CN114147157A

CN114147157A - Turning forging process of large cake forging

Info

Publication number: CN114147157A
Application number: CN202111560971.8A
Authority: CN
Inventors: 朱玉龙; 徐岳强; 朱小明; 汪福祥
Original assignee: Jiangyin Longyu Forging And Stamping Co ltd
Current assignee: Jiangyin Longyu Forging And Stamping Co ltd
Priority date: 2021-12-20
Filing date: 2021-12-20
Publication date: 2022-03-08

Abstract

The invention relates to a turning forging process of a large cake forging, which comprises the following steps: chamfering, drawing and cutting a riser of a steel ingot; step two: upsetting the forging; step three: transversely flattening; forging the steel ingot in a turning way, and flattening the steel ingot in a transverse direction; step four: pressing and chamfering; transversely flattening, transversely forging and forging the square, and chamfering; step five: rounding and forming; and rotationally upsetting after the transverse forging and rounding, and then flattening to the forging forming size. The invention changes the direction to flatten the square and changes the axis direction of the steel ingot, thus scattering the defects at the central part of the steel ingot, enabling the inclusion defects not to be gathered but to be scattered all around, greatly reducing the number of the defects in unit area, improving the product quality and having higher yield.

Description

Turning forging process of large cake forging

Technical Field

The invention relates to the technical field of forging of cake forgings, in particular to a turning forging process of a large cake forging.

Background

The large cake forging has a large diameter generally exceeding 2000mm and a small thickness generally about 200 mm and 300mm, and is commonly used for tube plates commonly used in pressure vessel equipment, cover plates in valve equipment in petrochemical industry and the like, as shown in fig. 1.

The raw material steel ingot is produced through a mold ingot, the internal structure of the steel ingot is very complex because of physical and chemical changes of molten steel in the process of smelting the steel ingot in the process of converting molten steel from liquid state to solid state, and the internal structure condition shown after cutting from the center is shown in a schematic section view of the steel ingot as shown in fig. 2: the water port end is a deposition cone area which is usually a negative segregation area, and the internal impurities are generally small; the top-off end is a floating impurity area formed by molten steel through chemical reaction, the impurities are the most, loose shrinkage cavities exist, the components are in positive segregation, the structure is thick, the worst material area is formed, and the part of materials need to be removed during production; the ingot body area is an available area of the steel ingot.

In the ingot body area, the outermost surface of the ingot body area is in contact with the inner wall of the ingot mold, molten steel is firstly solidified, the cooling speed is higher, and therefore grains are finest; inward is the growth of fine grain area on the surface to internal crystal boundary dendrite and is columnar crystal; because the inside is the most central part, the molten steel is the slowest to cool and is the place of final solidification, the volume is reduced when the liquid state is converted into the solid state, the outer surface of the steel ingot is solidified firstly, and the center is solidified finally, so the crystal grains at the central part are the coarsest and loose, the internal stress exists, and some impurities in the molten steel are solidified firstly because the upper riser end is solidified, the molten steel at the central part is solidified finally, the impurities in the molten steel cannot float upwards and only can be remained at the central part of the steel ingot, although the defects can be improved through the steelmaking process, the quality of the molten steel can be improved, but the defects can be reduced and cannot be completely removed.

Therefore, the cake forging improves the problem of internal looseness of the forging by forging the ingot body of the steel ingot so as to meet the standard requirement of product design, but other inherent material defects of raw materials are concentrated at the central part of the ingot body in the smelting process and cannot be removed, so that the quality grade of the product is directly influenced, see figure 3, and the cake forging is a defect schematic diagram of the cake forging produced by the prior art, the conventional forging method is characterized in that the ingot body of the steel ingot is vertically upset and then upset and formed along the axial direction of the ingot body, the axial direction of the steel ingot is not changed in the whole forging process, namely, the materials in the central area of the steel ingot are all compressed to the central position of the product and are concentrated at the most central position, so that the inclusion defects of the materials are all concentrated at the center of the forging, the area is small, the defects are concentrated, and the defects exceed the standard caused by the concentration of the dense defects or the over concentration of single defects when the forging is detected, can not be rejected by acceptance.

Disclosure of Invention

The invention aims to overcome the defects and provide a turning forging process of a large cake forging, so that inclusion defects are not gathered but scattered all around, the number of the defects in a unit area is greatly reduced, and the product quality is improved.

