Low-pressure sintering furnace and sintering process thereof

Abstract

The present application relates to a kind of low-pressure sintering furnace and sintering process thereof, including box, pressurization and pressure measurement system, sintering piece fixing mechanism, pressurization and pressure measurement system include stepper motor, torque tester, ball screw, pressurization plate, bottom plate;Box is equipped with support frame, support frame is designed as rectangular body shape, support frame both sides are also equipped with electric heating wire respectively, bottom plate is installed in the inside lower end of support frame, stepper motor lower end is drivenly connected with torque tester, torque tester lower end is fixed on the top of box, the lower end of torque tester drive end is drivenly connected with ball screw upper end after penetrating the box. Advantage: high work efficiency, can be pressed sample stack, such as sintering piece fixing mechanism, sintering multiple sample pieces at a time;Real-time monitoring and control can be carried out to pressing pressure in sintering process, so as to improve the quality of sintering piece.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of powder metallurgy sintering, in particular to a low-pressure pressurized sintering furnace and a sintering process thereof. BACKGROUND

[0002] The sintering furnace refers to a special equipment for enabling a powder compact to obtain required physical, mechanical properties and microstructure through sintering. At present, the sintering equipment used in the sintering process mainly includes a chain sintering furnace and a pressurized sintering furnace. However, many kinds of powder metallurgy components need to be continuously and stably pressurized during the sintering process, and the pressurization mode of the chain sintering furnace can only adopt a physical pressurization mode of a tooling, which cannot guarantee stable pressure output, which will greatly affect the quality of the sintered products.

[0003] In view of this, the present application provides a low-pressure pressurized sintering furnace and an operating method, aiming at solving the problem of providing stable pressure to a sintered component during the sintering process. SUMMARY

[0004] The present application aims to provide a low-pressure pressurized sintering furnace to solve the problems existing in the prior art, and to achieve the purpose of applying stable pressure to a sintered component during the sintering process by using four step motors controlled synchronously to transmit power to a pressurizing plate through a ball screw.

[0005] The technical scheme of the present application is as follows:

[0006] A low-pressure pressurized sintering furnace comprises a box body, a pressurizing and pressure measuring system and a sintered component fixing mechanism. The pressurizing and pressure measuring system comprises step motors, torque testers, ball screws and a pressurizing plate.

[0007] The box body is designed as a rectangular body, a furnace door is installed on one side of the box body, a support frame is installed in the box body, the support frame is designed as a rectangular body shape, electric heating wires are installed on both sides of the support frame, a bottom plate is installed at the inner lower end of the support frame, four groups of step motors are designed, a torque tester is drivingly connected to the lower end of each group of step motors, the torque tester is fixed on the upper surface of the box body, and the lower end of each group of torque testers is drivingly connected to the upper end of a ball screw after penetrating through the box body. The lower ends of the four groups of ball screws are rotatably installed at the four corner positions of the bottom plate. The upper end of the pressurizing plate is provided with four wire nuts, and the four groups of ball screws are rotatably penetrated through the wire nuts at the corresponding corner positions on the upper surface of the pressurizing plate.

[0008] The sintering piece fixing mechanism is designed with four groups, each group of sintering piece fixing mechanism includes a first stretching rod, a second stretching rod, a base, a stretching rod fixing block, a manual locking shaft and a support plate; the base is installed at the middle position of one side of the support plate, two first stretching rods and two second stretching rods are designed respectively, one end of the two first stretching rods is connected to one side of the first horizontal rod near the two ends respectively, the other end of the two first stretching rods is respectively inserted into the inside of one end of the two second stretching rods in a telescopic sliding manner, and a threaded hole is formed on the inside of the upper end of the two second stretching rods respectively, a locking bolt is screwed into the threaded hole respectively, the other end of the two second stretching rods is connected to one side of the second horizontal rod near the two ends respectively, the stretching rod fixing block is installed on the upper end of the base, the first horizontal rod is on the inside of the stretching rod fixing block, and the first horizontal rod and the stretching rod fixing block are fixed together through the manual locking shaft; each group of sintering piece fixing mechanism is respectively installed at the middle position of the four around of the support plate, forming two groups of left and right and two groups of front and back, and the support plate is placed on the upper surface of the base plate.

