Blanking die steel for manufacturing knife and shear products and design and preparation method of blanking die steel

Abstract

The invention provides blanking die steel for manufacturing knife and shear products and a design and preparation method of the blanking die steel. The design and preparation method comprises the steps that S1, the performance requirement of the blanking die steel for manufacturing the knife and shear products to be prepared is obtained; s2, acquiring a first component system; s3, performing phase diagram and performance calculation on the first component system to obtain a phase diagram calculation result and a performance calculation result; s4, screening out a second component system from the first component system; s5, determining a rolling process of the blanking die steel for manufacturing the to-be-prepared knife and shear product; s6, screening out a third component system through cost control calculation; and S7, preparing the blanking die steel for manufacturing the knife and shear products to be prepared. According to the cold work die steel, a control technical route capable of obtaining fine, dispersed and uniformly distributed carbides is accurately determined, and the cold work die steel for knife and shear blanking with high hardness and high toughness is achieved.

Description

[Technical field]

[0001] The invention relates to the technical field of iron and steel metallurgy, and in particular to a punching die steel for manufacturing knife and scissors products and a design and preparation method thereof. [Background technology]

[0002] At present, there are many kinds of knife and scissors products and they are developing vigorously. The blanking dies required for the corresponding preparation process of knife and scissors products are even more huge. The annual demand for cold-working die steel is tens of thousands of tons, and the value is measured in hundreds of millions of yuan. At present, in order to improve quality and reduce costs, high-quality and long-life cold-working die steel for knife and scissors preparation is widely demanded, and the quality and service life determine the production efficiency, profit margin, and product quality of the knife and scissors industry. Low-life molds not only seriously affect normal production efficiency and reduce corporate profit margins, but are also one of the important reasons that hinder the upgrading and development of enterprises and industries. Similar situations also exist in other industries outside the knife and scissors industry, such as automobiles, white appliances, consumer electronics, etc.

[0003] At present, the knife and scissors industry mainly uses two types of die steel, Cr12MoV and DC53. The main problems in the use of these two types of die steel are short blanking life, frequent cracking and passivation curling. Preliminary studies have also found that such materials are prone to mixed austenite, coarse carbides (above 10μm) and irregular shapes, resulting in low comprehensive performance. Developing cold-working die steel with high toughness and high wear resistance, Cr8 steel came into being, such as the domestic grade Cr8Mo2SiV cold-working die steel, which is used to improve toughness. However, actual production shows that this type of steel still has problems such as uneven carbides and unqualified flaw detection. Therefore, based on the existing die steel composition, organization and performance basis, it is of great significance to develop cold-working die steel with high wear resistance, high hardness and high toughness required for stamping in the knife and scissors industry.

[0004] Therefore, it is necessary to study a punching die steel for manufacturing knife and scissors products and a design and preparation method thereof to cope with the shortcomings of the prior art, so as to solve or alleviate one or more of the above problems. [Summary of the invention]

[0005] In view of this, the present invention provides a punching die steel for manufacturing knife and scissors products and a design and preparation method thereof. On the basis of not changing the composition system of traditional cold working die steel, a preferred alloy composition system that meets the performance requirements of knife and scissors punching die steel is efficiently and accurately screened out through a material integration calculation method, and a method combining the calculation of the thermal processing diagram of the rolling process and the calculation of the typical carbide precipitation equilibrium phase diagram of the heat treatment process with experiments is used to accurately determine the technical route for obtaining fine, dispersed and uniformly distributed carbides, thereby realizing cold working die steel for knife and scissors punching with both high hardness and high toughness.

[0006] In one aspect, the present invention provides a method for designing and preparing a punching die steel for manufacturing knife and scissors products, the method comprising the following steps:

[0007] S1: Obtain the performance requirements of the punching die steel used in manufacturing the knife and scissors products to be prepared;

[0008] S2: Obtaining the first component system of the punching die steel for manufacturing the knife and scissors products to be prepared through performance requirements;

[0009] S3: performing phase diagram and performance calculation on the first component system to obtain phase diagram calculation results and performance calculation results;

[0010] S4: Preset a phase diagram calculation threshold and a performance calculation threshold of the punching die steel for manufacturing the knife and scissors product to be prepared, and select the second component system from the first component system through the phase diagram calculation results and the performance calculation results;

[0011] S5: Determine the rolling process of the punching die steel for manufacturing the knife and scissors product to be prepared through the second component system;

[0012] S6: Through cost control calculation, the third component system is screened out based on the second component system;

[0013] S7: Prepare the punching die steel for manufacturing the knife and scissors product to be prepared by using the third component system and the rolling process determined in S5.

