CN117488049A - Heat treatment device and heat treatment method for low-carbon martensitic steel seal head - Google Patents
Heat treatment device and heat treatment method for low-carbon martensitic steel seal head Download PDFInfo
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- CN117488049A CN117488049A CN202311823728.XA CN202311823728A CN117488049A CN 117488049 A CN117488049 A CN 117488049A CN 202311823728 A CN202311823728 A CN 202311823728A CN 117488049 A CN117488049 A CN 117488049A
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- 238000010438 heat treatment Methods 0.000 title claims abstract description 168
- 238000000034 method Methods 0.000 title claims abstract description 57
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 51
- 239000010959 steel Substances 0.000 title claims abstract description 51
- 229910052799 carbon Inorganic materials 0.000 title claims abstract description 46
- 229910000734 martensite Inorganic materials 0.000 title claims abstract description 44
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 180
- 238000010791 quenching Methods 0.000 claims abstract description 116
- 230000000171 quenching effect Effects 0.000 claims abstract description 112
- 238000001816 cooling Methods 0.000 claims abstract description 85
- 230000002265 prevention Effects 0.000 claims abstract description 7
- 238000005507 spraying Methods 0.000 claims description 99
- 238000007789 sealing Methods 0.000 claims description 61
- 239000007921 spray Substances 0.000 claims description 57
- 230000008093 supporting effect Effects 0.000 claims description 49
- 230000008569 process Effects 0.000 claims description 36
- 238000004321 preservation Methods 0.000 claims description 26
- 238000004513 sizing Methods 0.000 claims description 22
- 238000004891 communication Methods 0.000 claims description 19
- 230000003014 reinforcing effect Effects 0.000 claims description 19
- 230000006835 compression Effects 0.000 claims description 15
- 238000007906 compression Methods 0.000 claims description 15
- 230000009471 action Effects 0.000 claims description 13
- 238000009434 installation Methods 0.000 claims description 12
- 238000005496 tempering Methods 0.000 claims description 11
- 238000003466 welding Methods 0.000 claims description 9
- 238000004519 manufacturing process Methods 0.000 claims description 8
- 230000002093 peripheral effect Effects 0.000 claims description 8
- 238000001514 detection method Methods 0.000 claims description 7
- 238000003754 machining Methods 0.000 claims description 5
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 4
- 238000012546 transfer Methods 0.000 claims description 4
- 238000003756 stirring Methods 0.000 claims description 2
- 241000277275 Oncorhynchus mykiss Species 0.000 claims 1
- 239000000463 material Substances 0.000 abstract description 10
- 238000005242 forging Methods 0.000 abstract description 4
- 230000006032 tissue transformation Effects 0.000 abstract description 4
- 230000005484 gravity Effects 0.000 description 7
- 230000000052 comparative effect Effects 0.000 description 6
- 238000010586 diagram Methods 0.000 description 6
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- 238000010521 absorption reaction Methods 0.000 description 5
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- 238000012360 testing method Methods 0.000 description 4
- 238000009864 tensile test Methods 0.000 description 3
- 230000009286 beneficial effect Effects 0.000 description 2
- 238000005520 cutting process Methods 0.000 description 2
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- 238000012544 monitoring process Methods 0.000 description 2
- 238000011056 performance test Methods 0.000 description 2
- 239000003208 petroleum Substances 0.000 description 2
- 238000003825 pressing Methods 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 238000006467 substitution reaction Methods 0.000 description 2
- 229910001339 C alloy Inorganic materials 0.000 description 1
- 229910001209 Low-carbon steel Inorganic materials 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- NCRHYAJHJHKMLB-UHFFFAOYSA-N chromium molybdenum nickel vanadium Chemical group [V][Mo][Cr][Ni] NCRHYAJHJHKMLB-UHFFFAOYSA-N 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
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Classifications
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/0068—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for particular articles not mentioned below
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/18—Hardening; Quenching with or without subsequent tempering
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/62—Quenching devices
- C21D1/667—Quenching devices for spray quenching
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D6/00—Heat treatment of ferrous alloys
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/0006—Details, accessories not peculiar to any of the following furnaces
- C21D9/0025—Supports; Baskets; Containers; Covers
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/0062—Heat-treating apparatus with a cooling or quenching zone
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/008—Martensite
Abstract
The invention provides a heat treatment device and a heat treatment method of a low-carbon martensitic steel seal head, wherein the heat treatment device comprises a quenching cooling device and an in-furnace deformation prevention device; according to the heat treatment method, when the seal head is heated and quenched and tempered in the heat treatment furnace, the seal head is in a state that the opening is downward, and the material performance and the dimensional accuracy of the low-carbon martensitic steel seal head can meet the technical requirements by being matched with the use of a quenching cooling device and an in-furnace deformation prevention device; the heat treatment method and the heat treatment device suitable for forging the large-diameter and large-wall-thickness end socket effectively solve the problems that low-carbon martensitic steel is insufficient in tissue transformation caused by insufficient water cooling strength, strength difference caused by different cooling states of the inner surface and the outer surface of the end socket, difference exists between the surface and the core strength caused by overlarge wall thickness of the end socket, and the like, and effectively ensure the dimensional accuracy and the performance of a product.
Description
Technical Field
The invention relates to the technical field of metal heat treatment, in particular to a heat treatment device and a heat treatment method for a low-carbon martensitic steel seal head.
Background
The pressure vessel is a closed device for containing gas or liquid and bearing a certain pressure, has wide application in the fields of chemical industry, metallurgy, petroleum, medicine, energy sources and the like, and can effectively store and transport various substances. The seal head is one of important structures of the pressure vessel, different seal head types can be adopted according to specific requirements, and common seal head types comprise a spherical seal head, a spherical cap seal head, an elliptic seal head, a dish-shaped seal head and a flat seal head, and the seal heads have the structural characteristics that the lower end face is flush, the inner surface has a certain depth and the top is airtight.
The low-carbon martensitic steel refers to a steel in which the low-carbon tempered martensitic structure is used after quenching and tempering of low-carbon steel or low-carbon alloy steel. The low-carbon martensitic steel has the advantages of higher strength, good plasticity, small cold embrittlement tendency, low fatigue notch sensitivity and the like, is used for various structural components in the fields of automobiles, petroleum, marine engineering, ships and the like, and is particularly widely applied to the manufacture of sealing heads of pressure vessels. Compared with medium-carbon and high-carbon martensitic steels, the low-carbon martensitic steels have lower carbon content, poorer hardenability, proper heating temperature increase, heat preservation time extension and cooling speed increase during quenching, and particularly when the carbon content is lower than 0.15%, the cooling strength of each part of the seal head in a quenching water tank needs to be particularly concerned so as to avoid the condition of unqualified final performance caused by uneven tissue transformation.
At present, for a high-pressure container with higher pressure and larger diameter, the manufacturing of a used low-carbon martensitic steel seal head generally adopts a mode of forging, heat treatment and machining; in the heat treatment process, due to the material characteristics of the low-carbon martensitic steel, when the wall thickness of the end socket is thicker, quenching water needs to be rapidly transported and cooled so as to ensure that the final material performance and uniformity meet the technical requirements; due to the structural characteristics of the seal heads, deformation prevention measures are required in the heat treatment process so as to ensure that the size of the final product is qualified.
The common end socket quenching mode is as follows: the head opening goes into water upwards, and this kind of mode has several defects: firstly, in the water inlet process, the outer surface of the seal head is firstly contacted with water, after the water is required to completely overflow the upper edge of the seal head, the water can enter the cavity of the inner surface of the seal head, so that the inner surface and the outer surface cannot be simultaneously contacted with water, the cooling is uneven, the material properties are different, and the deformation amount of the seal head in the quenching process is increased; secondly, the water flow at the cavity of the inner surface of the seal head is in a relatively static state, and the quick heat exchange between the seal head and the water cannot be realized.
