U.S. patent application number 15/566224 was filed with the patent office on 2018-11-15 for method of near-net-shape forged molding of coupler knuckle of railway vehicle.
This patent application is currently assigned to Jilin University. The applicant listed for this patent is Jilin University, Qingdao Zhongtianpeng Forging Manufacturing Co., Ltd.. Invention is credited to Qingmin CHEN, Yan YUE.
Application Number | 20180326472 15/566224 |
Document ID | / |
Family ID | 57341314 |
Filed Date | 2018-11-15 |
United States Patent
Application |
20180326472 |
Kind Code |
A1 |
CHEN; Qingmin ; et
al. |
November 15, 2018 |
METHOD OF NEAR-NET-SHAPE FORGED MOLDING OF COUPLER KNUCKLE OF
RAILWAY VEHICLE
Abstract
The present invention provides a method of near-net-shape forged
molding of the coupler knuckle of the railway vehicle. The present
invention solves the problems that the manufacturing the forged
coupler knuckle is difficult, and the process is complex, etc. The
method of the present invention includes the following steps:
material preparation, heating, blank prefabrication, pre-forging,
closed-die forging, quenched-tempered heat treatment using waste
heat, finish machining, flaw detection, etc. With the closed-die
forging technology, the near-net-shape molding of the coupler
knuckle can be achieved. The energy and the material are saved. The
contour shape and the size do not need to be machined. The use
ratio of the material can reach more than 92%. Moreover, during the
entire molding, the workpiece is in the three-dimensionally
stressed state all the time. The product has a dense texture, a
high toughness, a good fatigue resistance, and a long lifetime.
Inventors: |
CHEN; Qingmin; (Jilin,
CN) ; YUE; Yan; (Qingdao, CN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Jilin University
Qingdao Zhongtianpeng Forging Manufacturing Co., Ltd. |
Jilin
Qingdao |
|
CN
CN |
|
|
Assignee: |
Jilin University
Jilin
CN
Qingdao Zhongtianpeng Forging Manufacturing Co., Ltd.
Qingdao
CN
|
Family ID: |
57341314 |
Appl. No.: |
15/566224 |
Filed: |
April 14, 2017 |
PCT Filed: |
April 14, 2017 |
PCT NO: |
PCT/CN2017/080671 |
371 Date: |
October 13, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B21J 5/025 20130101;
B21K 7/12 20130101; C21D 9/0068 20130101; B21J 13/02 20130101; B21J
13/025 20130101; C21D 1/18 20130101 |
International
Class: |
B21J 5/02 20060101
B21J005/02; B21J 13/02 20060101 B21J013/02; B21K 7/12 20060101
B21K007/12; C21D 9/00 20060101 C21D009/00; C21D 1/18 20060101
C21D001/18 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 10, 2016 |
CN |
201610829867.7 |
Claims
1. A method of near-net-shape forged molding of a coupler knuckle
of a railway vehicle, comprising the following steps: Step (a)
material preparation; Step (b) heating: heating a rough at
1150.degree. C..+-.20.degree. C.; Step (c) blank prefabrication:
positioning the heated rough on an 800-ton multi-directional
forging apparatus for multi-directional forging to prefabricate the
blank; Step (d) blank pre-forging: closed-die forging the
prefabricated blank in a pre-forging die on a 2000-ton
multi-directional forging apparatus; Step (e) near-net-shape forged
molding: closed-die forging the pre-forged blank positioned in a
multi-directional forging die on a 6000-ton multi-directional
forging apparatus, so as to achieve near-net-shape molding; Step
(f) thermal treatment: performing a quenched-tempered heat
treatment on the forged blank using waste heat; Step (g) finish
machining: processing a pinhole of the coupler knuckle using a
numerical control machining machine; and Step (h) flaw detection:
performing a magnetic powder flaw detection on the finished
product.
2. The method of near-net-shape forged molding of the coupler
knuckle of the railway vehicle according to claim 1, wherein in the
Step (c) performing the blank prefabrication on the
multi-directional forging apparatus; moving a die in a vertical
direction and a die in a horizontal direction in an interleaved
manner; manufacturing the heated rough into a prefabricated blank
with a certain height and a certain thickness while removing an
oxide skin on a surface of the rough.
