CN113512638A - Online induction heat treatment method for steel pipe - Google Patents
Online induction heat treatment method for steel pipe Download PDFInfo
- Publication number
- CN113512638A CN113512638A CN202110748998.3A CN202110748998A CN113512638A CN 113512638 A CN113512638 A CN 113512638A CN 202110748998 A CN202110748998 A CN 202110748998A CN 113512638 A CN113512638 A CN 113512638A
- Authority
- CN
- China
- Prior art keywords
- pipe
- heat treatment
- quenching
- treatment method
- induction heat
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Classifications
-
- 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
- C21D9/08—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for tubular bodies or pipes
- C21D9/085—Cooling or 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
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/06—Surface hardening
- C21D1/09—Surface hardening by direct application of electrical or wave energy; by particle radiation
- C21D1/10—Surface hardening by direct application of electrical or wave energy; by particle radiation by electric induction
-
- 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
- C21D11/00—Process control or regulation for heat treatments
-
- 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
- C21D6/002—Heat treatment of ferrous alloys containing Cr
-
- 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
Abstract
The invention relates to the technical field of pipe heat treatment and discloses an online induction heat treatment method for a steel pipe, which comprises the following steps: s1, blanking of the pipe: a variable frequency motor is used for driving a rotating wheel group to drive the pipe to spirally advance for 360 degrees, and the advancing speed of the pipe is controlled by adjusting a frequency converter; s2, adjusting the distance between the inner wall of the induction coil and the outer diameter of the pipe; s3, heating: s3, quenching: the quenching water tank adopts a 360-degree spraying coil, and the pipe spirally advances to ensure uniform quenching of the pipe; s4, tempering: adopting medium-frequency induction heating, wherein the frequency of a tempering area is 2K-5kHz, and heating to a required temperature; s5, cooling: and after the air is discharged from the tempering area, air cooling is carried out on a mechanical cooling bed. According to the steel pipe online induction heat treatment method, the variable frequency motor is used for driving the rotating wheel set to drive the pipe to advance in a 360-degree spiral mode, the pipe advances in a 360-degree spiral mode, then the quenching water tank adopts the 360-degree spraying coil, the surface of the pipe can be simultaneously quenched, and the phenomenon that quenching tissues are uneven and soft spots appear is avoided.
Description
Technical Field
The invention relates to the technical field of pipe heat treatment, in particular to an online induction heat treatment method for a steel pipe.
Background
The basic principle of induction heat treatment is to place a workpiece in an inductor (coil), and when an alternating current with a certain frequency is introduced into the inductor, an alternating magnetic field is generated around the inductor. The electromagnetic induction action of the alternating magnetic field generates closed induction current-vortex in the workpiece. The induction heating mainly has the advantages that the deformation of the workpiece is small, and the power consumption is small; no public nuisance; thirdly, the heating speed is high, and the surface of the workpiece is oxidized and decarburized lightly; fourthly, the surface hardening layer can be adjusted according to the requirement and is easy to control; the heating equipment can be arranged on a machining production line, so that the mechanization and automation are easy to realize, the management is convenient, the transportation can be reduced, the labor is saved, and the production efficiency is improved; the martensite structure of the hardening layer is fine, and the hardness, the strength and the toughness are high; the surface layer of the workpiece after surface quenching has larger compression internal stress, and the workpiece has higher anti-fatigue breaking capacity. The pipe subjected to common heat treatment has the defects of bending, uneven structure, large section hardness gradient, low treatment efficiency, low yield and the like after heat treatment; in the face of large demands for pipes in domestic and foreign markets, the defects seriously affect the production and application of the pipes, and therefore an online induction heat treatment method for the steel pipes is provided.
Disclosure of Invention
Aiming at the defects of the prior art, the invention provides an online induction heat treatment method for steel pipes, which has the advantages of realizing continuous batch production, uniform heating, uniform finished product structure, small section hardness gradient, effectively avoiding the bending of the pipes after heat treatment, improving the yield and the production efficiency, and solving the problems in the background art.
In order to achieve the purpose, the invention provides the following technical scheme: an on-line induction heat treatment method for a steel pipe, comprising the following steps:
s1, blanking of the pipe: the variable frequency motor is used for driving the rotating wheel set to drive the pipe to spirally advance for 360 degrees, and the advancing speed of the pipe is controlled by adjusting the frequency converter.