The purpose of the invention is realized as follows:

a turning forging process of a large cake forging comprises the following steps:

the method comprises the following steps: chamfering, drawing and cutting a riser of a steel ingot;

step two: upsetting the forging;

step three: transversely flattening;

forging the steel ingot in a turning way, and flattening the steel ingot in a transverse direction;

step four: pressing and chamfering;

transversely flattening, transversely forging and forging the square, and chamfering;

step five: rounding and forming;

and rotationally upsetting after the transverse forging and rounding, and then flattening to the forging forming size.

Further, in the first step, the ingot body and the riser edge are flattened to be high and then are returned to the furnace.

And further, upsetting the forging with the water gap end of the steel ingot facing upwards in the second step.

Further, in the fifth step, upsetting is rotated by using a narrow anvil.

Further, in the fifth step, an upper flat anvil and a lower flat anvil with the width of 400mm are adopted for leveling.

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

the invention adopts the turning forging process, changes the forging direction of the defects in the central area of the ingot body, carries out upsetting and changes the direction of the flattening direction after the forging ratio is made, and changes the axial direction of the steel ingot, thereby scattering the defects at the central part of the steel ingot, enabling the inclusion defects not to be gathered but to be scattered all around, greatly reducing the number of the defects in unit area, enabling the deformation of the central part of the steel ingot to be larger after the turning forging, improving the loosening condition, dispersing the defects, improving the product quality, and having higher yield through ultrasonic flaw detection.

Drawings

FIG. 1 is a schematic structural diagram of a cake forging.

Fig. 2 is a schematic cross-sectional view of a steel ingot.

FIG. 3 is a schematic diagram of internal defects of a conventional cake forging.

FIG. 4 is a schematic view of the process of the present invention.

FIG. 5 is a schematic diagram of internal defects of the cake forging of the present invention.

Detailed Description

For a better understanding of the technical aspects of the present invention, reference will now be made in detail to the accompanying drawings. It should be understood that the following specific examples are not intended to limit the embodiments of the present invention, but are merely exemplary embodiments of the present invention. It should be noted that the description of the positional relationship of the components, such as the component a is located above the component B, is based on the description of the relative positions of the components in the drawings, and is not intended to limit the actual positional relationship of the components.

Example 1:

referring to fig. 4 and 5, fig. 4 is a schematic process diagram of a turning forging process of a large cake-type forging. As shown in the figure, the production product of the turning forging process of the large cake forging is the cake forging, 11.5 tons of steel ingots are adopted for cogging, the diameter of the forging is 2675mm, the thickness of the forging is 168mm,

the process flow comprises the following contents:

first time fire

At the initial forging temperature of 1180 ℃, chamfering and rounding the steel ingot, pressing the ingot body once, drawing out, cutting off a dead head at the final forging temperature of 850 ℃, flattening the edges of the ingot body and the dead head to be high, and then returning to the furnace;

second fire

Heating the forging to the initial forging temperature of 1180 ℃, and upsetting the forging with the water gap end of the steel ingot upward to reach the height of about 900 mm;

transversely flattening the steel ingot at the finish forging temperature of above 850 ℃, and then squaring and chamfering;

third fire

Heating the forge piece to the initial forging temperature of 1180 ℃, performing transverse forging and rounding, then performing rotary upsetting by using a narrow anvil, and rolling for one circle of excircle when the thickness of the forge piece is about 350 mm;

leveling to the forming size of the forged piece at the finish forging temperature of 850 ℃, and leveling by adopting an upper flat anvil and a lower flat anvil with the width of 400 mm.

The above is only a specific application example of the present invention, and the protection scope of the present invention is not limited in any way. All the technical solutions formed by equivalent transformation or equivalent replacement fall within the protection scope of the present invention.

Claims

1. The turning forging process of the large cake forging is characterized by comprising the following steps of:

step two: upsetting the forging;

step three: transversely flattening;

step four: pressing and chamfering;

step five: rounding and forming;

2. The turning forging process of the large cake forging as claimed in claim 1, wherein the turning forging process comprises the following steps: and in the step one, the ingot body and the riser edge are pressed to be high and then are returned to the furnace.

3. The turning forging process of the large cake forging as claimed in claim 1, wherein the turning forging process comprises the following steps: and in the second step, the water gap end of the steel ingot faces upwards, and the forging is upset.

4. The turning forging process of the large cake forging as claimed in claim 1, wherein the turning forging process comprises the following steps: and step five, using a narrow anvil to carry out rotary upsetting.

5. The turning forging process of the large cake forging as claimed in claim 1, wherein the turning forging process comprises the following steps: and in the fifth step, an upper flat anvil and a lower flat anvil which are 400mm wide are adopted for leveling.