3. The method of near-net-shape forged molding of the coupler
knuckle of the railway vehicle according to claim 1, wherein in the
Step (d) positioning the prefabricated blank in the pre-forging die
of the multi-directional forging apparatus; dividing the
pre-forging die into four portions including an upper portion, a
lower portion, a left portion, and a right portion; driving the
upper portion and the lower portion of the die by a vertical oil
cylinder of the multi-directional forging apparatus; driving the
left portion and the right portion of the die by a horizontal oil
cylinder of the multi-directional forging apparatus; controlling a
movement and a moving distance of each portion of the die by a
program; after each portion of the die is assembled, stopping
moving of each portion of the die; and pre-forging the
prefabricated blank into a certain shape and a certain size.
4. The method of near-net-shape forged molding of the coupler
knuckle of the railway vehicle according to claim 1, wherein in the
Step (e) achieving the near-net-shape molding of the coupler
knuckle by the multi-directional forging apparatus and the
multi-directional forging die; splitting the multi-directional
forging die horizontally and vertically in a mixing manner; after
the pre-forged blank is positioned in the multi-directional forging
die, at first, driving the left portion and the right portion of
the die in a horizontal direction to start to move by the
horizontal oil cylinder of the multi-directional forging apparatus;
extruding the pre-forged blank; after the left portion and the
right portion of the die are assembled, locking the die; driving
the upper portion of the die in the vertical direction to move
downward rapidly by a main oil cylinder; when the upper portion of
the die is about to contact the blank, slowing down the main oil
cylinder, and starting the closed-die forging, wherein a moving
speed of the upper portion of the die is adjustable in a stepless
manner and is controlled by the program; during the entire forging,
keeping a rate of deformation of the workpiece substantially the
same all the way; when a pressure of the main oil cylinder reaches
a predetermined value, finishing the entire forging process;
returning the upper portion of the die rapidly while moving an
upper ejection oil cylinder such that the workpiece is maintained
without moving upward together with the upper portion of the die;
splitting and returning the left portion and the right portion of
the die; next, driving the lower portion of the die by a lower
ejection oil cylinder to move upward to push out the workpiece; and
completing the near-net-shape forged molding.
5. The method of near-net-shape forged molding of the coupler
knuckle of the railway vehicle according to claim 1, wherein in the
Step (e) providing the horizontal die of the multi-directional
forging die with a built-in hydraulic cylinder and movable module;
during the closed-die forging, when the upper portion of the die
moves downward to reach a certain position, controlling the
built-in hydraulic cylinder by the program to start automatically
to push the movable module, so as to achieve a partial molding of a
pocket portion of the coupler knuckle workpiece; while the upper
portion of the die is returning rapidly, starting the built-in
hydraulic cylinder to return, so as to drive the movable module to
return; and after the movable module returns to an original
position, splitting and returning the left portion and the right
portion of the die.
6. The method of near-net-shape forged molding of the coupler
knuckle of the railway vehicle according to claim 1, wherein in the
Step (f) after the workpiece is molded, performing a
quenched-tempered heat treatment using the waste heat; after the
near-net-shape forged molding of the workpiece is completed,
measuring a temperature using an automatic temperature measuring
system; next, entering the workpiece into a soaking pit; based on
the comparison of the temperature measured by the automatic
temperature measuring system and the quenching temperature,
performing a heating-up treatment or a cooling-down treatment by
the soaking pit on the workpiece automatically; and monitoring and
automatically controlling a time for the workpiece to stay in the
soaking pit in real time by an accompanying automatic temperature
measuring system.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is the national phase of International
Application No. PCT/CN2017/080671, filed on Apr. 14, 2017, which is
based upon and claims priority to Chinese Patent Application No.
201610829867.7, filed on Sep. 10, 2016, the entire contents of
which are incorporated herein by reference.
TECHNICAL FIELD
[0002] The present invention relates to the technical field of
plastic molding of complex parts, particularly to a method of
near-net-shape forged molding of a coupler knuckle of a railway
vehicle.
BACKGROUND
[0003] The railway vehicle coupler is the key part which is
connected between the locomotive and the vehicle, and between
vehicles. Moreover, the main part of the coupler portion is the
coupler knuckle. Thus, the coupler knuckle is the key traction part
of the railway vehicle. The performance of the coupler knuckle has
a lot of things to do with the operating safety and reliability
railway train. As the railway transportation of China is developing
towards the direction of high speed and heavy load continuously,
the longitudinal impact of the train increases drastically. The
frictional wear of the contact surface of the coupler knuckle is
severe. It is therefore more and more difficult for the performance
of coupler knuckle to satisfy the requirement of modern railway
transportation. Thus, the safety and benefit of the railway
transportation are affected seriously. Currently, the manufacturing
of coupler knuckle mainly is cast molding. During cast molding,
organization defects such as air pore, slag inclusion, cavity
shrinkage, loosening, and so on, are formed in the coupler knuckle.
