Blast-furnace tuyere having excellent thermal shock resistance and high durability

Claim 1

A blast-furnace tuyere having excellent thermal shock resistance and high durability which consists essentially of a tuyere substrate composed of a member selected from the group consisting of copper and copper alloy; a self-fluxing alloy metallized layer sprayed on the surface of said substrate, said alloy being selected from the group consisting of nickel-base alloy consisting essentially of 65-90% nickel, 10-35% chromium, 1.5-4.5% silicon and 1.5-4.5% boron, and a cobalt-base alloy consisting essentially of 40-60% cobalt, 19-21% chromium, 1.5-4.5% silicon, 1.5-4.5% boron and a small amount of nickel and tungsten; a cermet layer sprayed on the surface of said alloy metallized layer, said cermet being selected from the group consisting essentially of a mixture of zirconia or alumina, having a purity of more than 90%, with a nickel-chromium alloy consisting essentially of 65-90% nickel and 10-35% chromium, in a mixing ratio of 30:70-70:30, a mixture of zirconia or alumina, having a purity of more than 90%, with a nickel base alloy consisting essentially of 65-90% nickel, 10-35% chromium, 1.5-4.5% silicon and 1.5-4.5% boron, in a mixing ratio of 30:70-70:30, a cobalt-base alloy consisting essentially of 40-60% cobalt, 19-21% chromium, 1.5-4.5% silicon, 1.5-4.5% boron and a small amount of nickel and tungsten, in a mixing ratio of 30:70-70:30, and a mixture of zirconia or alumina, having a purity of more than 90%, with a nickel-aluminum alloy consisting essentially of 80-95% nickel and 20-5% aluminum, in a mixing ratio of 30:70-70:30; and a ceramic coating layer selected from the group consisting of zirconia and alumina sprayed on the surface of said cermet layer; all percentages being by weight.

Claim 11

A method of manufacturing a blast-furnace tuyere having excellent thermal shock resistance and high durability, which comprises roughening a surface of a tuyere substrate composed of a member selected from the group consisting of copper and copper alloy; spraying a self-fluxing alloy on the surface of said substrate by means of a spraying device using plasma jet or oxy-acetylene flame as a heat source to form a self-fluxing alloy metallized layer, said alloy being selected from the group consisting of nickel-base alloy consisting essentially of 65-90% nickel, 10-35% chromium, 1.5-4.5% silicon and 1.5-4.5% boron, and a cobalt-base alloy consisting essentially of 40-60% cobalt, 19-21% chromium, 1.5-4.5% silicon, 1.5-4.5% boron and a small amount of nickel and tungsten; spraying a cermet powder on said self-fluxing alloy metallized layer by means of a spraying device using plasma jet or oxy-acetylene flame as a heat source to form a cermet layer said cermet being selected from the group consisting essentially of a mixture of zirconia or alumina, having a purity of more than 90%, with a nickel-chromium alloy consisting essentially of 65-90% nickel and 10-35% chromium, in a mixing ratio of 30:70-70:30, a mixture of zirconia or alumina, having a purity of more than 90%, with a nickel base alloy consisting essentially of 65-90% nickel, 10-35% chromium, 1.5-4.5% silicon and 1.5-4.5 % boron, in a mixing ratio of 30:70-70:30, a cobalt-base alloy consisting essentially of 40-60% cobalt, 19-21% chromium, 1.5-4.5% silicon, 1.5-4.5% boron and a small amount of nickel and tungsten, in a mixing ratio of 30:70-70:30, and a mixture of zirconia or alumina, having a purity of more than 90%, with a nickel-aluminum alloy consisting essentially of 80-95% nickel and 20-5% aluminum, in a mixing ratio of 30:70-70:30; and then spraying a member selected from the group consisting of zirconia and alumina having a purity of more than 90% on said cermet layer by means of a spraying device using plasma jet or oxy-acetylene flame as a heat source to form a ceramic coating layer; all percentages being by weight.

Claim 12

A method of manufacturing a blast-furnace tuyere having excellent thermal shock resistance and high durability, which comprises roughening a surface of a tuyere substrate composed of a member selected from the group consisting of copper and copper alloy; spraying a self-fluxing alloy on the surface of said substrate by means of a spraying device using plasma jet or oxy-acetylene flame as a heat source to form a self-fluxing alloy metallized layer, said alloy being selected from the group consisting of nickel-base alloy consisting essentially of 65-90% nickel, 10-35% chromium, 1.5-4.5% silicon and 1.5-4.5% boron, and a cobalt-base alloy consisting essentially of 40-60% cobalt, 19-21% chromium, 1.5-4.5% silicon, 1.5-4.5% boron and a small amount of nickel and tungsten; spraying a cermet powder on said self-fluxing alloy metallized layer by means of a spraying device using plasma jet or oxy-acetylene flame as a heat source to form a cermet layer said cermet being selected from the group consisting essentially of a mixture of zirconia or alumina, having a purity of more than 90%, with a nickel-chromium alloy consisting essentially of 65-90% nickel and 10-35% chromium, in a mixing ratio of 30:70-70:30, a mixture of zirconia or alumina, having a purity of more than 90%, with a nickel base alloy consisting essentially of 65-90% nickel, 10-35% chromium, 1.5-4.5% silicon and 1.5-4.5 % boron, in a mixing ratio of 30:70-70:30, a cobalt-base alloy consisting essentially of 40-60% cobalt, 19-21% chromium, 1.5-4.5% silicon, 1.5-4.5% boron and a small amount of nickel and tungsten, in a mixing ratio of 30:70-70:30, and a mixture of zirconia or alumina, having a purity of more than 90%, with a nickel-aluminum alloy consisting essentially of 80-95% nickel and 20-5% aluminum, in a mixing ratio of 30:70-70:30; and then spraying a member selected from the group consisting of zirconia and alumina having a purity of more than 90% on said cermet layer by means of a spraying device using plasma jet or oxy-acetylene flame as a heat source to form a ceramic coating layer; all percentages being by weight.