CN110670012A

CN110670012A - Carburizing steel shot and production device thereof

Info

Publication number: CN110670012A
Application number: CN201910959381.9A
Authority: CN
Inventors: 赵松乔; 韩庆吉
Original assignee: ZIBO TAA METAL TECHNOLOGY Co Ltd
Current assignee: ZIBO TAA METAL TECHNOLOGY Co Ltd
Priority date: 2019-10-10
Filing date: 2019-10-10
Publication date: 2020-01-10

Abstract

The invention relates to a carburizing steel shot and a production device thereof, which eliminates quenching stress by carburizing and quenching low-temperature tempering of a low-carbon steel shot. The carburized steel shot after quenching has the surface hardness of HRC57 or above and the core hardness of HRC25-45, and then is tempered to the required hardness, so that the steel shot has the characteristics of external strength and intermediate toughness, has higher cleaning and strengthening efficiency and high fatigue strength, meets the requirements of cleaning and strengthening high-hardness parts, and replaces high-carbon steel shots and grinding shots applied in the current strengthening field.

Description

Carburizing steel shot and production device thereof

Technical Field

The present disclosure relates to a carburized steel shot and a production apparatus thereof.

Background

The information in this background section is only for enhancement of understanding of the general background of the disclosure and is not necessarily to be construed as an admission or any form of suggestion that this information forms the prior art that is already known to a person of ordinary skill in the art.

Currently, the main metal abrasives on the market are: high carbon cast steel shots (or called high carbon steel shots) and low carbon steel shots. The high-carbon steel shot can obtain the hardness of more than HRC55 and can be used for strengthening the spray (cast) shot of high-hardness parts, but the high-carbon steel shot is easy to break in the using process and has low service life due to high carbon content. Although the low-carbon steel shot has longer fatigue life, the hardness can only be about HRC50, and the field of cleaning and strengthening of high-hardness parts is limited.

Therefore, it is a need for market development to develop a new type of metal abrasive and corresponding production equipment, so that the metal abrasive has both higher hardness and good fatigue resistance.

Disclosure of Invention

In view of the background technology, the present disclosure provides a carburizing steel shot and a corresponding production device thereof, so that the steel shot has the characteristics of strong outside and moderate toughness, has higher cleaning and strengthening efficiency and higher fatigue strength, and meets the requirements of cleaning and strengthening high-hardness parts.

Specifically, the following technical scheme is adopted in the disclosure:

in a first aspect of the present disclosure, there is provided a carburized steel shot characterized by: carburizing the surface of the low-carbon steel shot, and then quenching to form a carburized layer with the thickness of 0.2-2.0 mm on the surface, wherein the surface hardness reaches HRC57 or above, and the core hardness is HRC 25-45;

the carburizing steel shot is composed of the following chemical components in percentage by mass:

0.2-0.8% of C, more than 0.1% of Si, more than 0.35% of Mn, less than 0.05% of S, P, 0.3-1.6% of Cr, 0.001-0.2% of Mos, and the balance of Fe; alternatively, the first and second electrodes may be,

0.2-0.8% of C, more than 0.1% of Si, more than 0.35% of Mn, less than 0.05% of S, P, 0-1.6% of Cr, 0-0.2% of Mo0, and Ti: 0-0.2%, and the balance Fe.

In a second aspect of the present disclosure, there is provided a method for preparing the carburized steel shot, including the steps of:

sequentially carrying out pre-screening, carburizing, quenching and tempering on the low-carbon steel shots, and then carrying out screening and packaging to obtain the carburized steel shots;

the low-carbon steel shot comprises the following chemical components in percentage by mass:

0.1-0.2% of C, more than 0.1% of Si, more than 0.35% of Mn, less than 0.05% of S, P, 0.3-1.6% of Cr, 0.001-0.2% of Mos, and the balance of Fe; alternatively, the first and second electrodes may be,

0.1-0.2% of C, more than 0.1% of Si, more than 0.35% of Mn, less than 0.05% of S, P, 0-1.6% of Cr, 0-0.2% of Mo, and Ti: 0-0.2%, and the balance Fe.

