CN115821148B

CN115821148B - Production process of high-hardness long-service-life low-carbon steel shot

Info

Publication number: CN115821148B
Application number: CN202310160459.7A
Authority: CN
Inventors: 甘经习; 耿涛; 甘小磊
Original assignee: Shandong Yaozhou Grinding Materials Co ltd
Current assignee: Shandong Yaozhou Grinding Materials Co ltd
Priority date: 2023-02-24
Filing date: 2023-02-24
Publication date: 2023-05-16
Anticipated expiration: 2043-02-24
Also published as: CN115821148A

Abstract

A production process of a high-hardness and long-service-life low-carbon steel shot relates to the technical field of steel shot production. Which comprises the following steps: step one: tempering and deslagging molten steel; then, when the molten steel is continuously heated to 1630 ℃, putting aluminum wires accounting for 0.03% of the mass of the molten steel into a ladle, and pouring the molten steel into the preheated ladle for casting; step two: centrifugally pouring molten steel; step three: and (3) drying the steel shot, rounding, fine screening and packaging. According to the invention, the low-carbon steel shot with high hardness, excellent toughness and long service life is prepared by improving the production process of the low-carbon steel shot, and a set of steel shot automatic forming machine is designed by matching with a new process, so that the quality of the steel shot can be improved, and meanwhile, the production efficiency is improved.

Description

Production process of high-hardness long-service-life low-carbon steel shot

Technical Field

The invention belongs to the technical field of steel shot production, and particularly relates to a production process of a high-hardness and long-service-life low-carbon steel shot.

Background

In the production process of various industrial products, the products with the texture of the metal materials are required to be polished, derusted or descaled, and sometimes the surface roughness is required to be increased so as to enhance the adhesion of the metal surface to paint, or the strength and the wear resistance of the metal surface are required to be enhanced, and the requirements are all required to be met through shot blasting processing, so that the processing technology of the metal products and the quality of the products are improved. For example, in the processing of a steel plate spring in the automobile industry, the fatigue resistance life of the plate spring is prolonged from 8 ten thousand times to more than 14 ten thousand times by a shot blasting processing technology, and the number of steel plate pieces is correspondingly reduced. For another example, the wear resistance of the industrial gear is better enhanced after shot blasting treatment.

The hardness of the steel shot in the shot blasting process can directly influence the process quality, and when the hardness of the low-carbon steel shot is too high and the toughness is smaller, the steel shot can be cracked in the collision process; when the hardness of the low-carbon steel shot is too small, the processing effect is difficult to realize, the steel shot consumption is large, and the processing cost is increased.

In the practical process, the applicant finds that the quenching temperature in the steel shot heat treatment process can seriously affect the hardness data of the steel shot, and the quenching temperature is too high, so that the hardness of the steel shot is reduced. How to reasonably adjust the production process of the low-carbon steel shot to ensure that the low-carbon steel shot has the characteristics of high hardness, high toughness and long service life is a technical problem to be solved by the technicians in the field.

Disclosure of Invention

The invention aims at: the low-carbon steel shot with high hardness, excellent toughness and long service life is prepared by improving the production process of the low-carbon steel shot; the second invention aims to improve the production efficiency while improving the quality of the steel shot by designing an automatic steel shot forming machine matched with a new process.

In order to achieve the above purpose, the present invention provides the following technical solutions: a production process of a high-hardness and long-service-life low-carbon steel shot comprises the following steps:

step one: quenching and tempering the molten steel, and then deslagging; then, continuously heating molten steel until the temperature of the molten steel is raised to 1630 ℃, putting an aluminum wire accounting for about 0.03% of the mass of the molten steel into a ladle, and pouring the molten steel into the preheated ladle for casting;

step two: centrifugally pouring molten steel; pouring molten steel from a steel ladle into a centrifugal machine, throwing out the molten steel by the centrifugal machine to form steel shots, and firstly, throwing out the steel shots to meet the impact of high-pressure water of a water curtain outside the centrifugal machine; the steel shot is quenched for the first time at 1100-1250 ℃; changing into smaller steel shot particles and dropping the smaller steel shot particles into water, wherein the temperature of the steel shot is between 850 and 950 ℃, and finishing secondary quenching;

step three: and (3) drying the steel shot, rounding, fine screening and packaging.

Preferably, the material quality of the molten steel after tempering in the first step reaches the following index: c:0.13% -0.2%, S <0.02%, P <0.02%, si:0.15% -0.25%, mn:0.6% -1.5%.

