JPH0251459A - Roll for hot rolling - Google Patents

Abstract

PURPOSE:To improve strength at high temp. by kneading cement and super-fine powder with a dispersant and water and molding the kneaded material. CONSTITUTION:100 pts.wt., in total, of 100 pts.vol. cement of 10-30mum grain size such as alumina cement and 5-100 pts.vol. superfine powder of <=1mum average grain size such as fly ash are kneaded with 1-5 pts.wt. dispersant such as naphthalenesulfonic acid, a water reducing agent of high performance, a hardening regulating agent such as CaCl2 and <=30 pts.wt. water. A rotating shaft is set in a centrifugal mold and the kneaded material is injected into the mold, hardened, released from the mold, cured at >=20 deg.C and fired at a hot rolling temp. The surface of the resulting roll is plated or thermally sprayed with a metal such as Ni, Cr or Cu to form a surface layer of 0.001-0.2mm thickness.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a roll applied to metal processing, particularly hot rolling.

(Conventional technology and its problems) In recent years, progress in metal fuel rolling processing technology has been remarkable. These hot rolling methods include a direct rolling method in which molten metal is directly rolled, a powder rolling method in which powder metal is rolled and sintered, a blooming method in which a bloom of an ingot is rolled, and a flat plate rolling method. can be mentioned. By using these hot rolling processing methods, it is possible to perform rolling processing such as thick plate rolling, thin plate rolling, wire rod rolling, and shape rolling and pipe rolling to obtain H-shaped steel, etc., depending on the desired shape of the metal. It becomes.

The rolls used in these hot rolling processes have heat shock resistance to withstand casting of molten metal, high strength properties to withstand rolling loads, and hardness to withstand metal sticking under high temperature conditions. is required as performance. Conventionally, the material for these hot rolling rolls was 8K alloy tool steel.
A heat-resistant metal such as SCM of D+Cr-Mo steel is used. Methods for manufacturing rolls using these include, for example, using automatic programming or a CAD/CAM system to perform cutting with an NC machining center or NC electric discharge machine, followed by heat treatment, or using heat-resistant metal with ethyl silicate. There is also a method of precision casting into a formwork made of refractory aggregate, and a method of drying after removing the plaster cast from the formwork. Year). However, the method of cutting heat-resistant metals is difficult to program and the final manual finishing cost is high. The precision casting method makes it extremely difficult to match dimensional accuracy when manufacturing relatively large rolls. Gypsum rolls have low strength and are therefore significantly less durable. There were issues such as:

As a result of various studies to solve the above problems, the present inventors found that by using a specific hydraulic material, the manufacturing method is simple, the surface transferability is excellent, and the strength is high even at high temperatures. The present invention was completed based on the knowledge that it is possible to provide a hot rolling roll having the following properties.

(Means for Solving the Problems) That is, the present invention is a roll for hot rolling metal at high temperature, and 5 to 1.
000 parts by volume, 1 to 5 parts by weight of a dispersant and 30 parts by weight or less of water based on a total of 100 parts by weight of the cementitious material and ultrafine powder.

The present invention will be explained in detail below.

As the cementitious material (hereinafter referred to as cementum) used in the present invention, various Portland cements such as normal, early strength, super early strength, and white are used.

In addition, low heat cements such as moderate heat cement, blast furnace cement and 72-year-old cement, sulfate-resistant cement, alumina cement, etc. can also be used, and furthermore, calcium hydroxide, calcium oxide, etc. can be used if an appropriate curing method is used. It is also possible to use a cement containing blast furnace slag or fly ash in an amount greater than that of a normal mixed cement, and the use of high sulfate slag cement, improved blast furnace cement, etc. is also conceivable. From the viewpoint of heat resistance, it is preferable to use alumina cement or cement with high slag content. The particle size of these cement substances is usually 10 to 60 μm, but it goes without saying that particles smaller or larger than this can also be used as long as they have hydraulic properties.

Similarly, it is also possible to use these cementitious materials together with rapid hardening materials, expansion materials, high-strength admixtures, and various chemical admixtures that are normally used in cement concrete.