Disclosure of Invention
In view of the above, the invention provides a heat treatment device and a heat treatment method for a low-carbon martensitic steel end socket, and the provided heat treatment device comprises a quenching cooling device and an in-furnace deformation prevention device aiming at the material characteristics of the low-carbon martensitic steel and the structural characteristics of the end socket; according to the heat treatment method, when the seal head is heated and quenched and tempered in the heat treatment furnace, the seal head is in a state that the opening is downward, and the material performance and the dimensional accuracy of the low-carbon martensitic steel seal head can meet the technical requirements by being matched with the use of a quenching cooling device and an in-furnace deformation prevention device; the heat treatment method and the heat treatment device suitable for forging the large-diameter and large-wall-thickness end socket effectively solve the problems that low-carbon martensitic steel is insufficient in tissue transformation caused by insufficient water cooling strength, strength difference caused by different cooling states of the inner surface and the outer surface of the end socket, difference exists between the surface and the core strength caused by overlarge wall thickness of the end socket, and the like, and effectively ensure the dimensional accuracy and the performance of a product.
The technical scheme of the invention is as follows:
a heat treatment device of a low-carbon martensitic steel seal head comprises an anti-deformation device and a quenching cooling device;
the deformation preventing device is positioned in the heat treatment furnace and comprises a base and a telescopic rod fixedly connected with the base; a supporting head is fixed at the top end of the telescopic rod;
the top surface of the supporting head is matched with the shape of the inner surface of the sealing head to be heat treated, and the top surface of the supporting head is attached to the inner top surface of the sealing head;
when the heat treatment furnace is used for heating, the base is in a horizontal state, the telescopic rod is in a vertical state, and the height of the telescopic rod is adjusted according to the distance between the heating platform of the heat treatment furnace and the inner top surface of the seal head, so that the top surface of the support head is contacted and attached with the inner top surface of the seal head, the phenomenon that the top of the seal head collapses in the heat treatment process is avoided, and the dimensional accuracy of a finished product is further ensured;
the quenching cooling device comprises a communicating annular pipe, wherein the inner peripheral side of the communicating annular pipe is fixedly provided with upright posts, and the circumferential distance between two adjacent upright posts is 1-2 meters;
external spraying devices are fixed at the top ends of the upright posts and are connected with the communication annular pipe;
an internal spraying device is arranged in the area surrounded by the upright post and is fixedly connected with the inner side surface of the upright post;
The arrangement ensures that the internal spraying device is in the spraying range of the external spraying device;
the external spraying device comprises a support and a branch pipe, the support is fixedly connected with the top end of the upright post, and the branch pipe is rotationally connected with the support;
the branch pipe comprises a connecting section, a mounting section and a spraying section which are sequentially connected, wherein the connecting section is vertically arranged with the mounting section, the mounting section is vertically arranged with the spraying section, the connecting section and the spraying section are vertically arranged and distributed on the upper side and the lower side of the mounting section, the spraying section is positioned above, and the connecting section is positioned below;
a weight box is arranged on one side of the installation section, which is close to the connection section, and a compression bar is arranged on one side of the installation section, which is close to the spraying section, and the compression bar and the installation section are coaxially arranged;
the branch pipe, the compression bar and the weight box are taken as a whole, and can rotate around the connecting shaft of the support and the branch pipe under the arrangement that the support is rotationally connected with the branch pipe, so that the spray section rotates along the support, thereby forming included angles with the vertical surface in different angles; when the end enclosure is hoisted into the external cooling area by adopting a hanging chain, the edge of the open end of the end enclosure is positioned on the compression bar, and the plurality of spraying sections gather towards the center under the action of the gravity of the end enclosure, so that the outside of the end enclosure can be smoothly sprayed and cooled;
The internal spraying device comprises a main pipeline, an upper spraying ring and a lower spraying ring, wherein the upper spraying ring is connected with the main pipeline through a communicating pipe A, and the lower spraying ring is connected with the main pipeline through a communicating pipe B; the upper spray ring and the lower spray ring are coaxially arranged, and the diameter of the upper spray ring is smaller than that of the lower spray ring;
a horizontal beam is arranged on the periphery of the main pipeline and is fixedly connected with the upright post; through the arrangement of the cross beam, the internal spraying device is positioned in the area surrounded by the upright posts, and the circle centers of the upper spraying ring and the communicating annular pipe are positioned on the same straight line;
when the quenching device is used, the end socket to be quenched is lifted to the quenching cooling device, under the condition that the opening of the end socket faces downwards to quench water, the inner surface and the outer surface of the end socket can be impacted by high-pressure water flow at the same time, heat of the end socket is taken away rapidly, each part area of the end socket is guaranteed to be cooled rapidly, the effect that the internal structure of the end socket is fully transformed is achieved, and the cooling speed of the inner surface and the outer surface of the end socket is improved.
Preferably, the water outlets are arranged on the communicated ring pipe, and the number of the water outlets is the same as that of the external spraying devices; the water inlet of the communication ring pipe is connected with the high-pressure water pump A, and the water outlet is respectively connected with the connecting section of the external spraying device through a water inlet pipe; the water inlet pipe is a high-pressure rubber pipe; through the high-pressure water pump A, water enters the spraying section to quench the seal head to be quenched after being communicated with the annular pipe, the water inlet pipe, the connecting section and the mounting section.
Preferably, a baffle is fixed on the support to limit the outward inclination angle of the spray section, and the baffle is close to the side of the weight box; the spraying section rotates outwards under the action of the weight box; the spray section is in threaded connection with nozzles A which are uniformly distributed on the spray section; the spacing between adjacent nozzles A is 100-300mm, so that the spray uniformity of the outer surface of the seal head can be effectively ensured; the spray nozzle A is perpendicular to the spray section, and the included angle between the spray nozzle A and the compression bar is 30-60 degrees, so that water flow vortex can be well formed, and heat exchange of water flow in the quenching water tank is guaranteed.
Preferably, the seal head comprises, but is not limited to, a spherical seal head, an elliptic seal head, a dish-shaped seal head, a flat seal head and a spherical cap seal head; the product with the structural characteristics of flush lower end surface, certain depth of inner surface and airtight top can be suitable.
Preferably, the supporting head comprises a core block and a plurality of supporting pieces, wherein the core block is a cylinder, and the supporting pieces are uniformly distributed on the outer peripheral surface of the cylinder; the height of the supporting sheets is larger than that of the core blocks, when the supporting sheets are fixed on the outer peripheral surface of the cylinder, the supporting sheets enclose a cavity, and the top ends of the telescopic rods extend into the cavity and are fixedly connected with the supporting heads; the inner side of the bottom end of the supporting piece is provided with a chamfer angle, so that the top end of the telescopic rod can conveniently extend into the cavity; two support sheets are oppositely arranged, and the top ends of the core blocks between the two support sheets form a continuous cambered surface which is contacted with the inner top surface of the sealing head; when the telescopic rod is used, the top end of the telescopic rod is stretched into the cavity and is fixed into a whole, and the height of the telescopic rod is adjusted to enable the top surface of the supporting head to be attached to the inner top surface of the sealing head; when the seal head is placed in the heat treatment furnace for heating, the opening of the seal head faces downwards, and due to gravity, the arc top of the seal head can collapse, so that the dimensional accuracy of the seal head after heat treatment is affected.
Preferably, when the seal head is a spherical seal head, before the seal head to be quenched is not placed in the external cooling area, the included angle between the spray section and the outer side of the vertical surface is 8-9 degrees, and the arrangement is convenient for hoisting the seal head on site; when the end enclosure to be quenched is hung into an external cooling area under the action of a hanging chain, the lower end surface of the end enclosure presses a pressing rod due to gravity, and the end enclosure automatically rotates inwards along with falling of the end enclosure, and the end enclosure is gradually closed until the optimal quenching state is reached; after quenching is finished, the external spraying device is lifted along with the end socket and is automatically unfolded under the action of the weight box, so that the end socket is lifted out of the quenching cooling device.
Preferably, the main pipeline is connected with the high-pressure water pump B; the upper parts and the outer circles of the upper spray ring and the lower spray ring are respectively provided with a nozzle B which is uniformly arranged in a radial manner along the circular shape of the upper spray ring and the lower spray ring; the distance between the adjacent nozzles B is 100-300mm, the outlets of the nozzles B are consistent with the tangential direction of the ring, the included angle between the nozzles B and the horizontal plane is 30-60 degrees, and the direction of the sprayed water flow is the same as that of the external spraying device.