In a third aspect of the present disclosure, there is provided an apparatus for producing a carburized steel shot, comprising:

the carburizing furnace is provided with at least one feed and discharge port, an exhaust port, a carburizing medium inlet and a carbon potential sensor;

the carburizing agent system is communicated with the carburizing furnace;

the quenching tank is positioned below the material inlet and the material outlet;

a heating device located within the carburizing furnace;

the motor is used for controlling the carburizing furnace to rotate and is connected with a rotating shaft of the carburizing furnace through a speed reducer;

a motor for controlling the tilting of the carburizing furnace.

In a fourth aspect of the present disclosure, there is provided a carburizing and quenching method using the production apparatus, the method including the steps of:

(1) starting a heating device, and heating the carburizing furnace to 900-950 ℃;

(2) oil dripping and exhausting for 40-60 min through a carburizing medium inlet, and controlling the oil dripping speed to be 7.5-10 ml/min;

(3) adding the pre-screened low-carbon steel shot into a carburizing furnace, and starting a motor to enable the rotating speed of the carburizing furnace to be 2-10 revolutions per minute;

(4) carburizing for 40-80 min;

(5) after the carburizing is finished, cooling to 840-860 ℃;

(6) discharging and quenching in water at the discharging speed of 0.6-1.0 kg/s.

Compared with the related technology known by the inventor, one technical scheme of the present disclosure has the following beneficial effects:

the low-carbon steel shots are carburized, quenched and then tempered at low temperature, so that quenching stress is eliminated. The carburized steel shot after quenching has the surface hardness of HRC57 or above and the core hardness of HRC25-45, and then is tempered to the required hardness, so that the steel shot has the characteristics of external strength and intermediate toughness, has higher cleaning and strengthening efficiency and high fatigue strength, meets the requirements of cleaning and strengthening high-hardness parts, and replaces high-carbon steel shots and grinding shots applied in the current strengthening field.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this disclosure, illustrate embodiments of the disclosure and, together with the description, serve to explain the disclosure and not to limit the disclosure.

FIG. 1 is a schematic structural diagram of a steel shot production device.

FIG. 2 is a schematic view of the outlet structure of the carburizing furnace.

FIG. 3 is a schematic view of a structure for controlling the rotation of a carburizing furnace.

FIG. 4 is a schematic view of a carburizing medium inlet structure.

FIG. 5 is a schematic view showing a charging state of the carburizing furnace.

FIG. 6 is a schematic view showing a normal operation state of the carburizing furnace.

FIG. 7 is a schematic view showing a tilting and dumping state of the carburizing furnace.

The device comprises a carburizing furnace 1, a furnace container 1-1, a furnace container 2, a material inlet and outlet port 3, a carburizing medium inlet 4, a carbon potential sensor 5, a quenching tank 6, a rotating motor 7, a speed reducer 8, a rotating shaft 9, a furnace tilting motor 10, a supporting carrier roller 11, a bracket 12, an exhaust port 13, an exhaust pipe 14, a cover cap I, 15, a sealing gasket 16, a pipe hoop 17, a carburizing agent barrel 18, an electromagnetic valve 19, a flowmeter 20, a drip injector 21, a flange I, a flange 22, a signal line and a control line 23, an electric cabinet 24, a water inlet pipe 25, an overflow water pipe 26, a discharge pipe 27, a thermocouple 28, a resistance wire 29, a hand wheel-equipped speed reducer 30, a coupler 31, a seated bearing 32, a bearing 33, a bearing sleeve 34, a bearing cap 35, a cover cap II, a flange II, and a water tank.

Detailed Description

It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present disclosure. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of the stated features, steps, operations, and/or combinations thereof, unless the context clearly indicates otherwise.

