CN115044746A - Salt bath quenching and tempering heat treatment process method for spring steel wire - Google Patents
Salt bath quenching and tempering heat treatment process method for spring steel wire Download PDFInfo
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- 238000005496 tempering Methods 0.000 title claims abstract description 121
- 238000000034 method Methods 0.000 title claims abstract description 64
- 238000010438 heat treatment Methods 0.000 title claims abstract description 56
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- 238000003860 storage Methods 0.000 claims abstract description 74
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- 239000010959 steel Substances 0.000 claims abstract description 56
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- 229910002651 NO3 Inorganic materials 0.000 claims description 3
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 claims description 3
- IOVCWXUNBOPUCH-UHFFFAOYSA-M Nitrite anion Chemical compound [O-]N=O IOVCWXUNBOPUCH-UHFFFAOYSA-M 0.000 claims description 3
- 239000002923 metal particle Substances 0.000 claims description 3
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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
- C21D9/52—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for wires; for strips ; for rods of unlimited length
- C21D9/525—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for wires; for strips ; for rods of unlimited length for wire, for rods
-
- 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
- C21D1/63—Quenching devices for bath quenching
- C21D1/64—Quenching devices for bath quenching with circulating liquids
-
- 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
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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 Strip Materials And Filament Materials (AREA)
- Cleaning And De-Greasing Of Metallic Materials By Chemical Methods (AREA)
Abstract
A salt bath quenching and tempering heat treatment process method for spring steel wires is used for replacing the traditional oil quenching and lead bath tempering production process method. The equipment comprises the following components: paying off, heating furnace, molten salt quenching tank, molten salt tempering tank, cleaning and taking up. The molten salt quenching tank and the molten salt tempering tank adopt a method of separating a salt storage tank from a working area, solid salt is primarily melted by a molten salt primary melting device, the quenching tank and the tempering tank are filled to a certain liquid level by a salt pump, a steel wire directly passes through the molten salt quenching tank and the tempering tank, and after heat exchange between the molten salt and the steel wire, the molten salt flows back to the salt storage tank. And after the steel wire is discharged out of the molten salt tempering tank, blowing residual salt on the surface by using a hot air knife, and cleaning the surface by using water. The invention adopts low-melting-point molten salt to replace the traditional oil bath, eliminates the oil fume problem in the quenching process of the oil bath, adopts high-temperature molten salt to replace lead bath, eliminates the harm of lead dust to the body of workers in the lead bath process, and is very suitable for the spring steel wire production enterprises to upgrade, save energy and reform the process equipment.
Description
Technical Field
The invention provides a salt bath quenching and tempering heat treatment process method for a steel wire or a wire rod, which replaces the prior high-energy-consumption and high-pollution oil quenching and lead tempering heat treatment process, obtains a martensite structure by carrying out salt bath quenching on a heated steel piece, then continues to carry out salt bath tempering later, obtains the optimal structure performance, and is suitable for upgrading and transforming numerous spring steel wire heat treatment workshops and constructing energy-saving and environment-friendly projects.
Background
The demand of the cutter and spring industry for oil quenching and tempering products (hereinafter referred to as oil quenching steel wires) is increased year by year, the environmental protection is enhanced, the quality requirements of the products are higher and higher without the industry, and the requirements on pollutants and energy consumption of a production line are higher.
At present, the traditional spring steel wire production process adopts a scheme of oil quenching and lead tempering, the process is developed in the industry for nearly 100 years, the process is originally made available as a steel wire straightening means, and the process has attracted the attention of spring manufacturers since the process has excellent elasticity and very high fatigue strength. Oil quenched steel wire has begun to be widely used in north america and western europe for manufacturing various springs, and the range is gradually expanded later. The production of oil quenching steel wires in China starts in the early 7O's of the 2O century. According to the requirements of domestic market, metal product production enterprises represented by the first characteristics firstly build a first oil quenching steel wire test production line in China, and develop a series of researches on production processes of oil quenching steel wires by surrounding materials such as 50CrV, 60Si2Mn and 65Mn, thereby realizing industrial mass production.
