Manufacturing device and manufacturing method for high-corrosion-resistance nickel-based alloy elbow

Abstract

The invention relates to the field of metal pipe fitting machining, in particular to a high-corrosion-resistance nickel base alloy elbow manufacturing device and method.The high-corrosion-resistance nickel base alloy elbow manufacturing method is characterized in that a steel pipe blank is pushed into a mold after being guided and heated, and the mold is used for conducting elbow treatment on the steel pipe blank after diameter shrinkage; an inner core mold rod corresponding to the elbow of a steel pipe blank in shape is inserted into the steel pipe blank in a swinging mode in the elbow radian direction of the mold from an elbow section outlet of the mold, balls are evenly arranged on the inner core mold rod in the circumferential direction, the balls can move in the radial direction of the inner core mold rod and then are fixed, and the balls of the inner core mold rod are located in the mold. And the inner core mold rod forms multi-point type inner support on the inner wall of the steel pipe blank through the balls. According to the method, the crack occurrence rate of the machined Hastelloy C-276 alloy elbow is greatly reduced, continuous production can be achieved, and the production efficiency is high.

Description

Technical Field

[0001] The invention relates to the field of metal pipe processing, and in particular to a high corrosion-resistant nickel-based alloy elbow manufacturing device and a manufacturing method. Background Art

[0002] Hastelloy C-276 is a Ni-Cr-Mo corrosion-resistant alloy, and its chemical composition is typically Ni57% (mass fraction, the same below), Cr15.5%, Mo16%, Fe6%, W3.9%, C≤0.01%, Si≤0.08%, and is a type of nickel-based alloy. Compared with general stainless steel and other corrosion-resistant materials, it has the ability to resist various forms of corrosion damage (including uniform corrosion, local corrosion, and stress corrosion, etc.) in various corrosive environments (including electrochemical corrosion and chemical corrosion), especially in F - ,Cl - It has corrosion resistance that is difficult to match with other corrosion-resistant alloys in the oxidizing acid of plasma, in the reducing acid in the presence of oxygen or oxidants, in the mixed acid of oxidizing acid and reducing acid, and in wet chlorine and chlorine-containing aqueous solutions. It is an important pipeline accessory.

[0003] In order to deal with some harsh working conditions, Hastelloy C-276 elbows need to be processed and used as pipe bends. The current pipe bending method for ordinary alloys is described in the publication number "CN118682417A", which is to first cut the pipe to a specified size to form a pipe blank; then coat the pipe blank: coat the lubricating medium on the inner and outer walls of the pipe blank to form a coated tube; cold push and bend the pipe blank to obtain a cold-formed elbow; then put the cold-formed elbow into a heat treatment furnace for annealing; and after the heat treatment is completed, take out the elbow blank after cooling in the furnace; finally, machine the elbow blank to the required size; this processing method is effective for the manufacture of elbows of conventional alloys, but when it is applied to the processing of Hastelloy C-276 alloy elbows, the probability of cracks is high, which cannot meet the use requirements, and continuous production cannot be achieved, and the production efficiency is low, so it is urgent to solve. Summary of the invention

[0004] In order to avoid and overcome the technical problems existing in the prior art, the present invention provides a highly corrosion-resistant nickel-based alloy elbow manufacturing device and manufacturing method. The present invention greatly reduces the crack occurrence rate of Hastelloy C-276 alloy elbows after processing, and can be produced continuously with high production efficiency.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A highly corrosion-resistant nickel-based alloy elbow manufacturing device, wherein a steel pipe blank is guided and heated and then pushed into a mold, and the mold is used to perform elbow processing on the steel pipe blank after the steel pipe blank is reduced in diameter; an inner core mold rod corresponding to the shape of the steel pipe blank elbow is inserted into the steel pipe blank in a swinging manner along the elbow arc direction of the mold from the elbow section outlet of the mold, and balls are evenly arranged on the circumference of the inner core mold rod, and the balls can be moved radially along the inner core mold rod and then fixed, the balls of the inner core mold rod are located in the mold, and the inner core mold rod forms a multi-point internal support for the inner wall of the steel pipe blank through the balls.

[0007] As a further solution of the present invention: the mold is hinged with a rotating rod at the center point of the elbow section, and the rotating rod corresponds to the radius length of the mold elbow section; the inner core mold rod is fixed to the rod end of the rotating rod and arranged circumferentially along the elbow section of the mold.

[0008] As a further solution of the present invention: after the rotating rod is rotated to a set angle, it is stopped and positioned by a fixed pin; after the steel pipe blank leaves the mold, it abuts against a limit block to limit the cutting length of the steel pipe blank.

