CN119351826A

CN119351826A - A GH3625 high temperature alloy pipe and its production process

Info

Publication number: CN119351826A
Application number: CN202411929586.XA
Authority: CN
Inventors: 高玉光; 刘富强; 王锦永; 高杰; 齐希伦
Original assignee: Handan Xinxing Special Pipe Co ltd
Current assignee: Handan Xinxing Special Pipe Co ltd
Priority date: 2024-12-26
Filing date: 2024-12-26
Publication date: 2025-01-24
Anticipated expiration: 2044-12-26

Abstract

The invention belongs to the technical field of high-temperature alloy material processing, and particularly discloses a GH3625 high-temperature alloy pipe and a production process thereof, wherein the process comprises ingot smelting, ingot forging, bar solid solution treatment, primary blank processing, blank nondestructive inspection, primary reaming, secondary reaming, pierced billet extrusion, pierced billet solid solution treatment, cold rolling, finished pipe solid solution treatment and the like, and the GH3625 high-temperature alloy pipe is prepared by using the production process. The secondary reaming process solves the problem of the primary large reaming ratio causing the reaming, adopts the processes of double conical dies, carbon steel tail pads and the like in the extrusion of the pierced billet, is beneficial to the stable flow of metal, reduces extrusion force, reduces extrusion defects and improves the yield. The GH3625 superalloy tube produced by the invention has good surface quality, uniform crystal grain, high dimensional accuracy and good mechanical and corrosion resistance, and is suitable for producing and preparing GH3625 superalloy seamless tube, especially large-caliber tube.

Description

GH3625 high-temperature alloy pipe and production process thereof

Technical Field

The invention relates to the technical field of high-temperature alloy material processing, in particular to a GH3625 high-temperature alloy pipe and a production process thereof.

Background

GH3625 is a solid solution strengthening type nickel-based deformation superalloy taking molybdenum and niobium as main strengthening elements, also called UNS N06625 and Inconel 625, and has high strength, high toughness, excellent fatigue resistance and chloride ion stress corrosion resistance from low temperature to 980 ℃, and is widely applied to the fields of nuclear industry, aviation, aerospace, petrochemical industry and the like.

One of the common products of GH3625 alloy is a seamless pipe, and because of the characteristics of the GH3625 alloy, the GH3625 alloy pipe has the conditions of large deformation resistance and narrow deformation temperature interval in the hot working process, and is easy to crack and has slow forging process rhythm and poor precision when being processed by adopting a conventional hot punching process. At present, the hot extrusion process enables the blank to be in a three-dimensional compression stress state, is more beneficial to improving the plastic deformation capability of the material, and is suitable for hot processing of low-plasticity alloy, so that the main production process commonly used for GH3625 alloy pipes is primary reaming, extrusion of pierced billets and cold rolling. However, the prior art has the following problems that when a pipe with a larger caliber is produced, the pipe is often expanded in the extrusion process due to larger reaming deformation, and in order to reduce the reaming deformation, a means of drilling a large inner hole diameter during blank processing is adopted, so that the waste of materials is caused.

Disclosure of Invention

In order to solve the defects in the prior art, the invention aims to provide a GH3625 high-temperature alloy pipe and a production process thereof, so as to solve the problem of crack expansion caused by adopting a large reaming ratio in the prior art, avoid material waste caused by drilling a large inner hole diameter of a blank in the traditional process, reduce extrusion defects, improve the quality and the yield of the finished product by optimizing alloy components, extruding by a double-cone die, adding a carbon steel tail pad and other means, and simultaneously provide the GH3625 high-temperature alloy pipe prepared by the process.

In order to achieve the above purpose, the technical scheme adopted by the invention is as follows:

The invention provides a GH3625 superalloy tube, which comprises ：Mo：8～10%、Nb：3.25～4.00%、C：0.003～0.065%、Cr：20～23%、Fe≤5%、Cu≤0.30%、Al：0.10～0.25%、Ti：0.15～0.35%、Co≤1.0%、Si≤0.45%、Mn≤0.45%、S≤0.010%、P≤0.015%、B≤0.006%、Mg≤0.10%、W≤0.10%, mass percent of Ni and unavoidable impurities as the rest.

As the limitation of the invention, the GH3625 superalloy pipe is a seamless pipe with the outer circle diameter ranging from 19mm to 325mm and the wall thickness ranging from 1.5mm to 40 mm;

the seamless pipe has the properties that the tensile strength Rm is more than or equal to 690MPa, the Rp0.2 yield strength is more than or equal to 276MPa, the elongation is more than or equal to 30 percent, the grain size is more than or equal to 3.0 grade, and the corrosion rate according to the standard ASTM G28A method is less than 0.9 mm/year.