Units participating in the research of oil quenching steel wire production process and equipment in China in early stage and being found in various literatures include units such as Beijing iron and steel institute, Tianjin university, Tianjin compressor valve spring attack group, Beijing special steel plant and the like. The production test equipment adopted is mainly divided into two forms: one is a continuous production line of electric contact heating and lead bath tempering; the other is a tubular furnace heating and lead bath tempering continuous production line. Because the electric contact heating is influenced by factors such as dimensional tolerance, metallurgical quality, voltage fluctuation and the like of the steel wire, the product quality is difficult to stabilize all the time. Particularly, the later lead bath tempering production process is not suitable for industrial popularization under the push of the current environment-friendly and green manufacturing production concept.
Salt bath quenching cooling and heating have been developed for a long time in the heat treatment industries of bearings, gears and the like, the applicable temperature is from 100 ℃ to 600 ℃, and the salt bath quenching cooling and heating are gradually applied and popularized in the product industry as novel quenching media and heating modes. Researchers at the institute of first Steel technology utilize the isothermal quenching characteristic of the molten salt and develop a high-carbon steel bainite material with strength exceeding 1860MPa by using high-carbon high-Si steel, and simultaneously test the structure property change trend of the high-carbon steel bainite material in a molten salt heat preservation state and apply for a patent. In the production process of the thin steel wire diamond wire, Beijing, Qinhong metallurgical technology Limited company adopts molten salt quenching to replace water bath and lead bath quenching, successfully develops the brass wire of the diamond wire meeting the requirements of the solar photovoltaic industry, and applies for invention patents. In recent years, salt bath isothermal quenching technology of Beijing Dynasty Honghuo metallurgy technology Limited is introduced into Qingdao special steel, sand steel and Bao steel metal, and combined with the Central-iron bridge office, the university of Central and south, and the general iron and steel institute, the master batch coil of the ultrahigh-strength bridge cable galvanized steel wire is successfully developed, and at present, in super projects such as the Homen's two bridge, the Yangtong bridge, the Shantong bridge, the Linseudong bridge, the Wufengshan bridge, the Changtai bridge and the like, the molten salt quenching process and equipment are successfully used as upgrading tools of lead bath heat treatment, and receive lots of attention of the industry.
Disclosure of Invention
The method provides a salt bath quenching and tempering heat treatment process method which is used for replacing the traditional oil quenching and lead bath tempering production process method. The process comprises the following steps: paying off, heating by a heating furnace, quenching by fused salt, tempering by fused salt, blowing, cleaning and taking up. Carry out the first melting to solid salt through fused salt preliminary melting device, fused salt quenching and fused salt tempering are accomplished in quenching groove and tempering tank that correspond, and quenching groove and tempering tank link to each other rather than the storage salt jar that corresponds, and the storage salt jar has arranged the fused salt pump, fills to certain liquid level with quenching groove and tempering tank through the salt pump, and the steel wire is straight to be gone through fused salt quenching groove and tempering tank, and after fused salt and steel wire took place the heat exchange, the fused salt was refluxed to the storage salt tank. After the steel wire is taken out of the molten salt tempering tank, a hot air knife is adopted to sweep residual salt on the surface, and the surface is purified by water cleaning.
The primary melting of the solid molten salt is realized through the molten salt primary melting device, and then the molten salt is injected into the salt storage tank in times through the salt pump on the primary melting device.
And heating devices and thermocouples are arranged on the salt storage tank of the quenching tank and the salt storage tank of the tempering tank, so that the temperature of the salt storage tanks can be controlled.
The molten salt pump is arranged on the quenching tank salt storage tank and the tempering tank salt storage tank and is connected with the quenching tank through a pipeline, molten salt is injected into the quenching tank and the tempering tank through the molten salt pump, the liquid level and the molten salt amount of the quenching tank and the tempering tank are ensured, the molten salt flows out of two ends of the tank body after being injected, and the molten salt flows into the salt storage tank through the pipeline after being cached by the salt receiving hopper, so that the integral large circulation of the molten salt is realized.
Under the action of paying off and traction force of a rear wire rewinding machine, continuous wires or strip steel horizontally enter a quenching tank after being heated, salt bath quenching is completed in an immersed state, and then the wires or the strip steel enter a tempering tank to complete tempering treatment.
The quenching tank can be provided with a cooling air pipe, the air quantity is controlled by a variable frequency fan, the heat in the quenching process of the heated steel piece is led out, and the temperature constancy of the whole quenching tank and the salt storage tank of the quenching tank is ensured.