[0009] As a further solution of the present invention: the rod end of the inner core mold rod located in the mold is an adjusting screw, and two groups of symmetrically arranged connecting rods are hingedly provided on the ball seat of the ball, one group of connecting rods is hingedly matched with the rod body of the inner core mold rod, and the other group of connecting rods is matched with the adjusting screw to form a lead screw, so that the distance between the ball and the inner core mold rod can be adjusted while moving along the adjusting screw, and the ball on the inner core mold rod is arranged near the mold outlet.

[0010] As a further solution of the present invention: along the pushing direction of the steel tube blank, a roller guide frame for supporting the steel tube blank and a heating coil for heating the steel tube blank are sequentially arranged at the entrance of the mold; the roller guide frame and the heating coil are coaxially arranged with the reduction channel of the mold; a temperature measuring gun for measuring the temperature of the steel tube blank is arranged at the entrance of the mold, and a laser cutting machine for cutting the steel tube blank is arranged at the exit of the mold; the steel tube blank is pushed into the mold by the thrust plate, and a baffle arranged parallel to the thrust plate is also arranged on the mold to limit the displacement of the mold.

[0011] As a further solution of the present invention: the mold is of split design, including a reduction mold for reducing the diameter of the steel pipe blank and an elbow mold for elbowing the steel pipe blank, and the elbow mold and the reduction mold are fixed by mortise and tenon joints.

[0012] A method for manufacturing a high corrosion-resistant nickel-based alloy elbow comprises the following steps:

[0013] S1. Use Hastelloy C-276 alloy as the steel pipe blank and test the steel pipe blank to ensure that its performance meets the use requirements;

[0014] S2. Performing homogenization heat treatment on the steel pipe blank;

[0015] S3, using a high corrosion-resistant nickel-based alloy elbow manufacturing device as described in any one of claims 1 to 4 to process the elbow of the steel pipe blank;

[0016] S31, installing the steel pipe blank on the roller guide frame so that it is coaxially arranged with the heating coil and the reducing die;

[0017] S32, start the heating coil to heat the steel pipe blank to a set temperature, start the thrust plate to push the steel pipe blank linearly, and make the steel pipe blank pass through the reducing die and the elbow die in sequence;

[0018] S33, adjusting the distance between the ball on the inner core mold rod and the inner wall of the steel pipe blank so that the ball can form an inner support for the steel pipe blank;

[0019] S34, after the rotating rod drives the inner core mold rod to be inserted into the steel pipe blank, the rotating rod is locked;

[0020] S35, after the elbow of the steel pipe blank is formed and abuts against the limit stopper, the elbow steel pipe is cut by a laser cutting machine at the die outlet;

[0021] S36, unlocking the rotating rod and taking out the cut elbow steel pipe;

[0022] S37, repeat steps S34 to S36, and perform reciprocating cutting production.

[0023] As a further solution of the present invention: in step S1:

[0024] S11. Seamless steel pipe is used as the steel pipe blank, and the steel pipe blank is smelted by vacuum induction smelting, argon oxygen decarburization refining and electroslag remelting smelting technology;

[0025] S12. Analyze the composition of the steel pipe blank and calculate the PREN equivalent index of the steel pipe blank based on the content of chromium, molybdenum and tungsten elements. When the PREN equivalent index is less than or equal to 45.5, the steel pipe blank is scrapped;

[0026] PREN = A + 1.5 × (B + C);

[0027] Wherein, A represents the element content of chromium in the steel tube blank;

[0028] B represents the content of molybdenum in the steel pipe blank;

[0029] C represents the element content of tungsten in the steel pipe blank;

[0030] S13, sampling the steel pipe blanks, and testing the grain size according to ASTM E112 standard, and determining that the average grain size of the steel pipe blanks is 4 to 7. If the conditions are not met, the steel pipe blanks are scrapped;

[0031] S14. Sample the steel tube blanks and inspect for non-metallic inclusions according to ASTM E45. The level of non-metallic inclusions of types A, B, C, and D shall be determined according to the most serious one to determine whether the steel tube blanks meet the following conditions;

[0032]

[0033] If the conditions are not met, the steel pipe billet will be scrapped.

[0034] As a further solution of the present invention: in step S2, the steel pipe blank is subjected to a solution treatment process:

[0035] S21, heating the steel pipe billet in a furnace;

[0036] S211. When the temperature in the furnace is not higher than 500°C, the heating rate is not controlled;

[0037] S212, when the temperature in the furnace is in the temperature range of 500°C-1100°C, the heating rate is controlled to be 400°C / h-600°C / h;

[0038] S213, when the temperature in the furnace is in the temperature range of 1100°C-1130°C, the heating rate is controlled to be 200°C / h-300°C / h;

[0039] S22. Insulate the steel pipe billet at a temperature of 1130°C ± 10°C for 5 min / mm; if the total insulation time is less than 30 min, it shall be 30 min;

[0040] S23. Cool the steel pipe billet by water cooling, the cooling water temperature is 10℃~40℃, and the water immersion time shall not be more than 1min.