Preferably, the second step is carried out in an automatic steel shot forming machine; the automatic steel shot forming machine comprises a main frame, wherein a water inlet mechanism, a water outlet mechanism and more than one group of forming devices are arranged on the main frame; the forming device comprises a water curtain forming machine, a centrifugal machine and an annular water tank, wherein the water curtain forming machine is arranged on a main frame above the centrifugal machine, the annular water tank is sleeved on the periphery of the centrifugal machine, and a temperature controller is arranged in the annular water tank; the water inlet of the water curtain forming machine is communicated with a first water inlet branch of the water inlet mechanism, and a first water inlet electromagnetic valve and a first water inlet pump are arranged on the first water inlet branch; the water inlet of the annular water tank is communicated with a second water inlet branch of the water inlet mechanism, and a second water inlet electromagnetic valve and a second water inlet pump are arranged on the second water inlet branch; the water inlet mechanism and the water outlet mechanism of the automatic steel shot forming machine are respectively connected with a water outlet and a water return port of the water cooling tower, the water cooling tower is also provided with a water supplementing port, the water supplementing port is connected with a water source through a water supplementing branch, a water supplementing electromagnetic valve and a water supplementing pump are arranged on the water supplementing branch, and the water return port and the water supplementing port of the water cooling tower are far away from the water outlet; when the temperature controller detects that the water temperature in the annular water tank rises to 35 ℃, the second water inlet electromagnetic valve and the second water inlet pump on the second water inlet branch are automatically started, so that low-temperature cooling water in the water cooling tower can be injected into the annular water tank until the water temperature in the annular water tank is lower than 35 ℃.

Preferably, the water curtain forming machine comprises a bell-shaped outer cover body and an inner cover body, wherein the upper end of the outer cover body is fixed above the main frame in a lifting way, the upper end of the outer cover body is provided with a water inlet, and the water inlet of the outer cover body is connected with the first water inlet branch through a first water inlet electromagnetic valve; the inner cover body is arranged in the outer cover body through the lifting driving device, and the lower parts of the outer cover body and the inner cover body are converged inwards; a water curtain forming cavity is clamped between the outer cover body and the inner cover body, and an annular water curtain pouring opening is formed in the lower end of the water curtain forming cavity; cooling water in the cooling tower enters the water curtain forming cavity through the first water inlet branch, and then downwards poured out through an annular water curtain pouring opening at the lower end of the water curtain forming cavity to form an annular high-pressure water curtain; an annular high pressure water curtain is disposed around the centrifuge and falls completely into the annular pool.

Preferably, the outer cover is made of hard metal material; the inner cover body comprises an upper cover part and a lower box part, the upper cover part is bell-shaped and made of elastic rubber material, and the opening at the lower end of the upper cover part seals the upper end of the lower box part; the lower box part is cylindrical, and the lifting driving device is an electric telescopic rod; the fixed end of the electric telescopic rod is arranged in the lower box part, the telescopic end of the electric telescopic rod upwards penetrates out of the upper cover part and then is connected with the outer cover body, and the telescopic end of the electric telescopic rod is in sealing sleeve joint with the upper cover body; when the electric telescopic rod stretches, the lower box part can be driven to move downwards, and the gap between the lower box part and the lower end of the outer cover body is reduced, so that the thickness of the annular high-pressure water curtain is reduced, and the water pressure is increased; when the electric telescopic rod is shortened, the lower box part can be driven to move upwards, and the gap between the lower box part and the lower end of the outer cover body is increased, so that the thickness of the annular high-pressure water curtain is thickened, and the water pressure is reduced.

Preferably, an inner ring bracket and an outer ring bracket are arranged in the annular water tank; the inner ring support comprises an inner ring wall and an inner ring bottom plate, the outer ring support comprises an outer ring wall and an outer ring bottom plate, the inner ring wall and the outer ring wall take a rotating shaft of the centrifugal machine as a central shaft from inside to outside, are coaxially sleeved in an annular water tank outside the centrifugal machine, the inner ring bottom plate is arranged below a space between the inner ring wall and the centrifugal machine, and the outer ring bottom plate is arranged below a space between the outer ring wall and the inner ring wall; an inner ring discharging hole is formed in the inner ring bottom plate, an outer ring discharging hole is formed in the outer ring bottom plate, and electric switch movable doors are respectively arranged on the inner ring discharging hole and the outer ring discharging hole; the inner ring bottom plate and the outer ring bottom plate are respectively provided with a plurality of slag discharging holes.