High-pressure hot air generated by a cooling air pipe arranged in the quenching tank is introduced into an air box at the tail end of the tempering tank, and a hot air knife is formed around the workpiece, so that residual salt on the surface of the workpiece is swept.
And the workpiece is blown by the hot air knife and then enters a cleaning machine, the workpiece is cleaned by the nozzle, the cleaned salt water is separated by the multi-effect evaporator, and the recovered salt is injected into the quenching tank again.
And a radar liquid level meter is arranged on the salt storage tank, so that the fused salt amount in the salt storage tank is monitored in real time, and the fused salt amount exceeds the warning liquid level for supplement.
The filter has been arranged on the salt storage tank, and when producing the line stop work, all fused salts flow back to the salt storage tank again, are connected to the filter through the salt pump on the salt storage tank, carry out impurity filtering to the fused salt.
The molten salt in the salt storage tank adopts a mixed system of nitrate, nitrite and carbonate, the application range of the mixed system is 150-650 ℃, and the nano metal particles are supplemented periodically to ensure the quenching intensity of the molten salt.
Drawings
FIG. 1 is a layout of a salt bath quenching and tempering production line
FIG. 2 salt bath quenching and tempering production process
FIG. 3 shows the microstructure of 60Si2Mn after salt bath quenching and tempering
FIG. 4 shows the tensile fracture dimple morphology of 60Si2Mn after salt bath quenching and tempering
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be described in detail below. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the examples given herein without any inventive step, are within the scope of the present invention.
The embodiment of the invention relates to application of medium carbon spring steel wires in quenching and tempering processes, and the invention replaces the heat treatment production process of oil quenching and lead bath tempering to produce spring steel wires of 50CrV, 60Si2Mn, 65Mn and the like.
The invention aims to provide a molten salt quenching and tempering heat treatment process method for spring steel wires by replacing the traditional oil quenching and lead bath tempering, and the technical scheme of the invention is as follows:
1. a molten salt quenching and tempering heat treatment process method is used for replacing the traditional oil quenching and lead bath tempering production process method. The process comprises the following steps: paying off, heating by a heating furnace, quenching by fused salt, tempering by fused salt, blowing, cleaning and taking up.
Carry out the first melting to solid salt through fused salt preliminary melting device, fused salt quenching and fused salt tempering are accomplished in quenching groove and tempering tank that correspond, and quenching groove and tempering tank link to each other rather than the storage salt jar that corresponds, and the storage salt jar has arranged the fused salt pump, fills to certain liquid level with quenching groove and tempering tank through the salt pump, and the steel wire is straight to be gone through fused salt quenching groove and tempering tank, and after fused salt and steel wire took place the heat exchange, the fused salt was refluxed to the storage salt tank. After the steel wire is taken out of the molten salt tempering tank, a hot air knife is adopted to sweep residual salt on the surface, and the surface is purified by water cleaning.
Compared with the traditional spring steel wire heat treatment production process of oil quenching and lead tempering, the invention adopts molten salt quenching and molten salt tempering, eliminates oil smoke generated in the oil quenching process and fluctuation of the quenching workpiece structure performance caused by oil temperature fluctuation; compared with the traditional lead bath tempering, the tempering method of the molten salt is adopted in the process, the tempering temperature range is expanded from 300-500 ℃ of the lead bath tempering to 200-650 ℃, and the volatile matter in the operation process is reduced by more than 90%. The complicated physical chemistry collection mode that the evaporation of comparison lead dust adopted, salt bath volatile matter be N2 and NOx, a small amount of smoke and dust, and its gaseous emission is at 20mg/m thin year, and 600 ℃ smoke and dust volatilization volume is at 10mg/m thin year, is far less than the standard that the ultralow granting of steel industry, and the smoke and dust adopts the mode that the wet process sprayed to dissolve the recovery simultaneously, realizes the separation of salt water through triple effect evaporation plant after, retrieves volatilizing smoke and dust.
2. The primary melting of the solid molten salt is realized through the molten salt primary melting device, and then the molten salt is injected into the salt storage tank in times through the salt pump on the primary melting device.