[0009] A groove is formed on the middle position of the four around of the support plate, and the base is fixed in the groove.

[0010] A clamping groove is formed on the inside of the stretching rod fixing block, and the outside of the first horizontal rod is clamped in the clamping groove.

[0011] The manual locking shaft includes a U-shaped connecting piece, a locking plate and a fixing bolt, the locking plate is connected to one side of the mouth of the U-shaped connecting piece and the other side near the lower end position is designed with a threaded hole, the U-shaped connecting piece is clamped on the outside of the first horizontal rod and the stretching rod fixing block respectively, the locking plate is pressed on the outside of the horizontal rod, and the other side of the U-shaped connecting piece is pressed on the outside of the stretching rod fixing block through the fixing bolt screwed into the threaded hole.

[0012] Two positioning holes are formed on the side of the first horizontal rod near the locking plate; two positioning pins are designed on the inside of the locking plate, and the two positioning pins are respectively inserted into the two positioning holes.

[0013] The four groups of ball screws are respectively fixed at the upper end four corner positions of the support frame through the rotating mechanism, the rotating mechanism includes an upper ring, a lower ring and a bearing ring, a lower ring step is formed on the inside of the lower end of the upper ring, an upper ring step is formed on the inside of the upper end of the lower ring, the upper end and the lower end of the bearing ring are respectively clamped in the lower ring step and the upper ring step, and one side of the upper ring and the lower ring is respectively fixed at the inside position of the corner of the upper end of the support frame through the connecting piece; the bearing ring is rotatably sleeved on the outside of the optical axis above the thread of the ball screw.

[0014] A sintering process of a low-pressure pressurized sintering furnace, the specific steps are as follows:

[0015] Step (1), the sintered parts are fixed in the sintered part fixing mechanism, several sintered parts are stacked on the support plate, a two-stage stretching rod is stretched, the second-stage cross rod is controlled to press on the side surface of the lowermost sintered part, and the position of the first-stage stretching rod and the second-stage stretching rod is locked by rotating the locking bolt;

[0016] Step (2), the furnace door is opened, the sintered part fixing mechanism is placed in the sintering furnace between the pressing plate and the bottom plate, the four stepper motors are synchronously controlled to rotate the ball screws to drive the pressing plate to descend, the pressing plate is pressed on the uppermost sintered part according to the designed pressure, and the pressure is monitored in real time through the four torque testers to ensure that the pressure during sintering is in the set range.

[0017] Step (3), the furnace door is closed, heating is started through the electric heating wire, the predetermined sintering pressure and sintering temperature sintering process parameters are set on the sintering furnace control panel, and the sintered parts can be sintered.

[0018] The present application has the following beneficial effects:

[0019] The present application is mainly applied to sintering of pressed sample blanks in the field of powder metallurgy, and has the following advantages:

[0020] (1) complete functions, when sintering the sintered parts, sintering can be carried out in a vacuum, or sintering can be carried out in an inert gas atmosphere or a reducing gas atmosphere;

[0021] (2) high working efficiency, the pressed sample blanks can be stacked in the sintered part fixing mechanism, and multiple sample blanks can be sintered at a time;

[0022] (3) the pressing pressure during sintering can be monitored and controlled in real time, so that the quality of the sintered parts is improved. DRAWINGS

[0023] Figure 1 is a schematic view of the three-dimensional structure and the partial section of the present application.

[0024] Figure 2 is a schematic view of the section of the present application.

[0025] Figure 3 is a schematic view of the sintered part fixing mechanism of the present application.

[0026] Figure 4 is a schematic view of the manual locking shaft clamping of the sintered part fixing mechanism of the present application.

