Hydraulic circuit for casting blank production, control method thereof and casting blank production equipment

Abstract

The invention provides a hydraulic circuit for casting blank production, a control method thereof and casting blank production equipment. The hydraulic loop comprises a first hydraulic loop for casting blank production under non-heavy pressure and a second hydraulic loop for casting blank production under heavy pressure; the first hydraulic loop and the second hydraulic loop are switched through an electromagnetic reversing valve; the solenoid directional valve is a two-position three-way solenoid valve, a port P and a port T of the solenoid directional valve are communicated with the first hydraulic loop and the second hydraulic loop respectively, and a port A is communicated with a rodless cavity A of the oil cylinder; the second hydraulic loop is a roll gap control loop and comprises a proportional direction valve, a three-way pressure reducing valve, a first pressure sensor, a second pressure sensor and a displacement sensor; the three-way pressure reducing valve is communicated with a rod cavity B of the oil cylinder; the proportional direction valve and the displacement sensor form a position closed loop which is used for controlling the roll gap opening degree of the screw-down roll. The hydraulic circuit not only can meet the casting blank production process under heavy pressure, but also can meet the common casting blank production process, and the hydraulic circuits of the two production processes do not influence each other and can be switched at any time.

Description

Technical Field

[0001] The invention belongs to the technical field of iron and steel metallurgy, and in particular relates to a hydraulic circuit used for billet production, a control method thereof and billet production equipment. Background Art

[0002] In the production process of ingot, a large amount of reduction is applied to the ingot after the final solidification point to eliminate center segregation and looseness, thereby comprehensively improving the density of the ingot. This process is called heavy reduction.

[0003] In order to achieve the process requirements of heavy pressure reduction, it is necessary to apply a large pressure reduction force to the billet to deform the billet and change the internal structure of the billet. Therefore, the straightening machine using heavy pressure reduction technology must have a larger cylinder diameter and higher system pressure than ordinary straightening machines. Since there is a huge difference in the billet pressure reduction force between the heavy pressure reduction process and the non-heavy pressure reduction process, the production of billets with two different processes on the same casting machine has completely different requirements for the hydraulic system. Summary of the invention

[0004] The present invention provides a hydraulic circuit for ingot production, which can meet both the ingot production process under heavy pressure and the common ingot production process, and the hydraulic circuits of the two production processes do not affect each other, and the production process can be switched at any time.

[0005] The technical solution provided by the present invention is: a hydraulic circuit for producing ingots, the hydraulic circuit comprising a first hydraulic circuit for producing ingots under non-heavy pressure, and a second hydraulic circuit for producing ingots under heavy pressure;

[0006] Switching the first hydraulic circuit and the second hydraulic circuit by means of an electromagnetic reversing valve;

[0007] The cavity above the oil cylinder is the oil cylinder rodless cavity A, and the cavity below the oil cylinder is the oil cylinder rod cavity B;

[0008] The solenoid reversing valve is a two-position three-way solenoid valve, whose P port is connected to the first hydraulic circuit, T port is connected to the second hydraulic circuit, and A port is connected to the rodless chamber A of the oil cylinder;

[0009] The second hydraulic circuit is a roll gap control circuit, including a proportional directional valve, a three-way pressure reducing valve, a first pressure sensor, a second pressure sensor and a displacement sensor;

[0010] The three-way pressure reducing valve is connected to the rod chamber B of the oil cylinder;

[0011] The first pressure sensor is used to detect the pressure in the rodless chamber A of the oil cylinder;

[0012] The second pressure sensor is used to detect the pressure in the rod chamber B of the oil cylinder;

[0013] The displacement sensor is used to detect the displacement of the liquid level in the oil cylinder;

[0014] The proportional directional valve and the displacement sensor form a position closed loop, which is used to control the roll gap opening of the pressing roll.

[0015] As an implementation method, the proportional directional valve is a four-position four-way proportional valve, whose P port is connected to the pressure oil pipeline P, the T port is connected to the return oil pipeline T, and the A port is connected to the T port of the electromagnetic reversing valve.

[0016] As an implementation method, the A port of the three-way pressure reducing valve is connected to the rod chamber B of the oil cylinder, the B port is connected to the pressure oil pipeline P, and the L port is connected to the return oil pipeline T.