The invention also provides a production process of the GH3625 superalloy tube, which comprises the following steps in sequence:

S1, smelting an ingot, namely smelting the alloy material into the ingot by a vacuum induction smelting, vacuum casting an electrode and vacuum electroslag remelting technology;

S2, forging an ingot, namely heating the ingot to 1170-1190 ℃ for forging, wherein the final forging temperature is 950 ℃, and forging the ingot into a cylindrical bar with a forging ratio of 4-10;

S3, carrying out bar solid solution treatment, namely returning the cylindrical bar to the furnace to heat the cylindrical bar to 1130-1150 ℃ and using water as a cooling medium to realize rapid cooling, wherein the furnace temperature is 900 ℃ when the bar enters the furnace, the heat preservation time is 2.0 min-5.0 min/mm, and the temperature is raised to the target temperature at the speed of 150-250 ℃/h;

s4, firstly processing the blank, drilling an inner hole and turning an outer circle of the bar, and flattening two ends of the bar to obtain the blank;

s5, performing nondestructive inspection on the blank, and performing ultrasonic inspection on the blank obtained in the S4;

s6, reaming for the first time, and finishing reaming for the blank heated to the temperature for the first time by using a vertical reamer;

S7, machining the blank again, namely turning and polishing the outer circle of the blank subjected to primary reaming, enabling two ends of the blank to be flat-headed, machining a horn mouth with an angle alpha' at the inner circle of the head of the blank, machining an oblique angle with an angle beta at the outer circle of the tail, and machining a round corner at the joint of the oblique angle and the spindle body;

s8, secondary reaming is carried out, and the blanks heated to the temperature are subjected to secondary reaming by a vertical reamer;

S9, extruding the pierced billet, namely heating the blank subjected to secondary reaming in the step S8, and extruding the pierced billet by using a horizontal extruder;

S10, performing solid solution treatment on the pierced billets, heating the pierced billets to a temperature in stages by using a chamber furnace, and performing water cooling treatment;

S11, cold rolling, namely performing two-pass to seven-pass cold rolling treatment by adopting a Pelgi cold rolling mill, wherein the deformation of each pass is 30% -60%, the feeding amount is 2.6-5.6 mm/time, the rolling speed is 30-60 times/min, the cold rolling deformation of the last pass is controlled to be 30% -50%, the cold rolling oil of the intermediate tube after each pass of cold rolling is firstly removed in a degreasing tank, then the solution treatment of the intermediate tube is performed, and the intermediate tube is transferred to a mixed acid pickling tank for pickling and descaling, the solution treatment process of the intermediate tube in the cold rolling stage is that the heating time is 1150 ℃ and is 3.0-6.0 min/mm, and the intermediate tube is rapidly cooled by using water as a cooling medium;

S12, performing solution treatment on a finished pipe, namely heating the cold-rolled pipe with the inner diameter of 35mm or more to a temperature, and performing water cooling treatment, wherein the process is that the heating time is 3.0-8.0 min/mm at 960-1030 ℃, water is used as a cooling medium in 60S to realize rapid cooling, and the process is that the cold-rolled pipe with the inner diameter of 35mm or less and the wall thickness of 5mm or less is subjected to heat treatment by a protective atmosphere bright furnace annealing furnace, wherein the process is that the heating time is 3.0-8.0 min/mm at 960-1030 ℃, and the protective gas strong convection jet flow and water cooling jacket are adopted;

s13, finishing treatment, straightening, detection, surface treatment, flat head and packaging.

As further limitation of the invention, in S4, the angle alpha of the horn mouth opening machined at the inner circle of the head is 46 degrees, the deviation of the drilled inner hole is +/-0.5 mm, the deviation of the outer diameter of the finished product of the turning circle is +/-1 mm, the perpendicularity of the end surfaces at the two ends is less than or equal to 1mm, the inner surface and the outer surface are polished and polished to remove scratches, lathe tool defects, the surface roughness Ra is less than or equal to 1.6 mu m, the length deviation of the blank is +/-5 mm, and the concentricity of the inner circle and the outer circle is less than or equal to 1mm.

As a further limitation of the present invention, the primary reaming step in S6 includes:

① Heating the blank in an electromagnetic induction heating furnace for 2 times at the furnace temperature of 950 ℃ for 3.0-6.0 h, wherein the first heating power is 450 KW-550 KW, the frequency is 40-60 HZ, the temperature is 1100-1150 ℃ and the soaking time is 1.5-3.5 min, the second heating power is 600 KW-800 KW, the frequency is 62-90 HZ, the temperature is 1155-1180 ℃, and then discharging;

② The outer diameter of the blank before expanding is 8 mm-15 mm smaller than the inner diameter of the reaming barrel, and the inner wall of the reaming barrel is preheated to the temperature of 200 ℃;

③ After the blank is heated, uniformly smearing glass powder lubricant on the inner surface and the outer surface, then placing the blank into a reaming barrel, then placing a reaming head into a bell mouth of the head of the blank, and then reaming, wherein the reaming speed is 130-180 mm/s, the reaming ratio is 1.02-1.28, and after reaming, cooling the blank in water at the temperature of more than 900 ℃.

