RU2597852C2 - Ball valve half-body and preparation method thereof - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: invention can be used in making structural all-metal parts of pipeline valves, for example half-bodies of ball valves of different sizes. Initial billet is heated to deformation temperature and is placed in matrix of die. It is settled to height of 0.7-0.8 of initial billet height. Then, settled billet is pierced with forming male die with force to 120 MN with formation of bridge. Bridge is cut through with piercing, after which stamping billet is removed from die and placed on rolling machine mandrel. At that, billet outer surface contact with rolling machine shaped roller is provided. Billet is rolled out till design ball valve half body wall thickness.

EFFECT: higher strength of finished products due to uniform redistribution in zone of plastic deformations.

10 cl, 7 dwg, 1 ex

Description

The claimed group of inventions relates to the field of engineering, in particular to the valve industry, and can be used in the manufacture of all-metal body parts of pipe fittings, including complex profile configurations, for example, half-shells of ball valves of various sizes.

Various manufacturing techniques for ball valve half-shells are known depending on the nominal bore diameter (D _y ) of the half-shell. In the general case, all applied technologies with one or another feature are variants of hot or cold stamping known in the art. Through the application of one method or another, the half-body of a ball valve can be a part made of a pipe billet, a rolled shell, or a forged billet.

So, from the prior art there is a known method of manufacturing the body parts of pipe fittings described in the description of the invention according to the patent of the Russian Federation No. 2281823, which includes heating a cylindrical tube billet and forming a bottom and a nozzle of the body part from it, while the tube billet is placed in a stamp on a crimping punch and the formation of the bottom is carried out with a constant, and the nozzle with a variable wall thickness by crimping the workpiece with a die and then extruding the nozzle, which is conducted by a forming punch in the aforementioned stamp e without reinstalling the workpiece.

This method involves the use of a welded shell as a blank for stamping. A weld seam contributes to a weakening of the structural strength, therefore, when using welded joints in valve manufacturing for shutoff valves operating under high pressure, special methods are necessary to control x-ray welding of both the blank for stamping and the stamped blank, which complicates the manufacturing process of manufacturing parts. Thus, the half-shell obtained in a known manner, it is necessary to subject to periodic inspection for the quality of the weld.

The prior art also known a method of manufacturing forgings in the form of a hemisphere with a neck of steel sheets, including forging from an ingot of a complete forging into two hemispheres, followed by its cutting into two piece blanks. At the same time, forging of the forgings for a hemisphere part, for example, on D _y 1400 contains operations of drawing and draft ingot with removal of the profitable and bottom part of the ingot, piercing the hole, rolling on the mandrel to obtain a thickened part in the area of the future neck of the cylindrical forging and crimping operations in the middle part forgings with the formation of hemispheres. In this case, the metal utilization factor, taking into account the removal of the profitable and bottom part of the ingot, the waste of metal during two heating and waste into the otter when flashing and machining when removing allowances, is less than 0.6 (A.E. Artes et al. "Improving the manufacturing processes of parts valve production by plastic deformation methods. "Vestnik MGTU" Stankin ", No. 1 (13), pp. 8-12, 2011).

The disadvantage of this method is that when stamping half-shells of large diameter, the stability of the metal is lost during the landing of the neck, which leads to marriage. Thus, this method is applicable only for the manufacture of half-shells of small diameters.

There is also a known method of manufacturing half-shells of ball valves, including the following operations: cutting from a thick sheet S = 45, 50, 60, 100 mm, respectively, for half-shells on D _y = 400, D _y = 500, D _y = 600 and D _y = 1000 blanks in the form of a flat flange, its hot exhaust, crimping with the distribution and landing of the neck. Stamping of half-shells at D _y = 400, D _y = 500, D _y = 600 and D _y = 1000 is carried out on a powerful double-acting hydraulic press with a force of 80/40 MN. Moreover, the metal utilization factor is less than 0.7 (A.E. Artes “Forging and stamping. Pressure processing of materials”, article “Technological processes for manufacturing forgings from pipe billets”, No. 11, pp. 25-31, 2003) .