Preferably, the bottom of the annular water tank is obliquely arranged, a discharge hole and a water outlet are respectively formed in the lowest part of the bottom of the annular water tank, a discharge valve is arranged on the discharge hole, and a drain valve is arranged on the water outlet; the water outlet mechanism comprises a water outlet branch pipe and a water outlet main pipe; the water outlet is communicated with a water outlet main pipe through a water outlet branch pipe, and the water outlet main pipe is communicated with a water return port of the cooling tower through a water outlet pump; the front end of the steel shot conveyer belt is arranged below the discharge hole, and the rear end of the steel shot conveyer belt is connected with the round selecting machine.

Preferably, the main machine frame comprises a plurality of branch supporting frames, and each branch supporting frame is provided with a forming device; the branch support comprises an operation box body, a support column is arranged at the bottom of the operation box body, the operation box body is of a split structure comprising an upper box body and a lower box body, and the upper box body is buckled on the lower box body; an annular water tank is embedded in the lower box body, and a centrifugal machine is arranged in the center of the annular water tank; the upper cover of the upper box body is provided with a mounting groove, and the lower end of the outer cover body can be embedded and fixedly placed in the mounting groove; an access opening is formed in the upper cover, and an access movable door is arranged on the access opening.

Preferably, the main machine frame further comprises a bottom frame and a lifting frame, wherein the bottom frame is fixed on the ground, and the lifting frame is arranged on the bottom frame through more than two groups of lifting cylinders; the upper end of the outer cover body is fixedly arranged on the lifting frame.

Compared with the prior art, the invention has the beneficial effects that:

1. the steel shot finished product prepared by the method has the advantages of high hardness, good elasticity, no breakage and cracking, strong toughness, longer service life and the like, and the process does not need to carry out multi-link heat treatment steps, so that the equipment, the electric charge and the labor cost can be obviously saved, and the self benefit of enterprises is improved while the energy is saved and the consumption is reduced. Experiments prove that the hardness of the product prepared by the process is about 20 percent higher than that of the national standard cast steel shot (the hardness of the national standard cast steel shot is HRC 42), and the hardness of the low-carbon steel shot prepared by the invention is about HRC 49). The national standard cast steel shot taking S550 as an example has the fatigue life of about 2400 times; the fatigue life of the low-carbon steel shot produced by the process can reach 3300 times, which is improved by about 40 percent compared with the prior art. In actual production, the production efficiency can be improved by nearly 70 percent for customers. At present, the selling price of the low-carbon steel pellets is about 20 percent higher than that of national standard products, thereby realizing remarkable improvement of comprehensive benefits.

2. The national standard steel shot generally needs to be added with about 0.5 percent of carburant (the carbon content of the general material is about 0.3 to 0.4 percent), and the national standard steel shot needs to have the carbon content of more than 0.85 percent), while the low-carbon steel shot produced by the process does not need to be added with the carburant in the production process. In addition, carburant is consumed during the addition and use process, and carbon dioxide is generated by carbon and oxygen at high temperature, so that the carbon emission is increased. The low-carbon steel shot does not need to add extra carbon, and electricity is saved (the steel shot does not need to be quenched for the second time and tempered at low temperature like the national standard steel shot). By reducing the two heat treatment processes, about 300 degrees of electricity can be saved per ton of steel shot production, and consumption of other resources (such as water) can be synchronously saved.

It is estimated that if 5 ten thousand tons of low carbon steel pellets are produced, 250000kg of the carbon adding agent can be directly saved in the year, 1500 ten thousand degrees can be saved in the electricity saving way, and the carbon emission is obviously reduced compared with the production of 5 ten thousand tons of national standard steel pellets.

3. The invention specially designs the automatic steel shot forming machine for the production process after the matching improvement, can automatically control the thickness of the water curtain for the first quenching, can automatically adjust the temperature of cooling water in the annular water tank, can accurately control the temperature condition in the steel shot heat treatment process, and can collect the steel shots after the forming in a classified way, thereby saving labor procedures and ensuring the high-quality and high-efficiency production of the steel shots.

Drawings

FIG. 1 is a schematic view of an automatic steel shot forming machine;

FIG. 2 is a schematic structural view of a molding apparatus;

in the figure: 1. an access opening; 2. a lifting frame; 3. a first water inlet electromagnetic valve; 4. a water curtain forming machine; 5. an inner annular wall; 6. a first water inlet branch; 7. an upper case; 8. a lifting cylinder; 9. a second water inlet branch; 10. an outer annular wall; 11. an annular pool; 12. a chassis; 13. a lower box body; 14. an outer ring base plate; 15. an inner ring base plate; 16. a centrifuge; 17. a discharge valve; 18. a water outlet pipe; 19. a lower box part; 20. an outer ring discharge port; 21. an inner ring discharge port; 22. a drain valve; 23. a water inlet of the water curtain forming machine; 24. an electric telescopic rod; 25. a housing body; 26. an upper cover part.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

The invention relates to a production process of a high-hardness and long-service-life low-carbon steel shot, which comprises the following steps of:

step one: quenching and tempering the molten steel, and then deslagging; and then continuously heating molten steel until the temperature of the molten steel is increased to 1630 ℃, putting aluminum wires accounting for about 0.03% of the mass of the molten steel into a ladle, and pouring the molten steel into the preheated ladle for casting.