[0014] As described above, in any possible implementation, there is further provided an implementation, wherein the process of obtaining the first component system in S2 is performed by summarizing the components of conventional mold steels.

[0015] According to the aspects and any possible implementations described above, an implementation is further provided, wherein the phase diagram and performance calculations in S3 are performed in a wide range of component systems using JMatPro.

[0016] According to the above aspects and any possible implementation, an implementation is further provided, wherein the phase diagram calculation threshold in S4 is determined by the high temperature ferrite phase and carbide phase region.

[0017] According to the aspects and any possible implementations described above, an implementation is further provided, wherein the threshold is determined by calculating the CCT curve and the hardenability, and obtaining the minimum cooling rate and hardened layer thickness required for the material to obtain the highest hardness during quenching.

[0018] According to the above aspects and any possible implementation, an implementation is further provided, wherein the second component system is screened out from the first component system in S4 by satisfying a threshold and obtaining a martensitic structure.

[0019] According to the above aspects and any possible implementation, an implementation is further provided, wherein the rolling process is determined in S5 specifically by calculating the rolling process through a thermal processing diagram of the second component system.

[0020] According to the above aspects and any possible implementation manner, there is further provided an implementation manner, wherein the cost control calculation in S6 includes material cost and rolling mill selection.

[0021] According to the aspects described above and any possible implementation method, a punching die steel for manufacturing knife and scissors products is further provided, which is prepared by the design equipment method described above, and the mass percentage of the punching die steel for manufacturing knife and scissors products is: C: 0.70-0.75, Si: <0.2, Mn: <0.5, Cr: 5.10-5.20, Mo: 1.9-2.1, V: 0.25-0.6, P: <0.02, S: <0.01, and the remainder is Fe and unavoidable impurities.

[0022] According to the aspects and any possible implementations described above, an implementation is further provided, wherein the punching die steel for manufacturing the shear product has a uniform structure, finely dispersed carbides, and a hardness of more than 60HRC after heat treatment.

[0023] Compared with the prior art, the present invention can achieve the following technical effects:

[0024] 1): The present invention, without changing the composition system of traditional cold-working die steel, efficiently and accurately screens out the preferred alloy composition system that meets the performance requirements of knife, shear and blanking die steel through a material integration calculation method, and accurately determines the technical route for obtaining fine, dispersed and uniformly distributed carbides through a method combining calculation of the thermal processing diagram of the rolling process and calculation of the typical carbide precipitation equilibrium phase diagram of the heat treatment process with experiments, so as to realize cold-working die steel for knife, shear and blanking with both high hardness and high toughness;

[0025] 2): According to the performance requirements, production process and cost control of punching die steel for manufacturing knife and scissors products, the present invention uses the thermodynamic calculation software JMatPro to calculate a series of components, and screens out a component system that meets these three aspects, and then carries out production and manufacturing. Compared with the traditional method, it has more comprehensive results, optimal composition, lowest cost, fast time and good effect.

[0026] Of course, any product implementing the present invention does not necessarily need to achieve all of the above-mentioned technical effects at the same time.