[0041] As a further solution of the present invention: before the steel tube blank is subjected to the solid solution treatment, the steel tube blank is subjected to the intergranular corrosion test to analyze the influence of the solid solution treatment process on the corrosion rate of the sample. corr for:

[0042]

[0043] Where K is a constant, which is 8.76×10 4 ;

[0044] Δm is the mass loss of the steel tube blank;

[0045] A is the sample surface area of ​​the steel tube blank;

[0046] t is the corrosion time of the steel pipe blank;

[0047] ρ is the density of the steel pipe blank.

[0048] Compared with the prior art, the present invention has the following beneficial effects:

[0049] 1. The present invention adopts a technical solution of pushing the blank outward into the mold after heating, and arranges a ball structure in the inner core mold of the inner core mold rod, so that the tube blank and the ball are in "point contact", which plays an internal support role, reduces the ovality of the elbow, reduces the friction and forming resistance, and prevents wrinkles from appearing inside the elbow. At the same time, the distance between the ball and the inner wall of the tube blank can be adjusted by the top screw of the rod, which is suitable for the forming of elbows with different wall thicknesses. The crack occurrence rate of the Hastelloy C-276 alloy elbow after processing is greatly reduced through process improvement, and continuous production can be achieved with high production efficiency.

[0050] 2. After the elbow is formed to a specified size and one end of the elbow contacts the limit block, the present invention starts the laser cutting machine to quickly cut the material, which greatly improves the material cutting rate, and improves the raw material utilization rate and production efficiency. After the elbow is cut, the fixing pin is taken out to rotate the rotating rod outward. Due to the restriction of the limit block, the inner core mold rod slides inside the elbow until it is separated from the elbow. After separation, the elbow falls and is collected, and the rotating rod rotates inward, driving the inner core mold rod to reinsert into the elbow. At the same time, the fixing pin is inserted to fix the rotating rod, completing the inner core mold rod loading, and producing the next elbow, which is convenient and quick. Depending on the placement of the fixing pin, it can be suitable for the forming of elbows with different bending angles, and can produce elbows with 30°, 45°, 90° or other bending angles.

[0051] 3. The present invention produces elbows with different bending radii by using a combined mold. The mold adopts a tongue-and-groove combination, is easy to disassemble, and is firmly installed. The mold can be reused, which reduces the mold investment cost; the tube blank can be reduced to the required size through the diameter reduction mold, which is suitable for tube blanks with different outer diameters. The tube blank is heated by a multi-turn medium-frequency induction coil to make the material reach the forgeable temperature, improve the plastic toughness of the material, and is suitable for thin-walled, medium-walled and thick-walled elbow molding, reducing the tonnage requirements for molding equipment. The present invention changes the stress state of the tube blank material. The inner and outer arcs of the elbow are subjected to compressive stress during the molding process, and the wall thickness of the inner and outer arcs is not thinned. There is no need to increase the wall thickness of the additional blank, which reduces the material cost. At the same time, since the inner and outer arcs are not subjected to tensile stress during the molding process, the probability of cracks is reduced, and the product qualification rate is greatly improved compared with the traditional process, which is suitable for the manufacture of nickel-based alloys, titanium, zirconium and other difficult-to-form metal pipes. After one loading, continuous production can be achieved, and the utilization rate of raw materials and production efficiency are greatly improved compared with traditional processes.

[0052] 4. The present invention adopts the electroslag remelting process to make the inclusions of the material small and evenly distributed, reduce segregation, improve the hot workability and plasticity of the alloy, provide the plastic toughness required for the subsequent forming of pipe fittings, and ensure the quality of pipe fittings. By controlling the content of C and Si elements, the appearance of grain boundary carbides is prevented, the intergranular corrosion sensitivity of the alloy is reduced, and the content of Cr, Mo, and W is controlled to make the PREN equivalent reach 45.5, which can improve the alloy's resistance to pitting corrosion and crevice corrosion. By controlling the average grain size level number to 4 to 7, molding cracks can be effectively prevented, and the subsequent welding of elbows and pipes is beneficial, reducing the possibility of welding cracks; non-metallic inclusion control is also beneficial to improving the plasticity and toughness of the material, which is convenient for subsequent processing.

