SU681909A1 - Glass grease for hot deformation of metals - Google Patents

Abstract

GLASS LUBRICANTS FOR HOT DEFORMATION OF METALS containing oxides of silicon, aluminum, calcium, magnesium, sodium and potassium, in order to improve the quality of the outer surface of the deformed products and ensure optimum viscosity of the lubricant in the temperature range 1120-1250 "C, glass lubricant, additionally contains iron oxide and sodium tripolyphosphate with the following content of components, may.%: Alumina 5-7 Calcium oxide 5-8 Magnesium oxide 3-4 Sodium oxide 21-24 Potassium oxide 2-5 Oxide iron. 3-5 Sodium Tripolyphosphate 3-5. Silicon Oxide Up to 100i

Description

The invention relates to the field of hot deformation of metals and, in particular, to glass lubricants, and can be used for rolling the outer surface of blanks during the piercing and pressing of hollow products, for example, pipes made of various steels and sp. BOB, in the temperature range 1120 1250 ° s The use of effective technological lubricants in the production of hot-pressed products is one of the necessary conditions for achieving satisfactory pressing results. In case of unsatisfactory lubrication, the pressing process is either not possible at all or pressed products are rejected due to the presence of defects. During the pressing process, the lubricant is placed between the workpiece and the tool, namely, between the inner surface of the container and the outer surface of the liner; between the needle and the inner surface of the sleeve; between the die and the front end of the sleeve. As a rule, all these lubricants differ in their physical properties. It is known that when pressing with a lubricant, depending on its quality, only 10 to 30% of the required total pressing force can be spent to overcome friction between the billet and the container. The latter must be considered when choosing lubricants, especially when pressing hard-to-deform metals and alloys. The use of graphite lubricants for various processes of hot deformation of metals and alloys is known. In particular, in the practice of hot. pressing lightly alloyed steels using graphite with table salt for running the outer surface of the blanks. The disadvantage of this lubricant is high carburizing ability, the impossibility of its uniform deposition on the surface of the workpieces and the impossibility of creating a continuous lubricating film during the pressing process. These defects are deprived of a stack of lube with the correct selection in accordance with the temperature conditions of pressing and the properties of the deformable metal. Technological glass lubricants for hot pressing should have different viscosities depending on the application. Thus, the viscosity of glass grease for running-in of the outer surface of the blanks at pressing temperature should be in the range of 5-25 -. When reducing the lower limit, the layer of melted glass does not provide a continuous even coating and is characterized by weak shielding ability. As a result, due to the sticking deformable metal on the container sleeve, the quality of the pressed products deteriorates and tool wear is reduced. Exceeding the upper limit of the viscosity of the lubricant causes additional shear deformations in the surface layers of the metal being pressed. Additional efforts are required to overcome the viscosity of the lubricant, which ultimately leads to a deterioration in the quality of the pressed products and tool life. The lubricating ability of a lubricant also depends on the wetting ability of the lubricant. Therefore, the number of mandatory requirements for running on glass grease also includes the good wetting ability of the metal to be treated with lubricant and the absence of deficient and toxic components. Glass lubricants for rolling in blanks containing oxides of silicon, boron, sodium, calcium, titanium, cobalt, nickel, and silicon-fluoride sodium are known. However, the known glass lubricants In the temperature range of 1120-1250 C have a low viscosity (1-2 ns / m) and, as a result, the screening ability is unsatisfactory. The most approximate in terms of the composition of the components to the present invention is a glass lubricant containing silica, aluminum, calcium, sodium, potassium and fluorine. In this lubricant, a full or partial replacement of calcium oxide by magnesium oxide is allowed. The disadvantage of this lubricant is high viscosity at a temperature of 1120-1250 0, as a result of which there are high strain forces and a deterioration in the quality of the surface of the pierced sleeves and pressed products. In addition, the presence of fluorine in the composition of the lubricant affects the sanitary conditions of the staff.

The aim of the invention is the development of glass grease, ensuring the quality of the outer surface of the deformable products and the optimum viscosity of the lubricant in the temperature range-1120-1250 ° C.

The goal is achieved by the fact that the lubricant containing silica, aluminum, calcium magnesium, sodium and potassium additionally contains iron oxide and sodium tripolyphosphate in the following ratio, wt.%:

Alumina (Al-Oj) 5.0-7.0 Calcium oxide (CaO) 5.0-8.0 Magnesium oxide (MgO) 3.0-4.0 Sodium oxide () 21.0-24.0 Oxide potassium (KjO) 2.0-5.0 iron oxide (,) 3.0-5.0 sodium tripolyphosphate (,) 3.0-5.0

Silica (SiOj) Up to 100 The following non-deficient materials are used for the synthesis of glass grease. Silica is injected with quartz sand, alumina - with alumina or kaolin, calcium oxide and magnesia with dolomite and chalk, sodium oxide - with soda ash, and potassium oxide - with potash. The iron oxide can be introduced in the form of pure oxide () or in the form of flue dust (blast furnace production). Raw materials are pre-dried to a moisture content of not more than 2%, crushed to a fraction of 0, 5 mm and mix thoroughly.

