A surface high-precision forging process for valve ball blank forging

Abstract

The present application relates to the technical field of blank forging, in particular to a surface high-precision forging process for valve ball blank forging, the forging process is to make the ingot by vacuum consumable arc melting of the valve ball metal blank for several times, the ingot is subjected to surface treatment process to remove the surface oxidation layer or pore layer, then the blank is heated to perform open upsetting, followed by isothermal multi-pass forging, and cooling treatment after each pass forging; the surface high-precision forging process for valve ball blank forging can remove impurities and internal pores by vacuum consumable melting method, and can eliminate the defects of the blank by open upsetting process, can be based on the beta phase transformation point temperature for multiple upsetting deformation, is beneficial to the recrystallization of the blank, is beneficial to obtain higher strength, and multiple upsetting can make the overall material dense to prevent internal cracks of the blank, the forging process is beneficial to obtain the valve ball blank with better physical properties and precision.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of embryo forging, in particular to a surface high-precision forging process for valve ball embryo forging. BACKGROUND

[0002] The valve ball is evolved from the traditional plug valve, and its opening and closing part is a spherical body, which realizes the opening and closing purpose by rotating the spherical body around the valve rod axis.

[0003] The valve ball is widely used in the fields of oil drilling, deep-sea drilling and oil pump, and is the most critical component in the oil pump. Due to the harsh working environment and conditions in the oil drilling industry, there are some substances with high corrosivity such as water, various gases, wax, sand and the like in the sand-containing well, heavy oil well and high-pressure anti-dilution well, which requires the valve ball to have good sealing property, wear resistance and corrosion resistance, so that the ball valve has high use precision; at present, there are various types of valve ball embryos, and some high-precision valve balls need to be made of metal embryos, so the forging process of the metal embryo directly affects the physical properties and precision of the valve ball in the later stage, and therefore a high-precision forging process for valve ball embryo is needed. In view of this, the present application provides a surface high-precision forging process for valve ball embryo forging. SUMMARY

[0004] In order to make up for the above shortcomings, the present application provides a surface high-precision forging process for valve ball embryo forging.

[0005] The technical scheme of the present application is as follows:

[0006] A surface high-precision forging process for valve ball embryo forging, wherein the valve ball metal embryo is subjected to vacuum consumable arc melting to obtain an ingot, the ingot is subjected to surface treatment to remove the surface oxidation layer or pore layer, then the embryo is heated to perform blooming and upsetting, followed by isothermal multi-pass forging, and cooling treatment is performed after each pass forging.

[0007] Preferably, the valve ball metal embryo is made of metal titanium or titanium alloy. Metal titanium is an important structural metal, and titanium alloy has excellent characteristics such as high strength, good corrosion resistance and high heat resistance.

[0008] Preferably, the valve ball metal embryo is subjected to three times of melting in a vacuum consumable electric furnace to obtain the ingot, and the ingot is controlled to have a cubic structure. The main purpose of the cubic structure is to obtain uniform heating degree on each surface, so as to ensure that the structure of each part of the forging process can be fully treated.

[0009] Preferably, the specific process steps of the ingot surface treatment process are as follows: first, observe whether the surface of the ingot after air cooling, air cooling or water cooling forms a damage layer such as an oxide layer or a pore layer, then cut the ingot to remove the damage layer. If the damage layer such as the oxide layer or the pore layer is not removed and directly processed, it is easy to act as an impurity or appear a hole, which affects the strength of the overall structure after the material is forged.

[0010] Preferably, the specific process steps of the open-die upsetting are as follows: the open-die upsetting adopts a free forging hammer forging process, and is divided into three times of intermittent open-die upsetting, and the upsetting change rate of each time of open-die upsetting is controlled to be not less than 20%.

