JPH0468358B2 - - Google Patents

Description

[Detailed description of the invention]

Industrial Application Field The present invention is directed to the processing between a processing tool such as a plug or a guide shoe used in the hot manufacturing of seamless steel pipes and a workpiece such as a pipe material such as a round or square steel piece or a raw pipe. Regarding lubricants. Prior Art In an inclined roll perforator or a stretching mill such as a plug mill that hot-produces seamless steel pipes, a forward driving force is applied to a workpiece heated to around 1200°C by an inclined roll or the like. It is subjected to piercing rolling or elongation rolling. The main part of the drilling machine is the third
As shown in the figures and FIG. It consists of a pair of guide shoes 11 and 12 for preventing the workpiece 3 from protruding from the inclined rolls and making the perforation or elongation rolling operation unstable, and the two barrel-shaped rolls 7 and 8 are arranged in the same direction. They rotate at the same speed, and the roll axis is inclined at 6 to 7 degrees or 10 to 13 degrees with respect to the horizontal direction. Therefore, the frictional force between the rolls 7, 8 and the surface of the workpiece 3 has the function of causing the workpiece 3 to rotate together with the rolls 7, 8 and advance in the axial direction. For example, in a drilling operation, the workpiece 3 is subjected to a strong and continuous compressive force in the radial direction by the rolls 7 and 8 until it reaches the tip of the plug 1 after being bitten by the rolls 7 and 8. The plug 1 is pressed against the center of the workpiece 3, which is prone to forming holes due to the perpendicular tensile force from the rolls 7 and 8, to form a predetermined outer diameter. In addition, we manufacture seamless steel pipes with thick walls. The plug 1 used for the above-mentioned purpose is generally in the shape of a bullet as shown in FIG. Since the plug 1 is strongly pressed against the axis of the red-hot workpiece 3 that moves forward while rotating at high speed, the tip of the plug 1 is subject to wear, melting, and damage.
Problems such as cracking or seizure, and deformation of the body occur, and the life of the plug 1 is short. In addition, a similar condition occurs during drilling using a plug mill, which is the next step after drilling, which not only shortens the life of the plug 1, but also causes defects in the product, especially when using high alloy steel and special steel. This has become a major problem when manufacturing target pipes. Along with the above-mentioned plug 1, guide shoes 11 and 12 are important processing tools used in inclined roll punching machines and elongation rolling machines. The guide shoes 11 and 12 are generally plate-shaped bodies whose surfaces facing the workpiece 3 that is being perforated or stretched and rolled are concave, and clamp and restrain the workpiece 3 so that it protrudes from the inclined rolls and is perforated or stretched. This is to prevent the rolling operation from becoming unstable or to suppress the tube expansion diameter as necessary to obtain a hollow mother tube with a predetermined outer diameter. Therefore, the guide shoes 11 and 12 are constantly pressed against the red-hot workpiece 3 under a pressure of several tens of tons while the workpiece 3 is being punched or stretched, and the workpiece 3 is continuously pressed against the red-hot workpiece 3 by several tens of tons of pressure. The guide shoe 11,1 at a speed of seconds
In order to slide on the two surfaces, the guide shoe 11,1
The contact surface between the guide shoes 11 and 12 and the workpiece 3 reaches a high temperature of approximately 1300°C, and the contact surfaces of the guide shoes 11 and 12 with the workpiece 3 are easily worn and seize, causing the guide shoe to adhere to the surface of the product. Flaws called marks may occur. Recently, a guide shoe in which the shape of the guide shoe is a disk with a concave groove on the outer circumferential surface facing the workpiece 3 (hereinafter referred to as a disk-type guide shoe) has been put into practical use. The disc type guide shoe clamps and restrains the workpiece 3 with a pair of upper and lower concave grooves, and rotates the disc type guide shoe at a speed corresponding to the moving speed of the workpiece 3 during drilling or elongation rolling. , the aim is to reduce the friction between the workpiece 3 and the guide shoe and suppress wear and seizure of the guide shoe, but even if such a disc-type guide shoe is used, 9% chromium steel, 13