Preferably, in order to improve the stability of the upper spray ring, a reinforcing column A is arranged below the upper spray ring, and the bottom end of the reinforcing column A is connected with the upper surface of a communicating pipe B; a reinforcing column B is arranged below the lower spray ring, and the bottom end of the reinforcing column B is connected with the top surface of the cross beam; the arrangement can ensure that the internal spraying device is more stable when in use; the number of the reinforcing columns A and the reinforcing columns B is consistent with that of the cross beams.
Preferably, the connection mode of the water inlet pipe, the connection section and the communication ring pipe is one of threaded sealing connection, flange connection, quick plug connection, clamp connection, interference connection and bonding; the connection mode of the communication ring pipe and the high-pressure water pump A and the connection mode of the main pipe and the high-pressure water pump B are one of threaded sealing connection, flange connection, quick plug connection, welding connection, clamp connection, interference connection and bonding.
The heat treatment method comprises the following steps:
(1) Preparing a quenching cooling device:
a circular or square quenching water tank is adopted to drain water in the water tank;
the connecting ring pipe, the upright post, the external spraying device, the internal spraying device and the water inlet pipe of the quenching cooling device are assembled into a whole, and then are arranged in the middle position of the quenching water tank;
connecting the communication annular pipe with a high-pressure water pump A, and connecting the main pipeline with a high-pressure water pump B; completing the installation and connection of the quenching cooling device;
at the moment, the spraying section of the external spraying device is opened outwards under the action of the weight box, the included angle between the spraying section and the outer side of the vertical surface is 8-9 degrees, and enough space is reserved for hanging in the sealing head;
filling water into the quenching water tank, wherein the water level is slightly higher than the highest point of the spray section of the quenching cooling device in an empty load state, and waiting for the end socket to be quenched into water;
(2) Preparing an end socket exhaust pipe:
the quenching water inlet of the seal head is in a state that the opening is downward, so that gas in the inner cavity of the seal head cannot be discharged, and the water cooling effect of the inner cavity area can be affected; in order to solve the problem, before the seal head is quenched into a heat treatment furnace for heating, an exhaust pipe is welded in the seal head, and air in the inner cavity of the seal head and water vapor generated during quenching can be automatically discharged through the exhaust pipe due to gas pressure;
the steel pipe is adopted as an exhaust pipe, the steel pipe is bent into a V shape, one end of the steel pipe is welded in the inner top area of the seal head, the other end of the steel pipe is positioned outside the seal head, and the requirement of the exhaust pipe positioned outside is 1-1.5m higher than the top of the seal head; the sharp angle of the V-shaped exhaust pipe is fixed with the lower end surface of the sealing head;
the exhaust pipe part outside the seal head is fixed with the outer surface of the seal head by adopting reinforcing ribs; the fixing aim is to ensure that the exhaust pipe does not fall off in the heating process in the heat treatment furnace;
(3) Placing an inner sealing head of a heat treatment furnace:
placing a base of the anti-deformation device and a telescopic rod at the central position of a heating platform of the heat treatment furnace, then placing a supporting head at the top end of the telescopic rod, placing sizing blocks on the heating platform according to the diameter of the opening end of the sealing head, wherein the sizing blocks are uniformly distributed along the circumference of the opening end of the sealing head, and the circumferential arc length interval of each sizing block is not more than 2 meters; when the diameter of the opening end of the end socket is larger, the number of sizing blocks should be increased;
The gasket is arranged on the sizing block, the height of the sizing block is adjusted in a mode of adding the gasket on the sizing block, and when the top surface of the supporting head of the anti-deformation device in the furnace is attached to the top area of the inner cavity of the sealing head, the end face of the opening of the sealing head is contacted with each sizing block, so that the multi-point supporting effect of the top and the lower end face is realized;
the method comprises the steps that an opening end of an end socket is lifted by using a three-point lifting chain, the highest point of the top of an inner cavity of the end socket welded with an exhaust pipe is placed at the center position of a supporting head of an in-furnace anti-deformation device, and the welding position of the exhaust pipe and the position of a supporting sheet of the in-furnace anti-deformation device are staggered when placed, so that interference is avoided, the exhaust pipe is damaged, and the exhaust effect is affected; after the end sockets are placed, the lower end face is in a horizontal state so as to reduce deformation in the heating process;
the inner surface and the outer surface of the top area of the end socket, the inner surface of the lower end surface of the end socket and the outer surface of 180 degrees are respectively provided with a contact thermocouple, so that temperature monitoring in the heating process is performed;
(4) Heat treatment operation:
the heat treatment process of the low-carbon martensitic steel seal head comprises quenching and tempering, wherein the control precision of the furnace temperature of the heat treatment furnace is required to be satisfied with +/-5 ℃, and the seal head is required to be positioned in an effective heating area of the heat treatment furnace;
In the quenching heat treatment process, the charging temperature is less than or equal to 200 ℃, the heating rate is less than or equal to 100 ℃/h, the heat preservation temperature is 50-90 ℃ above the Ac3 temperature of the low-carbon martensite, and the heat preservation time is 2-4min/mm; when the quenching heat preservation time is close, a high-pressure water pump B communicated with a main pipeline of the internal spraying device is started to stir water in the quenching water tank to enable the water to have a certain water flow speed;
quenching and cooling: after heat preservation is finished, a furnace door of the heat treatment furnace is opened, an open end of the seal head is lifted by using a three-point hanging chain, the seal head is lifted to be above a quenching water tank from the heat treatment furnace, a driving position is adjusted, the seal head is positioned right above a quenching cooling device, a driving is fallen, and the seal head is placed in the quenching cooling device; in the process, the gas in the inner cavity of the end socket is discharged through the exhaust pipe, and the high-speed water flow sprayed out by the nozzle B of the internal spraying device can rapidly cool the inner surface of the end socket; the transferring time from the lifting of the sealing head from the heat treatment furnace to the complete water inlet is less than or equal to 2.5 minutes;
in the process of falling of the seal head, the opening end of the seal head contacts the compression bar due to self gravity, so that the external spraying device rotates inwards and gradually closes inwards; starting a high-pressure water pump A in the process of falling of the seal head, so that a nozzle A of an external spraying device rapidly cools the outer surface of the seal head;
Stopping when the end socket falls to an optimal quenching state, keeping the state for water cooling, and controlling the water cooling time to be 15-40 minutes according to different wall thicknesses of the end socket;
after the water cooling time is enough, hoisting the end socket; the external spraying device lifts up along with the end socket, and is automatically outwards unfolded under the action of the weight box, so that the end socket is lifted away from the quenching water tank, and quenching heat treatment is completed; wherein the water temperature of the quenching water tank before the end enclosure enters water is less than or equal to 25 ℃, and the water temperature of the quenching water tank after the end enclosure exits water is less than or equal to 35 ℃; the surface temperature of the seal head is less than or equal to 80 ℃ when water is quenched;
in the tempering heat treatment process, the charging temperature is less than or equal to 80 ℃, the heating rate is less than or equal to 100 ℃/h, the heat preservation temperature is 20-60 ℃ below the Ac1 temperature of the low-carbon martensite, and the heat preservation time is 4-6min/mm; after the heat preservation of the end enclosure, adopting the same mode as quenching and cooling, carrying out quick water cooling on the end enclosure, wherein the transfer time is less than or equal to 2.5 minutes, the surface temperature of the end enclosure is less than or equal to 80 ℃ when water is discharged, and discharging gas in the inner cavity of the end enclosure through an exhaust pipe in the water cooling tempering process; after the heat preservation of the seal head is finished, the heat treatment furnace can be cooled in an air cooling mode, the furnace door of the heat treatment furnace is opened, the seal head is lifted out, and the heat treatment furnace is placed in the air for cooling.
At this time, all the procedures of heat treatment are completed, and the end socket is subjected to subsequent performance detection and finish machining to complete manufacturing.