As described in the background of the invention, the current high carbon steel shot and low carbon steel shot do not have ideal effects as a metal abrasive, and in order to solve the above technical problems, in a first exemplary embodiment of the present disclosure, there is provided a carburized steel shot characterized in that: carburizing the surface of the low-carbon steel shot, and then quenching to form a carburized layer with the thickness of 0.2-2.0 mm on the surface, wherein the surface hardness reaches HRC57 or above, and the core hardness is HRC 25-45;

i: 0.2-0.8% of C, more than 0.1% of Si, more than 0.35% of Mn, less than 0.05% of S, P, 0.3-1.6% of Cr, 0.001-0.2% of Mo, and the balance of Fe; alternatively, the first and second electrodes may be,

II: 0.2-0.8% of C, more than 0.1% of Si, more than 0.35% of Mn, less than 0.05% of S, P, 0-1.6% of Cr, 0-0.2% of Mo0, and Ti: 0-0.2%, and the balance Fe.

In one or more embodiments of the present disclosure, the low carbon steel shot may be a pre-screened low carbon steel shot.

In one or more embodiments of the present disclosure, the low-carbon steel shot is composed of the following chemical components in percentage by mass:

Further, the low-carbon steel shot is prepared by the following method: smelting, atomizing and cooling to obtain low-carbon steel shots; or the low-carbon steel wire can be used for obtaining the low-carbon steel shot through cutting and rounding.

In a second exemplary embodiment of the present disclosure, a method for preparing the carburized steel shot is provided, which includes the steps of:

and (3) sequentially carrying out pre-screening, carburizing, quenching and tempering on the low-carbon steel shots, and then screening and packaging to obtain the carburized steel shots.

In one or more embodiments of the present disclosure, during the research process of carburizing treatment, the present disclosure searches for carburizing process condition parameters, and finds that, for low-carbon steel shots with specific chemical compositions, the performance differences of the carburized steel shots obtained by using different carburizing process condition parameters are large. The preferable process conditions of the carburizing treatment are as follows: the rotating speed of the furnace pipe is 2-10 revolutions per minute, the temperature is increased to 900-950 ℃, the feeding amount is 200-1000kg, oil dripping and gas exhausting are carried out for 40-60 min, the carburizing time is 40-80 min, the oil dripping speed is 150-200 drops per minute, and the volume of each drop is 0.02-0.1 mL (preferably 0.05 mL).

Furthermore, in the research process of carburization treatment, the method screens and optimizes a carburization medium, finally selects a mixture of kerosene and methanol as the carburization medium (or called a carburizing agent), and can effectively avoid the defects of easy generation of carbon deposit, unstable furnace gas components and carbon potential, difficult control and the like caused by the separate use of kerosene by controlling the rotating speed of a furnace pipe, the carburizing temperature and the oil dropping speed.

Adopting kerosene and methanol as carburizing medium, wherein the kerosene content is 15-30 wt%, and the methanol cracking product H is obtained at high temperature₂O、CO₂Is prepared from CH₄And [ C]Oxidizing to maintain the furnace gas components and carbon potential in certain range, and measuring and controlling with carbon potential sensor.

Methanol is used as a diluent, kerosene is used as a carburizing agent, and the characteristics of different carburizing agents can be fully exerted at different stages. In the exhaust stage, the temperature is low, the kerosene is not easy to be fully decomposed, and the dripping of the kerosene can be stopped; the methanol cracking temperature is low, the gas production rate is high, carbon black is not easy to form, methanol can be dripped into the methanol in large dripping amount, and the aim of removing the oxidizing atmosphere in the furnace as soon as possible is achieved. When the temperature of the furnace rises to above 850 ℃, kerosene can be dripped, and methanol is stopped dripping to improve the carbon potential of the furnace gas. In the stage of carbon potential regulation and strong cementation, the furnace temperature is raised to above 900 deg.C, the kerosene can be fully decomposed, the kerosene drop quantity can be increased, the carbon potential of furnace gas can be quickly raised, so that a large quantity of carbon can be absorbed on the surface of workpiece, the carbon concentration of surface can be raised as quickly as possible, and the carburization can be accelerated, so that the strong cementation time can be shortened. In the diffusion and cooling stage, the kerosene drop is reduced properly, and in order to maintain the positive pressure in the furnace, a small amount of methanol can be dropped, so that the carbon potential of the furnace gas is equal to the final requirement.