[0011] Preferably, the specific process steps of the three times of intermittent open-die upsetting are as follows:

[0012] Step one: first, the ingot after surface treatment is heated to below the β phase transition temperature by 28-50℃ by using an α+β forging process;

[0013] Step two: the heated ingot is subjected to six-face upsetting by using a press, and the upsetting change rate after upsetting of any one side is controlled to be 60-72%; the main purpose of six-face upsetting is to ensure that each side can obtain similar upsetting force, so that the material voids are removed and the overall structure is formed, which is beneficial to guarantee the material strength in the later period;

[0014] Step three: the ingot is heated to the β phase transition temperature again, and the heated ingot is subjected to six-face upsetting by using a press, and the upsetting change rate after upsetting of any one side is controlled to be 35-48%;

[0015] Step four: heating to above the β phase transition temperature by 20-50℃ and keeping warm, the heated ingot is subjected to six-face upsetting by using a press, and the upsetting change rate after upsetting of any one side is controlled to be 20-30%;

[0016] It needs to be explained that titanium and titanium alloy have the characteristic of allotropy transformation, that is, the crystal structure of material atoms of titanium and titanium alloy will change with the change of temperature; generally, titanium and titanium alloy are mainly in the form of α phase of close-packed hexagonal crystal at normal temperature, and in the form of β phase of body-centered cubic crystal at high temperature, when the heating temperature reaches the β phase transition temperature, the α phase of close-packed hexagonal crystal in titanium and titanium alloy is completely transformed into the β phase of body-centered cubic crystal, and the β phase is a body-centered cubic crystal, which has good plasticity and is beneficial to the later forging processing. The purpose of this step is mainly to promote the β phase of body-centered cubic crystal to improve the plasticity of the later forging, and the three times of upsetting makes the material dense, which does not conflict with the later isothermal multi-fire forging.

[0017] Preferably, the rate of the upsetting change rate in the open-die upsetting process is not less than 2mm / s.

[0018] Preferably, the specific process steps of the isothermal multi-fire forging are as follows: controlling the billet processing deformation temperature to be at least 50°C above the β phase transformation point temperature, forging by pressing with a press, and the isothermal multi-fire forging is not less than three times.

[0019] It should be noted that when forging is carried out at a temperature at least 50°C or higher above the β phase transformation temperature, the deformation is entirely or mainly concentrated in the β phase region. This allows for grain refinement based on the dynamic recrystallization of the β phase. After cooling, the material can transform back into the α phase. This step enables the uniformity of the transformed phase, meaning that a large amount of α phase will be dispersed and precipitated within the β grain boundaries and grains, playing a role in dispersion strengthening. This improves the strength and precision of the billet, resulting in a billet for valve balls.

[0020] Preferably, the isothermal multi-fire forging process applies a press pressing rate of 0.18-0.25 mm / s.

[0021] Preferably, the cooling process can be carried out by air cooling or wind cooling to reduce the temperature below the β phase transformation point, and the final forging process is carried out by water cooling for forming.

[0022] Compared with the prior art, the beneficial effects of the present invention are:

[0023] This high-precision surface forging process for valve ball blanks can remove impurities and internal pores through vacuum consumable melting, and eliminate blank defects through upsetting and drawing. Multiple upsetting and drawing deformations based on the β phase transformation point temperature are beneficial for blank recrystallization, which is conducive to obtaining higher strength. Furthermore, multiple upsetting and drawing can make the overall material dense to prevent internal cracking of the blank. This forging process is conducive to obtaining valve ball blanks with better physical properties and precision. Detailed Implementation

[0024] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] The present invention will describe the above technical solution in detail through the following embodiments:

[0026] Example 1

[0027] A high-precision surface forging process for valve ball blanks involves forging valve ball metal blanks into ingots through three vacuum consumable arc melting processes. The ingots undergo surface treatment to remove the surface oxide layer or porosity layer. Subsequently, the blanks are heated for upsetting and drawing, followed by isothermal multi-fire forging, and each forging is cooled after the first fire.

[0028] The valve ball metal blank is made of titanium alloy TC4. The valve ball metal blank is melted three times in a vacuum consumable electric furnace to obtain an ingot, and the ingot is controlled to be formed into a cubic structure.

[0029] The specific process steps of the ingot surface treatment process are as follows: First, the ingot is air-cooled and the surface is observed to see if an oxide layer, a pore layer or other damaged layer is formed. Then, the ingot is cut to remove the damaged layer.

[0030] The specific process steps for billet upsetting and drawing are as follows: Billet upsetting and drawing adopts a free forging hammer forging process, involving three intermittent billet upsetting and drawing operations, with the upsetting variation rate of each upsetting and drawing operation controlled to be no less than 20%. The specific process steps for the three intermittent billet upsetting and drawing operations are as follows:

[0031] Step 1: First, the surface-treated ingot is heated to 30°C below the β phase transformation temperature using the α+β forging process.