And S2, adjusting the distance between the inner wall of the induction coil and the outer diameter of the pipe.
S3, heating: intermediate frequency induction heating is adopted, the frequency of a quenching zone is 3K-6kHz, the heating temperature is 60-100 ℃ above Ac3, and sufficient austenitizing is realized.
S3, quenching: the quenching water tank adopts a 360-degree spraying coil, and the pipe spirally advances, so that the pipe is uniformly quenched.
S4, tempering: and (3) heating to a required temperature by adopting medium-frequency induction heating and heating at the frequency of 2K-5kHz in a tempering area.
S5, cooling: and after the air is discharged from the tempering area, air cooling is carried out on a mechanical cooling bed.
Further, in step S2, a safety space is reserved between the inner wall of the induction coil and the outer diameter of the pipe when the pipe is centered, so as to prevent the pipe from contacting the induction coil.
Further, in the step S3, quenching is divided into 4 zones, the zone 1 is rapidly heated, the zones 2 and 3 are kept warm, and the temperature in the zone 4 is properly lowered, so that the pipe is prevented from bending due to overlarge thermal stress when entering the end of the quenching water tank.
Furthermore, the tempering is divided into 5 areas, the temperature is rapidly increased in the area 1, and the temperature is preserved in the areas 2, 3, 4 and 5, so that the tempering time is ensured to be sufficient.
Further, in the step S1, a variable frequency motor is used to drive the rotating wheel sets, each rotating wheel set is composed of 2 rotating wheels, the pipe is placed on the rotating wheels to drive the pipe to advance spirally for 360 degrees, and the advancing speed of the pipe is controlled by adjusting the frequency converter.
Further, the test temperature was followed by a hand-held thermometer during quenching and the time for the steel pipe to drop to the set temperature was recorded by a stopwatch measurement.
Further, the pipe can be heated on line after the front pipe and the rear pipe are connected end to end during treatment, so that the phenomenon that the pipe is cooled unevenly due to the fact that quenching liquid enters the pipe from one end of the pipe is avoided, and the pipe can be effectively prevented from being bent due to uneven cooling in the heat treatment process.
Further, when the pipes are fed, the advancing speed of the pipe positioned on the rear side is greater than that of the pipe positioned on the front side, so that the pipe positioned on the rear side can push the pipe positioned on the front side to further move forwards.
Further, the tube needs to be separated after the heat treatment is completed, and the tube at the front side advances faster than the tube at the rear side during the separation, so that the tube at the front side and the tube at the rear side are separated.
Further, a pipe cutting device is arranged at the discharging position of the pipe separation, and the pipe after the separation is cut by the cutting device, so that the heat treatment and the cutting work of the pipe can be synchronously carried out.
The beneficial effects are as follows:
1. according to the steel pipe online induction heat treatment method, the variable frequency motor is used for driving the rotating wheel set to drive the pipe to advance in a 360-degree spiral mode, the pipe advances in a 360-degree spiral mode, then the quenching water tank adopts the 360-degree spraying coil, the surface of the pipe can be simultaneously quenched, and the phenomenon that quenching tissues are uneven and soft spots appear is avoided.
2. According to the steel pipe on-line induction heat treatment method, the pipe in the quenching area is spirally advanced, the temperature of the pipe entering a quenching water tank is reduced by 30-50 ℃, and the pipe is effectively prevented from being bent after heat treatment.
3. According to the steel pipe online induction heat treatment method, the pipe is uniformly heated, the finished product structure is uniform, the section hardness gradient is small, the pipe is effectively prevented from being bent after heat treatment, and the yield is improved.
4. The steel pipe online induction heat treatment method is high in automation degree, continuous batch production can be realized, production efficiency is improved, two front and rear pipes can be connected end to be heated online in the heat treatment process of the pipes, quenching liquid is effectively prevented from entering the inside of the pipes, and the phenomenon that the pipes are bent due to uneven cooling liquid of the steel pipes is effectively avoided.
