JPS635464B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a method for producing a Co-based alloy plate material that has excellent wear resistance and heat resistance. [Prior Art] In general, excellent wear resistance and heat resistance are required for manufacturing chain saw guides, saw teeth for woodworking, light metal and alloy cutting, and steam turbine blades. Various Co
Base alloy plate material is used. In addition, as one of these various Co-based alloy sheet materials, in weight% (hereinafter % indicates weight%), C: 0.05 to 2%, one or two of W and Mo: 2 to 20
%, Cr: 15 to 35%, and, if necessary, one or two of Ni and Fe: 1 to 25
%, with the remainder consisting of Co and unavoidable impurities. Co-based alloy sheet materials are widely known. This Co-based alloy sheet material is usually made into a sheet material having a thickness of approximately 1 to 4 mm by subjecting the ingot after casting to blooming forging, blooming rolling, hot rolling, and cold rolling. It is manufactured by solution treatment at a temperature of ~1250°C, and is put into practical use in this state. [Problems to be solved by the invention] However, in recent years, there has been a demand for higher speeds and higher performance even in the above-mentioned fields of application, and with this, the above-mentioned conventional Co-based alloy sheet materials have Further improvement in wear resistance is desired. [Means for solving the problem] Therefore, from the above-mentioned viewpoint, the present inventors focused on the above-mentioned conventional Co-based alloy sheet material and conducted research to further improve its wear resistance. As a result, after solution treatment, the conventional Co-based alloy sheet material described above has a structure in which primary carbides are dispersed in the matrix and secondary carbides are precipitated only at grain boundaries. When forming by hot working, processing end temperature: 700 to 1000℃, processing rate from 1000℃ to processing end temperature: 5 to 30
%, under final hot pressure conditions that satisfy
When aging treatment is performed at a temperature of It has a structure that precipitates within the grains, and since these secondary carbides are fine with a diameter of 1 μm or less, the hardness within the grains is about 250 in terms of Bitkers hardness in conventional Co-based alloy sheet materials. They obtained the knowledge that the wear resistance was improved from 300 to 300 or more, and that the wear resistance was significantly improved. Therefore, this invention was made based on the above findings, and includes: C: 0.05 to 2%, one or two of W and Mo: 2 to 20%.
%, Cr: 15 to 35%, and, if necessary, one or two of Ni and Fe: 1 to 25
%, with the remainder consisting of Co and unavoidable impurities, and processing finish temperature: 700 to 1000℃, processing rate from 1000℃ to processing finish temperature: 5 to 30
%, hot worked under final hot rolling conditions that satisfy
By aging Co-based alloy plate material at a temperature of 700 to 1000℃, primary carbides are dispersed in the matrix, secondary carbides are dispersed in the grain boundaries, and the grains have a diameter of 1 μm. The present invention is characterized by a method for producing a Co-based alloy sheet material having extremely excellent wear resistance and having a structure in which secondary carbides are dispersed as described below. Next, in the method of the present invention, the reason why the composition of the Co-based alloy sheet material, final hot working conditions, and aging treatment temperature are limited as described above will be explained. A Component composition (a) C The C component has the effect of forming carbides and improving wear resistance, but if its content is less than 0.05%, the precipitation of secondary carbides will be insufficient, and the desired result will not be achieved. Wear resistance cannot be ensured, and if the content exceeds 2%, plastic working becomes difficult, so the content was set at 0.05 to 2%. (b) W and Mo These components partially form a solid solution in the base material and have the effect of strengthening it and forming carbides to improve wear resistance, but the content is 2%. If the content is less than 20%, the desired effect cannot be obtained; on the other hand, if the content exceeds 20%, the plastic workability will decrease and the plate material will tend to become brittle. The amount was set at 2-20%. (c) Cr The Cr component has the effect of improving heat resistance by forming a solid solution in the base material, as well as improving wear resistance by forming carbides, but if its content is less than 15%, the desired effect may not be achieved. However, the content of
If it exceeds 35%, brittle phases such as σ phase will appear and plastic workability and ductility will decrease, so the content was set at 15 to 35%. (d) Ni and Fe These components dissolve in solid solution in the base material and have the effect of improving ductility and plastic workability, so they may be included as necessary when these properties are particularly required. , if its content is less than 1%, the desired effect of improving the above action cannot be obtained;
If it exceeds 25%, the wear resistance deteriorates significantly, so the content is set at 1 to 25%. B Final hot processing conditions If the processing end temperature exceeds 1000℃ or 1000℃
- When the working rate between the working end temperature is less than 5%, work hardening is insufficient and sufficient secondary carbides cannot be precipitated within the crystal grains after aging treatment, resulting in the desired It is no longer possible to ensure excellent wear resistance of the
If the temperature is less than 700℃ or the processing rate exceeds 30%, cracks will easily occur in the plate, so the temperature should be set at 700 to 1000℃ and the processing rate should be set at 5 to 30%. Ta. C Aging treatment temperature If the temperature is less than 700℃, fine secondary carbides cannot be sufficiently precipitated within the crystal grains, while if the temperature exceeds 1000℃, the secondary carbides will become coarse. Since it is not possible to ensure the desired wear resistance over
It was set as ℃. [Example] Next, the method of the present invention will be specifically explained with reference to Examples. Using a normal melting method, molten Co-based alloys having the respective compositions shown in Table 1 are prepared and cast into ingots with dimensions of diameter: 90mmφ x length: 350mm. to, 1200
Plate thickness: 10 by hot forging at a temperature of ~1000℃
mm plate material, hot rolled to a predetermined thickness at a temperature within the range of 1200 to 1000°C, and then final hot rolled under the conditions shown in Table 1 (in both cases, the starting temperature (1100℃) to make a hot-rolled sheet with a thickness of 2 mm, and then this hot-rolled sheet was subjected to aging treatment (in the air,
After holding for 1 hour, methods 1 to 21 of the present invention were carried out, respectively. In addition, for the purpose of comparison, final hot rolling was performed under the conditions shown in Table 1 (same conditions as the method of the present invention),
And, instead of aging treatment, conventional methods 1 to 18 were carried out by solution treatment under conditions of air cooling after holding in the air at a temperature of 1200℃ for 30 minutes.
were carried out respectively. Next, the plate materials obtained by the above-mentioned methods 1 to 21 of the present invention (hereinafter referred to as the present invention plate materials) and the plate materials obtained by the above-mentioned conventional methods 1 to 18 (hereinafter referred to as the conventional plate materials) were subjected to Okoshi method abrasion. Using a testing machine, the mating material: JIS/SUJ-2 (hardness: H _R C60),