Brief Description of the Drawings

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0028] Figure 1 is a phase volume fraction diagram of the components in Table 1 provided by one embodiment of the present invention;

[0029] Figure 2 1 is a CCT curve and hardenability curve diagram of components 1, 7, and 9 calculated according to an embodiment of the present invention;

[0030] Figure 3 is a graph of tempered hardness of components 1, 7, and 9 calculated according to one embodiment of the present invention;

[0031] Figure 4 is a thermal processing diagram of components 1, 7, and 9 calculated according to one embodiment of the present invention;

[0032] Figure 5 is a microstructure diagram of components 7 and 9 after annealing provided by one embodiment of the present invention;

[0033] Figure 6 This is a microstructure diagram of components 7 and 9 after quenching and tempering provided by an embodiment of the present invention. [Specific implementation method]

[0034] In order to better understand the technical solution of the present invention, the embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0035] It should be clear that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. The singular forms "a", "said" and "the" used in the embodiments of the present invention and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0037] The present invention provides a design and preparation method for punching die steel for manufacturing knife and scissors products, the design and preparation method comprising the following steps:

[0038] S1: Obtain the performance requirements of the punching die steel used in manufacturing the knife and scissors products to be prepared;

[0039] S2: Obtaining the first component system of the punching die steel for manufacturing the knife and scissors products to be prepared through performance requirements;

[0040] S3: performing phase diagram and performance calculation on the first component system to obtain phase diagram calculation results and performance calculation results;

[0041] S4: Preset a phase diagram calculation threshold and a performance calculation threshold of the punching die steel for manufacturing the knife and scissors product to be prepared, and select the second component system from the first component system through the phase diagram calculation results and the performance calculation results;

[0042] S5: Determine the rolling process of the punching die steel for manufacturing the knife and scissors product to be prepared through the second component system;

[0043] S6: Through cost control calculation, the third component system is screened out based on the second component system;

[0044] S7: Prepare the punching die steel for manufacturing the knife and scissors product to be prepared by using the third component system and the rolling process determined in S5.

[0045] The process of obtaining the first component system in S2 is carried out by summarizing the components of traditional mold steels.

[0046] The phase diagram and property calculations in S3 were performed by JMatPro in a wide range of composition systems.

[0047] The phase diagram calculation threshold in S4 is determined by the high temperature ferrite phase and carbide phase region.

[0048] The threshold is determined by calculating the CCT curve and the hardenability, and obtaining the minimum cooling rate and hardened layer thickness required for the material to obtain the highest hardness during quenching.

[0049] In S4, the second component system is selected from the first component system by satisfying the threshold and obtaining the martensitic structure. In the present invention, the first component system is set in a relatively broad component system by using JMatPro through summarizing the components of traditional die steels and the performance requirements of the punching die steel for manufacturing the knife and scissors products to be prepared.

[0050] The rolling process determination in S5 specifically includes: determining the rolling process by calculating the thermal processing diagram of the second component system.

[0051] The cost control calculation in S6 includes material cost and rolling mill selection.

[0052] The present invention also provides a punching die steel for manufacturing knife and scissors products, which is prepared by the design equipment method. The mass percentage of the punching die steel for manufacturing knife and scissors products is: C: 0.70-0.75, Si: <0.2, Mn: <0.5, Cr: 5.10-5.20, Mo: 1.9-2.1, V: 0.25-0.6, P: <0.02, S: <0.01, and the remainder is Fe and unavoidable impurities.

[0053] After heat treatment, the punching die steel for manufacturing the shear products has a uniform structure, fine and dispersed carbides, and a hardness of more than 60HRC.

[0054] Example 1

[0055] The present invention uses the thermodynamic calculation software JMatPro to calculate the series of components according to the performance requirements, production process and cost control of the punching die steel for the manufacture of knife and scissors products, and screens out the component system that meets these three aspects, and then produces and manufactures. After calculation and actual production inspection, the final composition is (by weight percentage): C0.70-0.75, Si<0.2, Mn<0.5, Cr5.10-5.20, Mo 1.9-2.1, V 0.25-0.6, P<0.02, S<0.01, and the balance is Fe and inevitable impurities. After heat treatment, the structure is uniform, the carbide is fine and dispersed, and the hardness reaches more than 60HRC. Different from the design method of traditional steel materials, the present invention uses the material calculation method to calculate from the thermodynamic phase diagram, rolling process, and the performance after heat treatment, and combines the material cost and the difficulty of process implementation to determine the optimal composition and the lowest cost, and produce the die steel suitable for punching in the manufacture of knife and scissors products in a targeted manner. The composition design process of the present invention utilizes the material calculation method, comprehensively considers the phase diagram, rolling process, performance after heat treatment, and material composition cost, and finally obtains several compositions that meet the requirements. According to the present invention, the composition and process are determined to produce the material, and the performance is tested to finally determine the most suitable composition to meet the requirements of highly customized materials.