Detailed Description
All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The invention provides a technical scheme that: an on-line induction heat treatment method for steel pipes comprises the following steps:
(1) the method comprises the following steps of (1) driving rotating wheel sets by using a variable frequency motor, wherein each rotating wheel set consists of 2 rotating wheels, placing a pipe on the rotating wheels, driving the pipe to spirally advance for 360 degrees, and controlling the advancing speed of the pipe by adjusting a frequency converter;
(2) the distance between the inner wall of the induction coil and the outer diameter of the pipe is preferably 10-15mm, the heating efficiency in the interval is high, the electric energy is saved, and meanwhile, a safe space is reserved to prevent the pipe from contacting the induction coil;
(3) medium-frequency induction heating is adopted, the frequency of a quenching area is 3K-6kHz, the frequency is selected according to the wall thickness of the pipe, the wall thickness frequency is correspondingly reduced to increase the current penetration depth, the heating temperature is 60-100 ℃ above Ac3, and the pipe is fully austenitized;
(4) 4 zones are quenched, the temperature of the zone 1 is rapidly increased, the temperature of the zones 2 and 3 is kept, the temperature of the zone 4 is reduced by 30-50 ℃, and the pipe is prevented from bending due to overlarge thermal stress when entering the end part of a quenching water tank;
(5) the quenching water tank adopts a 360-degree spraying coil, and the pipe spirally advances to ensure uniform quenching of the pipe;
(6) adopting medium-frequency induction heating, wherein the frequency of a tempering area is 2K-5kHz, the frequency is selected according to the wall thickness of the pipe, the frequency is correspondingly reduced when the wall thickness is large so as to increase the current penetration depth, and the pipe is heated to the required temperature;
(6) tempering for 5 zones, rapidly heating the zone 1, and preserving heat in the zones 2, 3, 4 and 5 to ensure sufficient tempering time;
(7) and after the air is discharged from the tempering area, air cooling is carried out on a mechanical cooling bed.
When the pipe is treated, the front pipe and the rear pipe can be connected at the head and then heated on line, so that the pipe is prevented from being cooled unevenly due to the fact that quenching liquid enters the pipe from one end of the pipe, and the pipe can be effectively prevented from being bent due to uneven cooling in the heat treatment process; when the pipes are fed, the advancing speed of the pipe positioned on the rear side is higher than that of the pipe positioned on the front side, so that the pipe positioned on the rear side can push the pipe positioned on the front side to further move forwards; the pipe needs to be separated after the heat treatment is completed, the advancing speed of the pipe located on the front side is higher than the advancing speed of the pipe located on the rear side when the pipe is separated, so that the pipe on the front side and the pipe on the rear side are separated, the pipe cutting device is arranged at the discharging position for separating the pipe, the pipe after the pipe is separated is cut through the cutting device, the heat treatment and the cutting work of the pipe can be synchronously performed, the device is convenient to process the pipe, the heat treatment and the cutting treatment can be rapidly performed on the pipe through the method, the pipe can be immediately cut after the heat treatment is completed, the batch production of the pipe can be realized, and the production efficiency of the pipe is further improved.
The pipes, instruments and equipment used in the invention can be purchased from the market or prepared by a conventional method, after the pipes are processed by the heat treatment method, the pipes are uniformly heated and quenched, soft spots are avoided, the finished product structure is uniform, the section hardness gradient is small, the bending of the pipes after the heat treatment is effectively avoided, and the yield is improved; meanwhile, the automation degree is high, continuous batch production can be realized, and the production efficiency is improved.
Examples
An on-line induction heat treatment method for 26CrMo steel pipes comprises the following steps:
(1) the method comprises the following steps of (1) driving rotating wheel sets by using a variable frequency motor, wherein each rotating wheel set consists of 2 rotating wheels, placing a pipe on the rotating wheels, driving the pipe to spirally advance for 360 degrees, and controlling the advancing speed of the pipe to be 3m/min by adjusting a frequency converter;
(2) the distance between the inner wall of the induction coil and the outer diameter of the pipe is 12 mm;
(3) intermediate frequency induction heating is adopted, the frequency of a quenching area is 4.5kHz, and the austenitizing temperature is 940 ℃;
(4) 4 zones are quenched, the temperature of the zone 1 is rapidly raised to 940 ℃, the temperature of the zones 2 and 3 is kept at 940 ℃, the temperature of the zone 4 is reduced to 890 ℃, and the pipe is prevented from bending due to overlarge thermal stress when entering the end part of a quenching water tank;
(5) the quenching water tank adopts a 360-degree spraying coil, and the pipe spirally advances to ensure uniform quenching of the pipe;
(6) adopting medium-frequency induction heating, wherein the frequency of a tempering area is 3kHz, and heating to 560 ℃;
(7) tempering for 5 zones, wherein the temperature in the 1 zone is rapidly increased to 560 ℃, and the temperature in the 2, 3, 4 and 5 zones is kept, so that the tempering time is ensured to be sufficient;
(8) and after the air is discharged from the tempering area, air cooling is carried out on a mechanical cooling bed.