The invention is further limited by the steps of S7, wherein the opening angle alpha' of a horn mouth machined at the inner circle of the head is 46 degrees, the machining angle beta at the outer circle of the tail is 35 degrees, the radius R of a fillet machined at the joint of an oblique angle and a spindle body is 20mm, the deviation of the outer diameter of a finished product is +/-1 mm, the perpendicularity of the end faces of the two ends is less than or equal to 1mm, the deviation of the length is +/-5 mm, the concentricity of the inner circle and the outer circle is less than or equal to 1mm, the defect is checked, the defect is cleaned, the defects of cracks, folding, scabbing and pits on the inner surface and the outer surface are cleaned, the depth-width-length ratio of the coping is greater than 1:5:10, the corners are smoothly transited, and the roughness Ra of all surfaces after cleaning is less than or equal to 1.6 mu m.

As a further limitation of the present invention, the secondary reaming step in S8 includes:

① Heating the furnace for 2 times in an electromagnetic induction heating furnace at the temperature of 950 ℃ for 2.0-4.0 hours, wherein the first heating power is 450 KW-550 KW, the frequency is 40-60 HZ, the temperature is 1100-1150 ℃ and the soaking time is 1.0-2.5 min, the second heating power is 600 KW-800 KW, the frequency is 65-100 HZ, the temperature is 1160-1185 ℃, and then discharging the furnace;

③ After the blank is heated, uniformly smearing glass powder lubricant on the inner surface and the outer surface, then placing the glass powder lubricant in a reaming barrel, then placing a reaming head in a bell mouth above the blank, and then reaming, wherein the reaming speed is 150-200 mm/s, and the reaming ratio is 1.05-1.35.

As a further limitation of the present invention, the step of extruding the pierced blank in S9 includes:

① Turning around the blank after secondary reaming is completed, transferring the blank into a secondary electromagnetic induction heating furnace, heating power 500 KW-800 KW, heating the blank to 1160 ℃ and discharging the blank from the furnace at the frequency of 40-70 HZ;

② The inner wall of the extrusion cylinder is heated to 300-500 ℃, and the surfaces of the extrusion die and the core rod are heated to 250-450 ℃;

③ Coating glass powder on the inner and outer surfaces of the blank, transferring the blank into an extrusion cylinder, wherein the inner diameter of the extrusion cylinder is 4.5 mm-10 mm larger than the outer diameter of the blank, and placing a glass pad at the inlet of an extrusion die;

④ Heating the tail pad prepared in advance to 950-1060 ℃, placing the tail pad at the tail part of the blank, and extruding the tail pad together with the blank;

⑤ The power system of the extruder enables the extrusion rod to push the blank to move towards the extrusion direction, the advancing speed of the blank is 60 mm/s-130 mm/s, the extrusion ratio of the pierced billet is 2.5-12.5, the metal of the blank is changed into the pierced billet through the cavity formed by the core rod and the extrusion die, and the extruded pierced billet is cooled to below 40 ℃ at a temperature above 960 ℃.

As a further limitation of the invention, the extrusion die adopts a double-cone die, wherein an internal inlet of the double-cone die consists of two die angles, the die angle gamma is 120 degrees, the die angle gamma ' is 30 degrees, the length of the bearing of the extrusion die is 12mm, the radius of a fillet of a transition area of the cross section of the die angle gamma and the cross section of the die angle gamma ' is 15mm, and the radius of a fillet of the transition area of the die angle gamma ' and the bearing is 12mm;

the tail pad is made of carbon steel, the outer diameter of the tail pad is the same as the outer diameter of the blank, the inner diameter of the tail pad is 4 mm-5 mm larger than the inner diameter of the blank, and the length of the tail pad is 100mm.

As a further limitation of the invention, the process of the solution treatment of the pierced billet in S10 is that the heating time is 1.5 min-2.0 min/mm at 980 ℃, the heating time is 2.5 min-5.0 min/mm at 1140 ℃ at 100-150 ℃/h, and the pierced billet is transferred to a water pool in 65S to be used as a cooling medium to realize rapid cooling.