Adopt the fused salt preliminary melting device of 1m heavy year-3 m to realize the first melting of solid fused salt, the solid fused salt that melts each time is in 1m heavy year, and the fused salt must carry out breakage, mechanical blending before the first melting, and the particle size of fused salt is below 15 mm. The initial melting temperature of the mixed molten salt is controlled to be 300-400 ℃, and then the molten salt is injected into the salt storage tank through a salt pump on the initial melting device until the operation requirement of the salt storage tank is met.
3. Heating devices and thermocouples are arranged on the quenching tank salt storage tank and the tempering tank salt storage tank, so that the temperature of the salt storage tanks can be controlled.
The salt storage tank is provided with a heating device and a temperature measuring device, the heating can adopt a gas radiant tube and an electric heating mode, and the arrangement mode of a heater comprises a vertical insertion mode, a bottom horizontal insertion mode and a vertical and horizontal combination mode.
The salt storage tank is designed to be heat-insulated, the outer part of the salt storage tank is heat-insulated by heat-insulation-resistant aluminum silicate, the tank body is designed to be double-layer welded, a vacuum layer is arranged between the double layers, and the vacuum degree is 70-100 Pa.
The temperature of the salt storage tank is measured by adopting multipoint temperature measurement, the temperature control is carried out by adopting one point temperature control, and the uniformity of the temperature reaches within +/-3 ℃.
4. The molten salt pump is arranged on the quenching tank salt storage tank and the tempering tank salt storage tank and is connected with the quenching tank through a pipeline, molten salt is injected into the quenching tank and the tempering tank through the molten salt pump, the liquid level and the molten salt amount of the quenching tank and the tempering tank are ensured, the molten salt flows out of two ends of the tank body after being injected, and the molten salt flows into the salt storage tank through the pipeline after being cached by the salt receiving hopper, so that the integral large circulation of the molten salt is realized.
The quenching tank-salt storage tank and the tempering tank-salt storage tank are two independent systems arranged in front and at back according to the process. The connection mode of the quenching tank and the tempering tank is the same as that of the salt storage tank. The salt storage tank is provided with a salt conveying pump, the salt pump conveys high-temperature molten salt to the quenching tank or the tempering tank through a pipeline, a liquid level of 100-300 mm is formed in the quenching tank or the tempering tank, then the molten salt flows back at two ends of the tank body to enter a salt receiving hopper for caching, then flows back to the salt storage tank through the pipeline and the molten salt due to self weight, and the salt storage tank is provided with a backflow hole, wherein the diameter of the backflow hole is 2-3 times of the diameter of a molten salt input pipeline.
The salt receiving hopper is arranged at the lower parts of the two ends of the quenching tank or the tempering tank and has the function of collecting the molten salt in the quenching tank and then refluxing the molten salt to the salt storage tank. The salt receiving funnel can be designed into a whole with the quenching tank or the tempering tank and can also be independently arranged, the pipeline connected with the salt receiving funnel and the salt storage tank is designed at the position of 100mm-200mm at the bottom of the funnel, a certain precipitation effect is formed in the funnel, and iron sheets and slag are prevented from entering the salt storage tank.
The large circulation of the whole molten salt is realized through a salt storage tank, a salt pump, a salt conveying pipeline, a quenching tank (tempering tank), a salt receiving funnel, a backflow pipeline and a salt return port.
5. Under the action of traction force of a rear wire rewinding machine, continuous wires or strip steel are paid off and then enter a heating furnace to be heated, then horizontally enter a quenching tank to finish salt bath quenching in an immersed state, and then enter a tempering tank to finish tempering treatment.
The take-up machine adopts a single-wire single control mode, and the power of the take-up machine is that an electric motor drives a take-up reel. The take-up can be one or more, and is designed according to the capacity of a workshop. The heating furnace can adopt electric radiant tube heating, gas open fire heating and gas radiant tube heating according to the product quality requirements, and the heating furnace can adopt N2, methanol cracking and open fire atmosphere.
Because a certain liquid level is formed in the quenching tank, the heated steel wires and steel strips can horizontally enter and exit the quenching tank, and immersion quenching is carried out in the quenching tank, wherein the immersion depth is controlled between 50mm and 150mm, so as to ensure the cooling speed and the cooling uniformity of the quenching workpiece. The steel wire and the band steel in the tempering tank can adopt the same immersion type of a quenching tank and can also adopt a compression roller immersion type, and the advancing tracks of the steel wire and the band steel are changed through a carrier roller at the inlet section of the tempering tank, a compression roller in the tank and a supporting pipe at the tail end of the tempering tank, so that the heat transfer and tempering treatment of workpieces in the tempering tank are completed.