[0017] As an implementation method, the first hydraulic circuit is a hot billet pressing circuit, including a first pressure reducing valve, a second pressure reducing valve, a first reversing valve and a second reversing valve;

[0018] The A port of the first pressure reducing valve is connected to the P port of the first reversing valve, and the B port is connected to the pressure oil pipeline PE;

[0019] The A port of the second pressure reducing valve is connected to the T port of the first reversing valve, and the B port is connected to the pressure oil pipeline PE;

[0020] The first reversing valve is a two-position four-way solenoid valve, and its A port is connected to the P port of the second reversing valve;

[0021] The second reversing valve is a two-position three-way solenoid valve, whose P port is connected to the A port of the first reversing valve, whose T port is connected to the oil return pipeline T, and whose A port is connected to the P port of the solenoid reversing valve.

[0022] Preferably, the three-way pressure reducing valve has two modes: pressure reducing and overflowing. When the pressure at the pressure reducing port A is less than the set value, the pressure oil at the port B will reach the port A through the valve body. When the pressure value at the port A reaches the set value, the valve core closes to keep the pressure at the port A unchanged. When the pressure at the port A is greater than the set value, the pressure oil at the port A will reach the port L through the valve body and leak back to the oil tank until the pressure at the port A reaches the set value.

[0023] The hydraulic circuit for casting production of the present invention controls the hot billet pressing circuit and the roll gap control circuit by switching the electromagnetic reversing valve, as follows;

[0024] (1) The solenoid reversing valve loses power, i.e. is in the spring position state.

[0025] When the second reversing valve is in the power-off state, the pressure oil enters the rodless chamber A of the oil cylinder, and the hydraulic oil in the rod chamber B of the oil cylinder returns to the oil tank through the return oil pipeline T through the overflow effect of the three-way pressure reducing valve, and the oil cylinder realizes the pressing action;

[0026] When the second reversing valve is energized, that is, it is in the solenoid position, the pressure oil of the first pressure reducing valve or the second pressure reducing valve is cut off, and the hydraulic oil in the rodless chamber A of the cylinder reaches the second reversing valve through the solenoid reversing valve, and returns to the oil tank after passing through the second reversing valve and the return oil pipeline T. The pressure of the three-way pressure reducing valve acts on the rod chamber B of the cylinder, lifting the cylinder, and the cylinder realizes the lifting action.

[0027] (2) The solenoid reversing valve is energized, that is, it is in the solenoid position state.

[0028] The first pressure reducing valve, the second pressure reducing valve, the first reversing valve, and the second reversing valve are disconnected from the cylinder, and the A port of the proportional directional valve is connected to the rodless chamber A of the cylinder. The proportional directional valve adjusts the size and direction of the valve core opening through the signal detected by the displacement sensor on the cylinder, and the cylinder moves.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] (1) The present invention switches the hydraulic circuit by means of an electromagnetic reversing valve, and can be used for both heavy pressure casting production and ordinary casting production. The two do not affect each other, and the switching is convenient. When one set of circuits is abnormal, it is convenient to switch to another set of circuits;

[0031] (2) The present invention uses a proportional reversing valve and a displacement sensor to control the roll gap opening when producing under heavy pressure, which has high control accuracy and ensures that the billet produces sufficient deformation to change the internal structure of the billet. In addition, the present invention preferably uses a first pressure reducing valve, a second pressure reducing valve, a first reversing valve and a second reversing valve to achieve ordinary hot billet pressing production, ensuring that the billet will not be deformed when producing under non-heavy pressure.

[0032] (3) The present invention uses a three-way pressure reducing valve at the outlet of the oil cylinder as a constant back pressure, which is convenient for using differential control and avoids the situation in which the hot billet pressure is too low and a suitable pressure reducing valve cannot be selected due to the large cylinder diameter of the oil cylinder during the production of billet castings by ordinary processes.

[0033] In addition, the hydraulic circuit of the present invention is simple, has few components and high reliability, is not limited to the casting billet, including square billets, etc., and has good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 Schematic diagram of a hydraulic circuit for billet production in an embodiment of the present invention.

[0035] Figure 2 It is a schematic diagram of the hydraulic path for the oil cylinder to realize the pressing action during ordinary hot billet pressing production in an embodiment of the present invention.

[0036] Figure 3 It is a schematic diagram of the hydraulic path for the oil cylinder to realize the lifting action during ordinary hot billet pressing production in an embodiment of the present invention.

[0037] Figure 4 Schematic diagram of the roll gap control circuit during billet production under heavy pressure in an embodiment of the present invention.

[0038] Figure 1-4 The reference numerals included in the figure are: first pressure reducing valve 1, second pressure reducing valve 2, first reversing valve 3, second reversing valve 4, third reversing valve 5, proportional directional valve 6, three-way pressure reducing valve 7, first pressure sensor 8.1, second pressure sensor 8.2, displacement sensor 9. DETAILED DESCRIPTION

[0039] The present invention is further described in detail below in conjunction with embodiments. It should be pointed out that the embodiments described below are intended to facilitate the understanding of the present invention. Some non-essential improvements and adjustments made to the present invention by technicians in this field based on the contents of the present invention above still fall within the scope of protection of the present invention.