[0053] 5. In the process of solution treatment, when the temperature is not higher than 500°C, Hastelloy C-276 will not be sensitized, so the heating rate can be uncontrolled; Hastelloy C-276 is sensitive to intergranular corrosion. After staying in the sensitization temperature range for a long time, it does not have sufficient thermal stability and carbides will precipitate at the grain boundaries. The material's intergranular corrosion resistance and toughness (impact absorption energy) will decrease. After experimental determination, Hastelloy The sensitization temperature range of C-276 is 500℃-1100℃, so in the temperature range of 500℃-1100℃, the heating zone heating rate is controlled at 400℃ / h-600℃ / h, which reduces the residence time at the sensitization temperature, reduces the precipitation of carbides at the grain boundary, and improves the intergranular corrosion resistance; due to the low thermal conductivity and slow heat transfer of nickel-based alloys, in the temperature range of 1100℃-1150℃, the heating zone heating rate is controlled at 200℃ / h-300℃ / h, the heating rate is small, the heat transfer is sufficient, and the temperature inside and outside the workpiece tends to The holding temperature is 1130℃±10℃, and the holding time is 5min / mm, which can fully dissolve M6C carbides and μ phases, reduce the segregation of dendrites and precipitates of the alloy, dissolve the second phase of the alloy structure, and improve the hot processing plasticity and billet opening rate. According to the test, when the temperature is higher than 1140℃ or the holding time is greater than 5min / mm, although the solid solution is more sufficient and the homogenization effect is better, it is easy to cause abnormal grain growth (the grain size can even reach level 1), and cracks are easy to occur during the subsequent forming process of the material. When the temperature is lower than 1130℃ or the holding time is less than 5min / mm, the homogenization effect is not good, and the product qualification rate is not significantly improved. Set the cooling method to water cooling, keep the water temperature at 10℃-40℃, and the water entry time shall not be greater than 1min; it can reduce the residence time of the alloy at the sensitization temperature, avoid the precipitation of carbides at the grain boundary, and affect the material's resistance to intergranular corrosion and toughness. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 It is a schematic diagram of the structure of the present invention.

[0055] In the figure:

[0056] 1. Steel pipe blank; 2. Die; 21. Reduction die; 22. Elbow die; 23. Baffle;

[0057] 3. Inner core mold rod; 31. Rotating rod; 32. Fixing pin;

[0058] 33. Limit stopper; 34. Adjusting screw; 35. Ball; 36. Connecting rod;

[0059] 4. Thrust plate; 5. Roller guide frame; 6. Heating coil; 7. Temperature measuring gun; 8. Laser cutting machine. DETAILED DESCRIPTION

[0060] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0061] See also Figure 1 In an embodiment of the present invention, a highly corrosion-resistant nickel-based alloy elbow manufacturing device and manufacturing method, the manufacturing steps are as follows:

[0062] S1. Select Hastelloy C-276 alloy as the steel pipe blank 1, and test the steel pipe blank 1 to ensure that its performance meets the use requirements;

[0063] S11. Seamless steel pipe is used as the steel pipe blank, and the steel pipe blank is smelted by vacuum induction smelting, argon oxygen decarburization refining and electroslag remelting smelting technology;

[0064] The electroslag remelting process is used to make the inclusions of the material small and evenly distributed, reduce segregation, improve the hot workability and plasticity of the alloy, provide the plasticity and toughness required for the subsequent forming of pipe fittings, and ensure the quality of pipe fittings.

[0065] S12, performing component analysis on the steel pipe blank 1, calculating the PREN equivalent index of the steel pipe blank based on the content of chromium, molybdenum and tungsten elements, and when the PREN equivalent index is less than or equal to 45.5, the steel pipe blank is scrapped;

[0066] PREN = A + 1.5 × (B + C);

[0067] Wherein, A represents the element content of chromium in the steel tube blank;

[0068] B represents the content of molybdenum in the steel pipe blank;

[0069] C represents the element content of tungsten in the steel pipe blank;

[0070] After the raw material billet is smelted, the chemical composition of the steel pipe billet 1 is analyzed by batch. The chemical composition of Hastelloy C-276 alloy is shown in the following table. In particular, the content of C, Si, P and S elements should not exceed the limit value.

[0071]

[0072] Control the content of Cr, Mo, and W to improve the material's resistance to pitting and crevice corrosion. Control the content of C and Si elements to prevent the appearance of grain boundary carbides and reduce the alloy's intergranular corrosion sensitivity. Control the content of Cr, Mo, and W to make the PREN equivalent reach 45.5, which can improve the alloy's resistance to pitting and crevice corrosion.

[0073] S13, sampling the steel pipe blanks, taking a sample for each furnace, each specification, and each heat treatment furnace of the raw materials, and testing the grain size according to ASTM E112 standard, and determining that the average grain size level of the steel pipe blank is 4 to 7. If the conditions are not met, the steel pipe blank is scrapped;

[0074] Coarse grains can easily lead to subsequent hot forming cracks in pipe fittings. The average grain size level should be 4 to 7 to effectively prevent forming cracks, and it is beneficial to the subsequent welding of elbows and pipes, reducing the possibility of welding cracks.