The disadvantage of this method is the loss of stability of the metal during the disembarkation of the neck when stamping half-shells of large diameter, which makes it impossible to unify this method for the production of half-shells of all sizes.

The rolling during the manufacture of hull parts is used in the formation of the cylindrical surfaces of the forgings, which is reflected in the description of the invention according to the patent of the Russian Federation No. 2449852, issued for "A method of manufacturing a reactor shell". This technical solution is the closest to the claimed method.

In accordance with this decision, the ingot is heated to the forging temperature and fed to the press head where the pin is forged to capture from the profit of the ingot. The resulting measured billet is again heated to forging temperature and served on the lower flat plate of the press. On the plate with the upper flat striker, the cylindrical billet is precipitated - flattened onto the plate. Reheat to forging temperature. A lower flat plate with a central hole is mounted on the press, on which, in turn, a heated workpiece is mounted. A hollow stitch is placed on the upper end of the workpiece and, by pressing the upper flat striker, the central hole in the workpiece is flashed. After flashing carry out additional heating of the workpiece. Then on the goats by means of variable compression and tilting of the workpiece, it is rolled out to the size of the forging of the shell. Then the resulting shell is corrected on a flat bottom plate by pressing the press both at the ends and along the generatrix of the cylinder.

The method contains an excessive number of operations of moving and heating the workpiece, which significantly increases the manufacturing time of the part and negatively affects the performance of the process in accordance with this method.

The objective of the claimed technical solutions is to provide the possibility of obtaining a body part of pipe fittings with a minimum allowance for machining through the combined use of stamping and rolling technologies.

The technical result achieved by using the claimed group of inventions is to ensure the absence of welds in the forgings of pipe fittings, which positively affects the strength of the product. In addition, the result achieved by using the proposed method is to increase the utilization of metal by reducing machining allowances. The technical result achieved by using the solution of the half-shell also consists in improving the structure of the metal of the half-shell and its operational characteristics by ensuring uniform redistribution of metal in the area of its plastic deformation in the manufacture of the half-shell.

,The problem is solved in that in the method of manufacturing a half-body ball valve containing a spherical part and a neck, including the draft of the initial billet with a flat striker in the matrix, piercing the central hole and rolling, according to the invention, the initial billet is heated to a temperature allowing the workpiece to be deformed, placed in a stamp press matrix, in which the workpiece is upset to a height h = 0.7-0.8 from the height of the original workpiece, and then the workpiece is stamped with a molding punch with a force of up to 120 M to form a bridge, resulting in that prosekayut drift-stamped blank, the stamped blank then is removed from the die and placed on a rolling machine with a mandrel contacting the outer surface of the stamped blank and figure roll rolling machine and the rolled preform to achieve the design thickness half shell wall. The forged bars _zag diameter D = 0,6-0,7D _throats, height may be used as the initial billet

,

_throats where D - diameter of the neck half-shells, D _polukorp. - the diameter of the spherical part of the half-shell, V _half-shell. - the volume of the half-shell.

,The diameter of the cut-through jumper is equal to half the diameter of the initial billet. For one revolution of the stamped blank on a rolling machine, the relative deformation of its wall is provided by 5-8% of the thickness of its wall, while the number of revolutions of the stamped blank during rolling is determined by the formula

,

where S _pc - the average thickness of the stamped blanks for rolling, mm;

S is the average thickness of the half-shell, mm;

Δh is the feed rate, mm.

The geometric dimensions and the shape of the mandrel and curly roll of the rolling machine correspond to the geometric dimensions and shape of the product, taking into account the technological allowance for machining the inner wall of the product in the formation zone of the neck of the half-shell and without the technological allowance for machining in the zone of forming the spherical part of the half-shell. Before rolling, the stamped workpiece can be subjected to additional heating to a temperature of 1250 ° C. When rolling, the force applied to the figured roll is proportional to the contact area of the figured roll with the rolling part. The operations of upsetting the initial billet, stamping and notching of the jumper, as a rule, are performed in one stamp.