Due to the adoption of the technical scheme, compared with the prior art, the invention has the following beneficial effects:

(1) The reaming process adopts secondary reaming, solves the quality problem of reaming caused by the adoption of a primary large reaming ratio in the traditional process, and simultaneously avoids the waste of materials caused by the fact that a blank drills an inner hole with a larger diameter;

(2) The extrusion die in the extrusion stage of the pierced billet adopts the double-cone die, which is favorable for smooth flow of metal, reduces extrusion force, reduces extrusion defects, improves the quality of the pierced billet, and avoids the conditions that the metal is unstable in deformation, the pierced billet is easy to crack and have layering defects in the wall thickness direction and the like due to the adoption of conventional flat die extrusion to a certain extent;

(3) According to the invention, the carbon steel tail pad is added behind the blank in the pierced billet extrusion stage, and when the pierced billet extrusion is finished, the blank with the tail of 25 mm-50 mm can be extruded smoothly, so that the material waste is avoided, and the yield is improved.

In conclusion, the method is suitable for producing GH3625 alloy pipes with larger caliber, the diameter range of the finished pipe can be 19 mm-325 mm, the wall thickness is 1.5 mm-40 mm, and indexes such as tensile strength, yield strength, elongation, grain size, corrosion rate and the like of the finished product are higher than the requirements of related standards on product technical indexes. The GH3625 high-temperature alloy pipe produced by the method has high dimensional accuracy, improves the material utilization rate, has good surface quality and uniform internal grains, and has good mechanical and corrosion resistance.

Drawings

FIG. 1 is a flow chart of a production process according to an embodiment of the present invention;

fig. 2 is a schematic structural diagram of the first blank processing in embodiment S4 of the present invention;

Fig. 3 is a schematic view of the structure of the re-blank processing in embodiment S7 of the present invention;

Fig. 4 is a schematic diagram of a double taper mold structure in embodiment S9 of the present invention.

In the figure, 1-first machining of blanks, 2-second machining of blanks, 3-double cone dies and 4-bearing.

Detailed Description

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are presented for purposes of illustration and explanation only and are not to be construed as limiting the invention.

The embodiment discloses a GH3625 superalloy tube, which is a seamless tube with an outer circle diameter ranging from 19mm to 325mm and a wall thickness ranging from 1.5mm to 40mm, and comprises the components of ：Mo：8～10%、Nb：3.25～4.00%、C：0.003～0.065%、Cr：20～23%、Fe≤5%、Cu≤0.30%、Al：0.10～0.25%、Ti：0.15～0.35%、Co≤1.0%、Si≤0.45%、Mn≤0.45%、S≤0.010%、P≤0.015%、B≤0.006%、Mg≤0.10%、W≤0.10%, mass percent and the balance of Ni and unavoidable impurities.

The GH3625 superalloy pipe has the properties that the tensile strength Rm is more than or equal to 690MPa, the Rp0.2 yield strength is more than or equal to 276MPa, the elongation is more than or equal to 30%, the grain size is more than or equal to 3.0 grade, and the corrosion rate according to the standard ASTM G28A method is less than 0.9 mm/year.

The embodiment also discloses a production process of the GH3625 high-temperature alloy pipe, taking a finished GH3625 high-temperature alloy pipe product seamless pipe with 219mm (diameter) multiplied by 12.7mm (wall thickness) as an example, as shown in figure 1, the production process flow and the specific production and processing process comprise the following steps:

S1, smelting an ingot, namely smelting the ingot from an alloy material by vacuum induction smelting, vacuum casting an electrode and vacuum electroslag remelting technology, wherein the electroslag remelting slag system adopts a CaF ₂、CaO、Al₂O₃、SiO₂ and MgO five-element slag system, and the content ratio is 65:10:15:5:5 (%).

S2, forging the ingot, namely heating the ingot obtained in the step S1 to 1170-1190 ℃ for forging, wherein the final forging temperature is 950 ℃, and forging the ingot into a cylindrical bar with the forging ratio of 4-10.

S3, bar stock solution treatment, namely returning the bar stock forged in the S2 to a furnace to heat the bar stock to 1130-1150 ℃, using water as a cooling medium to realize rapid cooling, realizing the purpose of reducing harmful precipitated phases, and realizing tissue uniformity, wherein the furnace temperature of the bar stock when entering the furnace is 900 ℃, the heat preservation time is 2.0-5.0 min/mm, and the temperature is raised to the target temperature at the speed of 150-250 ℃ per hour.

S4, processing the first blank, namely drilling an inner hole and turning an outer circle of the bar to obtain a first processed blank 1, wherein as shown in fig. 2, a horn mouth with an opening angle alpha is processed at the inner circle of the head of the first processed blank 1, wherein alpha can be preferably 46 degrees, the technical requirements for the first blank processing comprise that the deviation of the drilled inner hole is +/-0.5 mm, the deviation of the outer diameter of a finished product of the outer circle is +/-1 mm, the verticality of the end faces of the two end faces is less than or equal to 1mm, the defects of scratches, lathe tool lines and the like are removed through grinding and polishing of the inner surface and the outer surface, the surface roughness Ra is less than or equal to 1.6 mu m, the length deviation is +/-5 mm, and the concentricity of the inner circle and the outer circle is less than or equal to 1mm. No bevel is machined in this process.

