JP2582326B2 - Press mold manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a press die having an edge portion or a high pressure portion for processing a work.

[0002]

2. Description of the Related Art In a press die, for example, in the case of a trimming die for trimming a plate-like work into a predetermined shape, a trimming blade which is an edge portion for trimming a predetermined position of the trimming die is provided. Is provided.
This trimming blade must be higher in hardness than the other parts of the mold due to demands such as durability. Therefore, after molding a predetermined edge of the mold material into the shape of a trimming blade,
The formed part was quenched by heat treatment such as a frame hard to increase the hardness and used as a trimming blade. However, the material of the mold is not always suitable for such a heat treatment, and even if a heat treatment such as a frame hardening is performed, a desired hardness may not be obtained or a problem such as a crack may occur. Therefore, the trimming blade forming portion of the mold material is deleted, and the hardened welding material shown in JIS Z3251 or the like is welded and welded to the removed portion, and then the hardened portion is machined into a trimming blade shape. A method of forming a trimming blade has been performed.

[0003]

In the above-mentioned method of welding the hardfacing welding material, the composition of the hardfacing welding material is obtained so that a desired hardness can be obtained without performing a heat treatment after the hardfacing. Is adjusted, it is difficult to perform machining after welding overlaying, especially machining involving intermittent cutting such as milling, so that grinding must be performed and the number of machining steps increases. There's a problem. That is, the hardness at which intermittent cutting is possible is up to HRC45, and the hardness after welding of the above-mentioned welding material is HRC50 or more. In addition, it is also possible to restore the hardness to a predetermined hardness after annealing by temporarily annealing the overlaid portion to reduce the hardness after the weld overlay, but not only increases the heat treatment step, but also by heat treatment There is a possibility that the mold material may be distorted, so that a correction process such as grinding must be performed after quenching, and the number of steps cannot be reduced. The above problems are caused by the case where the edge portion of the punch in the bend mold is formed by the above-mentioned build-up welding method, or the case where the high pressure portion which strongly presses the work such as the bead portion of the die face and the shoulder portion of the punch in the draw mold is formed. It also occurs when forming by a fill welding method. Therefore, the present invention provides an easy-to-work edge after a build-up welding when forming an edge portion or a high pressure portion for work processing in a press die, and an edge portion or a high pressure portion having a predetermined hardness or more without performing a correction process. It is an object of the present invention to provide a method for manufacturing a press die from which a part can be obtained.

[0004]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention relates to a method of manufacturing a press die having an edge portion or a high pressure portion for processing a work, comprising the steps of: In a part which forms a weld by overlaying a build-up material on a part forming a part, and machining the build-up part into a required shape of an edge part or a high pressure part, as the build-up material,
The hardness of the overlaid portion is increased by performing sub-zero treatment after machining the overlaid portion using a material having a hardness after welding of HRC45 or less.

[0005]

[Function] The hardness of the overlaid portion after the overlay welding becomes less than or equal to the HRC 45 which is the limit value of the cutting process, so that the overlaid portion can be easily machined by the cutting process. Then, the hardness of the build-up portion is increased by the sub-zero processing after the machining, but the sub-zero processing does not generate oxidation or distortion, and the correction processing becomes unnecessary. In addition, if the martensitic transformation start temperature is about 150 ° C. or less, if the overlay material is used,
The hardness after welding can be suppressed to HRC45 or less, and the required hardness exceeding HRC45 can be increased by sub-zero treatment.

[0006]

Referring to the drawings, reference numeral 1 denotes a trimming mold,
The case where the trimming blade 11 is formed at the edge of the trimming mold 1 will be described below. First, a material of the trimming mold 1 is formed by casting, and then a portion of the material on which the trimming blade 11 is provided is deleted to provide a chamfered portion 12. Then, the overlay material is applied to the chamfered portion 12 as shown in FIG.
As shown in FIG. 3B, triple overlay welding is performed. If the martensitic transformation start temperature Ms of the build-up material is approximately 150 ° C. or less, most of the austenite in the structure of the build-up portion 13 after welding remains without being transformed into martensite, and therefore its hardness is HRC45. Lower machining can be performed by cutting. On the other hand, the overlay 13 is shown in FIG.
Since the trimming blade 11 does not have sufficient hardness only by machining into the shape of the trimming blade 11 as shown in FIG. 1, the trimming blade 11 is surrounded by the frame 2 as shown in FIG. Coolant 21 such as liquid nitrogen
And then sufficiently cooled to perform a sub-zero treatment for transforming retained austenite into martensite, so that the hardness of the trimming blade 11 is harder than HRC45.

[0007] The composition of the overlay material is iron (Fe).
To carbon (C) 0.5 to 1.5 and silicon (S
i) 0.2-2.0, manganese (Mn) 0.3-6.0,
Chromium (Cr) 0.3-10.0, cobalt (Co) 0.
It is preferable that the temperature is 3 to 10.0 and the other (molybdenum (Mo) vanadium (V)) is 0.2 or less. In this case, the martensitic transformation start temperature Ms obtained by the following equation 1 is about 150 ° C. or less. The amount of each component is adjusted within the above range.