Under the effect of alternating stress, these defects cause cracks,
leading to breakage. In practice and usage, the above phenomena
occur frequently, causing huge loss. The operating safety of the
railway vehicle is threatened seriously. Thus, forged coupler
knuckle has become the preferred coupler knuckle for the high-speed
train and heavy-loaded vehicle.
[0004] Since the cross-section of the coupler knuckle part changes
significantly, the shape is complex, and the molding is difficult.
Moreover, there are thin ribs that are not easy to forge. The
difficulty of forging is high. Thus, very few manufacturers can
achieve the forged molding.
[0005] Currently, the manufacturing method and process of forged
coupler knuckle are complex. Multiple times of heating, die
forging, and side cutting is necessary. Moreover, the blank after
forged molding is significantly different from the finished product
in terms of the shape and the size. It is necessary to rely on
machining to process the coupler knuckle product into a certain
shape and size. The energy and material are wasted. The
manufacturing cost is high.
SUMMARY
[0006] The purpose of the present invention is to solve the
problems that manufacturing forged coupler knuckles is difficult,
and the process is complex, etc. A method of near-net-shape forged
molding a coupler knuckle of a railway vehicle is proposed. With
the manufacturing method of the present invention, the forged
coupler knuckle blank with a high precision can be manufactured by
the simplest processing method. The near-net-shape, rapidly,
precise plastic molding of the forged coupler knuckle blank can be
achieved.
[0007] Technical solutions of the present invention are as
below:
[0008] A method of near-net-shape forged molding of the coupler
knuckle of the railway vehicle includes the following steps:
[0009] a. material preparation: based on the product model, a
certain length of steel rod of the corresponding mode is cut out
with a band-sawing machine;
[0010] b. heating: the rough is heated to 1150.degree.
C..+-.20.degree. C. by a 1500 KW medium-frequency induction heating
apparatus;
[0011] c. the heated rough is positioned in an 800-ton
multi-directional forging apparatus to be forged in multiple
directions, and the blank is prefabricated.
[0012] d. blank pre-forging: the closed-die forging is performed on
the prefabricated blank in the pre-forging die on a 2000-ton
multi-directional forging apparatus, such that the blank is
pre-forged with a certain shape and a certain size;
[0013] e. near-net-shape forged molding: the pre-forged blank is
positioned in the coupler knuckle dedicated multi-directional
forging die on a 6000-ton multi-directional forging apparatus to be
subject to the closed-die forging, such that the near-net-shape
molding is achieved;
[0014] f. thermal treatment: the forged blank is subject to a
quenched-tempered heat treatment using waste heat;
[0015] g. finish machining: a pinhole and so on of coupler knuckle
is processed using a numerical control machining special
machine;
[0016] h. flaw detection: the magnetic powder flaw detection is
performed on the finished product.
[0017] In Step d, the shape and the size of the blank are achieved
by the multi-directional forging apparatus and pre-forging
blank-making die.
[0018] Furthermore, in Step e, in the vertical direction, forged
coupler knuckle dedicated multi-directional forging apparatus has
three oil cylinders in total, i.e., a main oil cylinder, an upper
ejection oil cylinder, and a lower ejection oil cylinder. In the
horizontal direction, there are four oil cylinders in total, i.e.,
a left and a right molding and locking oil cylinders, and two
ejection oil cylinders.
[0019] Furthermore, in Step e, the multi-directional forged molding
die is a forged coupler knuckle dedicated die. The die uses a
mixing manner to split horizontally and vertically. The die is
composed of four portions, i.e., an upper portion, a lower portion,
a left portion, and a right portion. The left and right portions of
the die are provided with a built-in movable module which is driven
by a built-in oil cylinder, such that the molding of a pocket
portion of the forged coupler knuckle is achieved.
[0020] Furthermore, in Step e, the left and right portions of the
die are respectively driven by two oil cylinders of the
multi-directional forging apparatus in the horizontal direction to
lock.
[0021] Furthermore, in Step e, the lower portion of the die in the
vertical direction is fixed. The upper portion of the die is driven
by the main oil cylinder of the multi-directional forging
apparatus, so as to extrude and mold the rough in the
closed-die.