The ultrafine powder used in the present invention is one order of magnitude smaller than cementum, preferably two orders of magnitude smaller, and more preferably has an average particle diameter of 1 μm or less. There are no particular restrictions on the composition of the ultrafine powder, but one that is easily soluble in water is not suitable. In addition, the manufacturing method may be any method such as liquid phase, gas phase, pulverization and classification, or a combination thereof,
Although not particularly limited, from an economical point of view, those produced by crushing or classification, and those produced by gas phase as by-products, are by-products of the production of silicon, silicon-containing alloys, and zirconia. Siliceous dust (silica hume) and silica dust are effective. Other materials such as calcium carbonate, silica sol, opal silica, titanium oxide, aluminum oxide, zirconium oxide, various glasses, clay minerals such as bentonite and their calcined products, amorphous aluminosilicate, chromium oxide, activated carbon, blast furnace slag, and fly ash, etc. Fine powder can be used.

The amount of ultrafine powder to be used is 5 to 1,00 parts by volume per 100 parts by volume of cement from the viewpoint of fluidity, moldability, heat resistance, and high strength properties of the mixed material obtained by mixing and kneading each material.
Preferably it is 10 to 500 parts by volume. If it is less than 5 parts by volume, it is difficult to obtain good fluidity of the mixed material when the amount of water is small, and if it exceeds i, o o o parts by volume, it is difficult to obtain good fluidity, and the abrasion resistance of the surface is poor. In addition, the strength properties are also insufficient.

As the dispersant used in the present invention, dispersants generally used in the cement field can be used, but when using various types of Portland cement, it is effective to use a high performance water reducing agent. A high-performance water reducing agent is used to ensure the wettability and fluidity of mixed materials, and even when added in large amounts, it does not cause excessive air entrainment or delay in cement water use, and it creates an interface that has a large dispersion power. It is an activator. For example, salts of melamine sulfonic acid formaldehyde P-condensates, salts of alkylnaphthalenesulfonic acid formaldehyde P-condensates, salts of naphthalene sulfonic acid formaldehyde P-condensates, high molecular weight trigenine sulfonates, and polycarboxylate salts are the main ingredients. I can give an example of what I did. Among these, salts of formaldehyde condensates of naphthalenesulfonic acid and alkylnaphthalenesulfonic acids are preferred from the viewpoint of economy and dispersion effect.

The amount of dispersant used is 0.3 to 1% by weight based on cement in the conventional civil engineering and construction field, but in the present invention, it is desirable to use a larger amount than that, and the amount of dispersant used is 0.3 to 1% by weight based on cement. The total amount (hereinafter referred to as powder) is 1 to 5 parts by weight per 100 parts by weight, more preferably 1.5 to 3 parts by weight.
Parts by weight.

When using alumina cement, use a high-performance water reducing agent, and use various sulfates, nitrates, carbonates, lithium salts, inorganic salts such as CaCJ2, and Ca(OH) as hardening modifiers.
z, one or more of inorganic substances such as borax and boric acid, and organic acids such as citric acid, tripolyphosphoric acid, pyrophosphoric acid, tartaric acid and gluconic acid, or their salts, etc.
It is preferable to use 0.005 to 2 parts by weight per 100 parts by weight of cement. When using an organic acid or a salt thereof that has both a dispersing effect and a dispersing effect, it is not necessary to use a high performance water reducing agent.

In the present invention, the hot rolling roll using each of the above materials has a compressive strength of 600 kliFfA-Ir after hardening.
L'' or more, more preferably 1 eo 00 kC9 2 or more, and in combination with dry curing at 110°C, the compressive strength is 1,800 to 2.00.
0 indicates #fA2 or higher.

For this purpose, the leaves to be kneaded are important, and the powder 100
It is 30 parts by weight or less, more preferably 25 parts by weight or less.