Step two: centrifugally pouring molten steel; molten steel is injected into a centrifugal machine 16 from a ladle, steel shots are formed after the molten steel is thrown out of the centrifugal machine 16, and the thrown steel shots firstly encounter the impact of high-pressure water of a water curtain outside the centrifugal machine 16; the steel shot is quenched for the first time at 1100-1250 ℃; become smaller steel shot particles and fall into water, and the temperature of the steel shot is between 850 and 950 ℃ at the moment, so as to finish secondary quenching.

The material quality of the molten steel after tempering in the first step is up to the following index: c:0.13% -0.2%, S <0.02%, P <0.02%, si:0.15% -0.25%, mn:0.6% -1.5%.

The applicant obtains the experiments of the water inlet temperature and the steel shot hardness during the secondary quenching of the steel shot through the experiments as follows:

example 1

When the water temperature of the pool is 25 ℃, the hardness of 10 steel shots is randomly selected as follows: 51.2, 50.8, 49.5, 48.8, 52.6, 51.2, 49.5, 50.6, 50.8, 46.5, except for a highest value and a lowest value, the hardness of the steel shot of this group was HRC50.3.

Example two

When the water temperature is 30 ℃, the hardness of 10 steel shots is randomly selected as follows: 49.5, 50.6, 51.2, 50.2, 49.1, 48.8, 50.4, 51.5, 46.1, 49.8, with one highest value and one lowest value removed, the hardness average of the group of steel shots is HRC49.95.

Example III

When the water temperature is 35 ℃, the hardness of 10 steel shots is randomly selected to be respectively as follows: 50.4, 50.9, 49.2, 42, 9, 50.1, 48.5, 50.8, 49.6, 48.5, 52.1, with one highest value and one lowest value removed, the hardness average of the group of steel shots is HRC49.7.

Comparative example one

When the water temperature is raised to 40 ℃, the hardness of 10 steel shots is randomly selected as follows: 49.4, 48.3, 51.7, 50.1, 47.8, 49.3, 50.4, 50.1, 46.9, 48.3, except for a highest value and a lowest value, the hardness of the steel shot of the group is HRC49.2.

Comparative example two

When the water temperature is 45 ℃, the hardness of 10 steel shots is randomly selected to be respectively: 47.9, 48.8, 49.6, 52.1, 49.4, 48.9, 50, 41.3, 49.6, 48.7, except for a highest value and a lowest value, the hardness of the steel shot of the group has an average value of HRC48.86.

Comparative example three

When the water temperature is 50 ℃, the hardness of 10 steel shots is randomly selected as follows: 49.1, 50.2, 48.1, 47.2, 51.9, 46.8, 47.3, 49.3, 41.2, 49.2, except for a highest value and a lowest value, the hardness of the steel shot of this group has an average value of HRC48.4.

Comparative example four

When the water temperature is 55 ℃, the hardness of 10 steel shots is randomly selected to be respectively as follows: 46.5, 48.5, 50.1, 47.6, 46.5, 51.4, 45.9, 47.1, 49, 43.5, except for a highest value and a lowest value, the hardness of the steel shot of this group was HRC47.6.

Comparative example five

When the water temperature is 60 ℃, the hardness of 10 steel shots is randomly selected to be respectively: 47.9, 46.1, 49.7, 48.9, 46.3, 50.8, 44.6, 45.4, 46.5, 48.3, with one maximum and one minimum removed, the hardness of the steel shot of this group averaged 47.38.

Comparative example six

When the water temperature is raised to 65 ℃, the hardness of 10 steel shots is randomly selected as follows: 47.8, 45.9, 45, 42.5, 45.8, 51, 49.2, 45.6, 46.9, except for a highest value and a lowest value, the hardness of the steel shot of this group was HRC46.8.

Comparative example seven

When the water temperature is raised to 70 ℃, the hardness of 10 steel shots is randomly selected as follows: 45.1, 46.9, 45.2, 47.9, 45.1, 41.8, 48.6, 50.7, 45.2, 47, except for a highest value and a lowest value, the hardness of the steel shot of this group was HRC46.38.