[0022] Furthermore, in Step e, after closed-die forged molding, the
forged coupler knuckle workpiece is pushed out by four ejection oil
cylinders, i.e., the upper, the lower, the left, and the right
ejection oil cylinders.
[0023] The moving speed of the main oil cylinder is adjustable
within 50-80 mm/s in a stepless manner. The reduction is
automatically controlled by the multi-directional forging apparatus
based on the molding state of the workpiece, such that the rate of
deformation of the workpiece is kept substantially the same during
the entire molding.
[0024] The advantages of the present invention are as below:
[0025] (1) The molding precision is high. The contour, the shape,
and the size are realized by the near-net-shape molding without the
machining process. Thus, the raw material is saved (the raw
material is saved for more than 15%), and the machining workload is
saved.
[0026] (2) Compared with the current forging method, the heating
times and forging process are reduced. The energy is saved. The
productivity is improved.
[0027] (3) With the multi-directional closed-die forging
near-net-shape molding technology, during the plastic deformation,
the workpiece is in the three-dimensionally stressed state all the
time. The molded workpiece has a dense texture and reasonable
distribution of meat streamline. The bearing strength is
significantly improved. There is zero defect inside the workpiece.
The safety and the reliability can be guaranteed.
[0028] (4) Since the process of forged molding is simple, the
number of auxiliary apparatus is less. The yield of finished
product is high. An intellectualized manufacturing can be easily
achieved.
[0029] (5) Compared with other forging methods, the productivity is
improved for more than four times, and the manufacturing cost is
lowered for about 50%.
BRIEF DESCRIPTION OF THE DRAWINGS
[0030] FIG. 1 is the flowchart of the process of the present
invention.
[0031] FIG. 2 is the schematic diagram of the shape of the
prefabricated blank of the present invention;
[0032] FIG. 3 is the structural schematic diagram of the pre-forged
part of the present invention;
[0033] FIG. 4 is the structural schematic diagram of the forging
blank of the near-net-shape molding forging of the coupler knuckle
of the present invention;
[0034] FIG. 5 is the structural schematic diagram of the finished
product of the forged coupler knuckle of the present invention;
[0035] FIG. 6 is the structural schematic diagram of the
near-net-shape molding closed-die forging die of the present
invention.
DETAILED DESCRIPTION
[0036] Hereinafter, the present invention is further described with
reference to specific embodiments and drawings.
[0037] As shown in FIGS. 1-6, the method of near-net-shape forged
molding of the coupler knuckle of the railway vehicle of the
present invention includes the following steps:
[0038] Step (a) material preparation: based on the product model, a
certain length of steel rod of the corresponding mode is cut out
with a band-sawing machine.
[0039] Step (b) heating: the rough is heated to 1150.degree.
C..+-.20.degree. C. by a 1500 KW medium-frequency induction heating
apparatus.
[0040] Step (c) blank prefabrication: the heated rough is
positioned in an 800-ton multi-directional forging apparatus to be
forged in multiple directions, such that the blank is
prefabricated.
[0041] Step (d) blank pre-forging: the closed-die forging is
performed on the prefabricated blank in the pre-forging die on a
2000-ton multi-directional forging apparatus, such that the blank
is pre-forged with a certain shape and a certain size.
[0042] Step (e) near-net-shape forged molding: the pre-forged blank
is positioned in the coupler knuckle dedicated multi-directional
forging die on a 6000-ton multi-directional forging apparatus to be
subject to the closed-die forging, such that the near-net-shape
molding is achieved.
[0043] Step (f) thermal treatment: the forged blank is subject to a
quenched-tempered heat treatment using waste heat.
[0044] Step (g) finish machining: a pinhole and so on of coupler
knuckle is processed using a numerical control machining special
machine.
[0045] Step (h) flaw detection: the magnetic powder flaw detection
is performed on the finished product.
[0046] In the above Step (c), the blank is prefabricated on
multi-directional forging apparatus. The die in the vertical
direction and the die in the horizontal direction move in an
interleaved manner. The heated rough is made into the prefabricated
blank with certain height and thickness within the shortest time.
Meanwhile, the oxide skin on the surface of the rough is
removed.
[0047] In the above Step (d), the blank is prefabricated is
positioned in the pre-forging die of the multi-directional forging
apparatus. The pre-forging die is divided into four portions, i.e.,
upper, lower, left, and right portions. The two portions, i.e.,
upper and lower portions of the die are driven by the vertical oil
cylinder of the multi-directional forging apparatus. The two
portions, i.e., left and right portions of the die are driven by
the horizontal oil cylinder of the multi-directional forging
apparatus. The movement and moving distance of each portion of the
die are controlled by a program. After each portion of the die is
assembled, the moving stops. The prefabricated blank is pre-forged
into certain shape and size.
