CN116195384A - Disk harrow plate and preparation method thereof - Google Patents

Abstract

The invention particularly relates to a disc harrow plate and a preparation method thereof, which belong to the technical field of high-strength steel for agricultural machinery, wherein the microstructure of the edge part of the disc harrow plate takes martensite as a matrix, and the microstructure of the center part of the disc harrow plate takes ferrite and pearlite as the matrix; the structure distribution ensures the high wear resistance of the edge part of the disk harrow plate during working, and ensures the high toughness of the center part of the disk harrow plate, thereby avoiding brittle failure or cracking during service.

Description

Disk harrow plate and preparation method thereof

Technical Field

The invention belongs to the technical field of high-strength steel for agricultural machinery, and particularly relates to a disc harrow plate and a preparation method thereof.

Background

The disk harrow piece is used as a key component on a modern large-scale agricultural machine, plays a key role in cultivation of a large-area farmland, and plays roles in loosening soil, eliminating large particles in the soil and the like through rotating the disk harrow piece in the farmland. Because of the complex environment of farmlands, the disc harrow plate needs to be worn by sand and stone in the process of serving in soil, and parts are required to have high wear resistance; hard objects such as stones are encountered and the disc blade is required to have high toughness when in operation against the impact of stones in the field.

At present, the disk harrow plate is made of medium-high carbon steel such as boron steel (27 MnB, 30MnB, 34MnB and 40 MnB) and the like, and the thickness range is 3.0mm-12.0mm. The production process comprises blanking, thermoforming, shot blasting, paint baking and the like. The hot stamping process is to austenitize the flat plate completely, form the flat plate in a mold at high temperature, and cool the flat plate in water to obtain a martensitic structure with high hardness and high wear resistance. However, the toughness of parts with martensite as a matrix is too poor, and the phenomenon of brittle disc breakage easily occurs when hard objects such as stones are encountered in the service process of disc harrow blades, thereby influencing the working efficiency.

Disclosure of Invention

The invention aims to provide a disk harrow plate and a preparation method thereof, which are used for solving the problem of poor toughness of the existing disk harrow plate.

The embodiment of the invention provides a disc harrow piece, wherein the microstructure of the edge part of the disc harrow piece takes martensite as a matrix, and the microstructure of the center part of the disc harrow piece takes ferrite and pearlite as matrixes.

Optionally, the disk blade has an edge hardness of 47-57HRC and the disk blade has a core hardness of 18-23HRC.

Based on the same inventive concept, the embodiment of the invention also provides a preparation method of the disk harrow plate, which comprises the following steps:

opening the steel coil, and blanking to obtain a material to be cut;

cutting the material to be cut, and then stamping to obtain a disc blank;

heating the edge of the disc blank, and performing hot stamping quenching to obtain a disc quenching blank;

and (3) shot blasting is carried out on the disc quenching blank, and then paint baking is carried out, so that the disc harrow plate is obtained.

Optionally, the edge heating is induction heating.

Optionally, the heating width of the edge part is 30-150mm based on zero coordinates of the outer extension edge of the disc blank.

Optionally, the temperature of the edge heating is 860-940 ℃, and the heat preservation time of the edge heating is 1-10min.

Optionally, the time interval from the hot stamping quenching to the edge heating is less than or equal to 15s, and the pressure maintaining time of the hot stamping quenching is more than or equal to 30s.

Optionally, the steel coil is made of medium-high carbon steel.

Optionally, the medium-high carbon steel is one of 27MnB, 30MnB, 34MnB and 40 MnB.

Optionally, the temperature of the baking varnish is 150-240 ℃, and the time for baking varnish is 15-30min.

One or more technical solutions in the embodiments of the present invention at least have the following technical effects or advantages:

the disk harrow piece provided by the embodiment of the invention has the structure that the edge part takes martensite as a matrix, and the core part retains the ferrite and pearlite structure. The structure distribution ensures the high wear resistance of the edge part of the disk harrow plate during working, and ensures the high toughness of the center part of the disk harrow plate, thereby avoiding brittle failure or cracking during service.

The foregoing description is only an overview of the present invention, and is intended to be implemented in accordance with the teachings of the present invention in order that the same may be more clearly understood and to make the same and other objects, features and advantages of the present invention more readily apparent.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the description of the embodiments will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic view of a disk drag blade according to an embodiment of the present invention;

FIG. 2 is a schematic illustration of induction heating provided by an embodiment of the present invention;

FIG. 3 is a production process diagram provided by an embodiment of the present invention;

FIG. 4 is a microstructure view of a disk drag core provided in example 1 of the present invention;

FIG. 5 is a microstructure view of the disk blade edge provided in example 1 of the present invention;

fig. 6 is a flow chart of a method provided by an embodiment of the present invention.

