CN111531097A

CN111531097A - Forging method for eliminating wall thickness unevenness defect of cylinder type forging

Info

Publication number: CN111531097A
Application number: CN202010338951.5A
Authority: CN
Inventors: 张立根; 齐盛文; 姜啸远; 许松梅; 孟冬凝; 宋嘉鑫
Original assignee: Angang Heavy Machinery Co Ltd
Current assignee: Angang Heavy Machinery Co Ltd
Priority date: 2020-04-26
Filing date: 2020-04-26
Publication date: 2020-08-14
Anticipated expiration: 2040-04-26
Also published as: CN111531097B

Abstract

The invention relates to a forging method for eliminating the defect of uneven wall thickness of a cylinder type forging, which repairs a forging with the concentricity of an inner hole and an outer circle after forging being out of tolerance and the wall thickness of the thinnest part being smaller than the blank size required by a finish machining process; during the repair, firstly, a saddle reaming method is adopted to press the wall thickness of the forged piece to be the same as the wall thickness of the thinnest part, and a cylindrical piece with the concentric inner hole and the concentric outer circle and the larger inner diameter size and the larger outer diameter size than the finished product size of the cylindrical forged piece is obtained; and (3) penetrating a core shaft with the outer diameter the same as the inner diameter of the finished cylindrical forging into the inner hole of the cylindrical part, and forging the outer circle of the cylindrical part by the upper anvil and the lower anvil to finally obtain the finished cylindrical forging meeting the requirements. The method can repair the forged piece which needs to be scrapped originally to meet the requirement of machining size, thereby improving the yield and reducing the economic loss.

Description

Forging method for eliminating wall thickness unevenness defect of cylinder type forging

Technical Field

The invention relates to the technical field of forging, in particular to a forging method for eliminating the defect of uneven wall thickness of a cylinder type forging.

Background

The strength of each part of the blank has deviation due to the influence of uneven heating temperature of the cylindrical forging in the forging process, so that the problem of uneven wall thickness of the cylindrical forging when the mandrel is drawn out is solved. Due to the common existence of the problem, when a forging process is set, a forging processing enterprise has to adopt a method for increasing the forging allowance of the inner hole, and the allowance of some inner holes even reaches 2 times of the allowance of the outer circle. However, although the inner hole allowance is increased, when the problem of uneven wall thickness is serious or the inner hole and the outer circle have serious eccentricity, the forged piece still cannot meet the finish machining requirement, and finally the forged piece is scrapped, so that economic loss is caused.

Disclosure of Invention

The invention provides a forging method for eliminating the defect of uneven wall thickness of a cylindrical forging, which can repair the forging which needs to be scrapped originally when the cylindrical forging has the defect of uneven wall thickness or serious eccentricity of an inner hole and an outer circle, so that the forging meets the requirement of machining size, the finished product rate is improved, and the economic loss is reduced.

In order to achieve the purpose, the invention adopts the following technical scheme:

a forging method for eliminating the defect of uneven wall thickness of a cylinder forging comprises the following steps:

s1: casting a steel ingot, wherein the weight of the steel ingot is 1.5-2.5 times of that of a finished product of the cylinder forging;

s2: heating the steel ingot according to a set heating process curve;

s3: forging for the first time; forging a riser of the steel ingot into a jaw for clamping by a forging manipulator, cutting off the tail of the steel ingot, and then returning the steel ingot to a furnace for heating;

s4: forging for the second time; integrally upsetting a steel ingot, and then drawing the steel ingot into a cylinder; cutting off the jaw part, and returning to the furnace for heating after blanking is completed;

s5: forging for the third time; upsetting the blanked blank to the height-diameter ratio of 0.4-0.6, and punching a central hole by using a punch;

s6: forging for the fourth time; drawing out the punched blank to the length of the finished product of the cylinder forging by adopting a mandrel drawing method;

s7: measuring the drawn forge piece, if the concentricity of the inner hole and the outer circle is out of tolerance, measuring the wall thickness of the thinnest part of the forge piece, and if the wall thickness of the thinnest part of the forge piece is smaller than the size of the blank required by the fine machining process, performing the repair;

during the repair, firstly, a saddle reaming method is adopted to press the wall thickness of the forged piece to be the same as the wall thickness of the thinnest part, and a cylindrical piece with the concentric inner hole and the concentric outer circle and the larger inner diameter size and the larger outer diameter size than the finished product size of the cylindrical forged piece is obtained; and (3) penetrating a core shaft with the outer diameter the same as the inner diameter of the finished cylindrical forging into the inner hole of the cylindrical part, and forging the outer circle of the cylindrical part by the upper anvil and the lower anvil to finally obtain the finished cylindrical forging meeting the requirements.