[0075] S14. Take one sample from each batch of steel tube billets and conduct non-metallic inclusion inspection according to ASTM E45. The level of non-metallic inclusions of types A, B, C, and D shall be determined according to the most serious one to determine whether the steel tube billets meet the following conditions;

[0076]

[0077] If the conditions are not met, the steel pipe billet will be scrapped; non-metallic inclusion control is also beneficial to improving the plasticity and toughness of the material, facilitating subsequent processing.

[0078] S2, performing a solution treatment on the steel tube blank 1;

[0079] S211. When the temperature in the furnace is not higher than 500°C, the heating rate is not controlled; when the temperature is not higher than 500°C, Hastelloy C-276 will not be sensitized, so the heating rate can be uncontrolled.

[0080] S212. When the temperature in the furnace is in the range of 500℃-1100℃, the heating rate is controlled to be 400℃ / h-600℃ / h. Hastelloy C-276 is sensitive to intergranular corrosion. After staying in the sensitizing temperature range for a long time, it does not have sufficient thermal stability and carbides will precipitate at the grain boundaries. The material's intergranular corrosion resistance and toughness (impact absorption energy) will decrease. After testing, the sensitization temperature range of Hastelloy C-276 is 500℃-1100℃. Therefore, in the temperature range of 500℃-1100℃, the heating zone heating rate is controlled at 400℃ / h-600℃ / h to reduce the residence time at the sensitizing temperature, reduce the precipitation of carbides at the grain boundaries, and improve the intergranular corrosion resistance.

[0081] S213. When the temperature in the furnace is in the range of 1100℃-1130℃, the heating rate is controlled at 200℃ / h-300℃ / h. Nickel-based alloys have low thermal conductivity and slow heat transfer. In the temperature range of 1100℃-1130℃, the heating rate in the heating zone is controlled at 200℃ / h-300℃ / h. The heating rate is small and the heat transfer is sufficient, so that the temperature inside and outside the workpiece tends to be consistent.

[0082] S22. The steel pipe billet is kept warm at 1130℃±10℃ for 5min / mm; if the total holding time is less than 30min, it shall be kept warm for 30min; the M6C carbide and μ phase can be fully dissolved through the holding operation, the dendrite and precipitation phase segregation of the alloy can be reduced, the second phase of the alloy structure can be dissolved, and the hot working plasticity and billet opening rate can be improved. According to the test, when the temperature is higher than 1140℃ or the holding time is greater than 5min / mm, although the solid solution is more sufficient and the homogenization effect is better, it is easy to cause abnormal grain growth (the grain size can even reach level 1), and cracks are easy to occur in the subsequent forming process of the material. When the temperature is lower than 1120℃ or the holding time is less than 5min / mm, the homogenization effect is not good, and the product qualification rate is not significantly improved.

[0083] S23. Cool the steel pipe billet by water cooling, the cooling water temperature is 10℃~40℃, and the water immersion time shall not exceed 1min. Water cooling operation can reduce the residence time of the alloy at the sensitization temperature, avoid the precipitation of carbides at the grain boundary, and affect the material's resistance to intergranular corrosion and toughness.

[0084] Before the steel tube blank 1 is subjected to the solution treatment, the intergranular corrosion test is performed on the steel tube blank 1 to analyze the effect of the solution treatment process on the corrosion rate of the sample. The intergranular corrosion rate of the steel tube blank 1 is γ corr for:

[0085]

[0086] Where K is a constant, which is 8.76×10 4 ;

[0087] Δm is the mass loss of the steel tube blank 1;

[0088] A is the sample surface area of ​​the steel tube blank 1;

[0089] t is the corrosion time of the steel tube blank 1;

[0090] ρ is the density of the steel pipe blank 1.

[0091] The intergranular corrosion test was divided into 5 cycles, each cycle was 48 hours, and the corrosion rate was calculated by weighing method to determine the intergranular corrosion sensitivity related to chromium carbide precipitation.

[0092] The intergranular corrosion rate of C276 alloy after different solution treatments is shown in Table 1. It can be seen that with the increase of solution temperature and the extension of holding time, the intergranular corrosion rate shows a trend of first decreasing and then stabilizing. The solution temperature is 1130°C, the holding time is 2.4min / mm, and the precipitated phase in the matrix has been basically completely dissolved. With the increase of solution temperature, there is no obvious change in the precipitates in the matrix, and there is no obvious difference in the intergranular corrosion rate. As shown in the S2 test data, when the temperature is higher than 1130°C or the holding time is too long, although the solution is more sufficient and the homogenization effect is better, it is easy to cause abnormal grain growth. The solution treatment holding temperature of the pipe fittings in this application is 1130°C ± 10°C, and the holding time is calculated according to the wall thickness of the billet. The preferred holding time is 2.4min / mm.