Compared with the prior art, the invention has the beneficial effects that:
1. according to the heat treatment device and the heat treatment method, the deformation of the seal head can be avoided when the heat treatment furnace is heated by the deformation prevention device and the arrangement mode of the seal head in the furnace; by arranging the quenching cooling device, and matching with the heat treatment heat preservation temperature, the heat treatment heat preservation time, the heat treatment transfer time, the tempering, the water cooling, the water temperature control of a quenching water tank and other devices and key parameters, the rapid quenching and tempering of the low-carbon martensitic steel seal head can be realized, the dimensional deformation of the seal head in the heat treatment process is controlled on the premise of ensuring the sufficient transition of the structure, and the material performance and the dimensional precision of the low-carbon martensitic steel seal head are ensured to meet the technical requirements.
2. The heat treatment device and the heat treatment method provided by the invention can be suitable for heat treatment of the structural seal heads such as the spherical seal heads, the elliptic seal heads, the dish-shaped seal heads, the flat seal heads, the spherical cap seal heads and the like, and can be applied to products with the structural characteristics of flush lower end surfaces, certain depth on inner surfaces and airtight top, and have the advantages of high practicability and applicability.
3. In the heat treatment device provided by the invention, the external spraying device and the internal spraying device are used for generating high-pressure water flow under the action of the high-pressure water pump A and the high-pressure water pump B to be directed to the inner surface area and the outer surface area of the end socket, and meanwhile, the quenching cooling device can enable the water flow direction of the whole quenching water tank to be consistent and form vortex, thereby being more beneficial to heat exchange in the quenching process of the end socket and having the advantage of high efficiency.
4. The quenching cooling device is matched with the end socket exhaust pipe device, so that gas in the inner cavity of the end socket can be rapidly discharged, the periphery of the end socket is ensured to have no dead water area, heat can be rapidly taken away, and all surface areas obtain the same cooling strength. The method can be used for heat treatment of forging the large-diameter and large-wall-thickness end socket, and solves the problems that low-carbon martensitic steel is insufficient in tissue transformation caused by insufficient water cooling strength, strength difference caused by different cooling states of the inner surface and the outer surface of the end socket, deformation of the end socket in the quenching process is increased caused by uneven cooling of each area, and the strength of the surface and the core part caused by overlarge wall thickness of the end socket is greatly different.
5. The quenching cooling device has the advantages of reasonable structural design, rapid reaction, stable operation, convenient maintenance and low manufacturing and use cost.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required to be used in the description of the embodiments or the prior art will be briefly described below, and it will be obvious to those skilled in the art that other drawings can be obtained from these drawings without inventive effort.
Fig. 1 is a structural diagram of a spherical head.
Fig. 2 is a structural diagram of a spherical cap head.
Fig. 3 is a structural diagram of an elliptical head.
Fig. 4 is a structural diagram of a butterfly head.
Fig. 5 is a structural diagram of a plate head.
Fig. 6 is a schematic view showing the structure of a quenching apparatus in example 1.
Fig. 7 is a schematic view of the external shower device in embodiment 1.
Fig. 8 is a schematic view of the internal shower device in embodiment 1.
FIG. 9 is a schematic view of the communication loop in example 1.
Fig. 10 is a schematic view showing the connection of the base and the telescopic rod in embodiment 1.
Fig. 11 is a schematic view of the structure of the support head in embodiment 1.
Fig. 12 is a sectional view of the support head in embodiment 1.
Fig. 13 is a schematic structural view of the deformation preventing device in embodiment 1.
Fig. 14 is a schematic diagram showing connection between the exhaust pipe and the head in example 2.
FIG. 15 is a schematic view showing the placement of an inner head of a heat treatment furnace in example 2.
FIG. 16 is a sectional view showing the placement of an inner head of a heat treatment furnace in example 2.
FIG. 17 is a cross-sectional view of the quenching apparatus in the hollow state of example 2.
Fig. 18 is a schematic view of the embodiment 2 in which the open end (lower end face) of the head starts to contact the compression bar.
FIG. 19 is a schematic view showing an optimal quenching state of the quenching apparatus in example 2.
Fig. 20 shows a spherical cap head support head.
Fig. 21 is an oval head support head.
Fig. 22 is a butterfly head support head.
Fig. 23 is a flat head support head.
In the figure, the deformation preventing device comprises a 1-base, a 102-telescopic rod, a 103-supporting head, a 1031-core block, a 1032-supporting sheet, a 2-quenching cooling device, a 201-communicating ring pipe, a 2011-water outlet, a 2012-water inlet, a 2013-upright base, a 202-upright, a 203-external spraying device, a 2031-support, a 2032-branch pipe, a 20321-connecting section, a 20322-mounting section, a 20323-spraying section, a 2033-nozzle A, a 204-internal spraying device, a 2041-main pipe, a 2042-upper spraying ring, a 2043-lower spraying ring, a 2044-communicating pipe A, a 2045-communicating pipe B, a 2046-nozzle B, a 2047-cross beam, a 205-high pressure water pump A, a 206-high pressure water pump B, a 207-inlet pipe, a 3-weight box, a 4-pressure rod, a 5-baffle, a 6-reinforcing column A, a 7-reinforcing column B, an 8-end enclosure, a 9-vent pipe, a 10-reinforcing rib, a 11-filler and a 12-hanging chain.
Detailed Description
In order that those skilled in the art will better understand the technical solutions of the present invention, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention, and it is apparent that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the present invention without making any inventive effort, shall fall within the scope of the present invention.
The heat treatment device and the heat treatment method provided by the invention can be used for heat treatment of spherical sealing heads, elliptic sealing heads, dish-shaped sealing heads, flat sealing heads and spherical crown sealing heads, the sealing head structure is shown in figures 1-5, and the sealing heads can be applicable only by products with the structural characteristics of flush lower end surfaces, certain depth of inner surfaces and airtight top.
Because the spherical sealing head has the advantages of uniform stress form, strong bearing capacity under the same wall thickness and the like, the spherical sealing head has wider application compared with other sealing heads under the condition of high pressure level, and the depth of the cavity on the inner surface of the spherical sealing head is larger and is more representative in the heat treatment process, the spherical sealing head is taken as an example for the embodiment 1 and the embodiment 2 of the invention, and the patent content is described; the radius of the outer spherical surface of the spherical seal head is 1500mm, the outer diameter of the opening at the lower end of the seal head is 3000mm, the height of the seal head is 1800mm, and the wall thickness is 80mm.