[0056] By summarizing the composition of traditional mold steel, JMatPro is used to calculate the phase diagram and performance in a relatively broad composition system. Table 1 shows some of the calculated compositions (i.e., the first composition system). Figure 1It is the phase ratio fraction diagram of the components in Table 1. Through the analysis of the phase diagram, components No. 2, 3, 4, and 5 have high-temperature ferrite phase in the solidification stage, which is very likely to increase the difficulty of subsequent processes. The M7C3 carbide phase area in components No. 6 and 8 is relatively large, and the tendency of M23C6 carbide to transform into M7C3 carbide in the low temperature section is relatively strong. When the blanking die works for a long time, it is easy to cause slight changes in the mold size. Therefore, it is more appropriate to screen out components No. 1, 7, and 9. Then the performance is calculated. Through the CCT curve calculation and hardenability calculation, the minimum cooling rate and hardened layer thickness required for the material to obtain the highest hardness during quenching can be obtained. Figure 2 is the calculation result. Figure 2 It can be found that the three components can still obtain martensitic structure even at a cooling rate of 1℃ / s, and the hardened layer can reach more than 10mm, which is fully able to obtain the ideal hardness and hardened layer under simple heat treatment conditions. Secondly, the hardness after tempering was calculated. After quenching at 900℃, the hardness of the three components can reach 60HRC. After low-temperature tempering, the hardness remains basically stable, but after tempering at more than 300℃, the hardness drops significantly. At this time, it is the second component system. Finally, the thermal processing diagram is calculated to determine the rolling process, such as Figure 4 As shown. Component 1 has a stable thermal deformation range of 1000℃-1100℃, and the required strain rate is relatively large, which has higher requirements for rolling mills. Components 7 and 9 have a wider range of processing options, lower requirements for rolling mills, and are easier to produce. Therefore, components 7 and 9 are finally selected for experimental production, which is the third component system.

[0057] Table 1 Partially calculated component system

[0058] No. C Si Mn Cr Mo V 1 0.8 0.2 0.5 5.2 2.2 0.3 2 0.8 0.2 0.5 10 2.2 0.3 3 0.8 0.2 0.5 10 2.2 0.5 4 0.8 0.9 0.5 10 2.2 0.5 5 0.8 0.9 0.5 10 1.0 0.5 6 0.8 0.2 0.5 5.2 1.0 0.3 7 0.75 0.2 0.5 5.2 2.0 0.5 8 0.75 0.2 0.5 5.2 1.5 0.5 9 0.70 0.2 0.5 5.2 2.0 0.3

[0059] Conventional smelting and die casting were carried out according to components 7 and 9. The actual composition of the ingot is shown in Table 2. After the ingot was solution treated at 1200℃ for 4 hours, there was no eutectic carbide at all, which was consistent with the calculation results. After rolling, the rolled plate was annealed. The annealing process was to keep the temperature at 840℃ for 2 hours, then cool at a rate of 15℃ per hour to 650℃, and then take it out of the furnace and air cool it. After annealing, the carbide particles are fine and dispersed, such as Figure 5 As shown in the figure, the hardness of the rolled plates of the actual ingot No. 7 and 9 was 58.8HRC and 60.2HRC respectively after quenching at 900℃ for 20min and tempering at 180℃ for 2h, and the carbides were finely dispersed in the martensite matrix. Figure 6 The carbides of component 7 are more dispersed than those of component 9. When selecting mold steel, those with high toughness requirements can choose materials with component 7, and those who pursue cost-effectiveness can choose materials with component 9.

