of dust prevention, drying, molding, etc., it is possible to obtain molded thin metal plates with a fire-resistant coating of excellent quality at a relatively low cost. Since the formed thin metal plate is light and easy to handle and fix, it has the advantage that the cost of forming fireproof coatings on steel structures is low. When the thermally expandable fireproof coating is formed of an adhesive layer of a thermally foamable sheet, the coating is resistant to physical impact, has high reliability in terms of fireproofing performance, and is easy to apply.

〔Example〕

FIG. 2 is a schematic partial perspective view showing a state in which a fireproof coating is formed on a structural fireproof steel material used for a column material of a steel structure, that is, a round steel pipe 3 in this example. The uncoated surfaces of the coated semicircular thin steel plates 4a and 4b are brought into contact with and fixed to the surface of the round steel pipe 3.

As shown in the schematic partial cross-sectional view of FIG. 3, the semicircular shaped thin steel plates 4a and 4b have a three-layer structure in which, for example, a thermally expandable fireproof coating 5 is bonded to a thin steel plate 7 via an adhesive 6. As shown in the partial sectional view of FIG. 4, the tapping screw 8a,
It is fixed to the surface of the round steel pipe 3 via the wire 8b, or it is fixed to the surface of the round steel pipe 3 using an adhesive.

As shown in FIG. 4, the end 'a of the semicircular thin steel plate 4a
l+ 4a is bent upward so as to overlap the end 4b1゜4b of the semicircular formed thin steel plate 4b,
Using tapping screws 8a, 8b, end portions 4a, 4a
,, end portion 41)+, pierce through 4bt and screw onto the round steel pipe 3.

The tapping screws 8a, 8b are semicircularly formed thin steel plates 4a,
In addition to selecting the number of attachments according to the weight of the 4b and the required fire resistance, it is also desirable to use a material with excellent heat resistance, such as stainless steel. Further, when using the tapping screws 8a and 8b, washers may be used, and they are selectively used depending on the mechanical strength of the thermally expandable fireproof coating 5.

When using the self-tapping screws 8a and 8b, a predetermined number of through holes, for example, 3 to 4 holes, are drilled in advance in the formed thin steel plate, and the through holes are used to drill the structural fireproof steel material with a drill. Adopting the method of screwing in with a power tool can significantly shorten the working time. Furthermore, if the tapping screws 8a and 8b are coated with fire-resistant paint on their surfaces as necessary, or if a fire-resistant paint is applied after installation, reliability in terms of fire resistance can be increased.

Semicircularly formed thin steel plates 4a and 4b, which have a heat-expandable fireproof coating on one side and are shaped in advance into a rectangle, groove, or semicircle to match the surface shape of the structural fireproof steel, are used. In the present invention, this will be simply referred to as a formed thin steel sheet hereinafter.

Since the present invention uses a formed thin steel plate as described above, the fourth
As explained in the figure, at the construction site, the uncoated surfaces of the semicircular formed thin steel plates 4a and 4b, that is, the base metal surfaces, should be covered with the round steel tubes 3 that have been assembled as pillar materials. A fireproof coating can be formed on a steel structure by a simple method of abutting the surface from the outside and fixing it. The present invention eliminates the need for spraying refractories as in the past at construction sites, so no skill is required for the work, the work atmosphere is extremely good, and there is no need for processes such as drying, so the work period can be shortened. It can also be extremely short.

In addition, when adhesion is used as a fixing method, the adhesive may be applied to the surface of the structural fire-resistant steel material or the uncoated surface of the formed thin steel plate at the construction site using a roller method or spray method. Adhesive is applied to the non-coated surface of the formed thin steel sheet in advance at the factory, the surface of the adhesive is covered with a well-known peelable non-adhesive sheet, and the peelable non-adhesive sheet is peeled off and bonded at the construction site. It is also possible to adopt a method with high workability.

In the present invention, the uncoated surface of the formed thin steel sheet is used in a broad sense to include the use of an adhesive or the use of a peelable non-adhesive sheet as described above. be.

Next, FIGS. 5 and 6 are schematic cross-sectional views showing fireproof coatings according to different embodiments, and FIG. 5 shows semicircularly formed thin steel plates 4c and 4d that have the same shape and are indistinguishable between male and female. This is an embodiment in which the round steel tube 3 is coated using the same material, and has the advantage that the manufacturing cost of the formed thin steel plate is low.

FIG. 6 shows engaging flanges 4e, 4e, 4f, .
Connecting bolt 9a using semicircular formed thin steel plates 4e and 4f.

9b, this means does not perforate the round steel tube 3, so it has mechanical advantages.

Figures 7 and 8 show round steel pipes 10. An example of H-shaped steel 1) coated with fireproof coating, Fig. 7 shows a grooved thin steel plate 4g,
4h is attached with tapping screws 8c and 8d, and FIG. 8 shows an example in which web-formed thin steel plates 4i and 4j and flange-formed thin steel plate 4 are coated with H-section steel 1) using adhesive means.