Example 1
Referring to fig. 6 to 13, the embodiment provides a heat treatment device for a low-carbon martensitic steel spherical head, which comprises an anti-deformation device 1 and a quenching cooling device 2;
the deformation preventing device 1 is positioned in the heat treatment furnace and comprises a base 101 and a telescopic rod 102 welded with the base 101; the telescopic rod 102 can be fixed after being telescopic to a certain height, so that the height stability is maintained; a supporting head 103 is fixed at the top end of the telescopic rod 102;
The supporting head 103 comprises a core block 1031 and 6 supporting pieces 1032, wherein the core block 1031 is a cylinder, and the 6 supporting pieces 1032 are uniformly distributed on the outer peripheral surface of the cylinder;
the height of the supporting pieces 1032 is larger than the height of the core block 1031, when the supporting pieces 1032 are fixed on the outer peripheral surface of the cylinder, the 6 supporting pieces 1032 enclose a cavity, and the top end of the telescopic rod 102 extends into the cavity and is fixedly connected with the supporting head 103; a chamfer is arranged on the inner side of the bottom end of the supporting sheet 1032, so that the top end of the telescopic rod 102 can conveniently extend into the cavity; two support sheets are oppositely arranged, and the top ends of the core blocks between the two support sheets form a continuous cambered surface which is contacted with the inner top surface of the sealing head; the top ends of the two opposite supporting sheets 1032 and the core block 1031 between the two supporting sheets form a continuous cambered surface which is matched with the shape of the inner top surface of the spherical sealing head 8; when in use, the top end of the telescopic rod 102 is stretched into the cavity and is fixed as a whole, and the height of the telescopic rod 102 is adjusted to enable the top surface of the supporting head 103 to be attached to the inner top surface of the sealing head;
when the heat treatment furnace is used for heating, the opening of the spherical seal head 8 faces downwards, and due to gravity, the arc top of the spherical seal head 8 may collapse, so in the invention, the anti-deformation device 1 is placed in the heat treatment furnace, wherein the base 101 is in a horizontal state, the telescopic rods 102 are in a vertical state, the top ends of the telescopic rods 102 extend into cavities formed by 6 supporting sheets 1032 and core blocks 1031, and the height of the telescopic rods 102 is adjusted according to the distance between a heating platform of the heat treatment furnace and the inner top surface of the seal head 8, so that the top surface of the supporting head 103 contacts and is attached to the inner top surface of the seal head 8, and the collapse phenomenon of the top of the seal head 8 in the heat treatment process is avoided, and the dimensional accuracy of a finished product is further ensured;
The quenching cooling device 2 comprises a communication ring pipe 201, 9 upright posts 202, 9 external spraying devices 203 and an internal spraying device 204;
9 upright posts 202 are uniformly distributed on the inner periphery of the communication ring pipe 201; a column seat 2013 is fixed on the inner side surface of the communication ring pipe 201, and the column 202 and the communication ring pipe 201 are connected into a whole through the column seat 2013;
the water inlet 2012 of the communication loop 201 is connected with the high-pressure water pump A205;
the external spraying device 203 comprises a support 2031 and a branch 2032, wherein the branch 2032 is rotatably connected with the support 2031;
the support 2031 is mounted on top of the column 202;
the branch pipe 2032 comprises a connecting section 20321, a mounting section 20322 and a spraying section 20323 which are sequentially connected, the connecting section 20321 is vertically arranged with the mounting section 20322, the mounting section 20322 is vertically arranged with the spraying section 20323, the connecting section 20321 and the spraying section 20323 are vertically arranged and distributed on the upper side and the lower side of the mounting section 20322, the spraying section 20323 is located above, and the connecting section 20321 is located below;
the communicating ring pipe 201 is provided with water outlets 2011 the same as the external cooling devices in number, and the connecting section 20321 is connected with the water outlets 2011 of the communicating ring pipe 201 through a water inlet pipe 207; the water inlet pipe 207 is a high-pressure rubber pipe; through the high-pressure water pump A205, water enters the spraying section 20323 to quench the seal head 8 to be quenched after passing through the communication ring pipe 201, the water inlet pipe 207, the connecting section 20321 and the mounting section 20322;
A weight box 3 is fixed on one side of the installation section 20322, which is close to the connection section 20321, a compression bar 4 is fixed on one side of the installation section 20323, and the compression bar 4 and the installation section 20322 are coaxially arranged;
the branch pipes 2032, the compression bars 4 and the weight boxes 3 are taken as a whole, and can rotate around the connecting shafts of the support 2031 and the branch pipes 2032 under the arrangement that the support 2031 is connected with the branch pipes 2032 in a rotating way, so that the spraying section 20323 rotates along the support 2031 to form included angles with vertical surfaces in different angles;
in order to limit the outward inclination angle of the spraying section 20323, a baffle plate 5 is fixed on the support 2031, and the baffle plate 5 is close to the side of the weight box 3; the spray section 20323 rotates to the outside under the action of the weight box 3; the spray section 20323 is in threaded connection with nozzles A2033, and the nozzles A2033 are uniformly distributed on the spray section 20323; the interval between adjacent nozzles A is 200mm, so that the spray uniformity of the outer surface of the seal head 8 can be effectively ensured; the spray nozzle A is perpendicular to the spray section 20323, and the included angle between the spray nozzle A and the compression bar 4 is 45 degrees, so that water flow vortex can be well formed, and the heat exchange of water flow in the quenching water tank is ensured; the area surrounded by all the spraying sections 20323 is an external cooling area, and before the end enclosure 8 to be quenched is not placed in the external cooling area, the quenching cooling device 2 is in an empty load state, at the moment, the included angle between the spraying sections 20323 and the vertical surface is 8.5 degrees, and the arrangement is convenient for hoisting the end enclosure 8 on site; when the end enclosure 8 to be quenched is hung into an external cooling area under the action of the hanging chain 12, the lower end surface of the end enclosure 8 presses the pressing rod 4 due to gravity, and the end enclosure 8 automatically rotates inwards along with falling down, and gradually closes until the optimal quenching state is reached; after quenching is finished, the external spraying device 203 is lifted along with the end socket 8 and is automatically unfolded under the action of the weight box 3, so that the end socket 8 is lifted out of the quenching cooling device 2;
The internal spraying device 204 comprises a main pipeline 2041, an upper spraying ring 2042 and a lower spraying ring 2043, wherein the upper spraying ring 2042 is connected with the main pipeline 2041 through a communicating pipe A2044, and the lower spraying ring 2043 is connected with the main pipeline 2041 through a communicating pipe B2045; the upper spray ring 2042 is coaxially arranged with the lower spray ring 2043 and the diameter of the upper spray ring 2042 is 400mm smaller than the diameter of the lower spray ring 2043;
the main pipeline 2041 is connected with a high-pressure water pump B206; the upper part and the outer circle of the upper spray ring 2042 and the lower spray ring 2043 are respectively provided with a nozzle B2046, and the nozzles B2046 are uniformly distributed in a radial shape along the circular shape of the upper spray ring 2042 and the lower spray ring 2043; the distance between adjacent nozzles B2046 is 200mm, the outlets of the nozzles B2046 are consistent along the tangential circular direction, the included angle between the outlets and the horizontal plane is 45 degrees, and the direction of the sprayed water flow is the same as that of the external spraying device 203;
the periphery of the main pipeline 2041 is uniformly provided with horizontally arranged cross beams 2047, and the cross beams 2047 are fixedly connected with the upright posts 202; the internal spraying device 204 is positioned in the area surrounded by the upright posts 202 by the arrangement of the cross beam 2047, and the circle centers of the upper spraying ring 2042 and the communicating ring pipe 201 are positioned on the same straight line;
in order to improve the stability of the upper spray ring 2042, a reinforcing column A6 is welded below the upper spray ring 2042, and the bottom end of the reinforcing column A6 is connected with the upper surface of the communicating pipe B2045 in a welding mode; a reinforcing column B7 is welded below the lower spray ring 2043, and the bottom end of the reinforcing column B7 is connected with the top surface of the cross beam 2047 in a welding mode; the arrangement can ensure that the internal spraying device 204 is more stable when in use; the number of the reinforcing columns A6 and the reinforcing columns B7 is consistent with that of the cross beams 2047;
In this embodiment, the connection section 20321 is in threaded sealing connection with the water inlet pipe 207, and the connection mode of the water inlet pipe 207 with the communication loop 201, the communication loop 201 with the high-pressure water pump a205, and the main pipe 2041 with the high-pressure water pump B206 is in threaded sealing connection;
when the quenching device is used, the end socket 8 to be quenched is lifted to the quenching cooling device 2, under the condition that the opening of the end socket 8 is downward for quenching and water entering, the inner surface and the outer surface of the end socket 8 can be impacted by high-pressure water flow at the same time, the heat of the end socket 8 is taken away rapidly, the areas of all parts of the end socket 8 can be cooled rapidly, the effect of fully transforming the internal structure of the end socket 8 is achieved, and the cooling speed of the inner surface and the outer surface of the end socket 8 is improved.
