JPS58217675A - Enamel glazed article - Google Patents

Abstract

PURPOSE:To obtain a product not only low in baking stress but also excellent in the close adhesiveness, the strength and the corrosion resistance of the enamel layer thereof, in glazing the surface of a steel plate with enamel at a temp. equal to or less than the A1 transformation point of steel, by limiting the wt. ratio of the steel plate and the enamel layer to use a steel plate with a thin plate thickness. CONSTITUTION:In glazing one surface or both surfaces of a steel plate material with a thickness of 0.35-0.5mm. with enamel at a temp. equal to or less than the A1 transformation point of steel, the ratio y/x of the wt. y of an enamel layer per 1m<2> one surface of said material and the wt. x per 1m<2> material is brought to 0.03<y/x<0.15. In this case, as frit for enamel usd herein, low m.p. frit capable of being baked at a temp. equal to or less than the A1 transformation point of steel is pref.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hollowed product obtained by hollowing a steel sheet material at a low temperature below the A1 transformation point (723° C.) of steel.

Conventional hollowing is performed at a high temperature of 800 to 900° C., which is higher than the above-mentioned A1 transformation point. When the temperature of steel exceeds the A1 transformation point, its structure transforms from alpha iron to gamma iron, which is accompanied by a volume reduction. Therefore, if hollowing is performed above this temperature, the firing strain of the steel sheet will be large, and defects due to distortion and deformation will occur. The disadvantage is that there are too many. For this reason, in conventional hollow machining, selection of the thickness of the material was an important factor.

Table 1 shows the hollow film thickness of approximately 100μ by conventional hollow processing.
It shows the relationship between the material plate thickness and firing strain in the case of m, and the evaluation method was in accordance with the method described below.

Table 1 As shown above, in conventional high-temperature firing hollow machining at 800'C or higher, the distortion increases as the thickness of the material decreases. A fixing jig was used to reduce distortion during firing.

Therefore, it is desired to reduce the firing distortion caused by the steel transformation by performing the enameling at a temperature below the A1 transformation point of the steel.Furthermore, due to the recent rise in oil prices, the proportion of fuel consumption in the enameled processing cost has increased. As a countermeasure against the increase in the number of metals, there has been a desire for a hollow enamel that can be fired at a low temperature from the viewpoint of energy saving by firing at a low temperature.

The present invention uses a frit that can be fired at a temperature below the A1 transformation point (723° C.) of steel to provide a hollowed article with little firing distortion due to steel transformation.

The present invention provides a hollowed article that uses a steel plate with a particularly thin plate thickness and is excellent in not only sintering distortion but also adhesion of the hollowed layer, strength, and corrosion resistance.

As a result of various studies on enameling thin steel sheet materials of about 0.5 steel, the inventors found that firing strain is not only due to transformation of the steel, but also that the ratio of the weight of the steel to the weight of the enameled layer is an important factor. The findings show that this also has a large impact on the adhesion, strength, and corrosion resistance of the hollow layer.

Based on the above study results, the present invention has determined that when enameling one or both sides of a steel plate at a temperature below the A1 transformation point of the steel, the thickness of the material steel plate should be 0.35 to 0.5 mm, and the thickness of one side of the material should be 1 d.
The ratio of the weight y of the hollow layer per unit to the weight X per 1m2 of the material is 0.O3 (7/.

<It is regulated to 0.15.

The low melting frits shown in Table 2 are particularly suitable as the hollow frit used here. Table 2 also shows the coefficient of linear expansion of the frit and the working temperature when forming the hollow layer by firing.

Below Margin Table 2 Frisotom gives a milky white color, and has gloss, whiteness,
In terms of hiding power, adhesion, etc., it is as good as ordinary porcelain.

Frits B and C are transparent themselves, and by adding various pigments as mill additives, a hollow layer of a desired color tone can be provided. Especially these flints
It is compatible with pigments based on cadmium sulfide and cadmium selenide, which were not compatible with conventional lead-based low-melt frits, and is red.

It is also possible to change color tones such as yellow and orange.