[0027] Figure 5 is a schematic view of the manual locking shaft clamping of the sintered part fixing mechanism of the present application. Figure 4

[0028] Figure 6 is a schematic view of the first-stage stretching rod of the sintered part fixing mechanism of the present application.​

[0029] Figure 7 is a schematic view of the secondary stretching rod of the sintering piece fixing mechanism of the present application.

[0030] Figure 8 is a schematic view of the stretching rod fixing block of the sintering piece fixing mechanism of the present application.

[0031] Figure 9 is a schematic view of the present application.

[0032] Figure 10 is a schematic view of the rotating mechanism of the present application. DETAILED DESCRIPTION

[0033] Referring to the drawings Figures 1-10 A low-pressure pressurized sintering furnace, comprising a box body 1, a pressurizing and pressure measuring system, a sintering piece fixing mechanism 9, the pressurizing and pressure measuring system comprising a stepping motor 2, a torque tester 3, a ball screw 4, a pressurizing plate 5, a bottom plate 6;

[0034] As Figures 1-2 The box body 1 is designed as a rectangular body, one side of the box body 1 is provided with a furnace door, a support frame 7 is installed in the box body 1, the support frame 7 is designed as a rectangular body shape, and electric heating wires 8 are respectively installed on both sides of the support frame 7; the bottom plate 6 is installed at the inner lower end of the support frame 7; the stepping motor 2 is designed with four groups, each group of the stepping motor 2 is drivingly connected with a torque tester 3 at the lower end, the torque tester 3 is fixed on the upper surface of the box body 1, and each group of the torque tester 3 is drivingly connected with the upper end of a ball screw 4 after penetrating through the box body 1; the four groups of the ball screw 4 are respectively rotatably installed at the four corner positions of the bottom plate 6, and the ball screw 4 is rotatably penetrated through the nut 10 at the corresponding corner position of the upper surface of the pressurizing plate 5; the sintering piece fixing mechanism 9 is located above the bottom plate 6.

[0035] As Figures 3-8The sintered part fixing mechanism 9 is designed with four sets. Each set of the sintered part fixing mechanism 9 includes a primary tension rod 91, a secondary tension rod 92, a base 93, a tension rod fixing block 94, a manual locking shaft 95, a support plate 96, a primary crossbar 97, a secondary crossbar 98, and a locking bolt 99. The base 93 is installed in the middle position on one side of the support plate 96. Two primary tension rods 91 and two secondary tension rods 92 are designed. One end of each of the two primary tension rods 91 is connected to one side of the primary crossbar 97 near both ends. The other ends of the two primary tension rods 91 are respectively telescopically inserted into one end of each of the two secondary tension rods 92. Each of the two secondary tension rods 92 has a threaded hole on the inner side of its upper end, and a locking bolt 99 is screwed into the threaded hole. The other ends of the two secondary tension rods 92 are connected to one side of the secondary crossbar 98 near both ends. The tension rod fixing block 94 is installed on the upper end of the base 93. The primary crossbar 97 rests on the inner side of the tension rod fixing block 94. The primary crossbar 97 and the tension rod fixing block 94 are fixed together by a manual locking shaft 95. Each set of sintering part fixing mechanisms 9 is installed in the middle of the four sides of the support plate 96, forming two symmetrical sets on the left and right and two sets in the front and back. The support plate 96 is placed on the base plate 6. The bottom of the support plate can be designed with positioning pins, and the base plate is designed with corresponding positioning holes. The two cooperate to fix the support plate on the base plate to ensure the stability of the sintering part during sintering.

[0036] The support plate 96 has grooves at the center of its four sides, and the base 93 is fixed inside the grooves.

[0037] The inner side of the tension rod fixing block 94 has a slot 941, and the outer side of the first-stage crossbar 97 is locked in the slot 941.

