High-temperature component and method of producing the high-temperature component

A high-temperature component which requires cooling by a cooling medium, the high-temperature component comprising:

• a plurality of cooling passages through which the cooling medium is able to flow;
• a header portion to which downstream ends of the plurality of first cooling passages are connected;
• and
• at least one outlet passage for discharging the cooling medium flowing into the header portion to outside of the header portion,
• wherein a roughness of an inner wall surface of the at least one outlet passage is not greater than a roughness of an inner wall surface of the plurality of first cooling passages in a region where a flow-passage cross-sectional area of the outlet passage is the smallest, and
• wherein the at least one outlet passage includes a flow-passage cross-sectional area reduction portion where the flow-passage cross-sectional area of the outlet passage gradually decreases toward a downstream side.

A method of producing a high-temperature component which requires cooling by a cooling medium, the method comprising:

• a step of forming a plurality of cooling passages through which the cooling medium is able to flow;
• a step of forming a header portion to which downstream ends of the plurality of first cooling passages are connected;
• a step of forming at least one outlet passage for discharging the cooling medium flowing into the header portion to outside of the header portion;
• and
• a step of applying machine processing to at least a part of the inner wall surface of the at least one outlet passage,
• wherein the step of forming the at least one outlet passage includes forming the at least one outlet passage such that a roughness of an inner wall surface of the at least one outlet passage is not greater than a roughness of an inner wall surface of the plurality of first cooling passages in a region where a flow-passage cross-sectional area of the outlet passage is the smallest, and
• wherein the step of forming the at least one outlet passage includes forming the at least one outlet passage by metal additive fabrication or precision casting.