In this example, the first-machined blank 1 was obtained in the specification of phi 357mm (outer diameter)/phi 65mm (inner diameter) ×700mm (length).

S5, performing nondestructive inspection on the blank, and performing ultrasonic inspection according to the GB/T6402 requirement after the blank is processed, so that the blank meets the quality grade 3 requirement.

S6, primary reaming, namely finishing primary reaming of the blank heated to the temperature by using a vertical reamer, wherein the primary reaming step specifically comprises the following steps of:

① Preheating a resistance furnace, namely charging a blank into the furnace when the furnace temperature is 950 ℃, preserving heat for 3.0-6.0 h, wherein the implementation heat preservation time is 2.0-4.0 h, transferring the blank into an electromagnetic induction heating furnace, heating for 2 times, heating power 450 KW-550 KW for the first time, heating the blank at the frequency of 40-60 HZ to 1100-1150 ℃ and soaking the blank for 1.5-3.5 min, heating power 600 KW-800 KW for the second time, heating the blank at the frequency of 62-90 HZ and heating the blank at the temperature of 1155-1180 ℃, and discharging the blank;

In the embodiment, the inner diameter of the reaming barrel is 368.5mm, the model of the reaming head is phi 60/173mm, the reaming ratio is 1.21, and the reaming speed is 130-180 mm/s.

S7, machining the blanks again, namely turning the outer circle and polishing the blanks subjected to primary reaming to obtain the reworked blanks 2 shown in FIG. 3, machining a horn mouth with an angle alpha 'at the inner circle of the head of the reworked blanks 2, wherein alpha' can be preferably 46 degrees, machining an oblique angle beta at the outer circle of the tail of the reworked blanks 2, wherein beta can be preferably 35 degrees, machining a round corner at the joint of the oblique angle and the spindle body, and the round corner is preferably 20mm in radius. Checking whether the inner hole is defective or not, cleaning the defect, cleaning the inner hole without the defect, namely cleaning the defects such as cracks, folding, scars, pits and the like on the inner surface and the outer surface, wherein the sleek transition of corners is realized when the sleek depth-to-width ratio is greater than 1:5:10, the outer diameter deviation of a finished product is +/-1 mm, the two ends are flat heads, the perpendicularity of the end faces is less than or equal to 1mm, the length deviation is +/-5 mm, the concentricity of the inner and outer circles is less than or equal to 1mm, and the roughness Ra of the inner and outer surfaces after cleaning is less than or equal to 1.6 mu m.

S8, secondary reaming, namely finishing secondary reaming of the blank heated to the temperature by using a vertical reamer, wherein the reaming speed is 150-200 mm/S, and the reaming ratio range is 1.05-1.35, and the secondary reaming process specifically comprises the following steps:

In the embodiment, the inner diameter of the reaming barrel is 368.5mm, the model of the reaming head is phi 75-170/228 mm, the reaming ratio is 1.19, and the reaming speed is 150-200 mm/s.

S9, extruding the pierced billet, namely heating the blank subjected to secondary reaming in the step S8, and extruding the pierced billet by using a horizontal extruder, wherein the pierced billet extrusion process specifically comprises the following steps:

turning around the blank after secondary reaming is completed, transferring the blank into a secondary electromagnetic induction heating furnace, heating power 500 KW-800 KW, heating the blank to 1160 ℃ and discharging the blank from the furnace at the frequency of 40-70 HZ;

In the embodiment, the inner diameter of the extrusion cylinder is 375mm, the extrusion die is 279.1+/-0.2 mm, the core rod is 216.3mm, the extrusion ratio is 3.01, the extrusion speed is 80-120 mm/s, the extrusion margin is 30mm, the preheating temperature of the extrusion cylinder is 320 ℃, and the preheating temperature of the extrusion die and the core rod is 260 ℃. After extrusion, quality primary inspection can be performed, the size and the quality of the inner surface and the outer surface are inspected, the required outer diameter range is 271-275 mm, the wall thickness range is 28.5-31.5 mm, the length is 2500-2700 mm, and the existence of layering defects is detected.

As shown in FIG. 4, in the extrusion of the pierced blank, in order to enhance the smooth flow of the metal, reduce the extrusion force, reduce the extrusion defect, and improve the quality of the pierced blank, the extrusion die adopts a double-cone die 3, the internal inlet of the double-cone die 3 is composed of two die angles, the die angle gamma is 120 DEG, the die angle gamma ' is 30 DEG, the bearing 4 of the extrusion die has a length of 12mm, and in addition, a round corner with a radius of 15mm is machined in the transition area of the die angle gamma section and the die angle gamma ' section, and a round corner with a radius of 12mm is machined in the transition area of the die angle gamma ' and the bearing 4.