From the hardness data obtained by the above 10 sets of experiments with different water temperatures, it can be concluded that: after the water temperature increases, the hardness of the steel shot decreases. Therefore, the production process disclosed by the invention can ensure the hardness of the produced steel shot by controlling the water temperature of secondary water quenching.

And step two, the process flow is carried out in an automatic steel shot forming machine. As shown in fig. 1 and 2, the automatic steel shot forming machine comprises a main frame, wherein a water inlet mechanism, a water outlet mechanism and more than one group of forming devices are arranged on the main frame; the forming device comprises a water curtain forming machine 4, a centrifugal machine 16 and an annular water tank 11, wherein the water curtain forming machine 4 is arranged on a main frame above the centrifugal machine 16, the annular water tank 11 is sleeved on the periphery of the centrifugal machine 16, and a temperature controller is arranged in the annular water tank 11; a water inlet 23 of the water curtain forming machine is communicated with a first water inlet branch 6 of the water inlet mechanism, and a first water inlet electromagnetic valve 3 and a first water inlet pump are arranged on the first water inlet branch 6; the water inlet of the annular water tank 11 is communicated with a second water inlet branch 9 of the water inlet mechanism, and a second water inlet electromagnetic valve and a second water inlet pump are arranged on the second water inlet branch 9.

The water inlet mechanism and the water outlet mechanism of the automatic steel shot forming machine are respectively connected with a water outlet and a water return port of the water cooling tower, the water cooling tower is also provided with a water supplementing port, the water supplementing port is connected with a water source through a water supplementing branch, a water supplementing electromagnetic valve and a water supplementing pump are arranged on the water supplementing branch, and the water return port and the water supplementing port of the water cooling tower are far away from the water outlet. When the temperature controller detects that the water temperature in the annular water tank 11 rises to 35 ℃, the second water inlet electromagnetic valve and the second water inlet pump on the second water inlet branch 9 are automatically started, so that low-temperature cooling water in the water cooling tower can be injected into the annular water tank 11 until the water temperature in the annular water tank 11 is lower than 35 ℃.

The water curtain forming machine 4 comprises a bell-shaped outer cover body 25 and an inner cover body, the upper end of the outer cover body 25 is fixed above the main frame in a hoisting manner, the upper end of the outer cover body 25 is provided with a water inlet, and the water inlet of the outer cover body 25 is connected with the first water inlet branch 6 through the first water inlet electromagnetic valve 3; the inner cover body is arranged in the outer cover body 25 through a lifting driving device, and the lower parts of the outer cover body 25 and the inner cover body are converged inwards; the outer cover 25 and the inner cover are clamped to form a water curtain forming cavity, and an annular water curtain pouring opening is formed in the lower end of the water curtain forming cavity.

After cooling water in the cooling tower enters the water curtain forming cavity through the first water inlet branch 6, the cooling water is poured downwards through an annular water curtain pouring opening at the lower end of the water curtain forming cavity to form an annular high-pressure water curtain; an annular high pressure water curtain is disposed around the centrifuge 16 and falls completely into the annular sump 11.

The outer cover 25 is made of hard metal; the inner cover body comprises an upper cover part 26 and a lower box part 19, the upper cover part 26 is bell-shaped and made of elastic rubber material, and the opening at the lower end of the upper cover part 26 seals the upper end of the lower box part 19; the lower box part 19 is cylindrical, and the lifting driving device is an electric telescopic rod 24; the fixed end of the electric telescopic rod 24 is arranged in the lower box part 19, the telescopic end of the electric telescopic rod 24 penetrates out of the upper cover part 26 upwards and then is connected with the outer cover body 25, and the telescopic end of the electric telescopic rod 24 is in sealing sleeve joint with the upper cover body; when the electric telescopic rod 24 is extended, the lower box part 19 can be driven to move downwards, and the gap between the lower box part 19 and the lower end of the outer cover body 25 is reduced, so that the thickness of the annular high-pressure water curtain is reduced, and the water pressure is increased; when the electric telescopic rod 24 is shortened, the lower box part 19 can be driven to move upwards, and the gap between the lower box part 19 and the lower end of the outer cover body 25 is increased, so that the thickness of the annular high-pressure water curtain is increased, and the water pressure is reduced.