According to the quenching and tempering process of the traditional spring steel wire and strip steel, the temperature of a quenching tank is controlled to be 150-300 ℃, and the temperature of a tempering tank is controlled to be 200-450 ℃.
6. The quenching tank can be provided with a cooling air pipe, the air quantity is controlled by a variable frequency fan, the heat in the quenching process of the heated steel piece is led out, and the temperature constancy of the whole quenching tank and the salt storage tank of the quenching tank is ensured.
The air pipes arranged in the quenching tank adopt DN40-DN100 to dredge, the variable frequency fan is used for controlling the air quantity in the air pipes and the cooling intensity of the whole cooling system, the set temperature of the salt storage tank forms closed-loop temperature control when the variable frequency fan and the quenching tank work, and the heat carried by the quenching workpiece is led out in a mode of the air pipes.
7. High-pressure hot air generated by a cooling air pipe arranged in the quenching tank is introduced into an air box at the tail end of the tempering tank, and a hot air knife is formed around the workpiece, so that residual salt on the surface of the workpiece is swept.
The thickness of the wall thickness of the air pipe is 1mm, the air pipe is made of heat-resistant stainless steel, the air pipe is arranged in a quenching tank in a snake shape, high-temperature and high-pressure air with a certain temperature is finally formed, the air pipe is connected with a hot air knife device behind the tempering tank, residual salt on the surfaces of the steel wires and the strip steel is blown away, the temperature of the hot air knife reaches more than 200 ℃, the pressure reaches 0.3MPa-0.4MPa, and the blowing rate of the residual salt reaches 90%. The hot air knives are annularly arranged, and the diameter of the hot air knives is 2-5 times of the diameter of the steel wire or 3-4 times of the thickness of the strip steel.
8. And the workpiece is blown by the hot air knife and then enters a cleaning machine, the workpiece is cleaned by the nozzle, the cleaned salt water is separated by the multi-effect evaporator, and the recovered salt is injected into the quenching tank again.
After quenching, tempering and blowing treatment of workpieces such as steel wires, strip steel and the like are finished, the workpieces enter a cleaning machine, a fan-shaped and annular spraying state is formed through a water pump and a nozzle, the workpieces are cleaned, water vapor generated by cleaning is collected by a dust removal tower, the dust removal tower adopts a wet spraying, cooling and condensing mode, and the recovered water is injected into the cleaning machine again to finish water supplement of the cleaning machine. The cleaning machine is divided into two boxes, the spraying is divided into salt water spraying and clear water spraying, the two boxes are designed with liquid level meters, the supply of the salt water tank passes through the clear water tank, and the supply of the clear water tank comes from the dust removal tower or an external water system.
The brine tank is saturated brine in the concentration during long-time service life, salt particles can be separated out and condensed at the bottom of the tank, the saturated brine is connected with a multi-effect evaporator to realize brine separation, and the recovered salt enters a primary melting device to be melted and injected into a salt storage tank to complete material closed-loop control of molten salt in the whole system.
9. And a radar liquid level meter is arranged on the salt storage tank, so that the amount of the molten salt in the salt storage tank is monitored in real time, and the molten salt is supplemented when exceeding the warning liquid level.
The radar liquid level meter of the salt storage tank monitors the amount of the molten salt in the salt storage tank, and is provided with an alarm device, and the liquid is smaller than or larger than the early warning liquid level to realize chain alarm.
10. The filter has been arranged on the salt storage tank, and when producing the line stop work, all fused salts flow back to the salt storage tank again, are connected to the filter through the salt pump on the salt storage tank, carry out impurity filtering to the fused salt.
The salt storage tank is provided with a filter for filtering 1mm-5mm solid impurities and iron scales. The filter is taken as a manhole after being removed, and the filter is used for observing the state of the salt storage tank when the equipment stops running; meanwhile, the filter is also an injection port and a salt adding port of the primary molten salt.