As is well known, heat-resistant paints are paints with thermal functions.
There are fire-retardant paints, and fire-retardant paints include flame-retardant, non-combustible paints, and intumescent fire-retardant paints. The thermally expandable fireproof coating in the present invention refers to a fireproof coating mainly formed using an expandable fireproof coating. Expandable fire protection paint consists of a fire prevention chemical reaction catalyst raw material as a foaming raw material, a carbon generation raw material, a nonflammable gas generation raw material and pigment, and an emulsion, and the carbon generation raw materials include carbohydrates, polyhydric alcohols, and a nonflammable gas generation raw material. Dicyandiamide, melamine, chlorinated paraffin, etc. are used, and oil-based expandable fire protection paints have also been developed.

In the present invention, the fireproof coating is formed using the above-mentioned expandable fireproofing paint, but the present invention is not limited thereto.
Fire-retardant paints containing a combination of ethylenediamine phosphate and cyanuric acid derivatives or their salts as disclosed in Japanese Patent Publication No. 47285, and JP-A-59-1
As disclosed in Japanese Patent Publication No. 5474, expansible fire prevention paint is used to take advantage of its properties and is made into a sheet, and as disclosed in Japanese Patent Application Laid-open No. 136558, an elastic synthetic resin emulsion binder is used. Fire retardant paint containing sodium tetraborate hydrate can be used. Also,
In addition, there are sheet-like materials made of a combination of inorganic materials and intumescent fire prevention paints as disclosed in JP-A No. 62-21) 437, and sheet materials as disclosed in JP-A-62-133232. Is it possible to use combination materials consisting of inorganic fiber materials and expandable fireproofing materials?Is it possible to use materials such as combinations of inorganic fiber materials and expandable fireproofing materials? Select and adopt them to the extent that they do not lose their sexuality.

In the present invention, as mentioned above, formed thin steel plates are produced in advance in a factory, transported to a construction site, and fixed to structural fire-resistant steel materials, but such a method is only possible if the structural fire-resistant steel materials also comply with the standard steel standards. This is because the dimensions and manufacturing tolerances are strictly regulated, and the production plan for the formed thin steel sheets can be made to match these regulations.

In the production of formed thin steel sheets, the structure is designed with economic efficiency in mind, ranging from simple to complex structures depending on the type of thermally expandable fireproof coating and the purpose of use.

For example, in one example of a high-quality formed thin steel plate, the thin steel plate is rewound from the coil in an uncoiler, degreased, washed, and shear-formed to a predetermined size. A layer application, curing, and drying process is carried out, and then a finishing paint is applied to the surface. Therefore, the heat-expandable fire-resistant coating in the present invention includes the heat-expandable fire-resistant sheet 1-12, the inorganic heat-resistant adhesive 13, as shown in the partial schematic cross-sectional view of FIG.
, a three-layer structure such as the thin steel plate 7, as shown in the partial schematic cross-sectional view of FIG.
7. Including those with various structures up to multilayer structures consisting of peelable non-adhesive sheets 18 and the like.

Furthermore, in the present invention, when using a highly flexible thermally expandable fireproof coating, it is necessary to process it into a predetermined shape using a cutting tool or a bending tool when covering complex joints of structural fireproof steel materials. It is easy to use, and is not limited to columns and beams.
Enables quick coating work.

Next, the fire resistance performance of the present invention will be explained with reference to the drawings.

Figure 1) is a diagram showing a comparison of high-temperature yield strength between a well-known steel material (SS41) and a structural fire-resistant steel material targeted by the present invention, where the vertical axis is the stress level (kgf/am) and the horizontal axis is the test temperature (kgf/am). 'C)
Curve 19 shows the change in stress (kgf/M) of well-known steel materials, and curve 20 shows the change in stress (kgf/M) of structural fire-resistant steel.
/ff1ffl"). As is clear from the figure, the well-known steel material has an allowable stress (22kg
f/+am”), it is not possible to obtain the effect of using thermally foamable paint, which can be expected to have a heat insulation effect by foaming at 300 to 350°C.On the other hand, the structural fire-resistant steel materials targeted by the present invention: 600℃ as evident in curve 20
However, it maintains performance exceeding the allowable stress level (22 kg f/w''). Therefore, when a thermally expandable fire-resistant coating is applied to the structural fire-resistant steel material targeted by the present invention, high fire-resistant performance can be expected.

FIG. 12 shows the structural fireproof steel material targeted by the present invention, which is coated with a thermally expandable fireproof coating and charged into a heating furnace, and the vertical axis shows the temperature (°C
), the horizontal axis represents the heating time (min), and shows the temperature change when the fire resistance test was performed, where the curve 21 shows the furnace temperature change, and the curves 22a to 22e show the temperature changes of each test material. Foaming and insulation of the thermally expandable fireproof coating begins in the range of 100°C around the furnace temperature of 300°C, and as a result, the rate of temperature rise of the test material decreases, and as a result, the temperature remains at around 600°C even after 60 minutes. Therefore, the practical effects of the present invention are extremely large.