[0038] The manual locking shaft 95 includes a U-shaped connector 951, a locking plate 952, and a fixing bolt 953. One side of the U-shaped connector 951 is connected to the locking plate 952, and the other side, near its lower end, has a threaded hole 954. The two sides of the U-shaped connector 951 are respectively engaged with the outer sides of the primary crossbar 97 and the tension rod fixing block 94. The locking plate 952 presses against the outer side of the crossbar. The other side of the U-shaped connector 951 is screwed into the threaded hole 954 by the fixing bolt 953 and pressed against the outer side of the tension rod fixing block 94. This manual locking shaft design ensures quick replacement of the primary crossbar, secondary crossbar, primary tension frame, and secondary tension frame when using sintered parts of different sizes.

[0039] The primary crossbar 97 has two positioning holes 971 on the side near the locking plate 952; the locking plate 952 has two positioning pins 972 on its inner side, which are respectively inserted into the two positioning holes 971. The positioning hole and positioning pin design prevents unstable fixing and allows for quick positioning, ensuring safety and reliability.

[0040] like Figure 2, Figure 10 The four groups of ball screws 4 are fixed at the upper end four corner positions of the support frame 7 through rotating mechanisms, the rotating mechanisms include upper ring 41, lower ring 42 and bearing ring 43, the lower end inner side of the upper ring 41 is provided with a lower annular step, the upper end inner side of the lower ring 42 is provided with an upper annular step, the upper end and the lower end of the bearing ring 43 are clamped in the lower annular step and the upper annular step respectively, one side of the upper ring 41 and the lower ring 42 is fixed at the inner side position of the upper end corner of the support frame 7 through connecting pieces; the bearing ring 43 can be rotatably sleeved on the outside of the optical axis above the screw thread of the ball screw 4. The rotating mechanism design ensures stable rotation of the ball screw.

[0041] The sintering piece 20 is pressed by the pressing plate, thereby improving the quality of the sintering piece 20; the pressing plate is driven by the stepping motor through the ball screw, thereby pressing the sintering piece 20; the pressing plate is driven by four stepping motors at the same time, and the maximum pressing pressure is N; each stepping motor is connected with a torque tester, which is used for measuring the torque output by the stepping motor, thereby calculating the pressure applied to the sintering piece by the pressing plate under the current condition, so as to realize real-time feedback of the pressure applied to the sintering piece during the pressing sintering process; the sintering piece fixing mechanism can stack multiple same sintering pieces, thereby improving the sintering efficiency; the sintering piece fixing mechanism positions the sintering piece 20 in the transverse direction through the secondary stretching frame and the secondary horizontal rod at the end, thereby preventing transverse displacement during the pressing process; after the secondary stretching frame is adjusted to the appropriate position, the manual locking bolt can be rotated to fix the secondary stretching rod, so as to meet the fixing requirement of sintering pieces with different sizes; the box body is also provided with an air inlet and an air outlet, which are used for vacuumizing or introducing inert gas or reducing gas during sintering, thereby preventing chemical reaction between the sintering piece and some gas in the air during the sintering process, and ensuring the sintering quality. The application also designs a PLC controller, which is connected with the stepping motor, the torque tester and the thermocouple installed on the box body through electrical control, so as to accurately set the temperature and pressure, and to monitor and adjust in time, thereby ensuring sintering under the condition of low-pressure pressing and constant temperature, and improving the product quality.