11. The molten salt in the salt storage tank adopts a mixed system of nitrate, nitrite and carbonate, the application range of the mixed system is 150-650 ℃, and the nano metal particles are supplemented periodically to ensure the quenching intensity of the molten salt.
The blending and the components of the molten salt are determined according to the quenching-tempering process of the spring steel wire and the strip steel, and the temperature of the tempering tank is 100-200 ℃ higher than that of the quenching tank in general. Besides regular deslagging and filtering of the molten salt, the components of the molten salt are tracked according to the long-time thermal fatigue condition, and a reinforcing agent of nano particles is added in the molten salt to ensure the quenching intensity.
Example 1
By adopting the technology of the invention, the heating temperature of the developed 60Si2Mn spring steel wire is controlled at 880 ℃ by the heat treatment process, and the relationship between quenching, tempering and performance is shown in the table.
Table 1 quenching and tempering processes and corresponding properties are shown in the table:
tempering
Quenching
150℃
180℃
200℃
230℃
300℃
2300MPa
2200MPa
2000MPa
1900MPa
350℃
2100MPa
2000MPa
1920MPa
1820MPa
Example 2
The heat treatment process of the 65Mn spring steel wire by adopting the technology of the invention has the heating temperature controlled at 840 ℃, and the relation between quenching, tempering and performance is shown in the table.
Table 2 quenching and tempering processes and corresponding properties are shown in the table:
tempering
Quenching
150℃
180℃
200℃
230℃
300℃
2000MPa
1900MPa
1800MPa
1700MPa
350℃
1900MPa
1700MPa
1620MPa
1520MPa
Comparative example 1
The traditional oil quenching and lead bath tempering are adopted to develop the spring steel wire of 60Si2Mn, the heating temperature of the heat treatment process is controlled at 900 ℃, the quenching temperature of the oil bath cannot exceed 160 ℃, the temperature of the steel wire after deep quenching is very low, the later lead bath tempering temperature is increased to obtain excellent tissues so as to meet the requirements of large production efficiency and structural performance, and the relationship between the quenching, tempering and performance is shown in the table.
Table 3 quenching, tempering processes and corresponding properties are shown in table:
tempering
Quenching
100℃
120℃
140℃
160℃
400℃
2250MPa
2150MPa
1950MPa
1900MPa
450℃
2050MPa
1900MPa
1870MPa
1850MPa
Comparative example 2
The heat treatment process of the 65Mn spring steel wire by adopting the technology of the invention has the heating temperature controlled at 860 ℃, and the relation of quenching, tempering and performance is shown in the table.
Table 4 quenching, tempering processes and corresponding properties are shown in table:
tempering
Quenching
100℃
120℃
140℃
160℃
350℃
1950MPa
1850MPa
1780MPa
1700MPa
400℃
188MPa
1650MPa
1600MPa
1500MPa
Compared with the traditional oil quenching heat treatment, the salt bath quenching and salt bath tempering process has the advantages that the tensile strength of the steel wire is generally high, and the potential and social benefits of the salt bath in the aspect of environmental protection are better.
Claims (10)
1. A salt bath quenching and tempering heat treatment process method of spring steel wires is used for replacing the traditional oil quenching and lead bath tempering production process method, and the process comprises the following steps: paying off, heating furnace heating, salt bath quenching, salt bath tempering, purging, cleaning and taking up, primary melting is carried out on solid salt through a molten salt primary melting device, quenching and tempering are completed in a corresponding quenching tank and a corresponding tempering tank, the quenching tank and the tempering tank are connected with a corresponding salt storage tank, a molten salt pump is arranged on the salt storage tank, the quenching tank and the tempering tank are filled to a certain liquid level through the salt pump, a steel wire straightly passes through the molten salt quenching tank and the tempering tank, after heat exchange is carried out on the molten salt and the steel wire, the molten salt flows back to the salt storage tank, after the steel wire exits from the molten salt tempering tank, a hot air knife is adopted to purge residual salt on the surface, and the surface is purified through water cleaning.
2. The spring steel wire salt bath quenching and tempering heat treatment process according to claim 1, wherein the primary melting of solid molten salt is realized by a molten salt primary melting device, then the molten salt is injected into a salt storage tank in several times by a salt pump on the primary melting device, and a heating device and a thermocouple are arranged on the quenching tank salt storage tank and the tempering tank salt storage tank, so that the temperature of the salt storage tank can be controlled.