An inner ring bracket and an outer ring bracket are arranged in the annular water tank 11; the inner ring support comprises an inner ring wall 5 and an inner ring bottom plate 15, the outer ring support comprises an outer ring wall 10 and an outer ring bottom plate 14, the inner ring wall 5 and the outer ring wall 10 are coaxially sleeved in an annular water tank 11 outside the centrifugal machine 16 by taking a rotating shaft of the centrifugal machine 16 as a central shaft from inside to outside, the inner ring bottom plate 15 is arranged below a space between the inner ring wall 5 and the centrifugal machine 16, and the outer ring bottom plate 14 is arranged below a space between the outer ring wall 10 and the inner ring wall 5; an inner ring discharging hole 21 is formed in the inner ring bottom plate 15, an outer ring discharging hole 20 is formed in the outer ring bottom plate 14, and electric switch trap doors are respectively formed in the inner ring discharging hole 21 and the outer ring discharging hole 20; a plurality of slag discharging holes are arranged on the inner ring bottom plate 15 and the outer ring bottom plate 14.

The bottom of the annular water tank 11 is obliquely arranged, a discharge hole and a water outlet are respectively formed in the lowest part of the bottom of the annular water tank 11, a discharge valve 17 is arranged on the discharge hole, and a drain valve 22 is arranged on the water outlet; the water outlet mechanism comprises a water outlet branch pipe 18 and a water outlet main pipe; the water outlet is communicated with a water outlet main pipe through a water outlet branch pipe 18, and the water outlet main pipe is communicated with a water return port of the cooling tower through a water outlet pump; the front end of the steel shot conveyer belt is arranged below the discharge hole, and the rear end of the steel shot conveyer belt is connected with the round selecting machine.

The main machine frame comprises a plurality of branch supporting frames, and a forming device is arranged and fixed on each branch supporting frame; the branch bracket comprises an operation box body, a support column is arranged at the bottom of the operation box body, the operation box body is of a split structure comprising an upper box body 7 and a lower box body 13, and the upper box body 7 is buckled on the lower box body 13; an annular water tank 11 is embedded in the lower tank body 13, and a centrifugal machine 16 is arranged in the center of the annular water tank 11; a mounting groove is formed in the upper cover of the upper box body 7, and the lower end of the outer cover body 25 can be embedded and fixedly placed in the mounting groove; an access opening 1 is arranged on the upper cover, and an access movable door is arranged on the access opening 1.

The main frame also comprises a bottom frame 12 and a lifting frame 2, wherein the bottom frame 12 is fixed on the ground, and the lifting frame 2 is arranged on the bottom frame 12 through more than two groups of lifting cylinders 8; the upper end of the outer cover 25 is fixedly mounted on the lifting frame 2.

The operation process of the automatic steel shot forming machine is as follows:

first, cooling water is injected into the cooling tower, a second water inlet valve and a second water inlet pump on the second water inlet branch 9 are started, and the cooling water is injected into the annular water tank 11. In the initial state, the lifting cylinder 8 drives the lifting frame 2 to lift to the upper limit, so that the water curtain forming machine 4 is also in the upper limit; molten steel in the ladle is poured into the centrifuge 16 through the mounting groove. After the molten steel injection work is completed, the lifting cylinder 8 is started immediately to drive the water curtain forming machine 4 to descend to the lower limit until the lower end of the outer cover 25 is fixedly placed in the mounting groove. Then the first water inlet electromagnetic valve 3 and the first water inlet pump on the first water inlet branch 6 are started, and the length of the electric telescopic rod 24 is preset, so that the size of the annular water curtain pouring opening between the outer cover body 25 and the inner cover body is proper, cooling water entering the water curtain forming cavity is poured downwards through the annular water curtain pouring opening to form an annular high-pressure water curtain, the radius of the annular high-pressure water curtain is about 1 meter, and the annular high-pressure water curtain is arranged around the centrifugal machine 16 and completely falls into the annular water pool 11.

At this time, the centrifuge 16 is started, and molten steel is thrown out through the centrifuge 16 to form steel shots. The steel shot is impacted by water curtain high pressure water, the temperature of the steel shot is between 1100 and 1250 ℃, the steel shot becomes smaller steel shot particles after the first quenching is finished and falls into water, the temperature of the steel shot is between 850 and 950 ℃, and the second quenching is finished.

Because the formed sizes of the steel shots are different, the hollow steel shots or the steel shots with smaller sizes are lighter in texture and are not easy to throw out a longer distance after being blocked by the high-pressure water curtain, and the solid steel shots or the steel shots with the sizes meeting the requirements are easy to overcome the resistance of the high-pressure water curtain to throw out a longer distance. Thus, the inner and outer

annular walls

5, 10 of the device, which are disposed from inside to outside around the centrifuge 16, can act as a preliminary separation of the steel shot. The steel shot gathered on the outer annular bottom plate 14 between the outer annular wall 10 and the inner annular wall 5 is a compliant steel shot, while the steel shot gathered on the inner annular bottom plate 15 between the inner annular wall 5 and the centrifuge 16 is a hollow or low quality steel shot. Since the inner ring bottom plate 15 and the outer ring bottom plate 14 are provided with slag discharging holes, slag particles which do not meet the size requirement can directly fall to the bottom of the annular water tank 11 from the slag discharging holes.