In addition, in Friso) B, Al2 which is an intermediate oxide
O5, ZrO2, and TiO2 are one type and have a weight ratio of 2 to 9 in the total amount of 5 weight or less. Further, in frit C, SiO2/B2O3 is set to be 2.6 or more.

Typical examples of Ar B+ C in Table 2 are shown in Table 3 a, b, and c, respectively.

Table 3 The present invention will be explained in more detail below.

(1) Steel type used As a material for hollowing, there is a steel plate for hollowing specified by J I 803133. As for the chemical components, the carbon content is less than or equal to 0-o-o-a weight ratio (hereinafter simply expressed as ratio), Mn is 0.50% or less, P is 0.040% or less,
S is defined as O-040% or less.

The material used in the present invention has a carbon content of 0.00 in the steel plate.
It is suitable that the nitrogen content is 3% or less and the nitrogen content is 0.003 parts or less. The reason for this will be explained next.

Table 4 shows that on both sides of various steel materials of thin plate with a thickness of 0.4M,
This is a comparison of the occurrence of bubbles on the surface after firing at 700°C using frit L shown in Table 3.
0.1~00X100 hollow without bubbles on the surface
Those with 4 items are represented by △, and those with 4 or more items are represented by ×.

Table 4 From Table 4, the base material that generates few bubbles is A 4 +6, and the composition is a base material with a carbon content of 0.003% or less and a N content of 0.003% or less. be.

This is because when the steel contains a large amount of carbon during hollow firing, more gas is generated as 002, and when there is a large amount of N, more gas is generated as N2.

Therefore, by using a base material in which the carbon content in the steel is 0.003% or less and the N content is 0.003% or less, bubble generation can be eliminated.

(2) Material plate thickness The material plate thickness has a large effect on firing strain, deformation strength of the hollow layer due to falling steel balls, and workability.

The relationship between the thickness of the material and these properties was evaluated using the following methods and criteria.

■ As a firing strain test plate, a size 60 with a specified thickness and no distortion is used.
Apply hollow slip to one or both sides of the material between X300. The test plate 1 was supported horizontally with a jig 2 at intervals of 260 m as shown in FIG. 1, fired for 10 minutes at a firing temperature below the A1 transformation point of steel, and allowed to cool in the air. Therefore, firing distortion as shown in FIG. 2 occurs. 3 is a hollow layer.

As the amount of distortion, measure 1 mr of distortion from the original horizontal line in the center, and if the distortion is upwardly convex, +7! If it is convex downward, it is 11wn. If the value of l is 1m or less, ○, 1 to 2
When the parrot is a parrot, it is represented by △, and when it is 2 or more stages, it is represented by ×.

■ As an adhesion test plate, it has a specified thickness and is 100 x 10 in size.
A material with a weight of 0 gB, which was hollowed on one or both sides at a temperature below the A1 transformation point of steel, was used. JIS R430
1-1978 was placed horizontally on a table, and the test plate was fixed thereon. Next, place the diameter 36-51 specified in JISB1501 in the center of the test plate.
A 1yL steel ball (mass approximately 200.r) was dropped naturally from a height of 1m, and the state of peeling on the impact surface was examined.

The evaluation was based on the following criteria.

○: Due to impact, cracking of the hollow layer is observed, but no peeling has occurred.

△: Impact surface, some of the hollow layer is missing, but no peeling has occurred down to the base material.

x: Peeling down to the base material occurred on the impact surface.

■ Strength deformation of the hollow layer due to falling balls When performing the adhesion test described above, the amount of deformation of the dent created in the center of the test plate due to the falling ball from the original horizontal line was measured,
If there are 2 or more lines, ×; if there are 1 to 2 lines, △; or 1; the following cases are indicated by ○.

(2) Corrosion Resistance Test The same test plate as in 2 above was subjected to a salt spray tester for 10 days, and then evaluated based on the state of rust on the hollowed surface. Those with no rust at all are marked with ○, those with 2 to 3 pinhole-like rust are marked with △, and those with 4 or more rust are marked with x.