Claims

1. A low-pressure pressurized sintering furnace, characterized by comprising: It includes box, pressurization and pressure measurement system, sintering piece fixing mechanism, the pressurization and pressure measurement system includes stepper motor, torque tester, ball screw, pressurization plate and bottom plate. The box body is designed as a rectangular body, a furnace door is installed on one side of the box body, a support frame is installed in the box body, the support frame is designed as a rectangular body shape, and electric heating wires are respectively installed on both sides of the support frame; a bottom plate is installed at the inner lower end of the support frame; four groups of stepping motors are designed, each group of stepping motor is drivenly connected with a torque tester at the lower end thereof, the torque tester is fixed on the upper surface of the box body, and each group of torque tester is drivenly connected with the upper end of a ball screw after penetrating through the box body; four ball screws are respectively rotatably installed at the four corner positions of the bottom plate; four nuts are respectively installed at the four corner positions of the upper end of the pressing plate; and the four ball screws are respectively rotatably penetrated through the nuts at the corresponding corner positions of the upper surface of the pressing plate; the sintering piece fixing mechanism is located on the support plate on the upper surface of the bottom plate; the sintering piece fixing mechanism is designed as four groups; each group of sintering piece fixing mechanism comprises a primary stretching rod, a secondary stretching rod, a base, a stretching rod fixing block and a manual locking shaft; the base is installed at the middle position on one side of the support plate; two primary stretching rods and two secondary stretching rods are respectively designed; one end of the two primary stretching rods is respectively connected to one side of a primary horizontal rod near the two end positions; the other end of the two primary stretching rods is respectively correspondingly inserted into the inner end of the two secondary stretching rods and the inner side position on the upper end of the two secondary stretching rods is respectively provided with a threaded hole; a locking bolt is respectively screwed into the threaded hole; the other end of the two secondary stretching rods is respectively connected to one side of a secondary horizontal rod near the two end positions; the stretching rod fixing block is installed on the upper end of the base; the primary horizontal rod is located on the inner side of the stretching rod fixing block; the primary horizontal rod and the stretching rod fixing block are fixed together through the manual locking shaft; each group of sintering piece fixing mechanism is respectively installed at the middle positions around the support plate to form two groups of symmetric left and right and two groups of symmetric front and back; the middle positions around the support plate are respectively provided with grooves; the base is fixed in the grooves; the inner side of the stretching rod fixing block is provided with a clamping groove; the outer side of the primary horizontal rod is clamped in the clamping groove; the manual locking shaft comprises a U-shaped connecting piece, a locking plate and a fixing bolt; the locking plate is connected to one side of the mouth of the U-shaped connecting piece and is provided with a threaded hole near the other side of the lower end position; the U-shaped connecting piece is clamped on the outer side of the primary horizontal rod and the stretching rod fixing block; the locking plate is pressed on the outer side of the primary horizontal rod; the other side of the U-shaped connecting piece is pressed on the outer side of the stretching rod fixing block through the fixing bolt screwed into the threaded hole; the side of the primary horizontal rod near the locking plate is provided with two positioning holes; the inner side of the locking plate is provided with two positioning pins; the two positioning pins are respectively inserted into the two positioning holes; the four ball screws near the upper end are respectively fixed on the four corner positions of the upper end of the support frame through the rotating mechanism; the rotating mechanism comprises an upper ring, a lower ring and a bearing ring; the inner side of the lower end of the upper ring is provided with a lower annular step; the inner side of the upper end of the lower ring is provided with an upper annular step; the upper end and the lower end of the bearing ring are respectively clamped in the lower annular step and the upper annular step; one side of the upper ring and the lower ring is respectively fixed on the inner side position of the corner of the upper end of the support frame through the connecting piece; the bearing ring is rotatably sleeved on the outer side of the optical axis above the thread of the ball screw.

2. A sintering process of the low-pressure pressurized sintering furnace according to claim 1, characterized in that, Step (1), the sintered parts are fixed in the sintered part fixing mechanism, several sintered parts are stacked on the support plate, a two-stage stretching rod is stretched, the second-stage cross rod is controlled to press on the side surface of the lowermost sintered part, and the position of the first-stage stretching rod and the second-stage stretching rod is locked by rotating the locking bolt; Step (2), the furnace door is opened, the sintered part fixing mechanism is placed in the sintering furnace between the pressing plate and the bottom plate, the four stepping motors are synchronously controlled to rotate the ball screws to drive the pressing plate to descend, the pressing plate is pressed on the uppermost sintered part according to the designed pressure, and the pressure is monitored in real time through the four torque testers to ensure that the pressure during sintering is in the set range; Step (3), the furnace door is closed, heating is started through the electric heating wire, the predetermined sintering pressure and sintering temperature are set on the sintering furnace control panel, and the sintered parts can be sintered.

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