In one or more embodiments of the disclosure, in the process of experimental research, it is found that the toughness and the surface hardness of the carburized steel shot obtained at different quenching temperatures are different, the disclosure comprehensively considers the higher requirements of the carburized steel shot on the hardness and the fatigue resistance, and the selected quenching temperature is 840-860 ℃.

Furthermore, the temperature of the steel shot with the phase change is more than 727 ℃, considering that the heat of the steel shot can be lost in the process of pouring the steel shot into the quenching tank from the carburizing furnace, a quenching temperature higher than the phase change needs to be selected to compensate the heat loss, but if the temperature is too high, the crystal grains of the steel shot are relatively thick, the strength of the steel shot is poor, and the selected quenching temperature is 850 ℃ in combination with the actual situation.

In one or more embodiments of the present disclosure, the tempering condition is: and (3) tempering and heat preservation at 260-280 ℃ for 30-90 min, and tempering by adopting a tempering furnace or a carburizing furnace.

The inventor finds in the experimental research process that during batch carburization, granular materials are accumulated, so that carburized layers are prone to be uneven, and in order to effectively solve the problem and efficiently produce carburized steel shots, in a third exemplary embodiment of the present disclosure, a carburized steel shot production apparatus is provided, which includes:

the carburizing agent system is communicated with the carburizing furnace;

a heating device located within the carburizing furnace;

a motor for controlling the tilting of the carburizing furnace.

In one or more embodiments of the present disclosure, the carburizing furnace includes a furnace pipe, and a carburizing treatment region is arranged inside the furnace pipe. The rotary carburizing furnace is adopted in the method, so that the granular materials are continuously stirred in the furnace, and the uniformity of a carburized layer is ensured.

In one or more embodiments of the present disclosure, the at least one feeding/discharging port includes a feeding port and a discharging port, and the feeding port and the discharging port are both at the same end of the carburizing furnace and are used for feeding and discharging, or the feeding/discharging port and the discharging port share one port. Specifically, the feed inlet and discharge port is provided with a cover cap inserted with an exhaust pipe, the cover cap is connected with a carburizing furnace through a pipe hoop, the cover cap is conveniently opened for feeding and is detached for pouring, and the cover cap and the furnace liner are sealed to prevent air leakage.

In one or more embodiments of the present disclosure, the infiltrant system is in communication with the carburizing furnace through a carburizing medium inlet.

Furthermore, a carbon potential sensor is installed at the inlet of the carburizing medium, the carbon potential sensor extends into the carburizing furnace to measure the content of CO in the furnace, and the opening of an electromagnetic valve on a carburizing agent dripping pipeline is adjusted according to the feedback of the carbon potential sensor, so that the dripping amount of the carburizing agent is controlled.

Further, the tonicity agent system comprises: a container (such as a permeating agent barrel) capable of containing a permeating agent, an electromagnetic valve, a flowmeter and an instillator are sequentially connected through a pipeline according to the sequence.

Furthermore, the container is connected with the carburizing medium inlet through a pipeline, and the electromagnetic valve is connected with the electric cabinet through a signal line and a control line to control the adding amount of the carburizing agent and the carburizing agent.

In one or more embodiments of the present disclosure, the volume of the carburizing furnace is 500L. 200-1000kg can be charged at one time.

In one or more embodiments of the present disclosure, the quenching tank includes a water inlet pipe, an overflow water pipe, and a discharge pipe, and the material is poured out from the furnace and enters the quenching tank to complete the quenching treatment.