(2) Workability 60 pieces of embossing were performed on the same test plate as in 2 above using 11-enplaine, and the workability of the embossing was evaluated using O5x.

Table 6 uses various thicknesses of the A4 material in Table 4.
The results of the above-mentioned firing strain, deformation strength of the hollow layer due to falling steel balls, and workability are shown below.

The hollow layer in this case was formed by firing at 700° C. using frit a shown in Table 3, and had a thickness of about 100 μm.

Table 5 ;.

”: As is clear from the table, 0.36 to 0.5 wL is appropriate from the viewpoint of firing strain, deformation strength due to falling steel balls, and workability.

In other words, for plate thicknesses of 0.6 m or more, there are difficulties in workability, and processing methods such as embossing that enhance the decoration and further increase the strength of the material, or small bending with a radius of curvature of 2 or less] Second, it is difficult to process into complex shapes. However, if the material to be hollowed is thick, it will be heavier and the material will cost more. Especially for heating appliances and kitchen utensils used in household items, the fact that they are heavy means that they are not only heavy and difficult to handle, but also have a large heat capacity, and when used for the interior of heating appliances such as ovens, thicker plates However, it takes a long time to heat up, which is not desirable.

On the other hand, when the plate thickness becomes very thin (less than 0.3 words), the strength of the material itself becomes weaker, causing distortion due to firing, and
The strength after hollowing becomes weaker, and the deformation caused by falling steel balls becomes greater.

From the above, a plate thickness in the range of 0.36 to 0.6 mm is lightweight and advantageous in terms of construction, and allows for small bending processes with a radius of curvature of 2 mm and processing of complex shapes. .

(3) Relationship between the weight y of the hollow layer per 1 m2 of the material and the weight X per 1 m" of the material, ratio '/x. 0-4 +
0.5 wn, size 100% 1O-Ox, on one or both sides of the film shown in Table 3. 900 using Jant a
A hollow layer having a thickness of approximately 10 to 260 μm was formed by firing at C. Tables 6 and 7 show the results of evaluating firing strain, adhesion, drop strength, and corrosion resistance. Table 6 shows the case where the hollow layer is formed on one side of the material, and Table 7 shows the case where the hollow layer is formed on both sides of the material.

Table 6 Table 7 As is clear from these tables, the number of fired pots is small because they are fired below the Mu1 transformation point (723°C) of steel.
When is 0.02 or less, the amount of deformation due to falling balls after hollowing is large, and the weight ratio of the hollow layer is low, and the hollow film thickness is also thin, resulting in poor corrosion resistance.

On the other hand, when k is 0.17 or more, the weight of the hollow layer becomes large, and therefore, when the hollow film thickness becomes large, the hollow layer becomes weak against mechanical or thermal shock, so the adhesion due to falling steel balls increases. is decreasing.

From the above results, when hollowing is performed below the A1 transformation point of the steel, the strain due to the transformation of the steel is reduced, so 0.36
It is possible to hollow a thin plate with less than 0.6 wIL with less distortion, but the ratio of the weight of the hollow layer to the weight of the material is ○o.
3(V/, (o-15) is required.

As a result, distortion caused by transformation caused by conventional high-temperature firing at about 860°C is eliminated, and by optimizing the weight ratio of the hollow layer and the material, 0.36 to 0.5 M,
It is now possible to process highly accurate sheets with firing distortions of 3 ta or less even for thin plates. In the past, compared to thinner plates due to distortion, a thicker plate was used than necessary, so there was an impression that enamel was heavy. It is now possible to produce lightweight hollow hollows with excellent weather resistance, chemical durability, and abrasion resistance.

Example 1 A thin plate of A4 steel shown in Table 4 with a thickness of 0.4 mm was used as the material. 100 parts by weight of frit a in Table 3, 4 parts by weight of clay, 0.2 parts by weight of sodium nitrite, 0.
A mixture of 2 parts by weight and 46 parts by weight of water was coated on both sides of the material using a ball mill so that the weight ratio b of the hollow layer to the material was various.
Calcined at ℃. Various performances and whiteness of the hollow layer thus obtained were evaluated.