, где V_{полукорп.} - объем готового изделия, а D_{полукорп.} - диаметр сферической части полукорпуса.The problem is also solved by the fact that the half-body of a ball valve, including a spherical part and a neck, is a part made of forged bars by successively stamping and rolling in accordance with the inventive method, while

where V is a _semicorp. - the volume of the finished product, and D _half-shell. - the diameter of the spherical part of the half-shell.

The claimed group of inventions is illustrated by the following drawings.

In FIG. 1-7 are a schematic representation of a process for producing a half-body ball valve, with FIG. 1-4 show modifications of the workpiece in the stamp of a hydraulic press during the operations of stamping the workpiece, and FIG. 5-6 show the process of increasing the diameter of a part as a result of radial rolling (the initial and final moments of rolling). In FIG. 7 schematically depicts a bottom view of a stamped blank pre-installed between the mandrel and the figured roller before rolling.

The positions in the drawings indicate:

1 - blank

2 - stamp matrix,

3 - flat firing pin,

4 - upsetting workpiece,

5 - molding punch,

6 - stamped blank

7 - jumper,

8 - firmware

9 - mandrel ring rolling machine,

10 - figured roll,

11 - half-shell.

The inventive method consists of two main stages and is implemented as follows.

The description of the method is given by the example of manufacturing a half-shell part of a ball valve with a diameter of D _y = 1400 mm, although it can be projected onto a half-shell of any standard size, taking into account the declared ranges.

This method is implemented using a press that provides a quick change of a tool, for example a double-acting hydraulic press, and a radial ring rolling machine with specially made figured rolls.

A double-acting hydraulic stamping force of 140 MN, used in the implementation of the proposed method, is an open-type welded-in bed strung with pins, on which the main hydraulic actuator is mounted. The press is equipped with a three-position retractable table, which has the following positions: central and two extreme lateral and is designed for three plates with the possibility of installing three dies and an ejector at the same time.

To center the workpiece, two side hydraulic centralizers are provided before stamping.

, где V_{полукорп.} - объем готового изделия, а D_{полукорп.} - диаметр сферической части полукорпуса. Точное значение коэффициента также определяется величиной диаметра полукорпуса. Так, для изготовления полукорпуса на Д_у=1400 мм высоту исходной заготовки выбирают равной 1500 мм. При осуществлении первого этапа на гидравлическом прессе производят подготовку заготовки к раскатке, обеспечивая ее формообразование в соответствии с формой будущего полукорпуса. Для этого предварительно нагретую до температуры около 1150°C исходную заготовку 1 размещают в матрице 2 штампа гидравлического пресса. Профиль внутренней поверхности матрицы соответствует форме внешней поверхности изготавливаемого полукорпуса. С усилием примерно 120 МН плоским бойком 3 нагретую заготовку осаживают до полного заполнения внутренней полости матрицы под плоским бойком, при этом обеспечивают достижение высоты осаженной заготовки 4 (h) равным 0,7…0,8Н_заг. Затем незамедлительно осаженную заготовку прошивают формовочным пуансоном 5 с усилием 120 МН, который поворотным манипулятором пресса перемещают и центрируют относительно матрицы с осаженной заготовкой 6. После прошивки на заготовке остается перемычка 7 заданной толщины около 0,15 от высоты исходной заготовки. Так, при формировании полукорпуса диаметром Д_у=1400 мм толщина перемычки составляет 225 мм. Формовочный пуансон после этой операции меняют на прошивень 8, закрепленный на следующем поворотном манипуляторе. Прошивень также центрируют относительно матрицы с размещенной в ней осаженной заготовкой с перемычкой и просекают образовавшуюся при выполнении предыдущей операции перемычку («выдру») диаметром 390 мм (для Д_у=1400 мм). В общем случае размер просекаемого отверстия зависит от диаметра заготовки и равен примерно половине ее диаметра.Forged billets use a forged bar with a diameter of D _zag and a height of H _zag , made, for example, of steel 09G2S. The diameter of the rod of the initial billet is chosen depending on the desired neck diameter D of the finished half shell _throats from the ratio D = 0,6-0,7D _{zag throats.} The exact value of the coefficient is determined by the diameter of the half-shell. Thus, in the manufacture of half shell at D = 1400 mm _at the ratio assumes the form D = 0,6D _{zag throats.} In the General case, the height of the initial billet N _{ZAG is} calculated based on the volumetric indicators of the finished half-shell according to the formula

