CN114990300A - Heat treatment method of welded pipe die steel - Google Patents

Heat treatment method of welded pipe die steel Download PDF

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Publication number
CN114990300A
CN114990300A CN202210351272.0A CN202210351272A CN114990300A CN 114990300 A CN114990300 A CN 114990300A CN 202210351272 A CN202210351272 A CN 202210351272A CN 114990300 A CN114990300 A CN 114990300A
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workpiece
treatment
temperature
furnace
quenching
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CN202210351272.0A
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王钱钱
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Yangzhou Qianshang Precision Machinery Co ltd
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Yangzhou Qianshang Precision Machinery Co ltd
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Priority to CN202210351272.0A priority Critical patent/CN114990300A/en
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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
    • C21D6/00—Heat treatment of ferrous alloys
    • C21D6/04—Hardening by cooling below 0 degrees Celsius
    • 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
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00—Technologies related to metal processing
    • Y02P10/25—Process efficiency

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Heat Treatment Of Articles (AREA)

Abstract

The application discloses a heat treatment method of welded pipe die steel, which comprises the following steps: solution treatment, namely placing the workpiece in a furnace body, heating the workpiece along with the furnace, then preserving heat, placing the workpiece in hot oil at 60-100 ℃ for quenching, and finishing the solution treatment; high-temperature tempering treatment, namely heating the workpiece subjected to the medium solid solution treatment along with a furnace; vacuum oil quenching, namely heating the workpiece subjected to high-temperature tempering along with a furnace, heating and then preserving heat, and putting the workpiece into hot oil for quenching; refining, namely slowly heating and preheating the workpiece subjected to vacuum oil quenching, heating and preserving heat, and then putting the workpiece into hot oil at 60-100 ℃ for quenching; performing ultra-deep cooling treatment, namely placing the quenched workpiece in a freezing box, cooling to minus 150 ℃, preserving heat for 2.5 hours, and taking out; low-temperature tempering treatment, namely placing the workpiece subjected to ultra-deep cooling treatment in a furnace, keeping the temperature at 160 +/-10 ℃ for 5-6 hours, and cooling the workpiece to normal temperature by adopting air to finish primary low-temperature tempering treatment; and repeating the low-temperature tempering treatment once to finish the heat treatment process of the welded pipe die steel.