After the extrusion of the pierced billet is finished, in order to enable the blank with the tail of the blank to be approximately 25-50 mm to be extruded smoothly to form the pierced billet, material waste is avoided, a tail pad is arranged at the tail of the blank, the tail pad is made of carbon steel, the outer diameter of the tail pad is identical to the outer diameter of the blank, the inner diameter of the tail pad is 4-5 mm larger than the inner diameter of the blank, and the length of the tail pad is 100mm.

S10, performing solution treatment on the pierced billets, and performing water cooling treatment after the pierced billets are heated to a temperature by stages by using a chamber furnace, wherein the solution treatment process is that the heating time is 1.5 min-2.0 min/mm at 980 ℃, the heating time is 2.5 min-5.0 min/mm when the temperature is raised to 1140 ℃ at 100-150 ℃ per hour, and the pierced billets are transferred to a water tank in 65S and are rapidly cooled by using water as a cooling medium.

In this example, in particular, the 980℃heating time was 1.5min/mm and the 1140℃heating time was 3.0min/mm at a rate of 120℃/h.

S11, cold rolling, namely performing two-pass to seven-pass cold rolling treatment by adopting a Pelgi cold rolling mill, wherein the deformation amount of each pass is 30% -60%, the feeding amount is 2.6-5.6 mm/time, the rolling speed is 30-60 times/min, the cold rolling deformation amount of the last pass is controlled to be 30% -50%, the intermediate tube after each pass of cold rolling is subjected to cold rolling, firstly removing cold rolling oil in a degreasing tank, then performing solution treatment on the intermediate tube, and then transferring the intermediate tube to a mixed acid pickling tank for pickling and descaling, wherein the solution treatment process of the intermediate tube in the cold rolling stage is that the heating time is 3.0-6.0 min/mm at 1150 ℃, and the intermediate tube is rapidly cooled by using water as a cooling medium.

In this example, the two-pass cold rolling treatment was performed in such a manner that the deformation process was a pierced billet of phi 273mm (diameter) by 30mm (wall thickness), a cold-rolled intermediate product of phi 245mm (diameter) by 22mm (wall thickness), a cold-rolled product of phi 219mm (diameter) by 12.7mm (wall thickness), the first-pass deformation amount was 32.7%, and the second-pass deformation amount was 46.6%. Wherein the feed amount was 3.6 mm/time, and the rolling speed was 46 times/minute.

S12, performing solution treatment on a finished tube, wherein different treatment processes are selected according to tube type numbers for the solution treatment of the finished tube, the cold-rolled tube with the inner diameter of 35mm or more is heated to a temperature and then subjected to water cooling treatment, the process is that the cold-rolled tube is rapidly cooled by taking water as a cooling medium in 60S, the cold-rolled tube with the inner diameter of 35mm or less and the wall thickness of 5mm or less is subjected to heat treatment by a protective atmosphere bright furnace annealing furnace, the process is that the cold-rolled tube with the inner diameter of 960 ℃ to 1030 ℃ is heated for 3.0min to 8.0min/mm, and the protective gas is strongly convection jet flow and water cooling jacket cooling.

The solution treatment of the finished pipe in the embodiment adopts water cooling treatment, the process is that the heating time is 3.5min/mm at 1010 ℃, and the rapid cooling is realized by taking water as a cooling medium in 60S.

And performing performance detection on the prepared GH3625 superalloy tube finished product seamless tube with the specification of phi 219mm (diameter) multiplied by 12.7mm (wall thickness), and arbitrarily selecting No. 1-No. 3 for detection, wherein the detection data are shown in Table 1.

TABLE 1 GH3625 superalloy finished product seamless tube performance detection results

The GH3625 superalloy tube finished product seamless tube obtained by the production process provided by the invention has the tensile strength Rm, rp0.2 yield strength, elongation, grain size, corrosion rate of a standard ASTM G28A method and other test results which all meet the technical index requirement values.

Finally, it should be noted that the foregoing embodiments are merely for illustrating the technical solutions of the present disclosure, and not for limiting the same, and although the present disclosure has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that the technical solutions described in the foregoing embodiments may be modified or some or all of the technical features may be equivalently replaced, and these modifications or substitutions do not depart from the spirit of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present disclosure.

Claims

1. A GH3625 high temperature alloy pipe, characterized in that its composition by mass percentage is: Mo: 8-10%, Nb: 3.25-4.00%, C: 0.003-0.065%, Cr: 20-23%, Fe≤5%, Cu≤0.30%, Al: 0.10-0.25%, Ti: 0.15-0.35%, Co≤1.0%, Si≤0.45%, Mn≤0.45%, S≤0.010%, P≤0.015%, B≤0.006%, Mg≤0.10%, W≤0.10%, and the rest is Ni and unavoidable impurities.