【table】

【table】

[Table] A wear test was conducted under the following conditions: load: 18.2Kg, friction speed: 0.119m/sec, friction distance: 100m, lubricant: not used, and the specific wear amount was measured. These results are shown in Table 1. In addition, when the structure of these plates was observed using a metallurgical microscope, it was found that the plates of the present invention had primary carbides dispersed in the matrix, secondary carbides dispersed in the grain boundaries, and grains with a diameter of 1 μm or less. In contrast, conventional sheet materials have a structure in which fine secondary carbides are precipitated within the grain boundaries, whereas conventional sheets have a structure in which primary carbides are dispersed throughout the matrix, but secondary carbides are precipitated only at grain boundaries. It was full of giblets. [Effects of the Invention] From the results shown in Table 1, the plates of the present invention manufactured by the method of the present invention all have a structure in which fine secondary carbides are precipitated within the crystal grains. It is clear that this plate exhibits superior wear resistance compared to conventional plate materials, which have a structure in which carbides are precipitated only at grain boundaries. As described above, according to the method of the present invention, it is possible to produce a Co-based alloy sheet material having a structure in which fine secondary carbides with a diameter of 1 μm or less are precipitated within the crystal grains, and the precipitation of the secondary carbides is As a result, the hardness of the crystal grains themselves is significantly improved, resulting in industrially useful effects such as the Co-based alloy plate exhibiting extremely excellent wear resistance.

Claims (1)

[Claims] 1 C: 0.05 to 2%, one or two of W and Mo: 2 to 20
%, Cr: 15 to 35%, with the remainder being Co and unavoidable impurities (weight %), and processing finish temperature: 700 to 1000℃, from 1000℃ to processing finish temperature. Processing rate: 5-30
%, hot worked under final hot rolling conditions that satisfy
By subjecting Co-based alloy plate material to aging treatment at a temperature of 700 to 1000°C, its structure is changed so that primary carbides are dispersed in the matrix and secondary carbides are dispersed at grain boundaries.
A method for producing a Co-based alloy sheet material with excellent wear resistance, characterized in that it has a structure in which secondary carbides with a diameter of 1 μm or less are dispersed within the crystal grains. 2 C: 0.05-2%, one or two of W and Mo: 2-20
%, Cr: 15-35%, and further contains one or two of Ni and Fe: 1-25
%, with the remainder being Co and unavoidable impurities (wt%), Processing end temperature: 700 to 1000℃, Processing rate from 1000℃ to processing end temperature: 5 to 30
%, hot worked under final hot rolling conditions that satisfy
By subjecting Co-based alloy plate material to aging treatment at a temperature of 700 to 1000°C, its structure is changed so that primary carbides are dispersed in the matrix and secondary carbides are dispersed at grain boundaries.
A method for producing a Co-based alloy sheet material with excellent wear resistance, characterized in that it has a structure in which secondary carbides with a diameter of 1 μm or less are dispersed within the crystal grains.