Example 2
The heat treatment device provided in the embodiment 1 is adopted to heat treat the low-carbon martensitic steel ball-shaped end socket, and the low-carbon martensitic steel ball-shaped end socket is chromium-nickel-molybdenum-vanadium low-carbon martensitic steel for ships, and comprises the following elements in percentage by weight: 0.10% of C, 4.9% of Ni, 0.55% of Cr, 0.55% of Mo and 0.06% of V; the spherical sealing head has a structural form of a whole hemisphere, a 150mm tangent straight section is arranged at the opening end of the spherical sealing head for sampling detection, the wall thickness of the sealing head is 120mm during heat treatment, the inner diameter of the opening is 3000mm, and the inner height is 1650mm;
The heat treatment process of the low-carbon martensitic steel spherical end socket is as follows:
(1) The quenching cooling device 2 prepares:
a circular quenching water tank is adopted to drain water in the water tank;
the upright post 202, the external spraying device 203 and the internal spraying device 204 of the quenching cooling device 2 are assembled into a whole and then placed in the middle position of a quenching water tank;
the external spraying device 203 is connected with the high-pressure water pump A205, and the internal spraying device 204 is connected with the high-pressure water pump B206; completing the installation and connection of the quenching cooling device 2;
at this time, the spraying section 20323 of the external spraying device 203 is opened outwards under the action of the weight box 3, the included angle between the spraying section 20323 and the vertical surface is 8.5 degrees, and enough space is reserved for hanging in the seal head 8;
filling water into the quenching water tank, wherein the water level is slightly higher than the highest point of a spray section 20323 of the quenching cooling device 2 in an empty load state, and waiting for the end socket 8 to be quenched into water;
(2) The end cap 8 exhaust pipe 9 is prepared, see fig. 14:
the quenching water entering of the seal head 8 is in a state that the opening is downward, and the gas in the inner cavity of the seal head 8 cannot be discharged, so that the water cooling effect of the inner cavity area can be influenced; in order to solve the problem, before the seal head 8 is quenched into a heat treatment furnace for heating, an exhaust pipe 9 is welded in the seal head 8, and air in the inner cavity of the seal head 8 and water vapor generated during quenching can be automatically discharged through the exhaust pipe 9 due to gas pressure;
A steel pipe is adopted as an exhaust pipe 9, the steel pipe is bent into a V shape, one end of the steel pipe is welded in the inner top area of the seal head 8, the other end of the steel pipe is positioned outside the seal head 8, and the requirement of the exhaust pipe 9 positioned outside is 1.2m higher than the top of the seal head 8; the sharp angle of the V-shaped exhaust pipe 9 is fixed with the lower end surface of the sealing head 8;
the part of the exhaust pipe 9 outside the seal head 8 is fixed with the outer surface of the seal head 8 by adopting reinforcing ribs 10; the purpose of fixing is to ensure that the exhaust pipe 9 does not fall off during the heating process in the heat treatment furnace;
(3) Placing the seal head 8 in the heat treatment furnace, see fig. 15 and 16:
placing the base 101 and the telescopic rod 102 of the anti-deformation device 1 at the center of a heating platform of a heat treatment furnace, fixedly connecting the supporting head 103 with the top end of the telescopic rod 102, and staggering the welding position of the exhaust pipe 9 and the position of the supporting sheet 1032 of the anti-deformation device 1 in the furnace; according to the diameter of the opening end of the seal head 8, sizing blocks 11 are placed on a heating platform, the sizing blocks 11 are uniformly distributed along the circumference of the opening end of the seal head 8, the circumferential arc length interval of each sizing block 11 is 1.6 meters, and the number of sizing blocks is 6;
a gasket (not shown in the figure) is arranged on the sizing block 11, the height of the sizing block 11 is adjusted by adding the gasket on the sizing block 11, and the opening end face of the sealing head 8 is contacted with each sizing block 11 while the top surface of the supporting head 103 of the anti-deformation device 1 in the furnace is attached to the top area of the inner cavity of the sealing head 8, so that the multi-point supporting function of the top and the lower end face is realized; after the sealing head 8 is placed, the lower end surface is in a horizontal state so as to reduce deformation in the heating process;
The inner surface and the outer surface of the top area of the seal head 8, the inner surface of the lower end surface of the seal head 8 and the outer surface of 180 degrees are respectively provided with a contact thermocouple, so that temperature monitoring in the heating process is performed;
(4) Heat treatment operation, see fig. 17-19:
the heat treatment process of the low-carbon martensitic steel seal head 8 comprises quenching and tempering, the control precision of the furnace temperature of the heat treatment furnace is required to be satisfied with +/-5 ℃, and the seal head 8 is required to be positioned in an effective heating area of the heat treatment furnace;
in the quenching heat treatment process, the charging temperature is 200 ℃, the heating rate is 100 ℃/h, the heat preservation temperature is 870-880 ℃, and the heat preservation time is 3min/mm; when the quenching heat preservation time is close, a high-pressure water pump B206 communicated with a main pipeline 2041 of the internal spraying device 204 is turned on, and water in the quenching water tank is stirred to have a certain water flow speed;
quenching and cooling: after heat preservation is finished, a furnace door of the heat treatment furnace is opened, an opening end of the seal head 8 is lifted by using a three-point hanging chain 12, the highest point at the top of the inner cavity of the seal head 8 welded with the exhaust pipe 9 is arranged at the center position of the supporting head 103 of the in-furnace deformation preventing device 1, and the welding position of the exhaust pipe 9 is staggered from the position of the supporting sheet 1032 of the in-furnace deformation preventing device 1 during arrangement so as to avoid interference and damage to the exhaust pipe 9, thereby influencing the exhaust effect; lifting the sealing head 8 from the heat treatment furnace to the position above the quenching water tank, adjusting the driving position to enable the sealing head 8 to be positioned right above the quenching cooling device 2, driving down, and placing the sealing head 8 into the quenching cooling device 2; in the process, the gas in the inner cavity of the seal head 8 is discharged through the exhaust pipe 9, and the high-speed water flow sprayed out by the nozzle B2046 of the internal spraying device 204 can rapidly cool the inner surface of the seal head 8; the transferring time from the lifting of the sealing head 8 from the heat treatment furnace to the complete water entering is 2 minutes;
In the process of falling of the seal head 8, the opening end of the seal head 8 contacts the compression bar 4 due to self gravity, so that the external spraying device 203 rotates inwards and gradually closes inwards; starting a high-pressure water pump A205 in the falling process of the sealing head 8, so that a nozzle A of an external spraying device 203 can rapidly cool the outer surface of the sealing head 8;
stopping when the end socket 8 falls to an optimal quenching state, keeping the state for water cooling, and controlling the water cooling time to be 30 minutes according to different wall thicknesses of the end socket 8;
after the water cooling time is enough, lifting the sealing head 8; the external spraying device 203 is lifted along with the seal head 8, and is automatically unfolded outwards under the action of the weight box 3, so that the seal head 8 is lifted away from the quenching water tank, and the quenching heat treatment is completed; wherein the water temperature of the quenching water tank before the end enclosure 8 is filled with water is 25 ℃, and the water temperature of the quenching water tank after the end enclosure 8 is filled with water is 35 ℃; the surface temperature of the seal head 8 is 70 ℃ when water is quenched;
in the tempering heat treatment process, the charging temperature is 80 ℃, the heating rate is 100 ℃/h, the heat preservation temperature is 600-610 ℃, and the heat preservation time is 5min/mm; after the heat preservation of the end enclosure 8 is finished, the end enclosure 8 is rapidly cooled by water in the same way as quenching and cooling, the transfer time is 2.5 minutes, and the surface temperature of the end enclosure 8 is 80 ℃ when water is discharged; in the tempering process, the gas in the inner cavity of the seal head 8 is discharged through the exhaust pipe 9;
At this time, all the heat treatment steps are completed, and the end socket 8 is subjected to subsequent performance detection and finish machining to complete the manufacturing of the spherical end socket.
Comparative example 1
The difference from example 2 is that the heat treatment apparatus provided in example 1 was not used, and the remaining heat treatment parameters were the same as those in example 2.
The spherical head obtained in example 2 and the spherical head obtained in comparative example 1 were subjected to performance test and size test, respectively.
The performance detection method comprises the following steps: taking a straight section of the opening end of the end socket as a detection material, and cutting two test blocks with 180-degree angular intervals on the straight section; each test block is divided into three layers of an inner surface, a core and an outer surface in the wall thickness direction, each layer is processed into a warp-wise tensile test sample and a weft-wise tensile test sample, and room temperature tensile test and low temperature impact test are carried out.
The size detection method comprises the following steps: the wall thickness variation of the seal head is extremely small in the heat treatment process, and the deformation condition of the seal head is measured by the coordinate variation of the outer surface; and measuring the coordinates of the outer surface of the spherical top of the sealing head and the coordinates of the eight equally divided positions of the weft of the opening end by adopting a three-coordinate measuring instrument and taking the lower surface of the opening end of the spherical sealing head as a reference, and comparing the coordinate values before and after heat treatment to obtain the size deformation.