2. The GH3625 high temperature alloy pipe according to claim 1, characterized in that the GH3625 high temperature alloy pipe is a seamless pipe with an outer diameter ranging from 19 mm to 325 mm and a wall thickness ranging from 1.5 mm to 40 mm;

The seamless pipe has the following properties: tensile strength Rm≥690MPa, Rp0.2 yield strength≥276MPa, elongation≥30%, grain size≥3.0 grade, and corrosion rate according to standard ASTM G28 A method<0.9mm/year.

3. A production process for the GH3625 high temperature alloy tube according to claim 1 or 2, characterized in that it comprises the following steps performed in sequence:

S1. Ingot smelting: the alloy material is smelted into ingots through vacuum induction melting, vacuum casting electrode, and vacuum electroslag remelting technology;

S2. Ingot forging: heating the ingot to 1170°C to 1190°C for forging, with a final forging temperature of 950°C, forging it into a cylindrical bar with a forging ratio of 4 to 10;

S3, solution treatment of the bar, heating the cylindrical bar back to the furnace to 1130℃～1150℃, using water as the cooling medium to achieve rapid cooling; the furnace temperature when the bar enters the furnace is 900℃, the holding time is 2.0min～5.0min/mm, and the temperature is raised to the target temperature at a rate of 150℃～250℃/h;

S4, the first blank processing, the bar is drilled with an inner hole, the outer circle is turned, and the two ends are flattened to obtain a blank; a bell mouth with an opening angle of α is processed at the inner circle of the blank head;

S5, non-destructive testing of the blank, performing ultrasonic testing on the blank obtained in S4;

S6, primary hole expansion, using a vertical hole expander to expand the heated billet once;

S7, process the blank again, turn the outer circle of the blank after the hole expansion, polish it, flatten the two ends, process the bell mouth with an angle of α' at the inner circle of the head of the blank, process the bevel angle with an angle of β at the outer circle of the tail, and process the fillet at the connection between the bevel and the ingot body;

S8, secondary hole expansion, the billet heated to temperature is expanded by a vertical hole expander;

S9, rough pipe extrusion, heating the billet after the secondary hole expansion in step S8 and then using a horizontal extruder to extrude the rough pipe;

S10, solution treatment of the rough pipe, heating to temperature in stages in a chamber furnace and then water cooling;

S11, cold rolling, using a pilger cold rolling mill for two to seven passes of cold rolling treatment, each pass deformation of 30% to 60%, feed amount 2.6 to 5.6 mm/time, rolling speed 30 to 60 times/minute, and the last pass of cold rolling deformation is controlled at 30% to 50%; the intermediate tube after each cold rolling is firstly removed from the cold rolling oil in the degreasing tank, and then the intermediate tube is solution treated, and then transferred to the mixed acid pickling tank for pickling to remove the oxide scale; the solution treatment process of the intermediate tube in the cold rolling stage is 1150 ° C heating time 3.0min to 6.0min/mm, and water is used as the cooling medium to achieve rapid cooling;

S12, solution treatment of finished tubes, cold-rolled tubes with an inner diameter of 35mm and above are heated to temperature and then water-cooled, the process is: 960℃～1030℃ heating time 3.0min～8.0min/mm, water is used as cooling medium to achieve rapid cooling within 60S; cold-rolled tubes with an inner diameter of less than 35mm and a wall thickness of less than 5mm are heat-treated in a protective atmosphere bright furnace annealing furnace, the process is: 960℃～1030℃ heating time 3.0min～8.0min/mm, strong convection jet of protective gas + water cooling jacket cooling;

S13, finishing, straightening, testing, surface treatment, flat head, packaging.

4. The production process of a GH3625 high-temperature alloy pipe according to claim 3 is characterized in that, in S4, the bell mouth opening angle α processed at the inner circle of the head is 46°, the inner hole drilling deviation is ±0.5mm, and the outer diameter deviation of the outer circle finished product is ±1mm; the end surface verticality at both ends is ≤1mm; the inner and outer surfaces are ground and polished to remove scratches and tool mark defects, the surface roughness Ra is ≤1.6μm, the billet length deviation is ±5mm, and the concentricity of the inner and outer circles is ≤1mm.

5. A production process for GH3625 high temperature alloy pipe according to claim 4, characterized in that the first hole expansion step in S6 comprises:

①When the temperature of the electric furnace is 950℃, put the billet into the furnace and keep it warm for 3.0h~6.0h; transfer it to the electromagnetic induction heating furnace and heat it twice. The first heating power is 450KW~550KW, the frequency is 40~60HZ, the temperature reaches 1100℃~1150℃, and the temperature is evenly heated for 1.5~3.5min; the second heating power is 600KW~800KW, the frequency is 62~90HZ, the temperature reaches 1155℃~1180℃, and then it is taken out of the furnace;

② The outer diameter of the blank before expansion is 8mm to 15mm smaller than the inner diameter of the expansion tube, and the inner wall of the expansion tube is preheated to 200℃;

③ After the blank is heated, the inner and outer surfaces are evenly coated with glass powder lubricant, and then the blank is placed in the reaming tube, and the reaming head is placed in the bell mouth of the blank head, and then the hole is expanded; the expansion speed is 130mm/s~180mm/s, the expansion ratio ranges from 1.02 to 1.28, and after expansion, it is cooled in water above 900℃.