Detailed Description

The advantages and various effects of the present invention will be more clearly apparent from the following detailed description and examples. It will be understood by those skilled in the art that these specific embodiments and examples are intended to illustrate the invention, not to limit the invention.

Throughout the specification, unless specifically indicated otherwise, the terms used herein should be understood as meaning as commonly used in the art. Accordingly, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In case of conflict, the present specification will control.

Unless otherwise specifically indicated, the various raw materials, reagents, instruments, equipment and the like used in the present invention are commercially available or may be prepared by existing methods.

The technical scheme of the embodiment of the application aims to solve the technical problems, and the overall thought is as follows:

the method comprises the steps of adopting a cold forming and hot forming combined process means, cutting the blanked part into an accurate shape by laser, adopting cold stamping in the first step to obtain the shape of the disc harrow plate, adopting induction heating of the edge part of the disc harrow plate in the second step, rapidly austenitizing the edge part, standing Ma Cuihuo (adopting water quenching for boron steel) to obtain a tissue (hardness is 47-57 HRC) with martensite as a matrix at the edge part, and reserving ferrite and pearlite tissues (hardness is 18-23 HRC) at the center part. The structure distribution ensures the high wear resistance of the edge part of the disk harrow plate during working, and ensures the high toughness of the center part of the disk harrow plate, thereby avoiding brittle failure or cracking during service.

According to an exemplary embodiment of the present invention, there is provided a disk blade, the microstructure of the edge portion of which is based on martensite and the microstructure of the core portion of which is based on ferrite and pearlite.

In some embodiments, the disk blade has an edge hardness of 50-57HRC and the disk blade has a core hardness of 18-23HRC.

According to another exemplary embodiment of the present invention, there is provided a method for manufacturing a disk drag blade as described above, the method comprising:

s1, flattening a steel coil, and blanking to obtain a material to be cut;

specifically, the steel coil is firstly opened flat to form a flat plate, and then the flat plate is blanked into a required square to obtain the material to be cut.

In some embodiments, the coil of steel is medium and high carbon steel.

In this embodiment, the medium and high carbon steel includes one of 27MnB, 30MnB, 34MnB and 40 MnB.

S2, cutting the material to be cut, and then stamping to obtain a disc blank; in this step, the press is cold press, and the press is formed into a desired shape.

Specifically, the blanking material to be cut is laser cut into the precise shape required by the disk harrow plate, including the opening of the edge and the like. In other embodiments, the cutting may be performed by using a die-cutting method in addition to the laser cutting.

S3, heating the edge of the disc blank, and performing hot stamping quenching to obtain a disc quenching blank;

in some embodiments, the edge heating employs induction heating.

In some embodiments, the edge heating width is 30-150mm, based on zero coordinates of the outer peripheral edge of the disc blank.

In some embodiments, the edge heating temperature is 860-940 ℃, and the edge heating soak time is 1-10 minutes. The time of induction heating varies according to the thickness.

The reason for controlling the heating temperature of the edge to 860-940 ℃ and the heat preservation time to be 1-10min is that the region of the edge to be quenched is completely austenitized during heating, the martensite is ensured to be obtained as a matrix structure during quenching, the excessive value can cause coarse grains, reduce toughness, and the insufficient austenitization can be caused, so that more ferrite and the like exist in the structure, and the hardness and the wear resistance of the edge can not be ensured.

In some embodiments, the time interval from hot stamping quenching to heating of the edge is less than or equal to 15s, and the dwell time of the hot stamping quenching is less than or equal to 30s.

The time interval from hot stamping quenching to edge heating is controlled to be less than or equal to 15s, the transfer time can influence the temperature reduction, the transfer as soon as possible is to avoid partial ferrite from appearing due to too slow transfer in the transfer process, the hardness after quenching is influenced, the adverse effect of overlarge time interval value is that ferrite structure appears, and the hardness and the wear resistance of the edge cannot be ensured.

Specifically, the induction heated part is transferred to a hot stamping die for hot stamping quenching, and boron steel (namely 27MnB, 30MnB, 34MnB and 40 MnB) is quenched by water, wherein the time from induction heating to hot stamping is less than or equal to 15s, and the dwell time is more than or equal to 30s.

The hot stamping quenching process adopts a press quenching process, namely water quenching is carried out in the pressure maintaining process, so that the high edge hardness is obtained while the good shape is obtained.