[0032] Step 2: Use a press to perform six-sided upsetting on the heated ingot, and control the upsetting change rate after upsetting on any side to be 60%;

[0033] Step 3: Continue heating the ingot to the β phase transformation point temperature, and use a press to upset the heated ingot on all six sides again, controlling the upsetting change rate of any side after upsetting to be 35%.

[0034] Step 4: Heat to 50°C above the β phase transformation point and hold at that temperature. Use a press to upset the heated ingot on all six sides, ensuring that the upsetting change rate after upsetting on any one side is 20%.

[0035] The rate of change in upsetting during the blanking and upsetting process is controlled to be 2 mm / s.

[0036] The specific process steps of isothermal multi-fire forging are as follows: control the billet processing deformation temperature to be 50°C above the β phase transformation point, forge by pressing with a press, and perform isothermal multi-fire forging three times, with a press pressing rate of 0.18 mm / s applied during the isothermal multi-fire forging.

[0037] The cooling process can be carried out by air cooling or wind cooling to bring the temperature down to below the β phase transformation point, and the final forging process is carried out by water cooling.

[0038] Example 2

[0039] A high-precision surface forging process for valve ball blanks involves forging valve ball metal blanks into ingots through three vacuum consumable arc melting processes. The ingots undergo surface treatment to remove the surface oxide layer or porosity layer. Subsequently, the blanks are heated for upsetting and drawing, followed by isothermal multi-fire forging, and each forging is cooled after the first fire.

[0040] The valve ball metal blank is made of titanium alloy TC4. The valve ball metal blank is melted three times in a vacuum consumable electric furnace to obtain an ingot, and the ingot is controlled to be formed into a cubic structure.

[0041] The specific process steps of the ingot surface treatment process are as follows: First, the ingot is air-cooled and the surface is observed to see if an oxide layer, a pore layer or other damaged layer is formed. Then, the ingot is cut to remove the damaged layer.

[0042] The specific process steps for billet upsetting and drawing are as follows: Billet upsetting and drawing adopts a free forging hammer forging process, involving three intermittent billet upsetting and drawing operations, with the upsetting variation rate of each upsetting and drawing operation controlled to be no less than 20%. The specific process steps for the three intermittent billet upsetting and drawing operations are as follows:

[0043] Step 1: First, the surface-treated ingot is heated to 30°C below the β phase transformation temperature using the α+β forging process.

[0044] Step 2: Use a press to perform six-sided upsetting on the heated ingot, and control the upsetting change rate after upsetting on any side to be 60%;

[0045] Step 3: Continue heating the ingot to the β phase transformation point temperature, and use a press to upset the heated ingot on all six sides again, controlling the upsetting change rate of any side after upsetting to be 35%.

[0046] Step 4: Heat to 50°C above the β phase transformation point and hold at that temperature. Use a press to upset the heated ingot on all six sides, ensuring that the upsetting change rate after upsetting on any one side is 20%.

[0047] The rate of change in upsetting during the billet upsetting and drawing process is controlled at 10 mm / s.

[0048] The specific process steps of isothermal multi-fire forging are as follows: control the billet processing deformation temperature to be 50°C above the β phase transformation point, forge by pressing with a press, and perform isothermal multi-fire forging three times, with a press pressing rate of 0.18 mm / s applied during the isothermal multi-fire forging.

[0049] The cooling process can be carried out by air cooling or wind cooling to bring the temperature down to below the β phase transformation point, and the final forging process is carried out by water cooling.

[0050] Example 3

[0051] A high-precision surface forging process for valve ball blanks involves forging valve ball metal blanks into ingots through three vacuum consumable arc melting processes. The ingots undergo surface treatment to remove the surface oxide layer or porosity layer. Subsequently, the blanks are heated for upsetting and drawing, followed by isothermal multi-fire forging, and each forging is cooled after the first fire.

[0052] The valve ball metal blank is made of titanium alloy TC4. The valve ball metal blank is melted three times in a vacuum consumable electric furnace to obtain an ingot, and the ingot is controlled to be formed into a cubic structure.