Glass Lubricated Bath Ovens

batch operation at a temperature of 1200-1400 ° C, the melt is degassed, granulated into water, dried and crushed to a particle size of 0.10, 4 mm.

The proposed glass lubricant immediately before flashing or pressing is applied onto the outer surface of the heated blanks on a sloping table along a layer of glass lubricant powder or by spraying glass lubricant on a blank rotating around a longitudinal axis.

The following glass lubricant compositions were prepared and tested (see Table 1).

Compounds 1-3 - the proposed lubricant, part 4 - known lubricant.

In order to provide the required limits for the change in viscosity, the boundary contents of the components of the developed glass lubricants are determined from the principle of preserving the constant ratio of the amount of oxides that increase the viscosity (Sibj, AljO, CaO) to the amounts of alkali oxides (, K, j, 0),

A viscometer operating according to the principle of rotating coaxial cylinders was used to study the viscosity properties of the lubricants produced. The viscosity of glass grease is given in table. 2

Testing of lubricants was carried out according to the existing technology on a vertical piercing press with a force of 900 tons when piercing blanks with a diameter of 170 mm made of stainless steel 12X18H10T at a temperature of .1180-1200 ° C and subsequent pressing of pipes of 76x4.5 mm in size on a horizontal hydraulic press with a force of 3150 tons at a temperature of 1120 WITH.

During the flashing process, the behavior of the lubricants when reflowing on the workpiece, the condition of the outer surface and the difference in thickness of the stitched blanks, and conditions for pushing the stitched sleeves out of the container were controlled. When pressing the pipes, the pressing forces were controlled, the conditions for pushing the pressure trap out of the container after pressing the pipe and the quality of the outer surface of the pipe were controlled.

The test results are shown in Table. 3 and 4. As can be seen from the table. Zi4, the proposed lubricants ensured a satisfactory quality of the outer surface of the stitched sleeves with a grain ratio of up to 2 mm and pressed pipes. The proposed lubricants provide a continuous smooth coating on the workpieces, do not impede the processes of flashing, and reduce both the maximum and steady pressing forces. Pushing out the finished sleeves and pressure cones from the container hubs was easy, there were no cases of underpressing. However, glass lubricants with a boundary content of components with a viscosity of more than 25 Htc / M are already prone to the beginning of the formation of individual small scratches and the increase of pressing forces. How can you see from the table. 2, the compositions proposed have an optimal viscosity at temperatures of 1120 and, accordingly, and at these temperatures provide satisfactory results of the pressing firmware. At the same time, as follows from the table. 3 and 4, when using a known lubricant due to high viscosity and worse wetting ability (wetting angle more than 24), the wall thickness of the pierced sleeves reached 4 mm, and the difficulty of ejection of the pierced sleeves and pressure bars from the container sleeves reduced the production rate and increased overload and wear of technological tools. Significantly higher pressing forces and the presence of longitudinal risks on the pipes also indicated the unsuitability of the known lubricant for the given conditions of piercing and pressing. Thus, the proposed combination and ratio of components allows for optimum viscosity in the temperature range. 1120-1250С, and its application ensures the successful implementation of the processes of firmware and pressing and improving the quality of products. In addition, the wetting ability of the lubricant proposed is also higher than the well-known positive effect of its use. The lubricant offered does not contain scarce, expensive and toxic components and does not pollute the surrounding atmosphere with harmful intent. Table 1

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Claims (1)

GLASS GREASE FOR HOT METAL DEFORMATION, containing silicon, aluminum, calcium, magnesium, sodium and potassium oxides, characterized in that, in order to improve the quality of the outer surface of the deformable products and to ensure optimal viscosity of the grease in the temperature range 1120-1250 C, glass grease. additionally contains iron oxide and sodium tripolyphosphate in the following components, May.%: Oxide aluminum 5-7 Oxide calcium 5-8 Oxide magnesium 3-4 Oxide sodium 21-24 g Oxide potassium 2-5 Oxide gland 3-5 (L Sodium Tripolyphosphate 3-5 Oxide silicon Up to 100 ICLS9 with oo ABOUT