S4, shot blasting is carried out on the disc quenching blank, and then baking varnish is added, so that the disc harrow plate is obtained.

The purpose of shot blasting is to remove oxide skin on the surface, and the paint baking process is similar to the tempering process, so that the internal stress of edge quenching can be eliminated, and the toughness of the edge of the disc harrow plate is improved.

In some embodiments, the temperature of the paint bake is 150-240 ℃ and the time of the paint bake is 15-30 minutes.

The reason why the temperature of the baking varnish is controlled to be 150-240 ℃ and the time is controlled to be 15-30min is as follows: (1) ensuring the quality of baking varnish; (2) The process essence of the baking varnish is a tempering process, and the tempering process can reduce the internal stress in the material and improve the toughness; (3) The hydrogen embrittlement sensitivity can be reduced, the material is medium carbon steel, the martensite is used as a matrix in the structure after the edge quenching, the hydrogen embrittlement sensitivity is high, the hydrogen content in the material can be reduced in a low-temperature tempering process, and the hydrogen embrittlement sensitivity is reduced. Too high temperature enters a first tempering brittleness area to affect toughness, too long time and too low hardness are reduced too much, hardness cannot be guaranteed, too low temperature or too short time are used to affect baking finish quality, internal stress cannot be sufficiently eliminated, and the effect of reducing hydrogen embrittlement sensitivity cannot be achieved.

The disk drag of the present application and the method of preparing the same will be described in detail with reference to examples, comparative examples and experimental data.

Example 1

The disk harrow plate comprises the following components in percentage by mass,

C	Si	Mn	P	S	Alt	Cr	Ti	B	N
										0.339	0.247	1.43	0.009	0.001	0.041	0.19	0.052	0.0023	0.0035

the balance being iron and unavoidable impurities.

The preparation process is as follows:

the steel coil is uncoiled, blanked, cut by laser, stamped, induction heated, quenched, shot-blasted and lacquered. The thickness of the steel coil is 4mm, the diameter after laser cutting is 480mm, the induction heating width of the edge is 50mm, the induction heating temperature is 900 ℃, the heat preservation time is 5min, the steel coil is transferred into a pressure quenching die for water quenching, the pressure maintaining time is 32s, then the die is opened, and the die opening temperature is 100 ℃. Then the surface oxide skin is removed by shot blasting, and then the paint is baked at the temperature of 200 ℃ for 20min. The shape of the disk blade is shown in fig. 1, a schematic view of induction heating is shown in fig. 2, the structure of the disk blade core is shown in fig. 4, and the structure of the disk blade edge is shown in fig. 5.

Example 2

The disk harrow plate comprises the following components in percentage by mass,

C	Si	Mn	P	S	Alt	Cr	Ti	B	N
										0.331	0.235	1.38	0.008	0.002	0.042	0.15	0.043	0.0021	0.0040

the balance being iron and unavoidable impurities.

The preparation process is as follows:

the steel coil is uncoiled, blanked, cut by laser, stamped, induction heated, quenched, shot-blasted and lacquered. The thickness of the steel coil is 6mm, the diameter after laser cutting is 560mm, the induction heating width of the edge is 80mm, the temperature of induction heating is 900 ℃, the heat preservation time is 7min, the steel coil is transferred into a pressure quenching die for water quenching, the pressure maintaining time is 33s, then the die is opened, and the die opening temperature is 110 ℃. Then the surface oxide skin is removed by shot blasting, and then the paint is baked at the temperature of 210 ℃ for 22min.

Example 3

The disk harrow plate comprises the following components in percentage by mass,

C	Si	Mn	P	S	Alt	Cr	Ti	B	N
										0.302	0.241	1.29	0.007	0.001	0.043	0.17	0.047	0.0022	0.0038

the balance being iron and unavoidable impurities.

The preparation process is as follows:

the steel coil is uncoiled, blanked, cut by laser, stamped, induction heated, quenched, shot-blasted and lacquered. The thickness of the steel coil is 8mm, the diameter after laser cutting is 660mm, the edge induction heating width is 120mm, the induction heating temperature is 930 ℃, the heat preservation time is 8min, the steel coil is transferred into a pressure quenching die for water quenching, the pressure maintaining time is 40s, then the die is opened, and the die opening temperature is 105 ℃. Then the surface oxide skin is removed by shot blasting, and then the paint is baked at 220 ℃ for 25min.

