CN110560655A

CN110560655A - axial vibration centrifugal casting method

Info

Publication number: CN110560655A
Application number: CN201910805969.9A
Authority: CN
Inventors: 吴玉同; 李慧; 李栋; 郑欢欢; 封艳; 申德彪
Original assignee: Shanghai Zhuoran Engineering Ltd By Share Ltd; ZHUORAN (JINGJIANG) EQUIPMENT MANUFACTURING Co Ltd
Current assignee: Shanghai Zhuoran Engineering Ltd By Share Ltd; ZHUORAN (JINGJIANG) EQUIPMENT MANUFACTURING Co Ltd
Priority date: 2019-08-29
Filing date: 2019-08-29
Publication date: 2019-12-13
Anticipated expiration: 2039-08-29
Also published as: CN110560655B

Abstract

The invention discloses an axial vibration centrifugal casting method. The method comprises the following steps: 1) baking a pipe die, spraying a coating and installing baffles at two ends of the pipe die; 2) pouring molten metal from the pouring end of the pipe die, and starting a vibration device when the molten metal is filled to the non-pouring end of the pipe die, so that the pipe die generates axial vibration; 3) after the molten metal is poured, spraying water to cool the pipe die, and closing the vibration device when the solidification thickness of the molten metal reaches half of the thickness of the centrifugal casting steel pipe; 4) and (4) completely solidifying the molten metal, and pushing or pulling the pipe to realize the separation of the cast steel pipe and the pipe die. For the austenite cast steel pipe, the axial vibration of the pipe die breaks the cast dendrite and improves the grain size of the cast structure. For medium-low carbon cast steel pipes, the method has good inhibition effect on the carbon segregation of the cast steel pipes.

Description

axial vibration centrifugal casting method

Technical Field

the invention is applied to the field of centrifugal casting, and particularly relates to a centrifugal casting method for axial vibration of a pipe die.

Background

The centrifugal casting technology belongs to a mature technology in China, and not only are more manufacturers used for centrifugally manufacturing ductile iron pipes, gray iron pipes and cast steel pipes, but also the yield is high. However, for austenitic stainless steel seamless pipes or nickel-based heat-resistant seamless pipes, a process route of casting, forging, hot extrusion, and cold rolling into pipes is often adopted, and centrifugally cast steel pipes are rarely used as raw material blanks. In practice, austenitic stainless steel seamless tubes or nickel-based heat-resistant seamless tubes can be produced by a process in which a centrifugally cast tube blank is hot extruded into an extruded tube and then cold rolled. The process route is short, and the manufacturing cost is saved. Therefore, the seamless tube rarely adopts a centrifugal blank as a raw material blank, so that the production rhythm of the centrifugal machine cannot meet the smelting production requirement, and the grain size of the centrifugal cast tube blank cannot meet the requirement. Because austenitic stainless steel and nickel-based heat-resistant steel are austenitic structures from high temperature to room temperature, the grain size of the structures cannot be changed through heat treatment, and the grain is refined only through deformation processing such as extrusion, forging, cold rolling and the like, so that the grain size is improved, and the performance of the steel is improved. In order to obtain satisfactory grain size, when cast steel pipes are used as raw material blanks, as the cast crystal grain size of centrifugal cast steel pipe blanks is larger, multiple or large-deformation processing is needed, if the cast crystal grain size of the raw material blanks of the cast steel pipes can be reduced, the grain size is improved, the pressure can be reduced for subsequent processing, and the production cost is saved.

The published patent materials CN109014110A and CN206839085U show vibration methods for vertical centrifugal casting, which are suitable for centrifugal production of small batches of pieces and are not suitable for horizontal centrifugal casting of heavy centrifugal casting steel pipes with weight of more than several hundred kilograms.

Disclosure of Invention

the technical problem solved by the invention is as follows: an axial vibration centrifugal casting method is provided, which can reduce the cast crystal grains and improve the grain size when the austenite cast steel pipe is centrifugally cast.