The material is carburized in a furnace, after the treatment is finished, the carburizing furnace is adjusted to be in a tilting and material pouring working state, hot steel shots are poured into a quenching tank, the quenching tank consists of a water inlet pipe, an overflow pipe, a pipeline valve and a discharge pipe, and the water temperature of the quenching tank is controlled by controlling the water inlet amount and the water overflow amount, so that the treatment is finished.

In one or more embodiments of the present disclosure, the heating device is in the form of electrical heating.

Specifically, the heating elements are made of iron-chromium-aluminum alloy (0Cr21Al6Nb) heating strips wound into a spiral shape and are arranged on rock wool plates on the two sides and the bottom of the hearth. The carburizing furnace is provided with a thermocouple which is inserted into the furnace chamber from the furnace top, and the thermocouple feeds back and adjusts the heating power of the resistance wire, thereby controlling the furnace temperature.

In one or more embodiments of the present disclosure, the motor for controlling the tilting of the carburizing furnace is connected to the carburizing furnace through a speed reducer, a coupling and a bearing with a seat fixed on the support, and the motor rotates to drive the furnace body to tilt, so as to meet the requirements of working states of charging, normal working, tilting and dumping.

Specifically, when the carburizing furnace needs to be tilted, a motor for controlling the carburizing furnace to tilt drives the carburizing furnace to rotate to a position where an inlet faces the ground, and materials in the furnace can be poured out from a furnace mouth.

In one or more embodiments of the present disclosure, the apparatus further comprises: the supporting carrier roller is used for supporting the carburizing furnace.

In one or more embodiments of the present disclosure, the apparatus further comprises: and the bracket is used for supporting the furnace tilting motor.

In one or more embodiments of the present disclosure, the apparatus further comprises: and (5) tempering.

Carburization is widely used as a heat treatment method for making the surface layer of a workpiece high in carbon and keeping the core part of the workpiece as it is, but is not used in the field of metal abrasives. The gas carburization has an advantage in that stability and reproducibility of operation can be achieved by controlling the atmosphere, unlike low-pressure carburization. The gas carburizing has many kinds of equipment and large mechanical structure change, and can be generally divided into two types, namely a periodic type and a continuous type. The carburizing furnace is a pit type periodic furnace, a sealed box type furnace, a rotary type periodic furnace, a vibrating hearth type furnace, a push rod type continuous furnace and the like. The pit furnace, the sealed box furnace and the push rod type continuous furnace of the pit type gas carburizing furnace are widely applied. However, these widely used carburizing furnaces are not suitable for carburizing granular steel shots, the steel shots are easy to accumulate in the furnace, the phenomenon of uneven carburization occurs, and the requirement for preparing carburized steel shots cannot be met.

Correspondingly, the low-carbon steel shot carburizing and quenching method provided by the device comprises the following steps:

(2) oil dripping and exhausting for 40-60 min through a carburizing medium inlet, and controlling the oil dripping speed to be 150-200 drops/min;

(4) carburizing for 40-80 min;

(5) after the carburizing is finished, cooling to 840-860 ℃;

In order to make the technical solutions of the present disclosure more clearly understood by those skilled in the art, the technical solutions of the present disclosure will be described in detail below with reference to specific embodiments.

Example 1

A carburized cast steel shot is prepared by the following method:

(1) smelting: mixing the following components in percentage by mass: c: 0.17%, Si: 0.20%, Mn: 0.55%, S, P is less than 0.05%, Cr: 0.75%, Mo 0.14%, and the balance Fe were weighed and melted in a medium frequency electric furnace to obtain molten steel.

(2) And (3) granulation: pouring the molten steel into a tundish, converting the molten steel into water droplets by a centrifugal forming method, converting the droplets into spheres under the action of surface tension of the molten steel, and falling into a cooling pill water pool to form a semi-finished cast low-carbon steel pill.

(3) Drying: and fishing out the semi-finished cast low-carbon steel shot from the water tank, and drying the semi-finished cast low-carbon steel shot in a drying furnace until the water content is less than 0.2 wt%.