In the present invention, replacing cementitious material with inert inorganic powder is important from the viewpoint of improving heat resistance, and the higher the temperature is, the more remarkable the replacement effect is. The inert inorganic powder (hereinafter referred to as inert powder) used in the present invention is a powder made of particles of an inorganic powder material that is inert to water utilization reactions. Regarding the particle size of inert powder, the smaller the particle size, the larger the specific surface area, and fluidity cannot be ensured unless a large amount of water is used during kneading. 1 to 10, taking into account that the
0μm1 preferably 5-88μmS1 preferably 5-88μm
44 μm is good. Use of this inert powder improves heat resistance and curing shrinkage while maintaining high strength properties. There are no particular restrictions on the components of the inert powder, and oxides, non-oxide ceramics, etc. may be used. For example, silica, alumina, mullite, magnesia, spinel, silicon carbide, etc. are used. Furthermore, as these inert powders, materials prepared by pulverizing or pulverizing and classifying various ceramics, refractories, refractory aggregates, etc., can also be used. In addition, it is not appropriate for the inert powder to be easily soluble in water, and it is preferable to use one that does not have a high water absorption rate. - According to the required degree of heat resistance, the inert powder used must be able to withstand at least a high temperature higher than the required temperature.

The amount of inert powder used can be changed arbitrarily relative to the cementum, but 20 to 95 parts by volume per 100 parts by volume of the inert powder and cementum is effective from the point of view of improving heat resistance. It is. If it is less than 20 parts by volume, there is no effect on improving heat resistance, and if it exceeds 95 parts by volume, high strength cannot be obtained.

In the present invention, it is also possible to add aggregate having a larger particle size than the various materials. In the present invention, aggregate refers to particles with a particle size exceeding 100 μm, which can be used even with general sand or gravel, and is selected based on the criteria of a Mohs hardness of 6 or more, or a Knoop indenter hardness of 70r:NfAx” or more. Of course, it is possible to use hard aggregate.Also, it is also possible to use other materials such as metal and glass.If heat resistance is particularly required, chamotte, bauxite, and heavy sintered carbon can be used. shingle rock, crushed ceramics, blast furnace slag,
Oxide-based refractory aggregates such as chromium steel, magnesia, zirconia, andalusite, synthetic mullite, alumina, and spinel are preferred.

The amount of aggregate used is usually 1.0 parts by weight per 100 parts by weight of powder.
It is preferable to use up to about 100 parts by weight. However, this does not apply to special construction methods such as the pre-packed construction method and the post-packed construction method.

There are no particular restrictions on the kneading method or order of addition, as long as these materials are kneaded uniformly, and it is more preferable to perform vacuum defoaming during mixing. Furthermore, in the present invention, the above-mentioned materials can be combined with reinforcing materials such as steel frames and reinforcing bars, fibers, etc., and reinforcement such as tension and bending can be achieved. Examples of the fibers include fibers obtained by chatter cutting of cast iron, metal fibers such as steel fibers and stainless steel fibers, various natural or synthetic mineral fibers such as asbestos, ceramic fibers, and alumina fibers, carbon fa, fiber, and glass fibers. It is also possible to use conventionally used reinforcing materials such as steel rods and molded bodies of alumina fibers, and these reinforcing materials are often used especially for large-sized ones. From the viewpoint of not impairing fluidity, metal fibers with a length of about 61III or whiskers shorter than that are preferable. When considering heat resistance and expecting the combined effect of reinforcing materials and fibers up to high temperatures, metal fibers such as stainless steel fibers, whiskers, inorganic fibers, or molded products thereof are effective. In addition, in order to cool the roll as a means to improve productivity, a cooling pipe made of material selected according to the operating temperature is set inside the roll before pouring the mixed material, and the cooling pipe and roll are It is also effective to make it integrally molded.

The method for manufacturing the roll of the present invention is not particularly limited, and any conventional method can be used.