[0093] Table 1: Intergranular corrosion rate of C276 alloy after different solution treatments (mm / year)

[0094]

[0095] S3. A high corrosion resistant nickel-based alloy elbow manufacturing device is used to process the elbow of the steel pipe blank 1; a high corrosion resistant nickel-based alloy elbow manufacturing device includes a mold 2, which can be an integrated mold or a split mold. The mold 2 in this embodiment is a split mold and can be formed by 3D printing. The mold 2 includes a set of reducing molds 21 and multiple sets of elbow molds 22, and the reducing molds 21 and each elbow mold 22 are fixed by mortise and tenon joints. Through the reducing mold 11, the tube blank can be reduced to the required size and adapted to tube blanks with different outer diameters. For example, for an elbow with an outer diameter of 355.6 mm, 355.6 mm (I series tube) and 377 mm (II series tube) steel pipes can be selected as blanks; for an elbow with an outer diameter of 406.4 mm, 406.4 mm (I series tube) and 426 mm (II series tube) steel pipes can be selected as blanks. The source of raw materials is more extensive, which reduces the difficulty of purchasing raw materials. The combined elbow die 22 can be adapted to the processing of elbows with different bending radii.

[0096] The opening of the diameter reduction die 21 serves as the entrance of the die 2. Along the pushing direction of the steel tube blank 1, the entrance of the diameter reduction die 21 is provided with a roller guide frame 5 for supporting the steel tube blank 1 and a heating coil 6 for heating the steel tube blank 1 in sequence; the roller guide frame 5 and the heating coil 6 are coaxially arranged with the opening channel of the diameter reduction die 21; a temperature measuring gun 7 for measuring the temperature of the steel tube blank 1 is arranged at the opening of the diameter reduction die 21. A laser cutting machine 8 is arranged at the exit of the elbow die 22 for laser cutting the steel tube blank 1 leaving the die 2. The baffle 23 is arranged on the path after the steel tube blank 1 leaves the die 2, and is used to limit the further movement of the steel tube blank 1. The fixed length cutting of the steel tube blank 1 is achieved by adjusting the position of the baffle 23.

[0097] The thrust plate 4 is arranged in parallel with the opening of the diameter reduction die 21, and the steel pipe blank 1 is pushed by the thrust plate 4 to enter the die 2. The end of the die 2 away from the thrust plate 4 is provided with a baffle 23 arranged in parallel with the thrust plate 4, and is blocked by the baffle 23 to prevent the die 2 from being displaced under the action of the thrust plate 4.

[0098] The mold 2 is provided with a rotating rod 31 which is hinged with the mold 2. The length of the rotating rod 31 corresponds to the radius length of the elbow mold 22, and the hinge point is located at the center point of the elbow mold 22. The end of the rotating rod 31 is provided with an arc-shaped inner core mold rod 3. The inner core mold rod 3 is inserted into the elbow mold 22 from the axis of the outlet of the elbow mold 22 to provide internal support for the steel pipe blank 1.

[0099] One end of the inner core mold rod 3 located in the elbow mold 22 is designed as an adjusting screw 34. Two groups of connecting rods 36 are symmetrically arranged on the rod body of the inner core mold rod 3. The two groups of connecting rods 36 are respectively hinged with the rod body of the inner core mold rod 3 and the nut seat of the adjusting screw 34. The adjusting screw 34 can be replaced with other linear displacement adjustment parts to ensure that a V-shaped opening and closing action is generated between the two groups of connecting rods 36. The butt joint sections of the two groups of connecting rods 36 are hinged to the ball seat. Through the V-shaped opening and closing between the two groups of connecting rods 36, the distance between the ball 35 in the ball seat and the inner core mold rod 3 is adjusted. By arranging multiple groups of balls 35 along the circumferential direction on the inner core mold rod 3, a multi-point internal support can be formed for the inner wall of the steel pipe blank 1. After the rotating rod 31 drives the inner core mold rod 3 to be inserted into the steel pipe blank 1, the rotating rod 31 is limited by the fixing pin 32, so as to accurately locate the insertion depth of the inner core mold rod 3 so that there is still a certain distance between it and the laser cutting machine 8, and there will be no impact on each other.

[0100] The specific steps of pipe bending manufacturing are as follows:

[0101] S31, installing the steel pipe blank 1 on the roller guide frame 5 so that it is coaxially arranged with the heating coil 6 and the diameter reduction die 21;

[0102] S32, start the heating coil 6, heat the steel pipe blank 1 to the set temperature, start the thrust plate 4 to push the steel pipe blank 1 linearly, so that the steel pipe blank 1 passes through the reducing die 21 and the elbow die 22 in sequence; usually use a temperature measuring gun 7 to monitor the temperature of the tube blank, and start the thrust plate 4 when the temperature of the tube blank reaches 1150°C.