Description

Heat treatment method of welded pipe die steel
Technical Field
The application relates to the technical field of steel products, in particular to a heat treatment method of welded pipe die steel.
Background
At present, Cr12MoV high-quality die steel is generally selected as a raw material of a die, and is manufactured into die steel with the hardness of 63-65HRC after high-precision numerical control machining and vacuum gas quenching and hardening treatment, so that the die steel is suitable for producing stainless steel, copper or aluminum profiles and can also be used for producing high-frequency welded pipes. The existing heat treatment process technology has limitations, and the manufactured die has the following problems in the process of producing the stainless steel pipe: (1) easily cause the die to collapse, and the product generates strain, wrinkles, nail marks and fish scale marks. (2) Easily deformed, for example: out-of-round, irregular profile, etc. Therefore, the hardness and the strength of the steel forging of the welded pipe die need to be improved, so that the pipe forming is smooth, the stability is good, the pipe forming efficiency is high, and the phenomena of strain, nail marks and the like of the steel pipe are avoided.
Disclosure of Invention
It is an object of the present application to overcome the above problems or to at least partially solve or mitigate the above problems.
According to an aspect of the present application, there is provided a heat treatment method of a die steel for welded pipes, comprising:
step S1: solid solution treatment, namely placing the workpiece in a furnace body and raising the temperature along with the furnace, raising the temperature to 650 ℃ firstly, then raising the temperature to 850 ℃ secondly, and preheating twice; then raising the temperature to 1250 +/-10 ℃ at the speed of 215 plus 240 ℃/h, preserving the heat for 1.5-2 h, and then placing the workpiece in hot oil at the temperature of 60-100 ℃ for quenching to finish the solid solution treatment;
step S2: high-temperature tempering treatment, namely heating the workpiece subjected to the solution treatment in the step S1 along with a furnace at a speed of 215-;
step S3: vacuum oil quenching, namely heating the workpiece subjected to the high-temperature tempering treatment in the step S2 along with a furnace to 1030 +/-10 ℃, preserving the temperature for 4 hours, and then placing the workpiece in hot oil at the temperature of 100 plus 120 ℃ for quenching to finish the vacuum oil quenching treatment;
step S4: refining, namely slowly heating the workpiece subjected to the vacuum oil quenching treatment in the step S3 to 800-;
step S5: performing ultra-deep cooling treatment, namely placing the workpiece subjected to quenching treatment in the step S4 in a freezing box, cooling to minus 150-minus 180 ℃, preserving heat for 2.5 hours, and taking out to finish the ultra-deep cooling treatment;
step S6: low-temperature tempering, namely placing the workpiece subjected to the ultra-deep cold treatment in the step S5 in a furnace, keeping the temperature at 160 +/-10 ℃ for 5-6 hours, and cooling the workpiece to normal temperature by adopting air to finish primary low-temperature tempering;
step S7: and repeating the low-temperature tempering treatment in the step S6 once to finish the heat treatment process of the welded pipe die steel.
Optionally, in the step S1, in the solution treatment, the workpiece is placed in the furnace body and heated along with the furnace, the temperature is first raised to 500-; then raising the temperature to 1130 +/-10 ℃ at the speed of 205-215 ℃ per hour, preserving the temperature for 1.5-2 hours, and then quenching in hot oil at the temperature of 70-90 ℃ to finish the solid solution treatment.
Optionally, in the step S2 high-temperature tempering treatment, the temperature of the workpiece subjected to the solution treatment in the step S1 is increased with the furnace, specifically, the temperature is increased to 760 ℃ at a speed of 205-.
Optionally, in the step S3 vacuum oil quenching treatment, the workpiece subjected to the high temperature tempering treatment in the step S2 is heated with the furnace, is preheated at 500-.
Optionally, in the refining treatment of step S4, the workpiece processed by the vacuum oil quenching of step S3 is slowly heated to 815-.
Optionally, in the step S5 ultra-deep cooling treatment, the workpiece refined in the step S4 is placed in a freezer to be cooled to-150 ℃ to-180 ℃, and is taken out after being kept at the temperature for 2.5 hours, so that the ultra-deep cooling treatment is completed.
Optionally, in the step S6 low-temperature tempering treatment, the workpiece subjected to the ultra-deep cooling treatment in the step S5 is placed in a furnace, and is kept at 160 ℃ ± 10 ℃ for 5, 5.5 or 6 hours, and then is cooled to normal temperature by using air, so as to complete a low-temperature tempering treatment.
Optionally, the step S7 includes: then placing the workpiece in a furnace, keeping the temperature at 160 +/-10 ℃ for 5-6 hours, and cooling the workpiece to normal temperature by adopting air to finish secondary low-temperature tempering treatment; and finishing the heat treatment process of the welded pipe die steel.
The invention adds the solution refining heat treatment before quenching, can refine the net carbide in the steel, improve the form and the granularity of the carbide, lead the carbide to be distributed evenly, have fine and round granularity, lead the structure crystal grains of the steel matrix to be ultra-fine and improve the performance of the steel. The cryogenic temperature is reduced, so that the transformation of the residual austenite is more sufficient.