For example, production using waste or centrifugal molding is fully possible. In centrifugal molding, the rotating shaft is set in the mold in advance and the kneaded material is poured in and hardened, or the kneaded material is sequentially poured into the centrifugal mold and centrifugally molded to form a hollow tube.
After curing, the mold is removed, and inorganic adhesive materials such as colloidal silica, phosphate polymer, and materials used for manufacturing rolls are injected into the space between the hollow tube and the rotating shaft, and fixed by a method of hardening. do. Alternatively, there is the so-called 6-sealing method, which is fixed by pulling steel rods or steel wires placed inside, like prestressed concrete. Considering the fixation capacity 4, a considerable amount of force is applied as a rotating body. Therefore, it is preferable to set the shaft in advance and integrally mold it, or "caulking".The molded product obtained by molding the mixed wire material is cured, but there are no particular restrictions on the curing conditions.However, if cement When using calcium hydroxide or calcium oxide, or when using calcium hydroxide or calcium oxide,
A temperature higher than °C is preferred, and moist curing at 40-50'O or higher is more preferred. Furthermore, curing at higher temperatures and pressures is particularly preferred. It is important from the viewpoint of safety and the life of the roll that it be fired once at the hot rolling temperature before use.

In order to improve the yield strength of the roll surface, it is also possible to perform plating, thermal spraying, etc. on the surface. There are two methods of plating: electroless plating and electrolytic plating.
Various metal platings such as chromium, zinc, gold, silver, and tin, various alloy platings such as iron and nickel, composite platings in which alumina, silicon carbide, diamond, etc. are eutectoided as composite fine particles in the matrix liquid of these metals, It is also possible to perform various types of plating such as porous plating. Thermal sprayed aluminum, nickel, chromium, '141. Examples include spraying of metals such as stainless steel, zinc, tin, lead, iron, and alloys thereof, and spraying of ceramics such as alumina and tungsten carbide. The thickness of the surface layer by plating and thermal spraying is 0.001 to 0.2J1
A range of 1 is preferred. If the thickness of the surface layer is less than 0-01+u, the effect of improving the yield strength of the roll surface by forming the surface layer is small, and even if the thickness of the surface layer is greater than 0.2 mtn, the effect of improving the yield strength of the roll surface will be greater. Therefore, considering the purpose of the present invention to take advantage of good transferability, the thickness of the surface layer is preferably as small as possible, and the upper limit of the thickness is 0.2 mm. In addition, in various surface treatments, it is also effective to use inorganic adhesives such as silica, colloidal silica, and phosphate polymers using the Sol-Dal method in combination to improve adhesive strength. Furthermore, when performing hot rolling, it is also effective to coat the surface of the roll with graphite, boron nitrogen, etc. in order to improve the mold release properties of the processed product.

Products can be obtained by hot rolling metals such as aluminum alloys, copper alloys, cast iron, and cast steel using the rolls manufactured by the above method.

These metal materials include A1 alloy of JIS H5302 such as ADCi (Al-8i alloy 8 ADC10 and 12 (Al-8i-Cu alloy); AC2A% 4A%
JIS H5202 A1 alloys such as 413,4cs5A and 8A; Cu.

Cu alloys such as Cu-Zn (brass) and Cu-8n-P (phosphorus copper); FCIOI 15* 2L 25* 3
Cast iron such as 0 and 65; 5c37, 42 and 46 etc. (, T
l5G5101), 5CA1, 21 and 52, etc. (JI
SG5111), 5C81, 11 and 15 etc. (, Tl5
G5121) cast iron, etc. Hot rolling methods for these metal materials using rolls include direct rolling, in which molten metal is directly rolled, powder rolling, in which powder metal is rolled and sintered, and blooming, in which the blooming of an ingot is rolled. method, flat plate rolling method, etc. By using these hot rolling processing methods, it is possible to perform rolling processing such as thick plate rolling, thin plate rolling, wire rod rolling, and shape rolling and pipe rolling to obtain H-shaped steel, etc., depending on the desired shape of the metal. becomes.

These rolls can be incorporated into rolling mills using methods such as 2-high, 6-high, 4-high, universal type that combines horizontal rolls and vertical rolls, and Sendzimir type that combines large rolls and small rolls. It will be done. These are methods in which, for example, a desired product is continuously hot-rolled at a low speed of about 0.5 m/aeC for direct rolling to a high speed of 60]n/+eC for wire rod rolling. It is possible to hot-roll a metal material using the present roll manufactured by the above method.

