| abstract |
The first of the free-running consecutive oral cavity contains Ti and / or Zr so that the content of Ti is WTi (mass%), the content of Zr is WZr (mass%) and the content of WTi + 0.52WZr is 0.03 to 3.5 mass% do. Further, the content of S is WS (mass%), the content of Se is WSe (mass%), the content of Te is WTe (mass%), WS + 0.4 WSe + 0.25 WTe is 0.01 to 1.0 mass% Also, at least one of S, Se and Te is included so that (WTi + 0.52 WZr) / (WS + 0.4 WSe + 0.25 WTe) becomes 1 to 4. It is also preferable that the free-cutting-ability imparting compound phase containing at least any one of S, Se and Te is used as a main component of the metal element component of Ti and / or Zr and a binding component with the above-mentioned metal element component , And is dispersed and formed in the tissue in the range of 0.1 to 10% in terms of area ratio in cross section. The second of the free-running successful oral cavity contains Fe as a main component, 0.001 to 0.6 mass% of C, Ni in a range of 6 mass% or less, Cu in a range of 5 mass% And contains Al in a range of 3 mass% or less. (Ti) and Zr (Zr) such that the content of Ti is WTi (mass%), the content of Zr is WZr (mass%) and the content of X (mass%) = WTi + 0.52 WZr is 0.03 to 3.5 mass% WS (mass%) = WS + 0.4 WSe + 0.25 WTe is in the range of 0.01 to 1 mass (mass%), and the content of Se in WSe (mass%) and the content of Te in WTe %, And at least one kind selected from S, Se and Te. In the tool steel structure, it is preferable that Ti and / or Zr be the main component of the metal element component, and C is essential as a binding component to the metal element component, and the free cutting property imparting compound Phase is dispersed and formed in the tissue. In either case, it is difficult to have excellent machinability and to generate mechanical properties, particularly toughness, of the steel material along the short axis direction. |