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

according to the method, when the cylindrical forge piece has the defects of uneven wall thickness or serious eccentricity of the inner hole and the outer circle, the forge piece which needs to be scrapped originally can be repaired, so that the requirement on the machining size is met, the finished product rate is improved, and the economic loss is reduced.

Drawings

FIG. 1 is a schematic structural diagram of a cylinder forging in the embodiment of the invention.

FIG. 2 is a heating process curve of a steel ingot according to an embodiment of the present invention.

FIG. 3 is a flowchart of the procedure of pressing the jaws and cutting the ingot tail during the first hot forging according to the embodiment of the present invention.

FIG. 4 is a flow chart of the process of upsetting, elongating and cutting the ingot in the embodiment of the present invention.

FIG. 5 is a flowchart of a blank upsetting and punching process according to an embodiment of the present invention.

Fig. 6 is a schematic view of a mandrel drawing process according to an embodiment of the present invention.

FIG. 7 is a front view of a cylindrical forging with eccentric defects in the hole and the excircle of the forging after the mandrel is drawn out according to the embodiment of the invention.

Fig. 8 is a side view of fig. 7.

Fig. 9 is a schematic view of a process of reaming a bumper according to an embodiment of the present invention.

FIG. 10 is a schematic view of the forging process of the upper and lower anvils according to the embodiment of the present invention.

In the figure, 1, a cylinder forging 2, a steel ingot 3, a feeder head 4, an ingot tail 5, a mandrel I6, an upper flat anvil 7, a lower flat anvil 8, a cylinder 9, a strut 10, a saddle 11 and a mandrel II are shown

Detailed Description

The following further describes embodiments of the present invention with reference to the accompanying drawings:

as shown in FIGS. 1 to 10, the forging method for eliminating the defect of uneven wall thickness of the cylinder forging comprises the following steps:

s1: casting a steel ingot 2, wherein the weight of the steel ingot 2 is 1.5-2.5 times of that of the finished product of the cylinder type forging 1;

s2: the steel ingot 2 is heated according to a set heating process curve;

s3: forging for the first time; forging a riser 3 of the steel ingot 2 into a jaw for clamping by a forging manipulator, cutting off an ingot tail 4, and then returning the steel ingot 2 to a furnace for heating;

s4: forging for the second time; integrally upsetting the steel ingot 2, and then drawing the steel ingot into a cylinder; cutting off the jaw part, and returning to the furnace for heating after blanking is completed;

s6: forging for the fourth time; drawing the punched blank to the length of the finished product of the cylinder forging 1 by adopting a mandrel drawing method;

during the repair, firstly, a saddle reaming method is adopted to press the wall thickness of the forged piece to be the same as the wall thickness of the thinnest part, and a cylindrical piece 8 with the concentric inner hole and the concentric outer circle and the larger inner diameter size and the larger outer diameter size than the finished product size of the cylindrical forged piece is obtained; and (3) penetrating a core shaft (a core shaft II 11) with the same outer diameter and inner diameter as the finished cylindrical forging into the inner hole of the cylindrical part 8, and forging the outer circle of the cylindrical part 8 by using the upper anvil and the lower anvil to finally obtain the finished cylindrical forging 1 meeting the requirements.

The following examples are carried out on the premise of the technical scheme of the invention, and detailed embodiments and specific operation processes are given, but the scope of the invention is not limited to the following examples. The methods used in the following examples are conventional methods unless otherwise specified.

[ examples ] A method for producing a compound

In the embodiment, the cylinder type forging is as shown in fig. 1, the inner diameter (inner hole size) of the finished cylinder type forging (blank before finish machining) is phi 700mm, the outer diameter (outer circle size) is phi 1400mm, and the wall thickness is 350 mm; the forging process comprises the following steps:

firstly, the steel ingot 2 is heated according to the heating process curve of figure 2, so that the steel ingot 2 is completely austenitized, the deformation resistance of the steel ingot is greatly reduced, the plasticity of the steel ingot is improved, and the forging requirement is met.