[0040] The words “include”, “including” and the like used in the present invention should be interpreted as including rather than being exclusive or exhaustive, that is, as including but not limited to.

[0041] The expressions “first”, “second”, etc. used in the present invention may modify various constituent elements regardless of the order and / or importance, and are only used to distinguish one constituent element from another constituent element, but do not limit the corresponding constituent elements.

[0042] Embodiment 1:

[0043] like Figure 1 As shown, the hydraulic circuit in the casting production process includes a first pressure reducing valve 1, a second pressure reducing valve 2, a first reversing valve 3, a second reversing valve 4, a third reversing valve 5, a proportional directional valve 6, a three-way pressure reducing valve 7, a first pressure sensor 8.1, a second pressure sensor 8.2, a displacement sensor 9 and an oil cylinder.

[0044] The cavity above the oil cylinder is the oil cylinder rodless cavity A, and the cavity below the oil cylinder is the oil cylinder rod cavity B. The first pressure sensor 8.1 is used to detect the oil cylinder rodless cavity A, and the second pressure sensor 8.2 is used to detect the oil cylinder rod cavity B.

[0045] The first pressure reducing valve 1 is a manual pressure reducing valve, the A port of which is connected to the P port of the first reversing valve 3, and the B port of which is connected to the pressure oil pipeline PE.

[0046] The second pressure reducing valve 2 is a manual pressure reducing valve, the A port of which is connected to the T port of the first reversing valve 3, and the B port of which is connected to the pressure oil pipeline PE.

[0047] The first reversing valve 3 is a two-position four-way solenoid valve, whose P port is connected to the pressure reducing port A of the first pressure reducing valve 1, whose T port is connected to the pressure reducing port A of the second pressure reducing valve 2, whose A port is connected to the P port of the second reversing valve 4, and whose B port is blocked and unused.

[0048] The third reversing valve 5 is a two-position three-way solenoid valve, whose P port is connected to the A port of the second reversing valve 4, whose T port is connected to the A port of the proportional directional valve 6, and whose A port is connected to the rodless chamber A of the oil cylinder.

[0049] The proportional directional valve 6 is a four-position four-way proportional valve, whose P port is connected to the pressure oil pipeline P, the T port is connected to the return oil pipeline T, the A port is connected to the T port of the third reversing valve 5, and the B port is blocked and unused.

[0050] The three-way pressure reducing valve 7 is a manual pressure reducing valve, whose A port is connected to the rod chamber B of the oil cylinder, its B port is connected to the pressure oil pipeline P, and its L port is connected to the return oil pipeline T. The valve has two modes: pressure reducing and overflowing. When the pressure of the pressure reducing port A is less than the set value, the pressure oil of the B port will reach the A port through the valve body. When the pressure value of the A port reaches the set value, the valve core is closed to keep the pressure of the A port unchanged. When the pressure of the A port is greater than the set value, the pressure oil of the A port will reach the L port through the valve body and leak back to the oil tank until the pressure of the A port reaches the set value.

[0051] The first pressure reducing valve 1, the second pressure reducing valve 2, the first reversing valve 3, the second reversing valve 4 and the three-way pressure reducing valve 7 form a hot billet pressure control circuit, which is used in a common billet production process.

[0052] The proportional directional valve 6, the three-way pressure reducing valve 7, the first pressure sensor 8.1, the second pressure sensor 8.2 and the displacement sensor 9 form a roll gap control circuit for the heavy pressure casting production process.

[0053] The first pressure reducing valve 1 and the second pressure reducing valve 2 set the ingot starting pressure PD and the hot billet pressure PH respectively, and the selection is made through the first reversing valve 3.

[0054] The third reversing valve 5 is used for switching between the two control circuits, as follows:

[0055] (i) When the third reversing valve 5 is de-energized (spring position), the hot billet pressure control circuit is connected, and the ordinary (non-heavy pressure) billet production process is used.

[0056] The pressure oil PE is respectively obtained as the ingot pressure PD and the hot billet pressure PH through the first pressure reducing valve 1 and the second pressure reducing valve 2. These two pressures are respectively sent to the oil port P and the oil port T of the first reversing valve 3. The first reversing valve 3 selects one of the pressures to be output from the A port to the oil port P of the second reversing valve 4.