[0053] The specific process steps of the ingot surface treatment process are as follows: First, the ingot is air-cooled and the surface is observed to see if an oxide layer, a pore layer or other damaged layer is formed. Then, the ingot is cut to remove the damaged layer.

[0054] The specific process steps for billet upsetting and drawing are as follows: Billet upsetting and drawing adopts a free forging hammer forging process, involving three intermittent billet upsetting and drawing operations, with the upsetting variation rate of each upsetting and drawing operation controlled to be no less than 20%. The specific process steps for the three intermittent billet upsetting and drawing operations are as follows:

[0055] Step 1: First, the surface-treated ingot is heated to 30°C below the β phase transformation temperature using the α+β forging process.

[0056] Step 2: Use a press to perform six-sided upsetting on the heated ingot, and control the upsetting change rate after upsetting on any side to be 60%;

[0057] Step 3: Continue heating the ingot to the β phase transformation point temperature, and use a press to upset the heated ingot on all six sides again, controlling the upsetting change rate of any side after upsetting to be 35%.

[0058] Step 4: Heat to 50°C above the β phase transformation point and hold at that temperature. Use a press to upset the heated ingot on all six sides, ensuring that the upsetting change rate after upsetting on any one side is 20%.

[0059] The rate of change in upsetting during the billet upsetting and drawing process is controlled at 50 mm / s.

[0060] The specific process steps of isothermal multi-fire forging are as follows: control the billet processing deformation temperature to be 50°C above the β phase transformation point, forge by pressing with a press, and perform isothermal multi-fire forging three times, with a press pressing rate of 0.18 mm / s applied during the isothermal multi-fire forging.

[0061] The cooling process can be carried out by air cooling or wind cooling to bring the temperature down to below the β phase transformation point, and the final forging process is carried out by water cooling.

[0062] Example 4

[0063] A high-precision surface forging process for valve ball blanks involves forging valve ball metal blanks into ingots through three vacuum consumable arc melting processes. The ingots undergo surface treatment to remove the surface oxide layer or porosity layer. Subsequently, the blanks are heated for upsetting and drawing, followed by isothermal multi-fire forging, and each forging is cooled after the first fire.

[0064] The valve ball metal blank is made of titanium alloy TC4. The valve ball metal blank is melted three times in a vacuum consumable electric furnace to obtain an ingot, and the ingot is controlled to be formed into a cubic structure.

[0065] The specific process steps of the ingot surface treatment process are as follows: First, the ingot is air-cooled and the surface is observed to see if an oxide layer, a pore layer or other damaged layer is formed. Then, the ingot is cut to remove the damaged layer.

[0066] The specific process steps for billet upsetting and drawing are as follows: Billet upsetting and drawing adopts a free forging hammer forging process, involving three intermittent billet upsetting and drawing operations, with the upsetting variation rate of each upsetting and drawing operation controlled to be no less than 20%. The specific process steps for the three intermittent billet upsetting and drawing operations are as follows:

[0067] Step 1: First, the surface-treated ingot is heated to 30°C below the β phase transformation temperature using the α+β forging process.

[0068] Step 2: Use a press to perform six-sided upsetting on the heated ingot, and control the upsetting change rate after upsetting on any side to be 60%;

[0069] Step 3: Continue heating the ingot to the β phase transformation point temperature, and use a press to upset the heated ingot on all six sides again, controlling the upsetting change rate of any side after upsetting to be 35%.

[0070] Step 4: Heat to 50°C above the β phase transformation point and hold at that temperature. Use a press to upset the heated ingot on all six sides, ensuring that the upsetting change rate after upsetting on any one side is 20%.

[0071] The rate of change in upsetting during the blanking and upsetting process is controlled to be 2 mm / s.

[0072] The specific process steps of isothermal multi-fire forging are as follows: control the billet processing deformation temperature to be 50°C above the β phase transformation point, forge by pressing with a press, and perform isothermal multi-fire forging three times, with a press pressing rate of 0.25 mm / s applied during the isothermal multi-fire forging.

[0073] The cooling process can be carried out by air cooling or wind cooling to bring the temperature down to below the β phase transformation point, and the final forging process is carried out by water cooling.