where V is a _semicorp. - the volume of the finished product, and D _half-shell. - the diameter of the spherical part of the half-shell. The exact value of the coefficient is also determined by the diameter of the half-shell. So, for the manufacture of a half-shell at D _y = 1400 mm, the height of the initial billet is chosen equal to 1500 mm. During the first stage, the workpiece is prepared for rolling out on a hydraulic press, ensuring its shaping in accordance with the shape of the future half-shell. For this, the preform 1 preheated to a temperature of about 1150 ° C is placed in the die matrix 2 of the hydraulic press. The profile of the inner surface of the matrix corresponds to the shape of the outer surface of the manufactured half-shell. With a force of about 120 MN with a flat striker 3, the heated preform is upset until the matrix cavity is completely filled under the flat stripper, while ensuring that the height of the deposited preform 4 (h) is equal to 0.7 ... 0.8N _zag . Then, the immediately upsetting workpiece is flashed with a molding punch 5 with a force of 120 MN, which is moved and centered by the rotary manipulator of the press relative to the matrix with the deposited workpiece 6. After flashing, the workpiece 7 remains of a predetermined thickness of about 0.15 of the height of the original workpiece. So, when forming a half-shell with a diameter of D _y = 1400 mm, the thickness of the bridge is 225 mm. After this operation, the molding punch is changed to firmware 8, mounted on the next rotary manipulator. The firmware is also centered relative to the matrix with the upset blank placed in it with a jumper and the jumper (otter) formed with the previous operation is cut through with a diameter of 390 mm (for Д _у = 1400 mm). In the general case, the size of the cut-through hole depends on the diameter of the workpiece and is approximately half its diameter.

The firmware and notch operations are performed separately by the molding punch and stitched accordingly. Combining these operations and performing one flashing tool will reduce the stability of the firmware by increasing its wear.

Thus, as a result of the above stage, a stamped blank is obtained, the profile of the outer surface of which corresponds to the profile of the future forging of the half-shell. The height of the stamped workpiece is equal to the height of the half-shell.

The next half-shell manufacturing step is performed using a ring rolling mill.

A ring rolling mill (rolling machine) is a machine for manufacturing axisymmetric billets by means of hot radial-axial rolling, including rotating curly mandrel (inner roll) and roll (outer roll).

The choice of type of ring rolling machine is based on determining the required rolling force. The force in this case depends on the average pressure on the contract surfaces of the workpiece with a mandrel 9 and a figured roll 10 (inner and outer rolls). For the manufacture of parts of the half-shells in accordance with the claimed invention, a ring rolling machine with a force of at least 7 MN is used.

Since the maximum necessary force is applied to the rolls at the beginning of the rolling process, when the wall thickness of the workpiece is greatest, therefore, when choosing the maximum necessary effort of the rolling machine, they are based on the calculation of average pressures on the contact surfaces in the zone of formation of the spherical part of the half-shell, as in the areas of the most dense contact of the workpiece with the rolls at the beginning of the process.

Prepared at the first stage, the stamped blank is placed on the mandrel of the ring rolling machine. The shape and profile of the outer surface of the mandrel correspond to the shape and profile of the inner surface of the half-shell of the required size and, accordingly, the shape and profile of the outer surface of the figure roller correspond to the shape and profile of the outer surface of the half-shell with machining allowance in the zone of formation of the neck of the half-shell and without such allowance in the zone of formation of the spherical parts of a half-shell. If necessary, the workpiece is heated to a temperature of 1250 ° C before being mounted on the mandrel. This need may be due to the low power of the rolling machine. The rolling out is a technological operation by which a simultaneous increase in the outer and inner diameters of the stamped workpiece is made by reducing the thickness of its wall.