(4) Screening: and screening the dried steel shots to obtain coarse material semi-finished products with different specifications.

(5) And pre-screening, namely screening coarse grains and fine grains of the coarse material semi-finished product to obtain narrow-grain-grade materials with uniform granularity.

(6) Carburizing and quenching: the specific process conditions are as follows:

the test piece obtained by the test has the surface hardness of HRC57 or more and the core hardness of HRC 25-45.

(7) Tempering: and (3) after carburizing and quenching, tempering and preserving heat of the steel shot at 260-280 ℃ for 60 minutes to obtain the carburized steel shot.

(8) Fine screening and packaging: and (4) fine screening the tempered product and packaging to obtain a finished product.

Through determination, the obtained carburized cast steel shot comprises the following chemical components in percentage by mass:

0.2-0.8% of C, more than 0.1% of Si, more than 0.35% of Mn, less than 0.05% of S, P, 0.3-1.6% of Cr, 0.001-0.2% of Mos, and the balance of Fe.

Through measurement, the obtained carburized cast steel shot has the surface hardness of HRC57 or more and the core hardness of HRC 25-45. The ERVIN life value measured by the 100% substitution method is about 2750 times, while the life value of the high-carbon steel shot with the same hardness is only about 1750 times.

Example 2

A carburized grinding pill is prepared by the following method:

(1) low-carbon steel wire: the diameter of the finished steel wire is about 2-10 mm. The low-carbon steel wire comprises the following elements: c: 0.17%, Si: 0.20%, Mn: 0.55%, S, P less than 0.05%, the remainder being Fe.

(2) Cutting into sections: and after the finished low-carbon steel wire is guided and positioned by the guide wheel, cutting the finished low-carbon steel wire into sections with the length-diameter ratio smaller than 2 by using a rotary cutter.

(3) Rounding: the low-carbon steel wires cut into sections are sprayed at high speed by a shot blasting machine to remove sharp edges and corners of the section steel wires to be approximately spherical, and the section steel wires are subjected to elastic-plastic deformation in the impact process, so that higher residual stress is presented.

(4) And (4) pre-screening, namely screening coarse grains and fine grains of the product after rounding to obtain narrow-grade materials with uniform granularity.

(5) Carburizing and quenching: the specific process conditions are as follows:

(6) Tempering: and (3) after carburizing and quenching, tempering and preserving heat of the steel shot at 260-280 ℃ for 60 minutes to obtain the carburized steel shot.

(7) Screening and packaging: and (4) fine screening the tempered product and packaging to obtain a finished product.

Through determination, the obtained carburized grinding pill comprises the following chemical components in percentage by mass:

Through measurement, the obtained carburized grinding pill has the surface hardness of HRC57 or more and the core hardness of HRC 25-45. The ERVIN life value measured by the 100% substitution method is 2950 times, while the life value of the high-carbon steel shot with the same hardness is only about 1750 times.

Example 3

An apparatus for producing a carburized steel shot, comprising, as shown in fig. 1:

the carburizing furnace comprises a carburizing furnace 1, wherein the carburizing furnace 1 is provided with a feed and discharge port 2, an exhaust port 12, a carburizing medium inlet 3 and a carbon potential sensor 4;

the carburizing agent system is communicated with the carburizing furnace 1;

a quenching tank 5 is positioned below the material inlet and outlet 2;

a heating device positioned in the carburizing furnace 1;

the rotary motor 6 is used for controlling the carburizing furnace to rotate, and the rotary motor 6 is connected with a rotating shaft 8 of the carburizing furnace 1 through a speed reducer 7; the rotating shaft 8 is a hollow rotating shaft;

a furnace tilting motor 9 for controlling the tilting of the carburizing furnace 1;

a supporting roller 10 for supporting the carburizing furnace 1;

a bracket 11 for supporting the tilting motor 9.