[0074] Comparative Example 1

[0075] The only difference between Comparative Example 1 and Example 1 is that the upsetting change rate of this comparative example is 0.2 mm / s, while all other conditions are the same.

[0076] Comparative Example 2

[0077] The only difference between Comparative Example 2 and Example 1 is that the upsetting change rate of this comparative example is 1.5 mm / s, while all other conditions are the same.

[0078] Comparative Example 3

[0079] The only difference between Comparative Example 3 and Example 1 is that the isothermal multi-fire forging in this comparative example was carried out at a press rate of 10 mm / s, while all other conditions were the same.

[0080] Valve ball blanks were prepared as 10mm thick plate samples according to the forging processes of Examples 1-4 and Comparative Examples 1-3. The effect of upsetting change rate on the damage value of the blanks was compared, and the tensile strength Rm and yield strength Rp of each blank sample were compared. 0。2 The specific data is as follows:

[0081]

[0082]

[0083] The high-precision surface forging process for valve ball blanks in this embodiment, as shown in the table above, directly affects the maximum damage rate of the blank forging. When the upsetting change rate is greater than 2 mm / s, the maximum damage rate decreases with increasing upsetting change rate. When the upsetting change rate is less than 2 mm / s, the maximum damage rate initially increases dramatically and then gradually decreases to the level of 2 mm / s. Considering production efficiency, processing techniques below 2 mm / s should be avoided. Furthermore, the maximum damage rate affects the tensile strength and yield strength of the blank; the greater the damage, the lower the strength gradually decreases. In the multi-fire forging process, the press pressing rate within the process range does not affect the damage rate, while increasing the pressing rate will exacerbate the maximum damage value and is beneficial for strengthening tensile strength, but it will cause a decrease in yield strength. Based on the data in the table above, Embodiment 3 can be selected as the optimal forging process.

[0084] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A surface high precision forging process for valve ball blank forging, characterized by: The forging process is to make the valve ball metal blank into an ingot through multiple vacuum consumable arc melting, remove the surface oxide layer or pore layer through a surface treatment process, then heat the blank for breakdown upsetting, and then perform isothermal multi-pass forging, and cooling treatment after each pass of forging; The valve ball metal blank is obtained after three times of melting in a vacuum consumable electric furnace, and the ingot is controlled to be shaped into a cubic structure; The specific process steps of the breakdown upsetting are: the breakdown upsetting adopts a free forging hammer forging process, and is divided into three times of intermittent breakdown upsetting, and the upsetting change rate of each time of breakdown upsetting is controlled to be not less than 20%; The specific process steps of the three times of intermittent breakdown upsetting are: Step one: first heat the surface treated ingot to below 28-50℃ of the β phase transition temperature through an α+β forging process; Step two: use a press to perform six-sided upsetting on the heated ingot, and the upsetting change rate of any one side is controlled to be 60-72%; Step three: continue to heat the ingot to the β phase transition temperature, and then use a press to perform six-sided upsetting on the heated ingot, and the upsetting change rate of any one side is controlled to be 35-48%; Step four: heat to above 20-50℃ of the β phase transition temperature, and then use a press to perform six-sided upsetting on the heated ingot, and the upsetting change rate of any one side is controlled to be 20-30%; The rate of the upsetting change rate in the breakdown upsetting process is controlled to be not less than 2mm / s; The specific process steps of the isothermal multi-pass forging are: the deformation temperature of the blank is controlled to be above at least 50℃ of the β phase transition temperature, and the blank is forged through a press, and the isothermal multi-pass forging is not less than three times; The isothermal multi-pass forging applies a press down rate of 0.18-0.25mm / s; The cooling treatment can be air cooling or air cooling to below the β phase transition temperature, and the last pass of forging process is water cooling.

2. The surface high precision forging process for valve ball blank forging as claimed in claim 1 wherein: The valve ball metal blank is made of titanium or titanium alloy.

3. The surface high precision forging process for valve ball blank forging as claimed in claim 1 wherein: The specific process steps of the surface treatment process are: first observe whether an oxide layer or pore layer is formed on the surface of the ingot after air cooling, air cooling or water cooling, and then cut the ingot to remove the damaged layer.

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