The results of the performance test and the dimension test of example 2 and comparative example 1 were statistically compared, and the results are shown in tables 1 and 2, as follows:
Table 1 results of measurement of spherical head Performance
As can be seen from Table 1, in comparative example 1, the average value of yield strength was 783MPa, the average value of yield strength at the center portion thereof was 763MPa, the average value of yield strength at the inner and outer surface portions thereof was 793MPa, and the difference between them was 30MPa; the average elongation after break is 21%, the average area shrinkage is 72%, the average impact absorption energy at-20 ℃ is 209J, and the average impact absorption energy at-84 ℃ is 189J;
after the heat treatment device of the invention is used, the average value of the yield strength of the embodiment 2 is 849MPa, the average value of the yield strength of the central part position is 848MPa, the average value of the yield strength of the inner surface position and the outer surface position is 849MPa, and the difference between the two is only 1MPa; the average elongation after break is 22%, the average reduction of area is 75%, the average impact absorption energy at-20 ℃ is 233J, and the average impact absorption energy at-84 ℃ is 205J;
comparing example 2 with comparative example 1, it is known that with the heat treatment device of the present invention, the yield strength of the seal head is improved by 66MPa, and the difference between the yield strength of the wall thickness center portion and the yield strength of the inner and outer surface positions is reduced from 30MPa to 1MPa, mainly because after the water cooling strength of the spherical seal head is improved, the internal martensitic structure of the seal head is more fully transformed, especially the center position is improved; meanwhile, the average value of low-temperature impact absorption energy of the end enclosure at-20 ℃ and-84 ℃ is respectively improved by 24J and 16J, so that the strength and toughness of the end enclosure material are synchronously improved.
Table 2 measurement results of spherical head size
As is clear from Table 2, when the heat treatment apparatus of the present invention was not used in comparative example 1, the maximum deformation amount of the head after heat treatment was 25.8mm, the average deformation amount of the lower end face was 12.2mm, the deformation was uneven in the respective positions, and the head top collapse amount was the maximum deformation; after the heat treatment device disclosed by the invention is used in the embodiment 2, the maximum deformation of the seal head after heat treatment is 7.1mm, the average deformation of the lower end face is 6.3mm, and the deformation of the lower end face is uniform;
that is, although the top of the ball of the sealing head is collapsed and the open end is expanded outwards after the heat treatment, the maximum deformation of the spherical sealing head can be reduced from 25.8mm to 7.1mm by adopting the heat treatment device of the invention; in terms of process margin, the wall thickness of 18.7mm can be reduced; for the seal head with the heat treatment wall thickness of 120mm, the wall thickness of the seal head capable of being finished is increased from 94.2mm to 112.9mm, and the yield is increased by about 20%;
therefore, in the spherical seal head heat treatment process, the seal head is deformed in heat treatment due to the reasons of heating in a seal head furnace, quenching structure transformation and the like, and the deformation directly influences the process allowance of the seal head, thereby influencing the yield and the manufacturing cost; therefore, in the invention, the heat treatment device is used for carrying out heat treatment on the low-carbon martensitic steel spherical end socket, so that the heat treatment deformation amount is effectively controlled, the process allowance is reduced, the finish machining cutting amount is reduced on the basis of reducing the material input amount, and the manufacturing efficiency is improved.
Example 3
The support head of example 1 was deformed, see fig. 20-23, fig. 20 being a spherical cap head support head structure, fig. 21 being an elliptical head support head, fig. 21 being a butterfly head support head, fig. 23 being a flat head support head;
replacing the spherical head support head of the embodiment 1 with the spherical head support head of the fig. 20, and treating the spherical head by adopting the heat treatment method of the embodiment 2 to obtain the spherical head;
the spherical head support head of example 1 was replaced with the flat head support head of fig. 23, and the flat head was treated by the heat treatment method of example 2, to obtain a flat head.
Although the present invention has been described in detail by way of reference to preferred embodiments, the present invention is not limited thereto. Various equivalent modifications and substitutions may be made in the embodiments of the present invention by those skilled in the art without departing from the spirit and scope of the present invention, and it is intended that all such modifications and substitutions be within the scope of the present invention/be within the scope of the present invention as defined by the appended claims. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (9)
1. The heat treatment device of the low-carbon martensitic steel end socket comprises a deformation prevention device and a quenching cooling device, and is characterized in that,
the deformation preventing device is positioned in the heat treatment furnace and comprises a base and a telescopic rod fixedly connected with the base; a supporting head is fixed at the top end of the telescopic rod; the top surface of the supporting head is matched with the shape of the inner surface of the sealing head to be heat treated, and the top surface of the supporting head is attached to the inner top surface of the sealing head;
the quenching cooling device comprises a communicating annular pipe, wherein the inner peripheral side of the communicating annular pipe is fixedly provided with upright posts, and the circumferential distance between two adjacent upright posts is 1-2 meters;
external spraying devices are fixed at the top ends of the upright posts and are connected with the communication annular pipe;
the external spraying device comprises a support and a branch pipe, the support is fixedly connected with the top end of the upright post, and the branch pipe is rotationally connected with the support; the branch pipe comprises a connecting section, a mounting section and a spraying section which are sequentially connected, wherein the connecting section is vertically arranged with the mounting section, the mounting section is vertically arranged with the spraying section, the connecting section and the spraying section are vertically arranged and distributed on the upper side and the lower side of the mounting section, the spraying section is positioned above, and the connecting section is positioned below; a weight box is arranged on one side of the installation section, which is close to the connection section, and a compression bar is arranged on one side of the installation section, which is close to the spraying section, and the compression bar and the installation section are coaxially arranged;
The internal spraying device comprises a main pipeline, an upper spraying ring and a lower spraying ring, wherein the upper spraying ring is connected with the main pipeline through a communicating pipe A, and the lower spraying ring is connected with the main pipeline through a communicating pipe B; the upper spray ring and the lower spray ring are coaxially arranged, and the diameter of the upper spray ring is smaller than that of the lower spray ring; and a horizontal beam is arranged on the periphery of the main pipeline and is fixedly connected with the upright post.
2. The heat treatment device of the low-carbon martensitic steel seal head according to claim 1, wherein water outlets are arranged on the communicating ring pipe, and the number of the water outlets is the same as that of the external spraying devices; the water inlet of the communication ring pipe is connected with the high-pressure water pump A, and the water outlet is respectively connected with the connecting section of the external spraying device through a water inlet pipe; the water inlet pipe is a high-pressure rubber pipe.
3. The heat treatment device of the low-carbon martensitic steel end socket of claim 2, wherein a baffle is fixed on the support, and the baffle is close to the side of the weight box; the spray section is in threaded connection with nozzles A which are uniformly distributed on the spray section; the distance between adjacent nozzles A is 100-300mm; the spray nozzle A is perpendicular to the spray section, and the included angle between the spray nozzle A and the compression bar is 30-60 degrees.
4. The heat treatment device of the low-carbon martensitic steel seal head according to claim 3, wherein the support head comprises a core block and a plurality of support pieces, the core block is a cylinder, and the support pieces are uniformly distributed on the outer peripheral surface of the cylinder; the height of the supporting sheets is larger than that of the core blocks, when the supporting sheets are fixed on the outer peripheral surface of the cylinder, the supporting sheets enclose a cavity, and the top ends of the telescopic rods extend into the cavity and are fixedly connected with the supporting heads; and a chamfer is arranged on the inner side of the bottom end of the supporting piece.
5. The heat treatment apparatus of low carbon martensitic steel head according to claim 4, wherein when the head is a spherical head, the spray section forms an angle of 8-9 ° with the outside of the vertical surface before the head to be quenched is not placed in the external cooling zone.
6. The heat treatment device of the low-carbon martensitic steel end socket of claim 5, wherein the main pipeline is connected with a high-pressure water pump B; the upper parts and the outer circles of the upper spray ring and the lower spray ring are respectively provided with a nozzle B which is uniformly arranged in a radial manner along the circular shape of the upper spray ring and the lower spray ring; the distance between adjacent nozzles B is 100-300mm, the outlets of the nozzles B are consistent with the tangential direction of the ring, and the included angle between the outlets of the nozzles B and the horizontal plane is 30-60 degrees.