〔Effect of the invention〕

The present invention involves producing in advance in a factory a formed thin metal plate having a thermally expandable fireproof coating of excellent quality at a high efficiency and at low cost, and at the construction site, the formed thin steel plate is brought into contact with and fixed to the surface of the structural fireproof steel material. This makes it possible to carry out fireproof coating work on steel structures at the construction site efficiently, and the reliability of the formed fireproof coating is high, and the construction cost for forming fireproof coatings is low. It is possible to economically provide unprecedented high fire resistance performance, and it is also possible to freely design and select the thermally expandable fire resistant coating of the most appropriate quality depending on the purpose, making it possible to pursue the highest economic efficiency. It's easy. Also,
Because thermally expandable fireproof coatings are installed in well-controlled factories, there is little variation in quality, and production and construction inspections can be carried out using economical means such as visual inspections and non-destructive inspections, and maintenance and inspections are easy, so maintenance costs are low. There is an advantage that it can be done easily.

[Brief explanation of drawings]

Figure 1 is a diagram showing a comparison of the fire resistance of structural fire-resistant steel materials and welded structural rolled steel materials. Figure 2 is a schematic partial perspective view showing the situation in which a fire-resistant coating is formed on structural fire-resistant steel materials. Figure 3 is A schematic partial cross-sectional view of a formed thin steel plate, FIG. 4 is a schematic cross-sectional explanatory view of fixing a formed thin steel plate to a structural fire-resistant steel material, and FIGS. 5 to 8 are schematic explanatory views showing fire-resistant coatings according to different embodiments. , Figure 9 and Figure 1O are partial schematic cross-sectional views of thermally expandable fireproof coatings, Figure 1) is a diagram showing a comparison of high temperature strength of well-known steel materials and structural fireproof steel materials, and Figure 12 is a diagram showing the high temperature strength of structural fireproof steel materials. It is a figure which shows the temperature change when the formed thin steel plate which has a heat-expandable fireproof coating was fixed, and the fire resistance test was performed. 3...Round steel pipe, 4a-41...Semicircular formed thin steel plate,
4a,, 4a,, 4b,, 4b, --... end, 4
e,, 4e,, 4f,, 4f. ... Engaging flange, 5... Thermal expandable fireproof coating, 6.
... Adhesive material, 7... Thin steel plate, 8a, 8b... Tapping screw, 9a. 9b... Connection bolt, 10... Square steel pipe, 1)...
H-shaped steel, 12... Thermally expandable fireproof sheet, 13... Inorganic heat-resistant adhesive, 14... Finishing paint, 15a, ],
5b...Thermally expandable fireproof coating, 16...Rust-preventive paint, 1
7... Adhesive material, 18... Peelable non-adhesive sheet. Figure 1 on the left: Warm and false (“C) Agent: Patent attorney Masamitsu Aki Sawa and 1 other person 7i3 Figure 2

Claims (7)

[Claims] (1) The uncoated surface of a molded thin metal plate having a thermally expandable fireproof coating on one side has the following properties by weight: C 0.04 to 0.15%, Si 0.6% or less, Mn 0.5 to 1.6%, The surface of a structural fire-resistant steel material containing 0.005-0.04% Nb, 0.4-0.7% M0, 0.1% or less Al, and 0.001-0.006% N, with the balance consisting of Fe and unavoidable impurities. A fire-resistant coating of structural fire-resistant steel material that is abutted against and adhered to. (2) The uncoated surface of a molded thin metal plate having a thermally expandable fireproof coating on one side has the following properties by weight: C 0.04 to 0.15%, Si 0.6% or less, Mn 0.5 to 1.6%, In addition to Nb0.005~0.04%, Mo0.4~0.7%, Al0.1% or less, N0.001~0.006%, Ti0.005~0.10%, Zr0.005~0. 03%, V0.005-0.10%, Ni0.05-0.5%, Cu0.05-1.0%, Cr0.05-1.0%, B0.0003-0.002%, Ca0. 0005-0.005%, REM 0.001-0.02%, and the remainder is Fe and unavoidable impurities. Fireproof coating. (3) A fire-resistant coating for a structural fire-resistant steel material according to claim 1 or 2, wherein a formed thin metal plate is abutted and fixed via an adhesive. (4) The fireproof coating for a structural fireproof steel material according to claim 1 or 2, wherein the formed thin metal plate is abutted and fixed via a metal screw. (5) A fire-resistant coating for a structural fire-resistant steel material according to claim 1 or 2, wherein the formed thin metal plate is abutted and fixed via a weld pin. (6) The fire-resistant coating for a structural fire-resistant steel material according to claim 1 or 2, wherein the thermally expandable fire-resistant coating is formed of a coating layer of a thermally foamable paint. (7) The fire-resistant coating for a structural fire-resistant steel material according to claim 1 or 2, wherein the thermally expandable fire-resistant coating is formed of an adhesive layer of a thermally foamable sheet.