The technical scheme adopted by the invention is as follows: the axial vibration centrifugal casting method comprises the steps that an axial vibration centrifugal machine and an axial vibration pipe die are used for centrifugal casting, a vibration flange is machined in the middle of the axial vibration pipe die, the axial vibration centrifugal machine comprises an axial vibration device, the vibration device comprises a rotating wheel device and an eccentric device, the rotating wheel device comprises a rotating wheel I matched with the vibration flange, a steel plate for fixing the rotating wheel I and a rotating wheel II, the eccentric device comprises an eccentric wheel and a power mechanism of the eccentric wheel, and an eccentric groove matched with the rotating wheel II is machined in the eccentric wheel; the axial vibration centrifugal casting method comprises the following steps: 1) baking a pipe die, spraying a coating and installing baffles at two ends of the pipe die; 2) pouring molten metal from the pouring end of the pipe die, starting a power mechanism when the molten metal is filled to the non-pouring end of the pipe die, enabling an eccentric wheel to rotate, driving a steel plate to move left and right through a rotating eccentric groove under the action of a rotating wheel II, and driving a vibrating flange by a rotating wheel I on the steel plate to drive the pipe die to vibrate left and right axially; 3) after the molten metal is poured, spraying water to cool the pipe die, and closing the power mechanism when the solidification thickness of the molten metal reaches half of the thickness of the centrifugal casting steel pipe; 4) and (4) completely solidifying the molten metal, and pushing or pulling the pipe to realize the separation of the cast steel pipe and the pipe die.

The invention has the beneficial effects that: for the austenitic stainless steel or nickel-based heat-resistant steel centrifugal casting steel pipe, by adopting the casting method, the axial vibration of the pipe die can break cast dendrites, improve the grain size of cast structures, and reduce the pressure for subsequent deformation processing. For medium-low carbon cast steel pipes, the method has good inhibition effect on the carbon segregation of the cast steel pipes.

Drawings

FIG. 1 is a schematic view of an axial vibration centrifuge;

FIG. 2 is a schematic structural diagram of a vibration device;

FIG. 3 is a schematic view of an eccentric groove of the eccentric wheel;

FIG. 4 is an as-cast structure of a shock-free austenite cast steel pipe of a pipe die;

FIG. 5 is an as-cast structure of an austenite cast steel pipe with axial vibration of a pipe die;

Wherein: the device comprises a pipe die 1, a riding wheel group 2, a vibration device 3, a rotating wheel I4, a steel plate 5, a rotating wheel II 6, an eccentric wheel 7, an eccentric groove 8 and a vibration flange 9.

Detailed Description

Fig. 1 is a schematic structural diagram of an axial vibration centrifuge, which includes two sets of idler groups 2 and a vibration device 3. The two groups of riding wheel sets are respectively a driving riding wheel set and a driven riding wheel set, the driving riding wheel in the driving riding wheel set drives the pipe die 1 to rotate, and the other driven riding wheels support the pipe die 1 to rotate. The vibration device is arranged between the two groups of riding wheel sets, the structure of the vibration device is shown in the attached figure 2, and the vibration device comprises a rotating wheel device and an eccentric device, wherein the rotating wheel device comprises a rotating wheel I4, a steel plate 5 and a rotating wheel II 6. Distance between two runners I4 is unanimous with the width of the vibrations flange 9 of pipe die 1, and when pipe die 1 was rotatory, vibrations flange 9 drove runner I4 and rotates, and runner I4 fixed mounting is on steel sheet 5, and steel sheet 5 can only freely remove in the direction of pipe die axis, inject the removal of about direction and pipe die about in the upper and lower direction. The rotating wheel II 6 is arranged below the steel plate 5 and is matched with an eccentric groove 8 on the eccentric wheel 7. The eccentric device comprises an eccentric wheel 7 and a power mechanism for driving the eccentric wheel 7 to rotate, the power mechanism can be a hydraulic motor or an electric motor speed reducer, an eccentric groove 8 is machined in the eccentric wheel 7, and the shape and the position of the eccentric groove 8 are shown in figure 3. Eccentric groove 8 cooperatees with II 6 of runner, and when eccentric wheel 7 was rotatory under power unit's drive, eccentric groove 8 made II 6 of runner to remove about producing, and its displacement is the twice of eccentricity, and the removal of II 6 of runner removes to make the runner device drive pipe die 1 and produce vibrations in the axis direction, power unit slew velocity is fast more, and pipe die 1's vibration frequency is high more, and is big more to the destruction degree of dendrite, and the grain size improves better.