[0048] In the above Step (e), the near-net-shape molding of coupler
knuckle is achieved by multi-directional forging apparatus and
multi-directional forging die. Multi-directional forging die uses a
mixing manner to split horizontally and vertically. After the
pre-forged blank is positioned in the multi-directional forging
die, at first, two portions in the horizontal direction of the die,
i.e., the left and the right portions are driven by the horizontal
oil cylinder of the multi-directional forging apparatus and start
to move. The pre-forged blank is extruded. After the left portion
of the die and the right portion of the die are assembled, the die
is locked. The upper portion of the die in the vertical direction
is driven by the main oil cylinder to move downward rapidly. When
the upper portion of the die is about to contact the blank, main
oil cylinder slows down. The closed-die forging starts. The moving
speed of the upper portion of the die is adjustable in a stepless
manner and is controlled by the program. During the entire forging,
the rate of deformation of the workpiece is kept substantially the
same all the way. When the pressure of the main oil cylinder
reaches the predetermined value, the entire forging process is
over. The upper portion of the die rapidly returns. Meanwhile, the
upper ejection oil cylinder moves such that the workpiece is
maintained without moving upward together with the upper portion of
the die. The left and right portions of the die split and return.
Next, the lower portion of the die is driven by the lower ejection
oil cylinder to move upward to push out the workpiece, the
near-net-shape forged molding is completed.
[0049] In the above Step (e), the horizontal die of
multi-directional forging die is provided with a built-in hydraulic
cylinder and a movable module. During closed-die forging, when the
upper portion of the die moves downward to reach a certain
position, the built-in hydraulic cylinder is controlled by the
program to start automatically to push the movable module, so as to
achieve the partial molding of the pocket portion of the coupler
knuckle workpiece. While the upper portion of the die is returning
rapidly, the built-in hydraulic cylinder starts to return, so as to
drive the movable module to return. After the movable module
returns to original position, left and right portions of the die
split and return.
[0050] In the above Step (f), after the workpiece is molded, a
quenched-tempered heat treatment is performed using the waste heat.
After the near-net-shape forged molding of the workpiece is
completed, the temperature is measured using an automatic
temperature measuring system. Next, the workpiece enters the
soaking pit. Based on the comparison of the temperature measured by
the automatic temperature measuring system and the quenching
temperature, the soaking pit performs a heating-up treatment or a
cooling-down treatment on the workpiece automatically. The time for
the workpiece to stay in the soaking pit is monitored in real time
and automatically controlled by an accompanying automatic
temperature measuring system.
[0051] Hereinafter, a specific embodiment of the method of the
present invention is provided. In this embodiment, based on the
model of forged coupler knuckle, rod material with the diameter of
O150 mm and the length of 405 mm is prepared. The rod material
blank is heated at 1150.degree. C..+-.20.degree. C. The heated
rough is delivered into 800-ton multi-directional forging apparatus
by a mechanical arm. The rough is prefabricated. Meanwhile, the
oxide skin on the surface of the blank is removed. FIG. 2 is the
schematic diagram of the shape of the prefabricated blank. Next,
the mechanical arm delivers the prefabricated blank into the
pre-forging die. multi-directional forging apparatus processes the
prefabricated blank into a pre-forged part with certain shape and
size. FIG. 3 is the structural schematic diagram of the pre-forged
part. Next, the pre-forged blank is turned into the near-net-shape
molding multi-directional closed-die forging die shown in FIG. 6,
so as to achieve the near-net-shape forged molding of the coupler
knuckle. Using the waste heat after blank molding, the blank
workpiece is subject to evenly-heating treatment. Next,
quenched-tempered heat treatment is performed automatically. FIG. 4
is the structural schematic diagram of forged coupler knuckle blank
part after quenched-tempered heat treatment. FIG. 5 is the
structural schematic diagram of the finished product of the forged
coupler knuckle after the machining and flaw detection.
[0052] Hereinbefore, embodiments of the present invention are
described in detail with reference to the drawings. However, the
present invention is not limited to the above embodiments. Within
the range of knowledge of the ordinary person skilled in the art,
variations without departing the spirit of the present invention
should all fall within the scope of the present invention
patent.
* * * * *