When the prepared steel shots are collected, the discharge valve 17 on the discharge port is firstly opened, the second water inlet branch 9 is opened, and the cooling water is injected from the upper part of the annular water tank 11 by utilizing larger impact water flow, so that the cooling water in the tank can be cooled, and the steel slag at the bottom of the tank can be discharged in advance. And then the electrically operated shutter doors on the inner ring discharge port 21 and the outer ring discharge port 20 are successively opened in batches, so that the unqualified steel shots and the qualified steel shots are classified and collected. The collected qualified steel shots can be conveyed to a round selecting machine through a steel shot conveying belt for further sorting operation.

The foregoing description is only a preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art, who is within the scope of the present invention, should make equivalent substitutions or modifications according to the technical solution of the present invention and the inventive concept thereof, and should be covered by the scope of the present invention.

Claims

1. The production process of the low-carbon steel shot with high hardness and long service life is characterized by comprising the following steps of:

step two: centrifugally pouring molten steel; molten steel is injected into a centrifugal machine (16) from a ladle, steel shots are formed after the molten steel is thrown out by the centrifugal machine (16), and the thrown steel shots firstly encounter the impact of water curtain high-pressure water outside the centrifugal machine (16); the steel shot at the moment is between 1100 and 1250 ℃, becomes smaller steel shot particles after the first quenching is finished and falls into an annular water tank (11), and the temperature of the steel shot at the moment is between 850 and 950 ℃, so that the second quenching is finished; the temperature of cooling water in the annular water tank (11) is not higher than 35 ℃;

step three: drying the steel shot, rounding, fine screening and packaging;

step two, carrying out in an automatic steel shot forming machine; the automatic steel shot forming machine comprises a main frame, wherein a water inlet mechanism, a water outlet mechanism and more than one group of forming devices are arranged on the main frame; the forming device comprises a water curtain forming machine (4), a centrifugal machine (16) and an annular water tank (11), wherein the water curtain forming machine (4) is arranged on a main frame above the centrifugal machine (16), the annular water tank (11) is sleeved on the periphery of the centrifugal machine (16), and a temperature controller is arranged in the annular water tank (11); a water inlet (23) of the water curtain forming machine is communicated with a first water inlet branch (6) of the water inlet mechanism, and a first water inlet electromagnetic valve (3) and a first water inlet pump are arranged on the first water inlet branch (6); a water inlet of the annular water tank (11) is communicated with a second water inlet branch (9) of the water inlet mechanism, and a second water inlet electromagnetic valve and a second water inlet pump are arranged on the second water inlet branch (9); the water inlet mechanism and the water outlet mechanism of the automatic steel shot forming machine are respectively connected with a water outlet and a water return port of the water cooling tower, the water cooling tower is also provided with a water supplementing port, the water supplementing port is connected with a water source through a water supplementing branch, a water supplementing electromagnetic valve and a water supplementing pump are arranged on the water supplementing branch, and the water return port and the water supplementing port of the water cooling tower are far away from the water outlet; when the temperature controller detects that the water temperature in the annular water tank (11) rises to 35 ℃, a second water inlet electromagnetic valve and a second water inlet pump on the second water inlet branch (9) are automatically started, so that low-temperature cooling water in the water cooling tower can be injected into the annular water tank (11) until the water temperature in the annular water tank (11) is lower than 35 ℃;

the water curtain forming machine (4) comprises a bell-shaped outer cover body (25) and an inner cover body, the upper end of the outer cover body (25) is fixed above the main frame in a lifting manner, the upper end of the outer cover body (25) is provided with a water inlet, and the water inlet of the outer cover body (25) is connected with a first water inlet branch (6) through a first water inlet electromagnetic valve (3); the inner cover body is arranged in the outer cover body (25) through the lifting driving device, and the lower parts of the outer cover body (25) and the inner cover body are converged inwards; a water curtain forming cavity is clamped between the outer cover body (25) and the inner cover body, and an annular water curtain pouring opening is formed at the lower end of the water curtain forming cavity; cooling water in the cooling tower enters the water curtain forming cavity through the first water inlet branch (6) and then downwards poured out through an annular water curtain pouring opening at the lower end of the water curtain forming cavity to form an annular high-pressure water curtain; an annular high-pressure water curtain is arranged around the centrifugal machine (16) and falls into the annular water tank (11) completely;