[0060] Table 2 Actual smelting composition

[0061] No. C Si Mn Cr Mo V P S 7 0.725 0.122 0.432 5.14 1.998 0.594 0.01 0.008 9 0.704 0.092 0.394 5.15 2.04 0.26 0.01 0.008

[0062] The above is a detailed introduction to a punching die steel for manufacturing knife and scissors products and its design and preparation method provided in the embodiment of the present application. The description of the above embodiment is only used to help understand the method and its core idea of ​​the present application; at the same time, for ordinary technicians in this field, according to the idea of ​​the present application, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

[0063] For example, certain words are used in the specification and claims to refer to specific components. Those skilled in the art should understand that hardware manufacturers may use different nouns to refer to the same component. This specification and claims do not use differences in names as a way to distinguish components, but use differences in the functions of components as the criteria for distinction. As mentioned throughout the specification and claims, "including" and "comprising" are open-ended terms, so they should be interpreted as "including / including but not limited to". "Approximately" means that within an acceptable error range, those skilled in the art can solve the technical problem within a certain error range and basically achieve the technical effect. The subsequent description of the specification is a preferred embodiment of the present application, but the description is for the purpose of illustrating the general principles of the present application, and is not used to limit the scope of the present application. The scope of protection of the present application shall be determined by the definition of the attached claims.

[0064] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a product or system including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such a product or system. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the product or system including the elements.

[0065] It should be understood that the term "and / or" used in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0066] The above description shows and describes several preferred embodiments of the present application, but as mentioned above, it should be understood that the present application is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the application concept described herein through the above teachings or the technology or knowledge of the relevant field. The changes and modifications made by those skilled in the art do not deviate from the spirit and scope of the present application, and should be within the scope of protection of the claims attached to the present application.

Claims

1. A method for designing and preparing a punching die steel for manufacturing knife and scissors products, characterized in that: The design and preparation method comprises the following steps: S1: Obtain the performance requirements of the punching die steel used in manufacturing the knife and scissors products to be prepared; S2: Obtaining the first component system of the punching die steel for manufacturing the knife and scissors products to be prepared through performance requirements; S3: performing phase diagram and performance calculation on the first component system to obtain phase diagram calculation results and performance calculation results; S4: Preset a phase diagram calculation threshold and a performance calculation threshold of the punching die steel for manufacturing the knife and scissors product to be prepared, and select the second component system from the first component system through the phase diagram calculation results and the performance calculation results; S5: Determine the rolling process of the punching die steel for manufacturing the knife and scissors product to be prepared through the second component system; S6: Through cost control calculation, the third component system is screened out based on the second component system; S7: Prepare the punching die steel for manufacturing the knife and scissors product to be prepared by using the third component system and the rolling process determined in S5.

2. The design and preparation method according to claim 1, characterized in that: The process of obtaining the first component system in S2 is carried out by summarizing the components of traditional mold steels.

3. The design and preparation method according to claim 1, characterized in that: The phase diagram and property calculations in S3 were performed by JMatPro in a wide range of composition systems.

4. The design and preparation method according to claim 1, characterized in that: The phase diagram calculation threshold in S4 is determined by the high temperature ferrite phase and carbide phase region.

5. The design and preparation method according to claim 1, characterized in that: The performance calculation threshold in S4 is determined by calculating the CCT curve and the hardenability, and obtaining the minimum cooling rate and hardened layer thickness required for the material to obtain the highest hardness during quenching.

6. The design and preparation method according to claim 1, characterized in that: In the S4, the second component system is selected from the first component system by satisfying a threshold and obtaining a martensitic structure.

7. The design and preparation method according to claim 1, characterized in that: The rolling process determination in S5 specifically includes: determining the rolling process by calculating the thermal processing diagram of the second component system.

8. The design and preparation method according to claim 1, characterized in that: The cost control calculation in S6 includes material cost and rolling mill selection.

9. A punching die steel for manufacturing knife and scissors products, prepared by the design equipment method according to any one of claims 1 to 8, characterized in that: The mass percentage of the punching die steel used for manufacturing the knife and scissors products is: C: 0.70-0.75, Si: <0.2, Mn: <0.5, Cr: 5.10-5.20, Mo: 1.9-2.1, V: 0.25-0.6, P: <0.02, S: <0.01, and the balance is Fe and inevitable impurities.

10. The punching die steel for manufacturing knife and scissors products according to claim 9, characterized in that: After heat treatment, the punching die steel for manufacturing the shear products has a uniform structure, fine and dispersed carbides, and a hardness of more than 60HRC.

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