Method for producing green compact and method for producing sintered body
A method for producing a metallic green compact 61 relates to a method for producing the green compact 61 having at least one recess 62, including a step of subjecting a raw material powder filled in a resin mold 1 to cold isostatic pressing while placing a resin core material 11 having a shape corresponding to the recess 62 at a position corresponding to the recess 62 in the resin mold 1.
1. A method for producing a metallic green compact having at least one recess, wherein the method comprises a step of subjecting a raw material powder filled in a resin mold to cold isostatic pressing while placing a resin core material having a shape corresponding to the recess at a position corresponding to the recess in the resin mold, wherein the method uses a core material made of a resin material having a stress of 0.3 MPa to 3.5 MPa at a 20% strain in a uniaxial compression test, as the core material,
wherein the method uses a mold made of a thermoplastic resin having a Shore D hardness in a range of from 30 to 120 as the mold, and
wherein after unloading of a pressure in the cold isostatic pressing, the core material is restored by protruding from the recess while the core material is placed in the position corresponding to the recess in the resin mold, and
wherein the cold isostatic pressing is carried out while the core material, as a separate member from the mold, is placed at a position corresponding to the recess of the mold, with a wall of the mold sandwiched between the core material and the raw material powder.
2. The method according to claim 1 , wherein the core material comprises at least one selected from the group consisting of silicone resins and fluoro resins.
3. The method according to claim 1 , wherein the recess is in a form of a through-hole or a non-through depression.
4. The method according to claim 1 , wherein a titanium-based green compact made of titanium or a titanium alloy is produced as the green compact.
5. The method according to claim 1 , wherein an iron-based compact made of iron or an iron alloy is produced as the green compact.
6. The method according to claim 1 , wherein an applied pressure to the raw material powder in the cold isostatic pressing is 200 MPa or more.
7. The method according to claim 1 , wherein the mold has a thickness of from 0.5 mm to 2.0 mm.
8. The method according to claim 1 , wherein the mold is produced using a 3D printer.
9. The method according to claim 1 , wherein the raw material powder has an average particle size of from 10 μm to 150 μm.
10. The method according to claim 1 , wherein the core material is formed by a silicone sealant.
11. A method for producing a sintered body, wherein the method comprises a step of subjecting the green compact produced by the method for producing the green compact according to claim 1 to sintering and/or hot isostatic pressing.