[0057] (1) When the second reversing valve 4 is in the de-energized (spring position) state

[0058] The pressure oil passes through the second reversing valve 4 to the third reversing valve 5, and then enters the rodless chamber A of the oil cylinder. The hydraulic oil in the rod chamber B of the oil cylinder returns to the oil tank through the overflow effect of the three-way pressure reducing valve 7 through the return oil pipeline T, and the oil cylinder realizes the pressing action. The hydraulic path is as follows Figure 2When the pressing roller (i.e. the roller under the oil cylinder) contacts the surface of the ingot, the force of the oil cylinder remains balanced, the oil cylinder stops moving, and a constant pressing force is maintained on the ingot to maintain normal process production.

[0059] (2) When the second reversing valve 4 is in the energized (electromagnet position) state

[0060] The pressure oil of the first pressure reducing valve 1 or the second pressure reducing valve 2 is cut off, and the hydraulic oil in the rodless chamber A of the oil cylinder passes through the third reversing valve 5 to the second reversing valve 4, and then returns to the oil tank through the second reversing valve 4 and the return oil pipeline T. The pressure of the three-way pressure reducing valve 7 will act on the rod chamber B of the oil cylinder to lift the oil cylinder, and the oil cylinder realizes the lifting action. The hydraulic path is as follows Figure 3 shown.

[0061] (ii) When the electromagnet of the third reversing valve 5 is energized, the roll gap control circuit is connected, and the hot billet pressure control circuit is completely disconnected, which is used for the heavy pressure casting production process.

[0062] Roll gap control regulation circuit such as Figure 4 As shown, after the third reversing valve 5 is energized, it disconnects the first pressure reducing valve 1, the second pressure reducing valve 2, the first reversing valve 3, and the second reversing valve 4 from the cylinder, and connects the oil port A of the proportional directional valve 6 to the rodless chamber A of the cylinder. The proportional directional valve 6 adjusts the size and direction of the valve core opening according to the signal detected by the displacement sensor 9 on the cylinder, and the cylinder moves.

[0063] The proportional directional valve 6 and the displacement sensor 9 form a position closed loop for controlling the roll gap opening. The first pressure sensor 8.1 detects the rodless chamber A of the oil cylinder, and the second pressure sensor 8.2 detects the rod chamber B of the oil cylinder, which are used to calculate the pressing force acting on the billet. The three-way pressure reducing valve 7 provides a constant back pressure in the rodless chamber A of the oil cylinder, which can avoid the problem of excessive pressure in the rodless chamber A of the oil cylinder caused by the throttling effect of the valve port when the proportional directional valve 6 is fine-tuned at zero position, which is more conducive to the linear control of the position closed loop system.

[0064] A position closed-loop system is formed by the proportional directional valve 6, the displacement sensor 9, the pressing roller cylinder and the electronic control system. When the displacement sensor 9 detects that the position of the pressing roller cylinder is greater than the set value, the electronic control system sends a signal to control the proportional directional valve 6 to make the cylinder move downward until it reaches the set position. The proportional directional valve 6 returns to the middle position and the cylinder stops moving, and vice versa. That is, the position closed-loop control is realized through the proportional directional valve 6 and the displacement sensor 9.

[0065] Since the two control circuits are independent of each other, if one of the circuits has a problem during the production process, it can be quickly switched to the other control circuit. In addition, this solution only distinguishes the rod chamber circuit of the cylinder, so the isolation switching solution is simpler.

[0066] Using heavy pressure requires a large pressing force to deform the ingot. Therefore, the cylinder diameter of the straightening machine with heavy pressure process is 2 to 3 levels larger than that of the ordinary process cylinder. The force is more than 4 times larger under the same pressure. At this time, the hot billet pressure reduction needs to be reduced to below 1 MPa, and the control accuracy is difficult to guarantee. For this reason, the back pressure of the three-way pressure reducing valve 7 of the rodless chamber A of the cylinder and the second pressure reducing valve 2 can form a differential control. According to the calculation results, the pressure of the second pressure reducing valve 2 and the three-way pressure reducing valve 7 can be increased at the same time, so that the pressure reducing valves can be used at the optimal working pressure.

[0067] The components not mentioned above only play an auxiliary role in the system and are well-known components or common means in the industry, so they are not described one by one here.

[0068] Finally, it should be noted that the specific embodiments described in this article are merely examples of the spirit of the present invention, and are not intended to limit the implementation methods of the present invention. Those skilled in the art of the present invention may make various modifications or supplements to the specific embodiments described, or replace them in a similar manner. It is not necessary and impossible to provide all examples of all implementation methods here. However, these obvious changes or modifications derived from the essential spirit of the present invention still fall within the scope of protection of the present invention, and interpreting them as any additional limitation is contrary to the spirit of the present invention.