At present, when processing difficult-to-work steel materials such as % chromium steel or stainless steel, severe seizure occurs on the surface of the guide shoe, resulting in a reduction in product quality. Therefore, in the past, research has been conducted on various plug materials in order to extend the life of the plugs for drilling or elongation rolling used to manufacture these seamless steel pipes. For example, C: 0.1 to 0.5%; Mo：3.0
~7.0%, Cr: 1.5~3.5% tool steel was published in JP-A-55
-110762, and a method for generating oxide scale with high peeling resistance on the plug surface is disclosed in JP-A-54-17363 and JP-A-56-62922.
It is proposed in the Publication No. The oxide scale serves as a heat insulating layer covering the surface of the plug to prevent melting and thermal cracking of the plug, and
It melts when exposed to high temperatures of 1,300°C or higher and acts as a fluid lubricant at the interface between the workpiece and the plug, with the aim of preventing the workpiece from seizing on the plug. However, with the conventional technology mentioned above, the
Although there is some effect when drilling or elongating low alloy steel such as Cr steel or Cr-Mo steel such as JIS STPA 20 to 25, the high temperature 9% Cr steel, which is also under high pressure.
When used for drilling or elongating workpieces of high-alloy steel such as 13% Cr steel or high-Ni stainless steel (hereinafter simply referred to as high-alloy steel), the life of the plug is significantly reduced, and once There are also frequent cases where the product cannot be reused due to the use of . In addition to the aforementioned improvements to the plug itself, attempts have been made to extend the life of the plug by lubricating the gap between the plug and the workpiece. Research has been carried out using melting point fluxes, lime, glass, etc., either singly or in combination, but satisfactory results have not yet been obtained. Regarding the guide shoe, Japanese Patent Application Laid-Open No. 52-150357 proposed a seizing prevention method in which an anti-seize agent made of various salts and a binder that retains the salt is applied to the inner surface of the guide shoe and holes are formed. Japanese Unexamined Patent Publication No. 57-165106 proposes a guide shoe flaw prevention method in which a mill scale is interposed between the guide shoe and the workpiece during rolling. At present, it does not produce a satisfactory effect during rolling. Problems to be Solved by the Invention As mentioned above, various proposals have been made, but all of the methods involve the plug and the workpiece or the guide shoe and the contact between the plug and the workpiece when drilling or elongating the workpiece of high alloy steel. It is not an effective means to prevent seizure, abrasion, erosion, etc. between the workpiece and the workpiece, and therefore,
As a result of seizure and melting damage, defects occur on the product, which reduces product yield.Also, as a result of guide shoe wear, seizure, and melting damage, the operating rate decreases due to guide shoe replacement. Ta. An object of the present invention is to provide a new lubricant that can solve these problems. Means for solving the problems The present invention consists of iron oxide powder 10-80% by weight, silicate compound
A lubricant for hot working of steel (first invention product) consisting of 20 to 90% by weight, and 10 to 80% by weight of iron oxide powder,
A lubricant for hot working of steel (second invention product) comprising 10 to 80% by weight of a silicate compound and 10 to 80% by weight of an alkylene polymer or copolymer. The iron oxide powder used in the product of the present invention has 5% or less of particles with a size of 325 mesh or more, more preferably 1% or less of particles with a size of 325 mesh or more. Optimal. The silicic acid compounds used in the products of the present invention include salts made of silicic acid and metal oxides such as sodium metasilicate and sodium orthosilicate, concentrated aqueous solutions of alkali silicate glass such as water glass, and ultrafine particles of silicic anhydride in water. colloidal silicas such as those dispersed in silica, aluminosilicates such as mica,
Phyllosilicates are used. Furthermore, the alkylene polymers or copolymers used in the products of the present invention include polymers or copolymers of acrylic acid or esters, polymers or copolymers of vinyl esters such as vinyl acetate and ethylene vinyl acetate, and styrene. Suitable materials include emulsified microparticles that are insoluble in water, such as maleic acid copolymers and maleic ester polymers. In the composition of the lubricant of the present invention, both the first invention product and the second invention product contain 10 to 80% by weight of iron oxide powder;