6. A production process for a GH3625 high-temperature alloy pipe according to claim 5, characterized in that, in S7, the opening angle α' of the bell mouth processed at the inner circle of the head is 46°, the processing angle β at the outer circle of the tail is 35°, and the radius R of the fillet processed at the connection between the bevel and the ingot body is 20mm; the outer diameter deviation of the finished product is ±1mm; the verticality of the end faces at both ends is ≤1mm; the length deviation is ±5mm, and the concentricity of the inner and outer circles is ≤1mm; check whether the inner hole has defects and clean the defects; clean the cracks, folds, scars, and deep pit defects on the inner and outer surfaces, the grinding depth-width-length ratio is greater than 1:5:10, and the edges and corners are smoothly transitioned, and the surface roughness Ra of all surfaces after cleaning is ≤1.6μm.

7. A production process for GH3625 high temperature alloy pipe according to claim 6, characterized in that the secondary hole expansion step in S8 comprises:

① When the temperature of the electric furnace is 950℃, put it into the furnace and keep it warm for 2.0h~4.0h; transfer it to the electromagnetic induction heating furnace and heat it twice. The first heating power is 450KW~550KW, the frequency is 40~60HZ, the temperature reaches 1100℃~1150℃, and the temperature is evenly heated for 1.0~2.5min; the second heating power is 600KW~800KW, the frequency is 65~100HZ, the temperature reaches 1160℃~1185℃, and then take it out of the furnace;

② The outer diameter of the blank before expansion is 8mm to 15mm smaller than the inner diameter of the expansion tube, and the inner wall of the expansion tube is preheated to 200°C;

③ After the blank is heated, glass powder lubricant is evenly applied to the inner and outer surfaces, and then placed in the reaming tube, and then the reaming head is placed in the bell mouth above the blank, followed by reaming. The reaming speed is 150mm/s~200mm/s, and the reaming ratio ranges from 1.05 to 1.35.

8. A production process for GH3625 high temperature alloy pipe according to claim 7, characterized in that the step of extruding the rough pipe in S9 comprises:

① After the second hole expansion is completed, the blank is turned around and then transferred to the secondary electromagnetic induction heating furnace with a heating power of 500KW~800KW and a frequency of 40~70HZ. It is heated to 1160℃~1200℃ and then taken out of the furnace;

② The inner wall of the extrusion barrel is heated to 300℃～500℃, and the surface of the extrusion die and core rod is heated to 250℃～450℃;

③ Apply glass powder on the inner and outer surfaces of the blank, and then transfer it to the extrusion cylinder. The inner diameter of the extrusion cylinder is 4.5mm to 10mm larger than the outer diameter of the blank, and a glass pad is placed at the entrance of the extrusion die;

④ Heat the prepared tail pad to a temperature of 950℃～1060℃, place it at the tail of the billet, and extrude the tail pad together with the billet;

⑤ The power system of the extruder makes the extrusion rod push the billet to move in the extrusion direction. The billet advances at a speed of 60mm/s to 130mm/s. The extrusion ratio of the rough tube is 2.5 to 12.5. The billet metal passes through the cavity composed of the core rod and the extrusion die to become a rough tube. The extruded rough tube is cooled in water at a temperature above 960°C to below 40°C.

9. A production process for a GH3625 high-temperature alloy pipe according to claim 8, characterized in that the extrusion die adopts a double-cone die, the inner inlet of the double-cone die is composed of two die angles, the die angle γ is 120°, and the die angle γ' is 30°; the length of the sizing zone of the extrusion die is 12 mm; the fillet radius of the transition area between the die angle γ section and the die angle γ' section is 15 mm, and the fillet radius of the transition area between the die angle γ' and the sizing zone is 12 mm;

The tail pad is made of carbon steel, the outer diameter of the tail pad is the same as the outer diameter of the blank, the inner diameter of the tail pad is 4mm to 5mm larger than the inner diameter of the blank, and the length of the tail pad is 100mm.

10. A production process for a GH3625 high-temperature alloy pipe according to any one of claims 3 to 9, characterized in that the process of the rough pipe solid solution treatment in S10 is: heating at 980°C for 1.5min-2.0min/mm, heating to 1140°C at a rate of 100°C-150°C/h for 2.5min-5.0min/mm, and transferring to a water pool within 65S to use water as a cooling medium for rapid cooling.