It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.
Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.
Claims (10)
1. An online induction heat treatment method for steel pipes is characterized in that: the processing method comprises the following steps:
s1, blanking of the pipe: a variable frequency motor is used for driving a rotating wheel group to drive the pipe to spirally advance for 360 degrees, and the advancing speed of the pipe is controlled by adjusting a frequency converter;
s2, adjusting the distance between the inner wall of the induction coil and the outer diameter of the pipe;
s3, heating: intermediate frequency induction heating is adopted, the frequency of a quenching zone is 3K-6kHz, the heating temperature is 60-100 ℃ above Ac3, and sufficient austenitizing is carried out;
s3, quenching: the quenching water tank adopts a 360-degree spraying coil, and the pipe spirally advances to ensure uniform quenching of the pipe;
s4, tempering: adopting medium-frequency induction heating, wherein the frequency of a tempering area is 2K-5kHz, and heating to a required temperature;
s5, cooling: and after the air is discharged from the tempering area, air cooling is carried out on a mechanical cooling bed.
2. The steel pipe on-line induction heat treatment method according to claim 1, characterized in that: in the step S2, a safety space is reserved between the inner wall of the induction coil and the outer diameter of the pipe when the pipe is centered, so as to prevent the pipe from contacting the induction coil.
3. The steel pipe on-line induction heat treatment method according to claim 1, characterized in that: in the step S3, quenching is divided into 4 areas, the temperature of the area 1 is rapidly increased, the temperature of the areas 2 and 3 is kept, the temperature of the area 4 is properly reduced, and the pipe is prevented from bending due to overlarge thermal stress when entering the end of the quenching water tank.
4. The steel pipe on-line induction heat treatment method according to claim 1, characterized in that: the tempering is divided into 5 areas, wherein the temperature is rapidly increased in the area 1, and the temperature is preserved in the areas 2, 3, 4 and 5, so that the tempering time is ensured to be sufficient.
5. The steel pipe on-line induction heat treatment method according to claim 1, characterized in that: in the step S1, a variable frequency motor is used to drive the rotating wheel sets, each rotating wheel set is composed of 2 rotating wheels, the pipe is placed on the rotating wheels to drive the pipe to spirally advance for 360 degrees, and the advancing speed of the pipe is controlled by adjusting the frequency converter.
6. The steel pipe on-line induction heat treatment method according to claim 1, characterized in that: during quenching, the portable thermometer is used for tracking the testing temperature and the stopwatch is used for measuring and recording the time for the steel pipe to be reduced to the set temperature.
7. The steel pipe on-line induction heat treatment method according to claim 1, characterized in that: the pipe can be heated on line after the front pipe and the rear pipe are connected end to end during processing, so that the phenomenon that the pipe is cooled unevenly because quenching liquid enters the pipe from one end of the pipe is avoided.
8. The steel pipe on-line induction heat treatment method according to claim 1, characterized in that: when the pipes are fed, the advancing speed of the pipe positioned on the rear side is higher than that of the pipe positioned on the front side, so that the pipe positioned on the rear side can push the pipe positioned on the front side to further move forwards.
9. The steel pipe on-line induction heat treatment method according to claim 1, characterized in that: the pipes need to be separated after the heat treatment is completed, and the advancing speed of the pipes on the front side is higher than that of the pipes on the rear side during the separation, so that the pipes on the front side are separated from the pipes on the rear side.
