Abstract: A method for producing the metal cylinder material according to the present disclosure includes: a process A of forming a slitted cylinder-shaped body including at least one slit extending from one end face to the other end face of a cylinder barrel portion consisting of at least one metal plate material; a process B of forming a filler-equipped cylinder-shaped body including a filling portion obtained by filling the slit with a filler for the filler to be filled throughout the slit in a length direction of the slit; and a process C of, by inserting at least a probe of a friction stir rotation tool including the probe at least into the filling portion and executing FSP, reforming at least the filling portion of the filler-equipped cylinder-shaped body to obtain the metal cylinder material including an FSP portion.

Abstract: The method of producing a solid spherical powder according to the present disclosure includes: a step A of preparing a first powder raw material containing agglomerated particles and/or solidified particles having a particle diameter of 1 ?m to 1,000 ?m and introducing the first powder raw material into a plasma flame to produce a hollow spherical powder having a surface layer shell having a thickness of 1 ?m to 50 ?m; a step B of subjecting the hollow spherical powder to pulverization treatment to pulverize a hollow shape of the hollow spherical powder, thus obtaining a second powder raw material which is solid; and a step C of introducing the second powder raw material into a plasma flame, melting and solidifying the second powder raw material to obtain the solid spherical powder.

Abstract: The repair/modification method for metallic substrates according to the present invention includes: a step for preparing a metallic substrate having a first region that is divided in an in-plane direction of the substrate, the first region containing a defect and/or a structurally discontinuous portion; and a step for repairing the defect and/or modifying the structurally discontinuous portion by pressing a friction tool which does not have a probe against a top surface of the first region while rotating the friction tool so as to generate frictional heat while pressing on the top surface.