7. The heat treatment device of the low-carbon martensitic steel seal head according to claim 6, wherein a reinforcing column A is arranged below the upper spray ring, and the bottom end of the reinforcing column A is connected with the upper surface of the communicating pipe B; and a reinforcing column B is arranged below the lower spray ring, and the bottom end of the reinforcing column B is connected with the top surface of the cross beam.
8. The heat treatment device of the low-carbon martensitic steel seal head according to claim 7, wherein the connection mode of the water inlet pipe and the connection section and the communication ring pipe is one of screw thread sealing connection, flange connection, quick plug connection, clamp connection, interference connection and bonding; the connection mode of the communication ring pipe and the high-pressure water pump A and the connection mode of the main pipe and the high-pressure water pump B are one of threaded sealing connection, flange connection, quick plug connection, welding connection, clamp connection, interference connection and bonding.
9. A heat treatment method for a low carbon martensitic steel end socket by using the heat treatment device according to claim 1, characterized in that the process is as follows:
(1) Preparing a quenching cooling device:
a circular or square quenching water tank is adopted to drain water in the water tank;
the connecting ring pipe, the upright post, the external spraying device, the internal spraying device and the water inlet pipe of the quenching cooling device are assembled into a whole, and then are arranged in the middle position of the quenching water tank;
Connecting the communication annular pipe with a high-pressure water pump A, and connecting the main pipeline with a high-pressure water pump B; completing the installation and connection of the quenching cooling device;
at the moment, the spraying section of the external spraying device is opened outwards under the action of the weight box, and the included angle between the spraying section and the outer side of the vertical surface is 8-9 degrees;
filling water into the quenching water tank, wherein the water level is slightly higher than the highest point of the spray section of the quenching cooling device in an empty load state, and waiting for the end socket to be quenched into water;
(2) Preparing an end socket exhaust pipe:
welding an exhaust pipe in the end socket, and exhausting air in the inner cavity of the end socket and water vapor generated during quenching from the exhaust pipe;
the steel pipe is adopted as an exhaust pipe, the steel pipe is bent into a V shape, one end of the steel pipe is welded in the inner top area of the seal head, the other end of the steel pipe is positioned outside the seal head, and the requirement of the exhaust pipe positioned outside is 1-1.5m higher than the top of the seal head; the sharp angle of the V-shaped exhaust pipe is fixed with the lower end surface of the sealing head;
the exhaust pipe part outside the seal head is fixed with the outer surface of the seal head by adopting reinforcing ribs;
(3) Placing an inner sealing head of a heat treatment furnace:
placing a base of the anti-deformation device and a telescopic rod at the central position of a heating platform of the heat treatment furnace, then placing a supporting head at the top end of the telescopic rod, placing sizing blocks on the heating platform according to the diameter of the opening end of the sealing head, wherein the sizing blocks are uniformly distributed along the circumference of the opening end of the sealing head, and the circumferential arc length interval of each sizing block is not more than 2 meters; when the diameter of the opening end of the end socket is larger, the number of sizing blocks should be increased;
A gasket is arranged on the sizing block, and the end face of the opening of the sealing head is contacted with each sizing block while the top surface of the supporting head of the anti-deformation device in the furnace is attached to the top area of the inner cavity of the sealing head;
the method comprises the steps that an opening end of an end socket is lifted by using a three-point lifting chain, the highest point of the top of an inner cavity of the end socket welded with an exhaust pipe is placed at the center position of a supporting head of an in-furnace anti-deformation device, and the welding position of the exhaust pipe is staggered with the position of a supporting sheet of the in-furnace anti-deformation device during placement; after the end sockets are placed, the lower end face is in a horizontal state;
the inner surface and the outer surface of the top area of the end socket, the inner surface of the lower end surface of the end socket and the outer surface of 180 degrees are respectively provided with a contact thermocouple;
(4) Heat treatment operation:
the heat treatment process of the low-carbon martensitic steel seal head comprises quenching and tempering, wherein the control precision of the furnace temperature of the heat treatment furnace is required to be satisfied with +/-5 ℃, and the seal head is required to be positioned in an effective heating area of the heat treatment furnace;
in the quenching heat treatment process, the charging temperature is less than or equal to 200 ℃, the heating rate is less than or equal to 100 ℃/h, the heat preservation temperature is 50-90 ℃ above the Ac3 temperature of the low-carbon martensite, and the heat preservation time is 2-4min/mm; when the quenching heat preservation time is close, a high-pressure water pump B communicated with a main pipeline of the internal spraying device is started to stir water in the quenching water tank;
Quenching and cooling: after heat preservation is finished, a furnace door of the heat treatment furnace is opened, an open end of the seal head is lifted by using a three-point hanging chain, the seal head is lifted to be above a quenching water tank from the heat treatment furnace, a driving position is adjusted, the seal head is positioned right above a quenching cooling device, a driving is fallen, and the seal head is placed in the quenching cooling device; in the process, the gas in the inner cavity of the end socket is discharged through the exhaust pipe, and the high-speed water flow sprayed out by the nozzle B of the internal spraying device can rapidly cool the inner surface of the end socket; the transferring time from the lifting of the sealing head from the heat treatment furnace to the complete water inlet is less than or equal to 2.5 minutes;
starting a high-pressure water pump A in the process of falling of the seal head; stopping when the end socket falls to an optimal quenching state, keeping the state for water cooling, and controlling the water cooling time to be 15-40 minutes according to different wall thicknesses of the end socket;
after the water cooling time is enough, hoisting the end socket; the external spraying device lifts up along with the end socket, lifts the end socket away from the quenching water tank, and completes quenching heat treatment; wherein the water temperature of the quenching water tank before the end enclosure enters water is less than or equal to 25 ℃, and the water temperature of the quenching water tank after the end enclosure exits water is less than or equal to 35 ℃; the surface temperature of the seal head is less than or equal to 80 ℃ when water is quenched;
in the tempering heat treatment process, the charging temperature is less than or equal to 80 ℃, the heating rate is less than or equal to 100 ℃/h, the heat preservation temperature is 20-60 ℃ below the Ac1 temperature of the low-carbon martensite, and the heat preservation time is 4-6min/mm; after the heat preservation of the end enclosure, adopting the same mode as quenching and cooling to rapidly water-cool the end enclosure, wherein the transfer time is less than or equal to 2.5 minutes, and the surface temperature of the end enclosure is less than or equal to 80 ℃ when water is discharged; after the heat preservation of the seal head is finished, cooling is carried out in an air cooling mode, a furnace door of the heat treatment furnace is opened, the seal head is lifted out, and the heat treatment furnace door is placed in air for cooling;
And (3) finishing all the procedures of heat treatment, and finishing the manufacture of the seal head through subsequent performance detection and finish machining.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311823728.XA CN117488049A (en) | 2023-12-28 | 2023-12-28 | Heat treatment device and heat treatment method for low-carbon martensitic steel seal head |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311823728.XA CN117488049A (en) | 2023-12-28 | 2023-12-28 | Heat treatment device and heat treatment method for low-carbon martensitic steel seal head |
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20100183473A1 (en) * | 2007-10-29 | 2010-07-22 | Shinya Teramoto | Martensite type hot forging use non heat-treated steel and hot forged non heat-treated steel part |
| CN216039716U (en) * | 2021-10-13 | 2022-03-15 | 无锡锅容封盖制造有限公司 | Head heat treatment fixing tool |
| CN114540597A (en) * | 2022-03-29 | 2022-05-27 | 河南工学院 | Head spare quenching spray set |
-
2023
- 2023-12-28 CN CN202311823728.XA patent/CN117488049A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20100183473A1 (en) * | 2007-10-29 | 2010-07-22 | Shinya Teramoto | Martensite type hot forging use non heat-treated steel and hot forged non heat-treated steel part |
| CN216039716U (en) * | 2021-10-13 | 2022-03-15 | 无锡锅容封盖制造有限公司 | Head heat treatment fixing tool |
| CN114540597A (en) * | 2022-03-29 | 2022-05-27 | 河南工学院 | Head spare quenching spray set |
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