Specifically, the carburizing furnace 1 comprises a furnace pipe 1-1, a carburizing treatment area is arranged inside the furnace pipe 1-1, and an outlet of the carburizing treatment area is connected with a cover cap I14 through an outlet flange II 36.

As shown in figure 2, a material inlet and outlet port 2 is shared in feeding and discharging, a cap I14 with an exhaust pipe 13 is connected with a carburizing furnace 1 through a pipe hoop 16, the cap I14 is convenient to open and feed and detach the cap I14 for pouring, and a high-temperature-resistant sealing gasket 15 is arranged between the cap I14 and a furnace pipe 1-1 to prevent air leakage.

Specifically, the penetrant system comprises a penetrant barrel 17 for containing a mixture of methanol and kerosene, an electromagnetic valve 18, a flow meter 19 and a drip injector 20, which are sequentially connected through a pipeline according to the above sequence and communicated with the carburizing furnace 1 through a carburizing medium inlet 3, and the electromagnetic valve 18 is connected with an electric cabinet 23 through a signal line and a control line 22. A carbon potential sensor 4 is arranged at the carburizing medium inlet 3, the carbon potential sensor 4 extends into the carburizing furnace 1 to measure the content of CO in the furnace, and the opening degree of an electromagnetic valve 18 on a carburizing agent dripping pipeline is adjusted according to the feedback of the carbon potential sensor 4, so that the dripping amount of the carburizing agent is controlled.

More specifically, as shown in fig. 4, the rotary furnace pipe 1-1 is connected with the hollow rotating shaft 8 through a flange i 21, the hollow rotating shaft 8 is provided with a rolling bearing 32, the rolling bearing 32 is embedded in a bearing sleeve 33, and the bearing sleeve 33 and a bearing cover 34 are sealed to prevent gas leakage. When the device works, the furnace pipe 1-1 rotates, the cover cap II 35, the bearing cover 34 and the bearing sleeve 33 are fixed and do not rotate, and the carburizing agent inlet pipe and the carbon potential sensor 4 penetrate through the cover cap II 35 and extend into the furnace pipe 1-1 so as to add the carburizing agent into the furnace.

Specifically, the quenching tank 5 comprises a water inlet pipe 24, an overflow water pipe 25 and a discharge pipe 26, materials are carburized in the furnace, after the treatment is finished, the carburizing furnace 1 is adjusted to be in a tilting and material pouring working state, hot steel shots are poured into the quenching tank 5, and the water temperature of the quenching tank is controlled by controlling the water inlet amount and the overflow water amount, so that the quenching treatment is finished.

Specifically, the heating device is in the form of electric heating, and heating elements are wound by iron-chromium-aluminum alloy (0Cr21Al6Nb) heating belts into a spiral shape and are arranged on rock wool boards on the two sides and the bottom of a hearth. The carburizing furnace 1 is provided with a thermocouple 27 which is inserted into the furnace chamber from the furnace top, and the thermocouple 27 feeds back and adjusts the heating power of the resistance wire 28, thereby controlling the furnace temperature.

Specifically, as shown in fig. 3, the tilting motor 9 is connected to the carburizing furnace 1 through a speed reducer 29 with a handwheel, a coupling 30 and a bearing 31 with a seat fixed on the bracket 11, when the tilting furnace needs to be tilted for discharging, the motor drives the carburizing furnace 1 to rotate to a position where the inlet faces the ground, and the material in the furnace can be poured out from the furnace mouth, as shown in fig. 7. FIG. 5 is a schematic view of charging of a carburizing furnace, and FIG. 6 is a schematic view of normal operation of the carburizing furnace.

Example 4

A carburizing and quenching method for low-carbon steel shots by using the device in example 3, comprising the following steps:

(4) carburizing for 40-80 min;

(5) after the carburization is finished, cooling to 850 ℃;

The above embodiments are preferred embodiments of the present disclosure, but the embodiments of the present disclosure are not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present disclosure should be regarded as equivalent replacements within the scope of the present disclosure.