(Example) The present invention will be further explained below with reference to Examples.

Example 1 Using the composition shown in Table 1, the outer diameter 2 shown in FIG.
0 cm 5 width 4 cm, 6 an and 8 o 6 types of rolls are manufactured. Outer diameter 20 c 1 r L 1 inner diameter 7 o, width 4 cm.
Three types of rolls were centrifugally formed: , 6 儂 and 8 α. Centrifugal molding: low speed 300 r, p, m 5 min, medium speed 60
0 r, p, m 10 min, high speed 800 r, p,
It was carried out with m 20m1n. After molding, it was cured in water at 50°C for 1 day, dried at 110°C for 1 day, and then further heated to 700"C and held for 15 hours. The compressive strength, bending strength, and hardness were measured. The results are shown below. - Also listed in 1.

The roll was fixed to a rotating shaft made of SKDb with a diameter of 6.9 which had been obtained in advance as shown in FIG. That is, after passing the rotating shaft through the roll, an adhesive material (trade name: SUMITOMO CHEMICAL I!L) was injected into the clearance between the roll and the rotating shaft.Next, as shown in Figure 1, a washer The rotating shafts were set on the rolls using two bolts each.By tightening the bolts, tensile stress was applied to the rotating shafts inside the rolls, and prestress stress was generated on the rolls. 1 roll at 200”O
The adhesive material was cured by drying in the sun. Next, the obtained roll was used to directly roll a wire rod as shown in FIG.

The rolling material is AC2A (A1 alloy) and the rolling speed is 10 m/sec.
Three types of two-stage rolls were used at a roll peripheral speed of c, and the diameter was 0.9.
A wire rod of 5 crrL was directly rolled. Wire rod total length 5
Direct rolling was performed up to 0 km, but there was no roll damage or defective products, and all desired products were obtained.

Materials used: Cement: Product name: “Denka Alumina Cement No. 1”
([Kikagaku Kogyo ■#) Specific gravity 2.9 Ultrafine powder C Nijirikahium (average particle size 0.2 μm by transmission electron microscopy) Specific gravity 2.2 Inert Powder: Heavy burnt clay rock (China Great Wall Section, Mohs hardness 8) 44μm passing product specific gravity 3.5 Dispersing agent: Product name “Self 0-110PJ (manufactured by Daiichi Kogyo Seiyaku ■) Main component: Formaldehyde m compound of alkylnaphthalene sulfonic acid Aggregate E: Reduced iron powder 100μm passing product Product name "Metalette" (manufactured by Japan Magnetic Sensing ■) Fiber H: SUS 450 fiber by chatter cutting method, diameter 60 μm 1 length 3 mm (manufactured by Tokyo Steel ■) Hardening 6I4n agent: Na2SO4 (reagent - grade) Example 2 Same as Example 1 A roll was made in . 1 at 50°C after molding
After curing in the sun and in a humid air, the roll surface was deplated under the conditions shown in Table 2. Electroless plated roll 110
After drying at ℃ for 1 day, the temperature was further raised to 700 ℃ and held for 15 hours. The rotating shaft was fixed in the same manner as in Example 1. Next, direct wire rod rolling was performed in the same manner as in Example 1 using the electrolessly plated roll. Direct rolling was performed on wire rods up to a total length of 100 km, but there was no roll damage or defective products, and all desired products were obtained. The electroless plating layer had a thickness of about 0.1+u and remained firmly adhered to the roll without peeling or cracking even after 1100k direct rolling. In addition, after heating the electroless plating layer to 700°C, a sickle with a diameter of 100 mm was coated on the surface of the electroless plating layer with adhesive product name ``Bar Plock C-323J (Denki Kagaku Kogyo ■It) applied to less than 0.1 nm. After the adhesive has hardened, vertical tensile test (ASTM 190-72) is carried out.
I did it. The results are shown in Table-6.