Ms = 550−350 × C-40 × Mn−35 × V−20 × Cr−10 × Mo + 15 × Co + 0 × Si (Equation 1) The amount of addition to the build-up material is The range was set for the following reason. That is, in the case of carbon, since it is the most effective element for lowering the martensitic transformation start temperature Ms, if it is 0.5% or less, a large amount of other elements for lowering Ms must be added. While economic,
If it exceeds 1.5%, Ms is too low, so that other elements cannot be added, thereby causing a problem that properties such as toughness are lowered. Silicon is an element that improves the deoxidizing effect and the fluidity of the build-up material during welding. However, if the content is less than 0.2%, the effect is not exhibited, and if it exceeds 2.0%, the build-up material during welding is increased. The flow is so good that it is difficult to raise the meat. Also, manganese is an element that is excellent in deoxidizing effect and toughness increasing effect and has a large effect of lowering Ms after carbon. However, if it is 0.3% or less, these effects cannot be exhibited. On the other hand, if it exceeds 6.0%, the amount of scale generated increases, and the workability is impaired. Also,
Cobalt has the effect of delaying the precipitation of carbides and reducing the hardness after welding overlay. However, if it is 0.3% or less, the effect cannot be obtained, and if it exceeds 10.0%, Ms will increase too much and Since cobalt is an expensive element, the cost is high. Chromium is an element which has a high affinity for carbon and is a carbide having a high hardness to improve the wear resistance of the built-up portion. However, if the content is 0.3% or less, the effect cannot be obtained.
If it exceeds 0.0%, the hardness becomes too high, and crack resistance and toughness are impaired.

Various samples having different compositions were prepared as overlay materials and tested. Table 1 below shows the composition of each sample and the Ms of each sample determined by Equation 1 above. The hardness after overlay welding of each of the samples, the hardness after sub-zero treatment with dry ice (temperature -76 ° C), and the hardness after sub-zero treatment with liquid nitrogen (temperature -196 ° C) were measured. Was as shown in FIG.
The hardness after welding is indicated by ●, the hardness after sub-zero treatment with dry ice is indicated by △, and the hardness after sub-zero treatment with liquid nitrogen is indicated by ×. From this test result, Ms should be set to approximately 15 to reduce the hardness after welding to HRC45 or less, at which cutting can be performed.
It is understood that the temperature needs to be lower than 0 ° C. Further, it has been found that Ms needs to be approximately 0 ° C. or higher in order to increase the hardness to HRC 45 or more by sub-zero treatment with dry ice.
It has been found that the hardness can be increased to HRC45 or more even when the temperature falls below ℃. Therefore, in order to facilitate the machining of the build-up portion and obtain the required hardness by the sub-zero treatment, it is sufficient to use a build-up material having Ms of about 150 ° C. or less.

In the above embodiment, the case where the trimming blade is formed in the trimming die has been described. However, the case where the edge of the punch in the bend die is formed, the bead of the die face in the draw die or the shoulder of the punch is formed. The method according to the present invention can also be applied to a case where a high-pressure part for strongly pressing a workpiece such as a part is formed.

[0011]

As is apparent from the above description, according to the present invention, when forming an edge portion or a high-pressure portion for processing a work in a press die, machining after build-up welding is easy and correction processing is performed. Since the edge portion and the high pressure portion having the predetermined hardness or more can be obtained without performing the above, the man-hour required for manufacturing the mold can be reduced.

[Brief description of the drawings]

FIG. 1 shows each step of the method according to the invention.

FIG. 2 is a graph showing the relationship between the hardness of the overlay material and the martensite transformation start temperature.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 trimming mold 2 frame 11 trimming blade 13 overlay

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Keizo Tanaka, Inventor 1-10-1, Shinsayama, Sayama City, Saitama Prefecture Inside Honda Engineering Co., Ltd. (72) Inventor Noboru Nishikawa 1-1-10, Shinsayama, Sayama City, Saitama Prefecture (72) Inventor: Takeki Kawase 1186-16, Higashimatano-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture (72) Inventor: Masami Watanabe 36, Kita-Ohicho, Takatsuki-shi, Osaka (56) References JP-A-63-230236 (JP, A) JP-A-5-320744 (JP, A)

Claims (2)

(57) [Claims] 1. A method of manufacturing a press die having an edge portion or a high-pressure portion for processing a workpiece, wherein a build-up material is weld-welded to a portion of the die material forming the edge portion or the high-pressure portion, In the machining of the overlaid portion into a required shape of the edge portion or the high pressure portion, a material having a hardness after welding of HRC45 or less is used as the overlaid material, and a sub-zero treatment is performed after machining the overlaid portion. A method for manufacturing a press die, comprising: increasing the hardness of a built-up portion by performing the method. 2. The method according to claim 1, wherein said overlay material is a material having a martensitic transformation start temperature of about 150 ° C. or lower.