HEAT RESISTANT TUBE HAVING ALUMINA BARRIER LAYER

• Main Author: HASHIMOTO KUNIHIDE
• Format: Patent
• Language: English; Japanese
• Published: 11.07.2016
• Subjects: ALLOYS; CHEMISTRY; FERROUS OR NON-FERROUS ALLOYS; METALLURGY; TREATMENT OF ALLOYS OR NON-FERROUS METALS

PROBLEM TO BE SOLVED: To provide a heat resistant tube having an alumina barrier layer, which has an alumina barrier layer satisfactorily formed on the tube inner surface, and furthermore can be prevented from deteriorating in mechanical characteristics such as creep rupture strength and tensile ductility.SOLUTION: The heat resistant tube related to the present invention is a heat resistant tube which is for use in the pyrolysis of hydrocarbon and has an alumina barrier layer containing an Al oxide on the inner surface of a tube body, and in which the tube body has an Al content on the inner diameter side higher than the Al content on the outer diameter side. The tube body desirably has the Al content on the inner diameter side two or more times the Al content on the outer diameter side. The tube body desirably has the Al content on the inner diameter side 1.3 mass% or more higher than the Al content on the outer diameter side.SELECTED DRAWING: Figure 3 【課題】本発明は、アルミナバリア層を管内面に良好に形成しつつ、クリープ破断強度や引張延性等の機械的特性の低下を防ぐことのできるアルミナバリア層を有する耐熱管を提供する。【解決手段】本発明に係る耐熱管は、炭化水素の熱分解に用いられる、管本体の内面にＡｌ酸化物を含むアルミナバリア層を有する耐熱管であって、前記管本体は、内径側のＡｌ含有量が、外径側のＡｌ含有量よりも多い。前記管本体は、内径側のＡｌ含有量が、外径側のＡｌ含有量の２倍以上とすることが望ましい。前記管本体は、内径側のＡｌ含有量が、外径側のＡｌ含有量に比して、質量％にて１．３％以上多くすることが望ましい。【選択図】図３