The invention reduces the deformation and ensures the performance of the workpiece on the premise of no cracking of the workpiece by increasing the temperature of the quenching medium, namely by adopting hot oil at 60-100 ℃ as the quenching medium.
The process flows related to the invention are buckled and tightly combined with each other, so that the performance, particularly the hardness, of the workpiece is obviously improved, and the use requirement can be met.
The above, as well as additional purposes, advantages, and features of the present application, will become apparent to those of ordinary skill in the art upon examination of the following detailed description of specific embodiments of the application.
Detailed Description
A preferred embodiment of the present application provides a heat treatment method of die steel for welded pipes, comprising:
step S1: solid solution treatment, namely placing the workpiece in a furnace body and heating the workpiece along with the furnace, firstly heating the workpiece to 650 ℃ and then to 850 ℃ and preheating the workpiece twice; heating to 1250 ℃ +/-10 ℃ at the speed of 215-; then raising the temperature to 1130 +/-10 ℃ at the speed of 205-;
step S2: high-temperature tempering treatment, namely heating the workpiece subjected to the solution treatment in the step S1 along with a furnace, specifically, heating to 960 ℃ at the speed of 240 ℃/h in 215 plus materials for 4-6 h, then cooling to the normal temperature by adopting air to finish the high-temperature tempering treatment, heating the workpiece subjected to the solution treatment in the step S1 along with the furnace, specifically, heating to 760 ℃ at the speed of 215 ℃/h in 205 plus materials for 4-6 h, then cooling to the normal temperature by adopting air to finish the high-temperature tempering treatment;
step S3: vacuum oil quenching, heating the workpiece subjected to the high-temperature tempering treatment in the step S2 along with the furnace to 1030 +/-10 ℃, preserving the temperature for 4 hours, then placing the workpiece in 100-plus-120 ℃ hot oil for quenching to finish the vacuum oil quenching treatment, heating the workpiece subjected to the high-temperature tempering treatment in the step S2 along with the furnace, preheating the workpiece at the temperature of 500-plus-600 ℃ and the temperature of 815-plus-835 ℃ for two times, heating the workpiece to 1030 +/-10 ℃ at the speed of 205-plus-215 ℃ per hour, preserving the temperature for 1.5-2 hours, then quenching in 60-100 ℃ hot oil to finish the vacuum oil quenching treatment
Step S4: refining, namely, slowly heating the workpiece subjected to the vacuum oil quenching treatment in the step S3 to 800-;
step S5: performing ultra-deep cooling treatment, namely placing the workpiece subjected to quenching treatment in the step S4 in a freezing box, cooling to minus 150-minus 180 ℃, preserving heat for 2.5 hours, then taking out the workpiece to finish the ultra-deep cooling treatment, placing the workpiece subjected to refining treatment in the step S4 in the freezing box, cooling to minus 150-minus 180 ℃, preserving heat for 2.5 hours, then taking out the workpiece to finish the ultra-deep cooling treatment;
step S6: low-temperature tempering treatment, namely placing the workpiece subjected to the ultra-deep cooling treatment in the step S5 in a furnace, preserving the temperature at 160 +/-10 ℃ for 5-6 hours, cooling the workpiece to normal temperature by adopting air, and finishing the primary low-temperature tempering treatment, and placing the workpiece subjected to the ultra-deep cooling treatment in the step S5 in the furnace, preserving the temperature at 160 +/-10 ℃ for 5, 5.5 or 6 hours, cooling the workpiece to normal temperature by adopting air, and finishing the primary low-temperature tempering treatment;
step S7: repeating the low-temperature tempering treatment in the step S6 once to finish the heat treatment process of the welded pipe die steel, placing the workpiece in a furnace, keeping the temperature at 160 +/-10 ℃ for 5-6 hours, and cooling the workpiece to normal temperature by using air to finish secondary low-temperature tempering treatment; and finishing the heat treatment process of the welded pipe die steel.
The invention adds the solution refining heat treatment before quenching, can refine the net carbide in the steel, improve the form and the granularity of the carbide, lead the carbide to be distributed evenly, have fine and round granularity, lead the structure crystal grains of the steel matrix to be ultra-fine and improve the performance of the steel. The cryogenic temperature is reduced, so that the transformation of the residual austenite is more sufficient.
The invention reduces the deformation and ensures the performance of the workpiece on the premise of no cracking of the workpiece by increasing the temperature of the quenching medium, namely by adopting hot oil at 60-100 ℃ as the quenching medium.
The process flows related to the invention are mutually buckled and tightly combined, so that the performance, particularly the hardness, of the workpiece is obviously improved, and the use requirement can be met.
It is to be noted that, unless otherwise specified, technical terms or scientific terms used herein shall have the ordinary meaning as understood by those skilled in the art to which this application belongs.
The above description is only for the preferred embodiment of the present application, but the scope of the present application is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present application should be covered within the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims (8)