[0103] S33, adjusting the distance between the ball 35 on the inner core mold rod 33 and the inner wall of the steel tube blank 1, so that the ball 35 can form an inner support for the steel tube blank 1;

[0104] S34, after the rotating rod 31 drives the inner core mold rod 3 to be inserted into the steel pipe blank 1, the rotating rod 31 is locked;

[0105] S35, after the elbow of the steel pipe blank 1 is formed and abuts against the limit stopper 33, the elbow steel pipe is cut by the laser cutting machine 8 at the outlet of the mold 2;

[0106] S36, unlocking the rotating rod 31, so that it withdraws from the steel pipe blank 1, and taking out the cut elbow steel pipe;

[0107] S37, repeat steps S34 to S36, and perform reciprocating cutting production.

[0108] The basic principles of the present application are described above in conjunction with specific embodiments. However, it should be noted that the advantages, strengths, effects, etc. mentioned in the present application are only examples and not limitations, and it cannot be considered that these advantages, strengths, effects, etc. are required by each embodiment of the present application. In addition, the specific details disclosed above are only for the purpose of illustration and ease of understanding, not for limitation, and the above details do not limit the present application to being implemented by adopting the above specific details.

[0109] The block diagrams of the devices, apparatuses, equipment, and systems involved in this application are only illustrative examples and are not intended to require or imply that they must be connected, arranged, and configured in the manner shown in the block diagram. As will be appreciated by those skilled in the art, these devices, apparatuses, equipment, and systems can be connected, arranged, and configured in any manner. Words such as "including", "comprising", "having", etc. are open words, referring to "including but not limited to", and can be used interchangeably with them. The words "or" and "and" used here refer to the words "and / or" and can be used interchangeably with them, unless the context clearly indicates otherwise. The words "such as" used here refer to the phrase "such as but not limited to", and can be used interchangeably with them.

Claims

1. A highly corrosion-resistant nickel-based alloy elbow manufacturing device, characterized in that: After being guided and heated, the steel pipe blank (1) is pushed into a mold (2), and the mold (2) is used to perform elbow processing on the steel pipe blank (1) after the diameter is reduced; an inner core mold rod (3) corresponding to the elbow shape of the steel pipe blank (1) is inserted into the steel pipe blank (1) in a swinging manner along the arc direction of the elbow of the mold (2) from the elbow section outlet of the mold (2), and balls (35) are evenly arranged along the circumference of the inner core mold rod (3), and the balls (35) can be moved radially along the inner core mold rod (3) and then fixed, and the balls (35) of the inner core mold rod (3) are located in the mold (2), and the inner core mold rod (3) forms a multi-point internal support for the inner wall of the steel pipe blank (1) through each ball (35).

2. A highly corrosion-resistant nickel-based alloy elbow manufacturing device according to claim 1, characterized in that: The mold (2) is hingedly provided with a rotating rod (31) at the center point of the elbow section, and the rotating rod (31) corresponds to the radius length of the elbow section of the mold (2); the inner core mold rod (3) is fixed to the rod end of the rotating rod (31) and is arranged along the circumference of the elbow section of the mold (2).

3. A highly corrosion-resistant nickel-based alloy elbow manufacturing device according to claim 2, characterized in that: After the rotating rod (31) rotates to a set angle, it is stopped and positioned by a fixing pin (32); after the steel pipe blank (1) leaves the mold (2), it abuts against a limit stopper (33) to limit the cutting length of the steel pipe blank (1).

4. The high corrosion resistant nickel-based alloy elbow manufacturing device according to claim 1 is characterized in that: The rod end of the inner core mold rod (3) located in the mold (2) is an adjusting screw (34), and two groups of symmetrically arranged connecting rods (36) are hingedly arranged on the ball seat of the ball (35), one group of connecting rods (36) is hingedly matched with the rod body of the inner core mold rod (3), and the other group of connecting rods (36) is matched with the adjusting screw (34) to form a lead screw, so that the distance between the ball (35) and the inner core mold rod (3) is adjusted while moving along the adjusting screw (34), and the ball (35) on the inner core mold rod (3) is arranged near the outlet of the mold (2).

5. A highly corrosion-resistant nickel-based alloy elbow manufacturing device according to any one of claims 1 to 4, characterized in that: Along the pushing direction of the steel tube blank (1), a roller guide frame (5) for supporting the steel tube blank (1) and a heating coil (6) for heating the steel tube blank (1) are sequentially arranged at the entrance of the mold (2); the roller guide frame (5) and the heating coil (6) are coaxially arranged with the diameter reduction channel of the mold (2); a temperature measuring gun (7) for measuring the temperature of the steel tube blank (1) is arranged at the entrance of the mold (2), and a laser cutting machine (8) for cutting the steel tube blank (1) is arranged at the exit of the mold (2); the steel tube blank (1) is pushed into the mold (2) by the thrust plate (4), and a baffle (23) arranged parallel to the thrust plate (4) is also arranged on the mold (2) to limit the displacement of the mold (2).