The roller and / or mandrel rotates due to friction on the surface of the workpiece being rolled.

Rolling, as a rule, is carried out in one heating of the workpiece. However, in the manufacture of large-sized parts, for example, in the manufacture of large-diameter half-shells (1400 mm) or when using a rolling machine of insufficient power, intermediate preheating can be introduced as an additional operation.

The rolling process begins with the installation of the stamped workpiece in the working space of the ring rolling machine on the mandrel, while there is no condition for the fit of the workpiece. Then the mandrel and the figured roller are brought into contact with the workpiece, which is concluded between the mandrel and the figured roller. Various designs of rolling machines allow rotation of a separate mandrel or roll, as well as their simultaneous rotation.

Then the roll (or mandrel) is imparted a rotational movement and ensure the application of a deforming force to it in the radial direction. Thus, they initiate a local focus of deformation of the wall of the workpiece with subsequent plastic redistribution of the metal. The workpiece begins to rotate with the mandrel. Due to such rotation of the workpiece, its friction against the mandrel and figured roller, as well as displacement due to the perception of the deforming force of the mandrel, a change in the wall thickness of the workpiece is achieved.

The deforming force applied to the roll is determined in proportion to the contact area of the roll with the rolling part at the initial time:

;

;

- давление на длине контакта l₁ в локальном очаге деформации, Н/м²;Where

- pressure at the contact length l ₁ in the local deformation zone, N / m ² ;

- безразмерный коэффициент, характеризующий отношение большей и меньшей длины контакта валков с раскатываемой заготовкой;

- dimensionless coefficient characterizing the ratio of the larger and shorter contact lengths of the rolls with the rolled workpiece;

- напряжение текучести материала на сдвиг, кгс/мм²;

- the yield stress of the material in shear, kgf / mm ² ;

σ _t - yield strength of the material, kgf / mm ² ;

- меньшая длина контакта валка с заготовкой, мм;

- shorter contact length of the roll with the workpiece, mm;

H - the height of the workpiece, mm;

r ₁ is the radius of the mandrel, mm;

r ₂ is the radius of the figured roll, mm;

r _in - the inner radius of the workpiece in a given section at the initial time, mm;

r _n - the outer radius of the workpiece in a given section at the initial time, mm;

Δh is the feed rate, mm;

µ = s _cp / l ₂ ;

s _av - the average wall thickness of the workpiece at the initial moment of rolling, mm

It was experimentally established that for one revolution of the workpiece on the mandrel, the wall deforms (reduces its thickness) by 5-8%, from which we can conclude that the achievement of the specified design dimensions of the half-shell will occur in N revolutions:

,

,

where S _pc - the average thickness of the stamped workpiece before rolling, mm;

S is the average thickness of the finished half-shell, mm;

Δh is the feed rate, mm;

So, for example, when rolling the half-shell to D _y = 1400 mm, about N = 15 revolutions of the rolls of the rolling machine with a maximum force of P = 6.1 MN is enough.

Upon reaching the specified end position of the drive roll, which provides the specified thickness of the half-shell and the geometry of the workpiece, the rolling process stops. The calculated parameters of the finished half-shell are set programmatically, and when they are reached, the rolling machine automatically stops.

The resulting part is left on the mill of the rolling machine until it cools completely, after which the manipulator removes and performs mechanical processing.

Thus, the result is a half-hull 11 of a ball valve, in which there are no welds, which significantly improves operational characteristics.

The invention also relates to a half-housing device, which includes a neck and a spherical part and is made by the claimed method.

The half-shell is characterized by the absence of a weld, which ensures increased reliability and exact compliance with the calculated dimensions. At the same time, the resulting half-shell is characterized by the fulfillment of the following ratio in overall dimensions, depending on the dimensions of the initial billet

где V_{полукорп.} - объем готового изделия, а D_{полукорп.} - диаметр сферической части полукорпуса.

where V is a _semicorp. - the volume of the finished product, and D _half-shell. - the diameter of the spherical part of the half-shell.