Preferably it is 20 to 40% by weight. If the amount of iron oxide powder is too small, the lubricating effect will be reduced, and if it is too large, it will be difficult to homogeneously mix and disperse it in the binder. This not only causes problems such as clogging of the iron oxide powder in the conduit, but also causes unevenness in the density of the iron oxide powder in the applied lubricant coating, resulting in a decrease in the lubricating effect. The content of silicic acid compound is 20 to 20 in the case of the first invention product.
The content is preferably 90% by weight, 10 to 80% by weight in the case of the second invention, and preferably 30 to 60% by weight in either case. If the amount of silicic acid compound is too large, it will dissolve the oxide scale formed on the surface of the tool, resulting in a reduction in the life of the tool, while if it is too small, it will cause the workpiece to be processed at a high temperature during drilling or elongation rolling. It becomes impossible to suppress the iron oxide powder from exfoliating from the surface of the tool that is in contact with the tool, resulting in a decrease in the lubricating effect. Further, the amount of the alkylene polymer or copolymer added to the second invention product is preferably 10 to 80% by weight,
More preferably, it is 30 to 50% by weight. This alkylene polymer or copolymer is used to improve the peeling resistance of the applied coating film in environments where water is used. If the lubricant exceeds the limit, the viscosity of the lubricant will increase, making it difficult to apply the lubricant to the tool, or the inside of the conduit for feeding the lubricant in the lubricant applicator (not shown). This can lead to problems such as lubricant clogging. Function: Before using the tool, a lubricant consisting of 10 to 80% by weight of iron oxide powder and 20 to 90% by weight of a silicate compound, which is the first invention, is applied to the tool, and the tool is heated under high temperature and high pressure. By interposing iron oxide powder and a silicate compound between the workpiece and the tool and performing drilling or elongation rolling, the iron oxide powder has a heat insulating effect and a lubricating effect. The silicic acid compound prevents the iron oxide powder coating from peeling off from the tool surface when the lubricant comes into contact with the hot rolled material, and also prevents the iron oxide powder coating from peeling off from the tool surface at high temperatures of 1200 to 1300°C. It accelerates the melting of the material and liquefies it at a high temperature to exhibit a lubricating effect, which has the effect of preventing wear, seizure, melting damage, or deformation of the tool. In addition, the second invention product is composed of 10 to 80% by weight of iron oxide powder, 10 to 80% by weight of a silicic acid compound, and 10 to 80% by weight of an alkylene polymer or copolymer. By using the product as a lubricant, it is possible to improve the water resistance or peeling resistance at room temperature when the product of the present invention is applied to the tool and ready for use, and the lubricant coating film is not perforated or stretched. This has the effect of preventing peeling or falling off due to exposure to cooling water or contact between tools before use. Examples Next, the effects of the hot working lubricant of the present invention will be explained based on examples. Example 1 FIG. 1 is a conceptual diagram of a test for drilling 13% Cr stainless round steel using the lubricant of the present invention for lubricating the plug of a Mannesmann drilling machine.
After brushing lubricant onto multiple new plugs that had been stored at room temperature (approximately 20°C), they were thoroughly dried by blowing hot air with a blower. The thickness of the lubricating coating after drying was approximately 100 to 500 μm.
Each time it is used to drill a single workpiece, it is inspected.
Plugs determined to be reusable were submerged in a water tank and cooled until the temperature of the body of the plug reached 100°C to 200°C, then lubricant was applied and dried in the same manner as described above. It was later reused. In this manner, the above-mentioned test was repeated until the product was inspected after use and was determined to be unusable and discarded. The results are shown in Table 1. Bengara 1 used in this test had a particle size of 325 mesh or more and 0.1% or less, and Bengara 2 had a particle size of 325 mesh or larger and 5%.