Claims

1. A carburized steel shot is characterized in that the surface of a low-carbon steel shot is carburized and then quenched, a carburized layer with the thickness of 0.2-2.0 mm is formed on the surface, the surface hardness reaches HRC57 or above, and the core hardness is HRC 25-45;

2. A carburized steel shot according to claim 1, characterized in that said low carbon steel shot consists of the following chemical components in mass percent:

0.1-0.2% of C, more than 0.1% of Si, more than 0.35% of Mn, less than 0.05% of S, P, 0-1.6% of Cr, 0-0.2% of Mo, and Ti: 0-0.2%, the balance being Fe;

3. A method for the preparation of a carburized steel shot according to claim 1 or 2, characterized in that it comprises the steps of:

4. The production method according to claim 3, wherein the carburizing treatment is carried out under the process conditions: the rotating speed of the furnace pipe is 2-10 revolutions per minute, the temperature is increased to 900-950 ℃, the feeding amount is 200-1000kg, oil dripping and gas exhausting are carried out for 40-60 min, the carburizing time is 40-80 min, and the oil dripping speed is 7.5-10 mL/min.

5. The process according to claim 3, wherein a mixture of kerosene and methanol is used as the carburizing medium, wherein the kerosene content is 15 to 30 wt%;

further, the selected quenching temperature is 840-860 ℃; furthermore, the selected quenching temperature is 850 ℃;

further, the tempering conditions are as follows: tempering and heat preservation at 260-280 ℃ for 30-90 min.

6. A production device of carburized steel shots is characterized by comprising:

the carburizing agent system is communicated with the carburizing furnace;

a heating device located within the carburizing furnace;

a motor for controlling the tilting of the carburizing furnace.

7. The apparatus of claim 6, wherein the carburizing furnace comprises a furnace pipe, and a carburizing treatment area is arranged inside the furnace pipe;

further, at least one business turn over material mouth includes feed inlet and discharge gate, and feed inlet and discharge gate all are in the same one end of carburizing furnace for feeding and the ejection of compact, perhaps, a mouth is used in business turn over material sharing.

8. The apparatus of claim 6 wherein said infiltrant system is in communication with the carburizing furnace through a carburizing medium inlet;

further, a carbon potential sensor is arranged at the inlet of the carburizing medium and extends into the carburizing furnace to measure the content of CO in the furnace;

further, the tonicity agent system comprises: the container, the electromagnetic valve, the flowmeter and the drip chamber which can contain the penetrant are sequentially connected through the pipeline according to the sequence;

furthermore, the container is connected with the carburizing medium inlet through a pipeline, and the electromagnetic valve is connected with the electric cabinet through a signal wire and a control wire;

the quenching tank comprises a water inlet pipe, an overflow water pipe and a discharge pipe, and the materials are poured out from the furnace and then enter the quenching tank to finish quenching treatment.

9. The apparatus of claim 6, wherein said heating means is in the form of electrical heating;

furthermore, the heating elements are spirally wound by iron-chromium-aluminum alloy (0Cr21Al6Nb) heating belts and are arranged on the two sides of the hearth and on the rock wool plate at the bottom of the hearth, and the carburizing furnace is provided with a thermocouple and is inserted into the hearth from the top of the furnace;

furthermore, a motor for controlling the tilting of the carburizing furnace is connected with the carburizing furnace through a speed reducer, a coupling and a bearing with a seat fixed on a bracket, and the motor rotates to drive the furnace body to tilt;

further, the apparatus further comprises: the supporting carrier roller is used for supporting the carburizing furnace;

further, the apparatus further comprises: a bracket for supporting the tilting motor;

further, the apparatus further comprises: and (5) tempering.

10. A carburizing and quenching method using the production apparatus according to any one of claims 6 to 9, characterized by comprising the steps of:

(4) carburizing for 40-80 min;

(5) after the carburizing is finished, cooling to 840-860 ℃;