Since the inventive half-shell is obtained as a result of a combination of stamping tools and methods with radial rolling technologies, the structural properties of the half-shell metal are significantly different from the properties of the half-shell obtained by standard stamping methods. During stamping, there is practically no deformation in the zone of formation of the spherical part, and in the neck zone the degree of deformation is maximum, thus, anisotropy of properties takes place, which negatively affects the operational characteristics (in particular, durability) of the half-shell, since restoration of properties and normalization of the metal are required. During rolling, a uniform distribution of the deforming force is ensured during the rotation of the stamped workpiece over the entire surface of the part without differentiation of deformation, which leads to the absence of anisotropy, the formation of a fine-grained homogeneous structure of the metal of the half-shell. Thus, the result is a half-shell with a homogeneous metal structure, which increases the degree of its wear resistance and durability.

The inventive half-shell is also characterized by minimal allowances for machining due to the fact that during the rolling process there is no need for additional processing of the spherical part of the half-shell. Therefore, there is no machining allowance in this zone, and in the neck formation zone, the allowance is minimal, since the rolling accuracy is much higher than the stamping accuracy. Due to this minimization of allowances, metal is saved on the manufacture of a half-shell, an increase in its utilization coefficient (K _{use metal} ), since with an equal mass of half-shells obtained by stamping and rolling, the mass of the initial billet (rough weight) in the manufacture of a half-shell by the claimed method is significantly lower.

Claims (10)

1. A method of manufacturing a half-shell ball valve having a spherical part and a neck, including the draft of the original billet with a flat striker in the matrix, piercing the central hole and rolling, characterized in that the initial billet is heated to a temperature that allows its deformation, placed in the matrix of the press die, in which they are deposited to a height of 0.7-0.8 from the height of the initial workpiece, after which the deposited workpiece is stitched with a molding punch with a force of up to 120 MN with the formation of a jumper, which rosekayut drift-pin, stamped blank then is removed from the die and placed on a rolling machine with a mandrel contacting the outer surface of the stamped blank with a shaped roller rolling machine and stamped blank is rolled to achieve the design thickness half shell of the ball valve wall. 2. The method of claim. 1, characterized in that as the initial preform used forged rod diameter D = 0,6-0,7D _{zag throats} height

,
_throats where D - diameter of the neck half-shells,
D _half-shell. - the diameter of the spherical part of the half-shell,
V _half-shell. - the volume of the half-shell. 3. The method according to p. 1, characterized in that the diameter of the stitched jumper is equal to half the diameter of the original workpiece. 4. The method according to p. 1, characterized in that for one revolution of the stamped workpiece on a rolling machine provide a relative deformation of the wall of the workpiece, comprising 5-8% of its thickness. 5. The method according to p. 1, characterized in that the geometric dimensions and the shape of the mandrel and figured roller correspond to the geometric dimensions and shape of the product, taking into account the technological allowance for machining the inner wall of the product in the formation zone of the neck of the half-shell and without technological allowance for machining in the zone the formation of the spherical part of the half-shell. 6. The method according to p. 1, characterized in that before rolling the stamped billet is heated to a temperature of 1250 ° C. 7. The method according to claim 1, characterized in that when rolling, the force applied to the figured roller is proportional to the contact area of the figured roller with the rolling part. 8. The method according to p. 1, characterized in that the number of revolutions of the stamped workpiece during rolling is determined by the formula

where S _pc - the average thickness of the stamped blanks for rolling, mm;
S is the average thickness of the half-shell, mm;
Δh is the feed rate, mm. 9. The method according to p. 1, characterized in that the draft of the original billet, firmware and notching of the jumper is carried out in one stamp. 10. The half-body of a ball valve, made with a spherical part and a neck, characterized in that it is made by the method according to p. 2.

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