Claims

1. A hydraulic circuit for casting production, wherein the upper cavity of the oil cylinder is the oil cylinder rodless cavity A, and the lower cavity of the oil cylinder is the oil cylinder rod cavity B; wherein: The hydraulic circuit comprises a first hydraulic circuit for producing a cast billet under non-heavy pressure, and a second hydraulic circuit for producing a cast billet under heavy pressure; Switching the first hydraulic circuit and the second hydraulic circuit by means of an electromagnetic reversing valve; The solenoid reversing valve is a two-position three-way solenoid valve, whose P port is connected to the first hydraulic circuit, T port is connected to the second hydraulic circuit, and A port is connected to the rodless chamber A of the oil cylinder; The second hydraulic circuit is a roll gap control circuit, including a proportional directional valve, a three-way pressure reducing valve, a first pressure sensor, a second pressure sensor and a displacement sensor; The three-way pressure reducing valve is connected to the rod chamber B of the oil cylinder; The first pressure sensor is used to detect the pressure in the rodless chamber A of the oil cylinder; The second pressure sensor is used to detect the pressure in the rod chamber B of the oil cylinder; The displacement sensor is used to detect the displacement of the liquid level in the oil cylinder; The proportional directional valve and the displacement sensor form a position closed loop, which is used to control the roll gap opening of the pressing roll.

2. The hydraulic circuit according to claim 1, characterized in that: The proportional directional valve is a four-position four-way proportional valve, wherein the P port is connected to the pressure oil pipeline P, the T port is connected to the return oil pipeline T, and the A port is connected to the T port of the electromagnetic reversing valve.

3. The hydraulic circuit according to claim 1, characterized in that: The A port of the three-way pressure reducing valve is connected to the rod chamber B of the oil cylinder, the B port is connected to the pressure oil pipeline P, and the L port is connected to the return oil pipeline T.

4. The hydraulic circuit according to claim 1, characterized in that: The first hydraulic circuit is a hot billet pressing circuit, comprising a first pressure reducing valve, a second pressure reducing valve, a first reversing valve and a second reversing valve; The A port of the first pressure reducing valve is connected to the P port of the first reversing valve, and the B port is connected to the pressure oil pipeline PE; The A port of the second pressure reducing valve is connected to the T port of the first reversing valve, and the B port is connected to the pressure oil pipeline PE; The first reversing valve is a two-position four-way solenoid valve, and its A port is connected to the P port of the second reversing valve; The second reversing valve is a two-position three-way solenoid valve, whose P port is connected to the A port of the first reversing valve, whose T port is connected to the oil return pipeline T, and whose A port is connected to the P port of the solenoid reversing valve.

5. The hydraulic circuit according to claim 1, characterized in that: The three-way pressure reducing valve has two modes: pressure reducing and overflowing. When the pressure at the pressure reducing port A is lower than the set value, the pressure oil at the port B will reach the port A through the valve body. When the pressure at the port A reaches the set value, the valve core will close to keep the pressure at the port A unchanged. When the pressure at the port A is higher than the set value, the pressure oil at the port A will reach the port L through the valve body and leak back to the oil tank until the pressure at the port A reaches the set value.

6. The control method of the hydraulic circuit according to claim 1, characterized in that: When the electromagnetic reversing valve loses power, that is, is in the spring position state, When the second reversing valve is in the power-off state, the pressure oil enters the rodless chamber A of the oil cylinder, and the hydraulic oil in the rod chamber B of the oil cylinder returns to the oil tank through the return oil pipeline T through the overflow effect of the three-way pressure reducing valve, and the oil cylinder realizes the pressing action; When the second reversing valve is energized, that is, in the solenoid position, the pressure oil of the first pressure reducing valve or the second pressure reducing valve is cut off, and the hydraulic oil in the rodless chamber A of the oil cylinder reaches the second reversing valve through the solenoid reversing valve, and returns to the oil tank through the second reversing valve and the return oil pipeline T. The pressure of the three-way pressure reducing valve acts on the rod chamber B of the oil cylinder, so that the oil cylinder is lifted, and the oil cylinder realizes the lifting action; When the electromagnetic reversing valve is energized, that is, in the electromagnet position state, the first pressure reducing valve, the second pressure reducing valve, the first reversing valve, and the second reversing valve are disconnected from the cylinder, and the A port of the proportional directional valve is connected to the rodless chamber A of the cylinder. The proportional directional valve adjusts the size and direction of the valve core opening through the signal detected by the displacement sensor on the cylinder, and the cylinder moves.

7. A casting production equipment, characterized by: Comprising a hydraulic circuit as claimed in any one of claims 1 to 5.

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