1. A heat treatment method of welded pipe die steel is characterized by comprising the following steps:
step S1: solid solution treatment, namely placing the workpiece in a furnace body and heating the workpiece along with the furnace, firstly heating the workpiece to 650 ℃ and then to 850 ℃ and preheating the workpiece twice; then raising the temperature to 1250 +/-10 ℃ at the speed of 215 plus 240 ℃/h, preserving the heat for 1.5-2 h, and then placing the workpiece in hot oil at the temperature of 60-100 ℃ for quenching to finish the solid solution treatment;
step S2: high-temperature tempering treatment, namely heating the workpiece subjected to the solution treatment in the step S1 along with a furnace at a speed of 215-;
step S3: vacuum oil quenching, namely heating the workpiece subjected to the high-temperature tempering treatment in the step S2 along with a furnace to 1030 +/-10 ℃, preserving heat for 4 hours, and then placing the workpiece in 100 plus or minus 120 ℃ hot oil for quenching to finish the vacuum oil quenching treatment;
step S4: thinning treatment, namely slowly heating the workpiece subjected to the vacuum oil quenching treatment in the step S3 to 800-;
step S5: performing ultra-deep cooling treatment, namely placing the workpiece subjected to quenching treatment in the step S4 in a freezing box, cooling to minus 150-minus 180 ℃, preserving heat for 2.5 hours, and taking out to finish the ultra-deep cooling treatment;
step S6: low-temperature tempering, namely placing the workpiece subjected to the ultra-deep cold treatment in the step S5 in a furnace, keeping the temperature at 160 +/-10 ℃ for 5-6 hours, and cooling the workpiece to normal temperature by adopting air to finish primary low-temperature tempering;
step S7: and repeating the low-temperature tempering treatment in the step S6 once to finish the heat treatment process of the welded pipe die steel.
2. The heat treatment method for the die steel of the welded tube as claimed in claim 1, wherein in the step S1, the workpiece is placed in the furnace body and heated along with the furnace, the temperature is raised to 600 ℃ at first, then to 835 ℃ at 815 ℃ and preheated twice; then raising the temperature to 1130 +/-10 ℃ at the speed of 205-.
3. The heat treatment method for the die steel of the welded pipe as claimed in claim 1, wherein in the step S2 high temperature tempering treatment, the temperature of the workpiece subjected to the solution treatment in the step S1 is raised along with the furnace, specifically, the temperature is raised to 760 ℃ at a speed of 205-.
4. The heat treatment method for the mold steel for welded tubes as claimed in claim 1, wherein in the step S3 vacuum oil quenching treatment, the workpiece after the high temperature tempering treatment in the step S2 is heated with the furnace, preheated at 600 ℃ and 835 ℃ of 500-.
5. The heat treatment method for the die steel of the welded tube as claimed in claim 1, wherein in the step S4 refining treatment, the workpiece processed by the step S3 vacuum oil quenching is slowly heated to 815-.
6. The heat treatment method of die steel for welded pipe according to claim 1, wherein in the step S5 ultra-deep cooling treatment, the workpiece refined in the step S4 is placed in a freezer to be cooled to-150 ℃ to-180 ℃, and is taken out after being kept at the temperature for 2.5 hours, thereby completing the ultra-deep cooling treatment.
7. The heat treatment method for die steel of welded pipe according to claim 1, wherein the step S6 of low temperature tempering treatment, the workpiece after the step S5 of ultra deep cooling treatment is placed in a furnace and kept at 160 ℃ ± 10 ℃ for 5, 5.5 or 6 hours, and then cooled to normal temperature by air, and a low temperature tempering treatment is completed.
8. The heat treatment method of die steel for welded pipe according to claim 1, wherein said step S7 includes: then placing the workpiece in a furnace, preserving heat for 5-6 hours at the temperature of 160 +/-10 ℃, cooling to normal temperature by adopting air, and finishing secondary low-temperature tempering treatment; and finishing the heat treatment process of the welded pipe die steel.
CN202210351272.0A 2022-04-02 2022-04-02 Heat treatment method of welded pipe die steel Pending CN114990300A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202210351272.0A CN114990300A (en) 2022-04-02 2022-04-02 Heat treatment method of welded pipe die steel

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202210351272.0A CN114990300A (en) 2022-04-02 2022-04-02 Heat treatment method of welded pipe die steel

Publications (1)

Publication Number Publication Date
CN114990300A true CN114990300A (en) 2022-09-02

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Application Number Title Priority Date Filing Date
CN202210351272.0A Pending CN114990300A (en) 2022-04-02 2022-04-02 Heat treatment method of welded pipe die steel

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