10. The steel pipe on-line induction heat treatment method according to claim 1, characterized in that: the pipe cutting device is arranged at the discharging position for pipe separation, and the pipe after separation is cut by the cutting device, so that the heat treatment and cutting work of the pipe can be synchronously carried out.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110748998.3A CN113512638A (en) | 2021-07-01 | 2021-07-01 | Online induction heat treatment method for steel pipe |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110748998.3A CN113512638A (en) | 2021-07-01 | 2021-07-01 | Online induction heat treatment method for steel pipe |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN113512638A true CN113512638A (en) | 2021-10-19 |
Family
ID=78066753
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110748998.3A Pending CN113512638A (en) | 2021-07-01 | 2021-07-01 | Online induction heat treatment method for steel pipe |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113512638A (en) |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002105531A (en) * | 2000-09-28 | 2002-04-10 | High Frequency Heattreat Co Ltd | Induction heating heat-treatment apparatus for pipe |
| CN101078042A (en) * | 2007-06-28 | 2007-11-28 | 朱兴发 | Medium frequency induction heating treatment method for steel pipe, petroleum well pipe and drill pipe |
| CN102312074A (en) * | 2011-10-25 | 2012-01-11 | 衡阳华菱钢管有限公司 | Pipeline inductive on-line heat treatment method |
| CN107586934A (en) * | 2017-09-21 | 2018-01-16 | 江苏南钢通恒特材科技有限公司 | Big rod senses hardening and tempering process and big rod sensing tempering product line |
| CN108546804A (en) * | 2018-07-06 | 2018-09-18 | 江苏南钢通恒特材科技有限公司 | Incude tempering product line |
-
2021
- 2021-07-01 CN CN202110748998.3A patent/CN113512638A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002105531A (en) * | 2000-09-28 | 2002-04-10 | High Frequency Heattreat Co Ltd | Induction heating heat-treatment apparatus for pipe |
| CN101078042A (en) * | 2007-06-28 | 2007-11-28 | 朱兴发 | Medium frequency induction heating treatment method for steel pipe, petroleum well pipe and drill pipe |
| CN102312074A (en) * | 2011-10-25 | 2012-01-11 | 衡阳华菱钢管有限公司 | Pipeline inductive on-line heat treatment method |
| CN107586934A (en) * | 2017-09-21 | 2018-01-16 | 江苏南钢通恒特材科技有限公司 | Big rod senses hardening and tempering process and big rod sensing tempering product line |
| CN108546804A (en) * | 2018-07-06 | 2018-09-18 | 江苏南钢通恒特材科技有限公司 | Incude tempering product line |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP0933437B1 (en) | Method of heat-treating a hollow cylindrical workpiece | |
| RU2608257C2 (en) | Annealed steel types production device and method of said steel types production | |
| CN105369015A (en) | 42 CrMo shaft part quenching and heat-treatment technology | |
| CN103468916A (en) | Heat treatment process for bevel gear | |
| CN113430337B (en) | Integral quenching and tempering heat treatment method for H13 round steel | |
| CN113512638A (en) | Online induction heat treatment method for steel pipe | |
| CN108531920A (en) | A kind of pre-treating technology of hydraulic plunger workpiece | |
| CN110229947B (en) | Axle tube well type furnace quenching method | |
| CN102409143A (en) | Heat treatment process of carbon structural steel | |
| CN103667615A (en) | Thermal treatment method of 42CrMo workpiece | |
| CN115637312A (en) | Online induction annealing heat treatment method for steel bar | |
| CN105648448A (en) | Bevel gear heat-treatment technology | |
| JPS63274713A (en) | Heat treatment method for bar-like parts | |
| CN102199702A (en) | Composite strengthening heat treatment technology of internal combustion engine crankshaft | |
| JPH06145793A (en) | Method for preventing decarburization of seamless steel tube | |
| RU2484149C1 (en) | Method of thermal treatment of welded tubes | |
| CN106834650B (en) | A kind of method for obtaining low-carbon and low-alloy casting skin forged steel axle ultra-fine pearlite | |
| CN1234882C (en) | Strong magnetic field quick complete annealing process for medium carbon low alloy structure steel | |
| CN108559830A (en) | A kind of system that hydraulic plunger workpiece is heat-treated | |
| RU2132396C1 (en) | Process of manufacture of pipes from carbon steel | |
| CN108588727B (en) | A kind of surface processing technique of hydraulic plunger workpiece | |
| CN107419175A (en) | Fatigue life good economical tool steel and its production method | |
| SU1731837A1 (en) | Method of heat treatment of rolled products | |
| SU1323584A1 (en) | Method of hardening bulky articles of cylindrical form | |
| RU2034050C1 (en) | Straight seam electric welded pipes thermal treatment method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| RJ01 | Rejection of invention patent application after publication | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20211019 |