Method of making a tool comprising carbide and steel by brazing
A tool includes a cemented carbide part and a maraging steel part, wherein the two parts are joined by brazing. The cemented carbide part has a hard phase embedded in a metallic binder phase matrix. The maraging steel part has a hardness of between 350 and 600 HV1 with a standard deviation between 0 and 20 HV1. A method of making such tool is also provided.
1. A tool comprising:
a cemented carbide part, wherein the cemented carbide part has a hard phase embedded in a metallic binder phase matrix, wherein at least 50 wt % of the hard phase is WC;
a maraging steel part with a hardness of between 350 and 600 HV1 with a standard deviation between 0 and 20 HV1, wherein the maraging steel part has a hardness of between 400 and 460 HV1 with a standard deviation of between 0 and 14 HV1; and
a braze joint joining said cemented carbide part and said maraging steel part, wherein said braze joint includes Ti, and wherein said braze joint includes a TiC layer with a thickness of between 0.03 and 5 μm adjoining to the cemented carbide part.
2. The tool according to claim 1 , wherein the braze joint has a thickness of between 20 and 200 μm.
3. The tool according to claim 1 , wherein a shear strength of the braze joint is at least 130 MPa.
4. The tool according to claim 1 , wherein the braze joint includes Cu, Ag and Sn.
5. The tool according to claim 1 , wherein the braze joint includes Ag in an amount of from 30 to 80 wt %, Cu in an amount of 15 to 65 wt %, Ti in an amount of 0.3 to 15 wt % and Sn in an amount of 0 to 10 wt %.
6. Tool according to claim 1 , wherein the maraging steel includes 13 to 25 wt % Ni and one or more alloying elements selected from Co, Mo, Ti, Al and Cr in an amount of 10 to 27 wt %, less than 0.3 wt % C and balance Fe.
7. The tool according to claim 1 , wherein the maraging steel includes 13 to 25 wt % Ni, 7 to 15 wt % Co, 3 to 10 wt % Mo, 0.1 to 1.6 wt % Ti, 0.05 to 0.15 wt % Cr, 0 to 0.2 wt % Al, less than 0.3 wt % C and balance Fe and unavoidable impurities.
8. A method of making a tool according to claim 1 comprising the steps of:
providing a cemented carbide part;
providing a maraging steel part, wherein the maraging steel part has a hardness of between 400 and 460 HV1 with a standard deviation of between 0 and 14 HV1;
placing a braze material having Ti in an amount of 0.3 to 15 wt % of the braze material between and in contact with the cemented carbide part and the maraging steel part;
subjecting the cemented carbide part and the maraging steel part with the braze material in between to a brazing step in a furnace at a temperature between 700 and 1200° C., for a time period of between 5 and 60 minutes, and wherein the brazing takes place in vacuum; and
subjecting at least the maraging steel part to an ageing step at a temperature of between 300 and 700° C. for between 5 minutes and 12 hours.
9. The method of making a tool according to claim 8 , wherein the brazing step is performed at a temperature between 700 and 950° C., for a time period of between 5 and 15 minutes.
10. The method of making a tool according to claim 8 , wherein the ageing step is performed at a temperature of between 55° and 600° C. for between 3 to 6 hours.
11. The method of making a tool according to claim 8 , wherein the braze material has a solidus temperature of between 488 and 1123° C. and a liquidus temperature of between 612 and 1180° C., and wherein the braze material, in addition to Ti, further includes one or more elements selected from Ag, Cu, Sn, In, Zr, Hf and Cr.
12. The method of making a tool according to claim 8 , wherein the thickness of the braze material prior to brazing is between 25 and 200 μm.
13. The method of making a tool according to claim 8 , wherein a clamping force of between 0.5 to 10 MPa is applied during the brazing step.