| 摘要 |
A carbon deposition preventive double-layered tube for handling carbon compounds at not less than 500 DEG C., the double-layered tube comprising: (a) the layer to be exposed to the carbon compounds, constructed from an alloy which is composed of Cr, Ni, and Fe in porportions shown within a triangular region I of an equilibrium diagram (FIG. 1), the region I bounded by a line from a point (A(Cr: 52% by weight, Ni: 48% by weight, Fe: 0% by weight) to a point B(Cr: 28% by weight, Ni: 36% by weight, Fe: 36% by weight), a line from the point B to a point C(Cr: 28% by weight, Ni: 72% by weight, Fe: 0% by weight), and a line from the point C to the point A; and (b) the other layer which is not exposed to the carbon compounds, constructed from an alloy which is composed of Cr, Ni, and Fe in proportions shown within a pentagonal region II of the equilibrium diagram, the region II bounded by a line from the point B to the point C, a line from the point C to a point F(Cr: 0% by weight, Ni: 100% by weight, Fe: 0% by weight), a line from the point F to a point E(Cr: 0% by weight, Ni: 90% by weight, Fe: 10% by weight), a line from the point E to a point D(Cr: 20% by weight, Ni: 30% by weight, Fe: 50% by weight), and a line from the point D to the point B. |