the outer cover body (25) is made of hard metal; the inner cover body comprises an upper cover part (26) and a lower box part (19), the upper cover part (26) is bell-shaped and made of elastic rubber material, and the opening at the lower end of the upper cover part (26) seals the upper end of the lower box part (19); the lower box part (19) is cylindrical, and the lifting driving device is an electric telescopic rod (24); the fixed end of the electric telescopic rod (24) is arranged in the lower box part (19), the telescopic end of the electric telescopic rod (24) upwards penetrates out of the upper cover part (26) and then is connected with the outer cover body (25), and the telescopic end of the electric telescopic rod (24) is in sealing sleeve joint with the upper cover body; when the electric telescopic rod (24) stretches, the lower box part (19) can be driven to move downwards, and the gap between the lower box part (19) and the lower end of the outer cover body (25) is reduced, so that the thickness of the annular high-pressure water curtain is reduced, and the water pressure is increased; when the electric telescopic rod (24) is shortened, the lower box part (19) can be driven to move upwards, and the gap between the lower box part (19) and the lower end of the outer cover body (25) is enlarged, so that the thickness of the annular high-pressure water curtain is thickened, and the water pressure is reduced.

2. The process for producing the high-hardness long-life low-carbon steel shot according to claim 1, wherein the material quality of the molten steel subjected to tempering in the first step is as follows: c:0.13% -0.2%, S <0.02%, P <0.02%, si:0.15% -0.25%, mn:0.6% -1.5%.

3. The production process of the high-hardness long-life low-carbon steel shot according to claim 2, wherein an inner ring bracket and an outer ring bracket are arranged in the annular water tank (11); the inner ring support comprises an inner ring wall (5) and an inner ring bottom plate (15), the outer ring support comprises an outer ring wall (10) and an outer ring bottom plate (14), the inner ring wall (5) and the outer ring wall (10) take a rotating shaft of a centrifugal machine (16) as a central shaft from inside to outside, the inner ring support is coaxially sleeved in an annular water tank (11) outside the centrifugal machine (16), the inner ring bottom plate (15) is arranged below a space between the inner ring wall (5) and the centrifugal machine (16), and the outer ring bottom plate (14) is arranged below a space between the outer ring wall (10) and the inner ring wall (5); an inner ring discharging hole (21) is formed in the inner ring bottom plate (15), an outer ring discharging hole (20) is formed in the outer ring bottom plate (14), and electric switch movable gate is respectively formed in the inner ring discharging hole (21) and the outer ring discharging hole (20); a plurality of slag discharging holes are arranged on the inner ring bottom plate (15) and the outer ring bottom plate (14).

4. The production process of the high-hardness long-life low-carbon steel shot according to claim 3, wherein the bottom of the annular water tank (11) is obliquely arranged, a discharge hole and a water outlet are respectively formed in the lowest part of the bottom of the annular water tank (11), a discharge valve (17) is arranged on the discharge hole, and a drain valve (22) is arranged on the water outlet; the water outlet mechanism comprises a water outlet branch pipe (18) and a water outlet main pipe; the water outlet is communicated with a water outlet main pipe through a water outlet branch pipe (18), and the water outlet main pipe is communicated with a water return port of the cooling tower through a water outlet pump; the front end of the steel shot conveyer belt is arranged below the discharge hole, and the rear end of the steel shot conveyer belt is connected with the round selecting machine.

5. The production process of the high-hardness long-service-life low-carbon steel shot according to claim 4, wherein the main frame comprises a plurality of branch brackets, and each branch bracket is provided with a forming device; the branch support comprises an operation box body, a support column is arranged at the bottom of the operation box body, the operation box body is of a split type structure comprising an upper box body (7) and a lower box body (13), and the upper box body (7) is buckled on the lower box body (13); an annular water tank (11) is embedded in the lower box body (13), and a centrifugal machine (16) is arranged in the center of the annular water tank (11); the upper cover of the upper box body (7) is provided with a mounting groove, and the lower end of the outer cover body (25) can be embedded and fixedly arranged in the mounting groove; an access opening (1) is arranged on the upper cover, and an access movable door is arranged on the access opening (1).

6. The production process of the high-hardness long-service-life low-carbon steel shot according to claim 5, wherein the main frame further comprises a bottom frame (12) and a lifting frame (2), the bottom frame (12) is fixed on the ground, and the lifting frame (2) is arranged on the bottom frame (12) through more than two groups of lifting cylinders (8); the upper end of the outer cover body (25) is fixedly arranged on the lifting frame (2).