-j') Whiteness W was calculated using the following formula using the values of L, &, b, using a color difference meter to obtain the color stimulus value according to CIE display.

w = 1oo-, l(*00-L)2+a2+b
'Here, the larger the W value, the whiter it is, and in the case of an ordinary hollow titanium recrystallization type opalescent frit, the whiteness W was 90.

If the weight ratio k between the hollow layer and the material on one side is O-03 or less, the degree of deformation due to falling steel balls is ×, and the corrosion resistance is also −×
The whiteness was also below TO, and the base material was dull.

However, when y4 is 0.03 or more, the whiteness is 86-9
2, demonstrating sufficient concealment power. Further, when y4 was 0.15 or more, the adhesion due to falling steel balls was poor.

Example 2 Boguchi, which is fired below the A1 transformation point of steel, contains an alkaline component (N
ap), 20, Li20, CaO, etc.) increase. Cadmium sulfide or cadmium selenide sulfide is used as a cap pigment to produce a vivid red color in conventional hollow hollows, but when frits such as those mentioned above are used, they oxidize and the color darkens, making it impossible to obtain a clear color tone.

Therefore, using Friso) b in Table 3, 2 parts by weight of cadmium sulfide and 1 part by weight of cadmium selenide sulfide were added to 100 parts by weight.
parts by weight, 6 parts by weight of clay, 0.1 part by weight of sodium nitrite, and 143 parts by weight of water, and a ball mill lip was applied to a 0.4 inch thin steel plate and fired at 670'C.

If the weight ratio k of the hollow layer on one side of the moon and the material is less than 0-03, the corrosion resistance will be poor because the hollow layer is thin, and the color hiding power will be low, so the base material will fade. appear. When h was still 0.15''2 or more, the adhesion due to falling steel balls was poor.

[Brief explanation of the drawing]

FIG. 1 shows the state before firing for measuring the firing strain of the hollow hollow, and FIG. 2 shows the state after firing. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2

Claims (1)

[Scope of Claims] (1) An article made by enameling one or both sides of a steel plate at a temperature below the A1 transformation point of steel, where the thickness of the steel plate material is 0.
36 to 0.51 m, and the ratio of the weight y of the hollow layer per 1 m' on one side of the material to the weight X per 1 m' of the material'/
An enameled article characterized in that x is 0.03〈y8〈o.15. 2)) The enameled article according to claim 1, wherein the carbon content in the steel plate is 0.003% by weight or less, and the nitrogen content is 0.003% by weight or less. (3) The frit constituting the hollow layer is at least 5i02. B2O3, Na2O, ZrO2, TiO
Consists of 2°F20r F2 + F205,
In terms of weight ratio, 5102 is 30-36%, B2O5 is 15-36%
20%, Na2O 7-9%, ZrO2 5-1o%,
The enameled article according to claim 1, wherein TiO2 is 10 to 17%, F20 is 7 to 16%, F2 is 2 to 10%, and P2O5 is Q.6 to 2.6%. (4) The frit constituting the hollow layer is at least 5i02. B2O3, Na2O, F20. Zr
1O, F2 and the intermediate oxide A1205 +
It is composed of at least one component selected from the group of Zr 02 and TiO2, and the weight ratio is 5102 to 3.
1-39chi, B2O5 13-21%, Na2O 14
~22%, F20 1-6, ZnO 13-20,
2. The enameled article according to claim 1, wherein F2 is 2 to 10 tI6, and the intermediate oxide is one type of 5 tI or less, and the total amount is 2 to 9%. (5) The frit constituting the hollow layer is at least 8102. B2O3, Na2O, Al2O3, L1
20+ to 20%, composed of CaO, weight ratio Te5102ka40~ss%, B2O5 10~20%, N
a2O is 16-25%, A1203 is 8-16%, Li
2O is 1-10q6, F20 is 1-7%, CaO is 1-10q6
6% and 5102/B2O3 is 2.6 or more.