Comparative example 1

The presently disclosed disk drag patent was selected for comparison in this comparative example, its application publication number is CN 106521102A, the mass percentages of its components are shown in the following table,

C	Si	Mn	P	S	Alt	Cr	Ti	B	N
										0.3	0.25	1.28	0.012	0.002	0.045	0.3	0.044	0.0008	0.0037

the balance being iron and unavoidable impurities.

The production process comprises quenching treatment and tempering treatment, the heating temperature is 890-930 ℃, the heat preservation time is 13-25min, and the quenching medium is cooling water. The tempering temperature is 190-210 ℃ and the tempering time is 4-10h.

Experimental example

The disk blades prepared in examples 1-3 and comparative example 1 were subjected to performance testing, and the test results are shown in the following table.

	Hardness of core	Hardness of edge (Induction heating zone)
			Example 1	20-22	53-55
Example 2	19-21	51-53
			Example 3	19-21	49-51
Comparative example 1	48-53	48-53

From the table, hardness core and edge hardness of the disc harrow plate prepared by the method provided by the embodiment of the application are different, high toughness is ensured by low hardness of the core, and wear resistance is ensured by high hardness of the edge. The whole harrow piece of the disc harrow piece of the comparative example is high in hardness, and the risk of crushing in the service process is higher.

Meanwhile, the method provided by the embodiment of the application has no tempering link, and the comparative example needs to be tempered for a long time, so that the production efficiency is affected. Because the invention only has local area induction hardening, the toughness of the whole disc harrow plate can be ensured under the condition of no tempering.

One or more technical solutions in the embodiments of the present invention at least have the following technical effects or advantages:

(1) The structure (hardness is 47-57 HRC) with martensite as a matrix at the edge of the disk harrow plate, and the ferrite and pearlite structure (hardness is 18-23 HRC) is reserved at the center, so that the structure distribution ensures the high wear resistance of the edge of the disk harrow plate during working, and ensures the high toughness of the center of the disk harrow plate, thereby avoiding brittle failure or cracking during service;

(2) The method provided by the embodiment of the invention adopts a cold forming and hot forming combined process means, the blanked part is cut into an accurate shape by laser, the cold stamping is adopted in the first step to obtain the shape of the disc harrow plate, the edge of the disc harrow plate is heated in an induction way in the second step, the edge is rapidly austenitized, the edge is immediately Ma Cuihuo (boron steel is quenched by water), the structure (the hardness is 47-57 HRC) with martensite as a matrix is obtained, and the ferrite and pearlite structure (the hardness is 18-23 HRC) is reserved in the center.

Finally, it is also noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.

While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. It is therefore intended that the following claims be interpreted as including the preferred embodiments and all such alterations and modifications as fall within the scope of the invention.

It will be apparent to those skilled in the art that various modifications and variations can be made to the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention also include such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.

Claims (10)

1. The disc harrow piece is characterized in that the microstructure of the edge part of the disc harrow piece takes martensite as a matrix, and the microstructure of the center part of the disc harrow piece takes ferrite and pearlite as matrixes.

2. The disk blade of claim 1, wherein the disk blade has a side hardness of 47-57HRC and a core hardness of 18-23HRC.

3. A method of manufacturing a disk drag blade according to claim 1 or 2, said method comprising:

opening the steel coil, and blanking to obtain a material to be cut;

cutting the material to be cut, and then stamping to obtain a disc blank;

heating the edge of the disc blank, and performing hot stamping quenching to obtain a disc quenching blank;

and (3) shot blasting is carried out on the disc quenching blank, and then paint baking is carried out, so that the disc harrow plate is obtained.

4. A method of manufacturing a disk drag blade according to claim 3, wherein the edge heating is by induction heating.

5. A method of producing disk blades according to claim 3, wherein the edge heating width is 30-150mm, based on zero coordinates of the outer peripheral edge of the disk blank.

6. A method of producing disk rakes according to claim 3, wherein the temperature of the edge heating is 860-940 ℃ and the holding time of the edge heating is 1-10min.

7. The method for producing disk drag blades according to claim 3, wherein a time interval from the hot press quenching to the heating of the edge is 15s or less, and a dwell time of the hot press quenching is 30s or more.

8. A method of manufacturing a disk drag blade according to claim 3, wherein the coil of steel is medium and high carbon steel.

9. The method of claim 8, wherein the medium and high carbon steel is one of 27MnB, 30MnB, 34MnB and 40 MnB.

10. A method of manufacturing a disk drag blade according to claim 3, wherein the temperature of the baking varnish is 150-240 ℃, and the time of the baking varnish is 15-30min.

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