Secondly, forging for the first heating time; as shown in fig. 3, the risers 3 of the ingot 2 are pressed into a jaw shape suitable for gripping by the forging manipulator; the ingot tail 4 of the steel ingot 2 is cut off, so that poor quality materials of the ingot tail 4 are prevented from being left on the forging. And returning the steel ingot 2 to the heating furnace after the operation is finished, wherein the heating time can meet the requirement of the next large-deformation upsetting process, and the heat preservation temperature is 1220-1280 ℃.

Thirdly, forging for the second heating time; as shown in fig. 4, the ingot 2 is upset and drawn out as a whole in order to eliminate various casting defects generated during ingot casting by a large forging deformation, and after the casting defects are eliminated, the jaw portion is removed in preparation for upset and punching at the next heat. And then returning the steel ingot 2 to the heating furnace, wherein the heat preservation temperature is 1220-1280 ℃, and the heat preservation time is more than 2 hours.

Fourthly, forging for the third time; as shown in fig. 5, the blanked blank is placed on a rotary table, the whole is upset to a height-diameter ratio of about 0.6, and a punch is used to punch a hole in the center of the blank, so that a center hole is punched in the center of the blank. If the inner hole of the cylinder forging is smaller than the diameter of the punch, the punch with the diameter 50mm larger than that of the first mandrel is selected for punching, and then the first mandrel is directly used for drawing at the next firing time. If the size of the inner hole of the barrel forging exceeds the diameter of the punch, the inner hole of the blank is firstly expanded by utilizing a horse bar hole expanding process after the center punching is completed, and then a proper mandrel I5 is selected for carrying out a mandrel drawing process. After the process is finished, the blank is returned to the heating furnace, the heat preservation temperature is 1220-1280 ℃, and the heat preservation time is more than 2 hours.

And fifthly, as shown in fig. 6, performing a mandrel drawing process on the blank punched with the central hole, wherein the drawing sequence is to draw a part near the end face of the right end (in the direction shown in the figure, the same below) of the forged piece, then draw the left end part, and then draw from right to left. The two ends are drawn out firstly to prevent the end cracks of the forging caused by temperature reduction and plasticity reduction, and the two ends are drawn out from the right to the left to prevent the forging from being difficult to separate from the mandrel I5 after the forging is locked.

And sixthly, observing and measuring the forge piece after the elongation of the mandrel is finished, wherein if the defects that an inner hole and an outer circle are obviously eccentric as shown in figures 7 and 8 occur, and the minimum thickness part of the wall thickness of the forge piece is very close to or even smaller than the wall thickness of a blank required by finish machining, the forge piece needs to be repaired. Before repairing, the forge piece is returned to the heating furnace, the heat preservation temperature is 1220-1280 ℃, and the heat preservation time is more than 2 hours.

And seventhly, as shown in fig. 9, by utilizing a bar hole expanding device (comprising a bar 9 and a saddle 10) and controlling the distance between the upper anvil surface of the upper flat anvil 6 and the upper surface of the bar 9, the wall thickness of the forged piece reaches the minimum wall thickness size, even if the wall thickness of the blank is consistent, a cylindrical piece 8 with a hole and an excircle which are slightly larger than the target forged piece is obtained. And after reaming, returning the cylindrical part 8 to the heating furnace, wherein the heat preservation temperature is 1220-1280 ℃, and the heat preservation time is more than 2 hours.

And eighthly, as shown in fig. 10, selecting a second mandrel 11 with the outer diameter size being the same as the size of the hole in the finished cylindrical forge piece 1 to perform a mandrel drawing process, and performing matched forging and pressing on the upper flat anvil 6 and the lower flat anvil 7, wherein the rolling reduction of the upper flat anvil 6 needs to be strictly controlled during the mandrel drawing process, and the hole in the forge piece and the excircle of the forge piece are gradually tightened through frequent and light pressing. The inner hole of the forging is controlled by the size of the outer circle of the mandrel II 11, and the outer circle of the forging is observed by a forger and is controlled in size. After the working procedure, the finished product of the cylinder forging 1 with coaxial outer circle and inner hole and uniform wall thickness is obtained.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions and the inventive concepts thereof according to the present invention should be equivalent or changed within the scope of the present invention.

Claims

1. A forging method for eliminating the defect of uneven wall thickness of a cylinder forging is characterized by comprising the following steps:

s2: heating the steel ingot according to a set heating process curve;