3. The spring steel wire salt bath quenching and tempering heat treatment process as claimed in claim 1, wherein the salt storage tanks of the quenching tank and the tempering tank are provided with molten salt pumps, the molten salt pumps are connected with the quenching tank through pipelines, molten salt is injected into the quenching tank and the tempering tank through the molten salt pumps, the liquid levels and the molten salt amount of the quenching tank and the tempering tank are ensured, the molten salt flows out from two ends of the tank body after being injected, and the molten salt flows back into the salt storage tanks through the pipelines after being cached by salt receiving funnels, so that the integral large circulation of the molten salt is realized.
4. The spring steel wire salt bath quenching and tempering heat treatment process of claim 1, wherein a steel wire or a steel wire rod horizontally enters a quenching tank after being heated under the actions of paying off and traction force of a rear wire rewinding machine, and is quenched in a salt bath under an immersed state, and then enters a tempering tank to finish tempering treatment.
5. The spring steel wire salt bath quenching and tempering heat treatment process according to claim 1, wherein a cooling air pipe can be arranged in the quenching tank, the air volume is controlled by a variable frequency fan, the heat in the quenching process of the heated steel part is led out, and the temperature constancy of the whole quenching tank and a salt storage tank of the quenching tank is ensured.
6. The spring steel wire salt bath quenching and tempering heat treatment process of claim 5, wherein high-pressure hot air generated by a cooling air pipe arranged in the quenching tank is introduced into an air box at the tail end of the tempering tank, and hot air knives are formed around the workpiece, so that residual salt on the surface of the workpiece is swept.
7. The spring steel wire salt bath quenching and tempering heat treatment process of claim 1, wherein a workpiece enters a cleaning machine after being blown by a hot air knife, the workpiece is cleaned through a nozzle, the cleaned salt water is separated through a multi-effect evaporator, and the recovered salt is injected into the quenching tank again.
8. The spring steel wire salt bath quenching and tempering heat treatment process according to claim 1, wherein a radar liquid level meter is arranged on the salt storage tank, the amount of molten salt in the salt storage tank is monitored in real time, and the amount of molten salt exceeds a warning liquid level for supplement.
9. The spring steel wire salt bath quenching and tempering heat treatment process as claimed in claim 1, wherein a filter is arranged on the salt storage tank, when the production line stops working, all the molten salt flows back to the salt storage tank again, and is connected to the filter through a salt pump on the salt storage tank to filter impurities in the molten salt.
10. The spring steel wire salt bath quenching and tempering heat treatment process of claim 1, wherein a mixed system of nitrate, nitrite and carbonate is adopted as the molten salt in the salt storage tank, the application range is 150-650 ℃, and the nano metal particles are periodically supplemented to ensure the quenching intensity of the molten salt.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210512699.4A CN115044746A (en) | 2022-05-12 | 2022-05-12 | Salt bath quenching and tempering heat treatment process method for spring steel wire |
| CN202310529959.3A CN117107044A (en) | 2022-05-12 | 2023-05-11 | Salt bath quenching tempering heat treatment process method for spring steel wire |
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| CN202210512699.4A CN115044746A (en) | 2022-05-12 | 2022-05-12 | Salt bath quenching and tempering heat treatment process method for spring steel wire |
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| CN202310529959.3A Pending CN117107044A (en) | 2022-05-12 | 2023-05-11 | Salt bath quenching tempering heat treatment process method for spring steel wire |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116287664A (en) * | 2023-05-15 | 2023-06-23 | 江苏永钢集团有限公司 | High-speed wire on-line heat treatment equipment and process based on energy recycling |
-
2022
- 2022-05-12 CN CN202210512699.4A patent/CN115044746A/en not_active Withdrawn
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2023
- 2023-05-11 CN CN202310529959.3A patent/CN117107044A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116287664A (en) * | 2023-05-15 | 2023-06-23 | 江苏永钢集团有限公司 | High-speed wire on-line heat treatment equipment and process based on energy recycling |
| CN116287664B (en) * | 2023-05-15 | 2023-08-08 | 江苏永钢集团有限公司 | High-speed wire on-line heat treatment equipment and process based on energy recycling |
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| CN117107044A (en) | 2023-11-24 |
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Application publication date: 20220913 |