By adopting the axial vibration centrifugal machine and the matched pipe die, the axial vibration centrifugal casting method comprises the following steps: 1) baking a pipe die, spraying a coating and installing baffles at two ends of the pipe die; 2) pouring molten metal from one end (namely a pouring end) of the pipe die, starting a power mechanism when the molten metal is filled to the other end (namely a non-pouring end) of the pipe die, rotating an eccentric wheel 7, driving a steel plate 5 to move left and right under the action of a rotating wheel II 6 by a rotating eccentric groove 8, and driving a vibration flange 9 to drive a pipe die 1 to vibrate left and right axially by a rotating wheel I4 on the steel plate 5; 3) and after the molten metal is poured, cooling the pipe die by spraying water, and closing the power mechanism when the solidification thickness of the molten metal reaches half of the thickness of the centrifugal casting steel pipe. The point in time at which the power mechanism is switched off can be determined by simulation, or by the temperature of the inner surface during centrifugation of the molten metal, or can be determined empirically. 4) And (4) completely solidifying the molten metal, and pushing or pulling the pipe to realize the separation of the cast steel pipe and the pipe die.

The axial vibration centrifugal machine is used together with the pipe die, when austenitic stainless steel or nickel-based heat-resistant steel metal liquid is cooled, the axial vibration of the pipe die can break cast dendrites, the grain size of cast tissues is improved, and the pressure is relieved for subsequent deformation processing. FIG. 4 shows the as-cast structure of a cast steel pipe when a pipe die of a certain nickel-based alloy is free of vibration, the wall thickness of the cast steel pipe is about 73mm, the length of a dendrite reaches above 45mm, FIG. 5 shows the as-cast structure of the cast steel pipe after the pipe die is vibrated in the axial direction, the wall thickness of the cast steel pipe is about 75mm, the length of the dendrite is about 23mm, and compared with FIG. 4, the length of the dendrite after the pipe die is vibrated in the axial direction is shortened by half.

The axial vibration centrifugal casting method can also be used for producing other centrifugal cast steel pipes, and the grain size of cast steel pipes with medium-low carbon content, such as 20Cr or 35CrMo, can also be greatly improved. The results of the investigation show that the cast steel pipe with medium and low carbon also has the function of inhibiting carbon segregation. Because the content of carbon in austenitic stainless steel or nickel-based heat-resistant steel is very low, the austenitic stainless steel or nickel-based heat-resistant steel has ultralow carbon content, and the carbon segregation is not obvious. The following table shows carbon segregation data of 20Cr and 35CrMo centrifugal cast steel pipes, numbers in a sampling position column in the table show that the cast steel pipes are sampled layer by layer from the inner surface to the outer surface, the cast steel pipes are divided into 12 layers averagely according to the thickness, and carbon analysis is carried out after the layer-by-layer sampling, and the results prove that the maximum value and the difference value of the carbon segregation are obviously reduced after axial vibration, particularly the difference value is reduced by 30-40%, and the axial vibration centrifugal machine and the casting method thereof have good inhibition effect on the carbon segregation of the medium-low carbon cast steel pipes.

Claims

1. The utility model provides an axial vibrations centrifugal casting method, uses axial vibrations centrifuge and axial vibrations pipe die to carry out centrifugal casting, its characterized in that: the vibration pipe die is characterized in that a vibration flange (9) is machined in the middle of the axial vibration pipe die, the axial vibration centrifugal machine comprises an axial vibration device (3), the vibration device comprises a rotating wheel device and an eccentric device, the rotating wheel device comprises a rotating wheel I (4) matched with the vibration flange (9), a steel plate (5) for fixing the rotating wheel I (4) and a rotating wheel II (6), the eccentric device comprises an eccentric wheel (7) and a power mechanism of the eccentric wheel (7), and an eccentric groove (8) matched with the rotating wheel II (6) is machined in the eccentric wheel (7); the axial vibration centrifugal casting method comprises the following steps:

1) Baking a pipe die, spraying a coating and installing baffles at two ends of the pipe die;

2) Pouring molten metal from the pouring end of the pipe die, starting a power mechanism when the molten metal is filled to the non-pouring end of the pipe die, enabling an eccentric wheel (7) to rotate, driving a steel plate (5) to move left and right under the action of a rotating wheel II (6) through a rotating eccentric groove (8), and driving a vibrating flange (9) through a rotating wheel I (4) on the steel plate (5) to drive the pipe die to vibrate left and right axially; (ii) a

3) After the molten metal is poured, spraying water to cool the pipe die, and closing the power mechanism when the solidification thickness of the molten metal reaches half of the thickness of the centrifugal casting steel pipe;

4) And (4) completely solidifying the molten metal, and pushing or pulling the pipe to realize the separation of the cast steel pipe and the pipe die.