Table-2 Table-6 Example 6 Using the composition shown in Table-4, the outer diameter 5 shown in FIG.
A roll with an outer diameter of 50α, an inner diameter of 15cIL, and a width of 100α was centrifugally formed to produce a roll with a width of 100crIL and a width of 100crIL. Centrifugal molding at low speed 413r, p, m5
min, medium speed 803 r, p, m 10 min, high speed 1269 r, p-m 20 min. After centrifugal molding, it was cured in humid air at 50°C for 1 day, dried at 110°C for 1 day, and then further heated to i,o o o°C, held for 10 hours, and then compressive and bending strengths were measured. . The results are shown in Table 4. Next, the obtained roll was fixed to a rotating shaft made of 8KD 6 with a diameter of 14.9 cnL obtained in advance as shown in FIG. That is, after passing the rotating shaft through the roll, an adhesive material (trade name: Sumiceramu S-17DJ (Sumitomo Chemical ■1!1)) was injected into the clearance between the roll and the rotating shaft.Next, as shown in Figure 2, a washer was inserted. The rotating shafts were set on the rolls using two bolts each.By tightening the bolts, tensile stress was applied to the rotating shafts inside the rolls, and prestress stress was generated on the rolls.These rolls was dried at 200°C for one day to cure the adhesive material.

Next, a flat plate of cast steel SC81 was hot rolled using a roll as shown in FIG. Processing conditions are entrance plate thickness 3.631
+11. The outlet plate thickness was 2.54 m, the plate width was 70 cIIL1, the roll circumferential speed was 3 m/sec, the plate temperature was i, and the plate temperature was 2-step rolling at ooo°C, and the plate was hot-rolled to a total length of 5 Q km. There were no defective products and all desired products were obtained.

Materials used: Ultrafine powder D: Ultrafine alumina powder (average particle size 0.2 μm as measured by transmission electron microscopy) Aggregate F: Heavy burnt ash rock (China Great Wall Ware, particle size 0.6~
1.01111. Mohs hardness 8) Fiber Engineering: Alumina fiber Trade name: "Denka Arsene" (Kikagaku Kogyo ■) Other conditions were the same as in Example 1 Example 4 Same as in Example 6 using the composition shown in Table 5 manufactured a roll. After molding, cure in humid air at 50℃ for 8 days to 110
After drying for 1 day at °C, further i,oo.

The temperature was raised to °C and maintained for 10 hours. After curing in water at 50°C for 8 days, compressive and bending strengths were measured. The results are shown in Table-5. The rotation shaft was fixed in the same manner as in Example 6. Next, hot rolling processing equivalent to that in Example 6 was performed using the obtained roll. The plate material was rolled to a total length of 5 Q km, and all the desired products were obtained without any damage to the rolls or defective products.

Table 5 Materials used Cementitious Bar Ordinary Portland Cement (Andes Cement Joint Project @Yo) Ratio N3.1 Slag: Blast furnace water slag slag (Powderiness is 3.0 in plain 1st shift)
550 cIrL2/g) Specific gravity 3.0 Gypsum: Anhydrite (Powderness is 4,500 cm2/g plain value) Specific gravity 2.9 Aggregate a Niotabi Chamotte (fine powder, 0.7 m1z or less)
The rest is the same as Example 1 and Example 3.

(Effects) According to the present invention, it is possible to easily form a roll with high mechanical strength at high temperatures and to provide a roll with excellent surface transferability.

[Brief explanation of the drawing]

Figure 5g1 is a schematic diagram of the hot rolling force loe of a wire rod using the roll manufactured in Example 1. Figure 2 shows the roll 119? produced in Example 6. This is a diagram. FIG. 6 is a schematic diagram of hot rolling of a flat plate using the roll manufactured in Example 3. Code 1: Roll 2: Horn 3: Port 4: Rotating shaft 5: AM rolling material 6: Adhesive mesh 7: Flat plate hot rolling material Fig. 1

Claims (1)

[Claims] (1) A roll for hot rolling metal at high temperature, with 5 to 1,000 parts by volume of ultrafine powder per 100 parts by volume of cementitious material, and 100 parts by weight of the cementitious material and ultrafine powder in total. A roll for hot rolling processing, the main components of which are 1 to 5 parts by weight of a dispersant and 30 parts by weight or less of water.