【table】

[Table] Summary ◎ Good ○ Fairly good △ Fairly poor ×
Defective As is clear from Table 1, a lubricant consisting of 10 to 80% by weight of Bengara, 20 to 90% by weight of a silicate compound such as sodium metasilicate, water glass, colloidal silica, or mica is used, and roll cooling water is used. The life of the plug when drilling is stopped is 2 times longer than when drilling is performed with roll cooling water flowing as in normal drilling.
~3 passes increase. Next, Bengara 10-80% by weight, sodium metasilicate,
Water glass, colloidal silica, or mica 10 to 80% by weight, acrylic acid polymer resin, vinyl acetate polymer resin, or styrene maleic acid polymer resin 10 to 80% by weight
When using a lubricant consisting of 80% by weight, the short life is 4 to 5 passes, and the long life is 6 to 5 passes.
The result was 8 passes, and the effect of extending the life is remarkable compared to the 2 to 3 passes of conventional products. Example 2 Next, the lubricant of the present invention was used to lubricate the disk-type guide shoe of the Mannesmann drilling machine, and 13
%Cr stainless steel round steel drilling test was conducted.
The outline will be explained according to FIG. For the test, a pair of well-maintained upper and lower disc-type guide shoes 5, 6 was installed, and the disc-type guide shoes 5, 6 were driven by a motor through a speed reducer (not shown) to move the workpiece 3
is rotated at a speed corresponding to the moving speed of. Further, when lubricant is supplied to the grooves on the outer periphery of the disc type guide shoes 5, 6 from the lubricant supply device 9 through the nozzle 10 and applied to the disc type guide shoes 5, 6, the disc type guide shoes 5, 6,
It is instantaneously dried by the heat retained by the disc-shaped guide shoes 5 and 6, and serves to lubricate the workpiece 3 with the disc-type guide shoes 5, 6. Although the lubricant supply device and nozzle for the lower disk-type guide shoe 6 are not shown in FIG. 2, the lubricant is supplied to the lower disk-type guide shoe 6 as well as the upper disk-type guide shoe 5. configured to be supplied. In this test, during drilling, the roll cooling water was slightly squeezed, and the cooling water for the guide shoes 5 and 6 was stopped. The results are shown in Table 2.

[Table] The Bengara used in this test had a particle size of 325 mesh or larger and less than 0.1%. It is clear from Table 2 that the lubricant of the present invention has a remarkable effect on preventing seizure of guide shoes. In this example, the lubricant of the present invention was used for drilling round steel, but the lubricant is not limited to round steel. It can also be used for drilling for directly manufacturing hollow shell pipes for seamless steel pipes from square steel pieces. It has the effect of In this example, Bengara was used as the iron oxide powder,
As the silicate compound, sodium metasilicate, water glass, colloidal silica, or mica is used, and as the alkylene polymer or copolymer, acrylic acid polymer resin, vinyl acetate polymer resin, or styrene maleic acid polymer resin is used. However, the lubricant of the present invention is not limited to the composition of this example, and within the scope of not changing the gist of the present invention,
It goes without saying that various combinations are possible. Effects of the invention At the contact surface between the workpiece and a processing tool such as a plug, disc-shaped or plate-shaped guide shoe used when manufacturing seamless steel pipes using an inclined roll punching machine or an elongation rolling machine, By using the lubricant of the present invention as a lubricant, it has a remarkable effect on preventing seizure and erosion on the contact surface and suppressing wear, so the life of the machining tool can be greatly extended, and the product can be improved. The occurrence of scratches is reduced, and the effect is tremendous.

[Brief explanation of the drawing]

Figure 1 is a conceptual diagram of drilling using the lubricant of the present invention for lubricating the plug of a Mannesmann drilling machine, and Figure 2 is a conceptual diagram of drilling using the lubricant of the present invention for lubricating the disk-type guide shoe of a Mannesmann drilling machine. Fig. 3 is a plan view of the inclined roll perforator, and Fig. 4 is a cross-sectional view taken along the line X-X in Fig. 3.
It is a line arrow view. In the figure, 1... plug, 2... core metal, 3... workpiece material, 5, 6... disk type guide shoe, 7,
8...Roll, 9...Lubricant supply device, 10...
nozzle.

Claims (1)

[Claims] 1. Iron oxide powder 10-80% by weight, silicate compound 20-90%
A lubricant for hot working of steel consisting of % by weight. 2 Iron oxide powder 10-80% by weight, silicate compound 10-80%
Weight %, and alkylene polymer or copolymer
A lubricant for hot working of steel consisting of 10 to 80% by weight.