6. A highly corrosion-resistant nickel-based alloy elbow manufacturing device according to any one of claims 1 to 4, characterized in that: The mold (2) is of split design, comprising a diameter reduction mold (21) for reducing the diameter of the steel pipe blank (1) and an elbow mold (22) for elbowing the steel pipe blank (1); the elbow mold (22) and the diameter reduction mold (21) are fixed by mortise and tenon joints.

7. A method for manufacturing a high corrosion resistant nickel-based alloy elbow, characterized in that: The steps include: S1. Selecting Hastelloy C-276 alloy as a steel pipe blank (1), and testing the steel pipe blank (1) to ensure that its performance meets the use requirements; S2, performing homogenization heat treatment on the steel tube blank (1); S3, using a high corrosion-resistant nickel-based alloy elbow manufacturing device as described in any one of claims 1 to 4 to process the elbow of the steel pipe blank (1); S31, installing the steel pipe blank (1) on the roller guide frame (5) so that it is coaxially arranged with the heating coil (6) and the diameter reduction die (21); S32, starting the heating coil (6) to heat the steel pipe blank (1) to a set temperature, and then starting the thrust plate (4) to push the steel pipe blank (1) in a straight line, so that the steel pipe blank (1) passes through the reducing die (21) and the elbow die (22) in sequence; S33, adjusting the distance between the ball (35) on the inner core mold rod (33) and the inner wall of the steel tube blank (1) so that the ball (35) can form an inner support for the steel tube blank (1); S34, after the rotating rod (31) drives the inner core mold rod (3) to be inserted into the steel pipe blank (1), the rotating rod (31) is locked; S35, after the elbow of the steel pipe blank (1) is formed and abuts against the limit stopper (33), the elbow steel pipe is cut by a laser cutting machine (8) at the exit of the mold (2); S36, unlocking the rotating rod (31) and taking out the cut elbow steel pipe; S37, repeat steps S34 to S36, and perform reciprocating cutting production.

8. The method for manufacturing a high corrosion resistant nickel-based alloy elbow according to claim 7, characterized in that: In step S1: S11, selecting a seamless steel pipe as a steel pipe blank (1), and smelting the steel pipe blank (1) by using vacuum induction smelting, argon oxygen decarburization refining and electroslag remelting smelting technology; S12, performing component analysis on the steel pipe blank (1), calculating the PREN equivalent index of the steel pipe blank (1) based on the content of chromium, molybdenum and tungsten elements, and when the PREN equivalent index is less than or equal to 45.5, the steel pipe blank (1) is scrapped; PREN = A + 1.5 × (B + C); Wherein, A represents the element content of chromium element in the steel tube blank (1); B represents the element content of molybdenum element in the steel tube blank (1); C represents the element content of tungsten in the steel tube blank (1); S13, sampling the steel tube blank (1), performing grain size detection according to ASTM E112 standard, and determining that the average grain size of the steel tube blank (1) is 4 to 7 levels. If the condition is not met, the steel tube blank (1) is scrapped; S14. Sampling the steel tube blank (1), and performing non-metallic inclusion inspection according to ASTM E45, and determining the level of non-metallic inclusions of types A, B, C, and D according to the most serious one, to determine whether the steel tube blank (1) meets the following conditions; If the conditions are not met, the steel pipe blank (1) is scrapped.

9. The method for manufacturing a high corrosion resistant nickel-based alloy elbow according to claim 7, characterized in that: In step S2, the steel tube blank (1) is subjected to a solution treatment process: S21, heating the steel pipe blank (1) in a furnace; S211. When the temperature in the furnace is not higher than 500°C, the heating rate is not controlled; S212, when the temperature in the furnace is in the temperature range of 500°C-1100°C, the heating rate is controlled to be 400°C / h-600°C / h; S213, when the temperature in the furnace is in the temperature range of 1100°C-1130°C, the heating rate is controlled to be 200°C / h-300°C / h; S22, heat-insulating the steel tube blank (1) at a temperature of 1130° C.±10° C. for a heat-insulating time of 5 min / mm; if the total heat-insulating time is less than 30 min, heat-insulating for 30 min is performed; S23, cooling the steel pipe blank (1) by water cooling, the cooling water temperature is 10°C to 40°C, and the water immersion time shall not be longer than 1 minute.

10. The method for manufacturing a high corrosion resistant nickel-based alloy elbow according to claim 9, characterized in that: Before the steel tube blank (1) is subjected to a solution treatment, an intergranular corrosion test is performed on the steel tube blank (1) to analyze the effect of the solution treatment process on the corrosion rate of the sample. The intergranular corrosion rate γ corr for: Where K is a constant, which is 8.76×10 4 ; Δm is the mass loss of the steel tube blank (1); A is the sample surface area of ​​the steel tube blank (1); t is the corrosion time of the steel tube blank (1); ρ is the density of the steel tube blank (1).

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