Joint method

A joint method of bringing a first member into contact with a second member, the method comprising:

• removing a first part of a first projection of a first substrate, wherein the first projection is opposed to a second projection of a second substrate;
• and
• removing a second part of the second projection opposed to the first projection to form a groove region between the first projection and the second projection, wherein the first member and the second member each have a thickness that varies depending on parts at a joint position;
• joining the first member and the second member to each other by butt welding after the first part and the second part are removed;
• and
• filling the groove region by buildup welding after the joining,
• wherein the removing the first part forms a first inclined surface in the first projection facing the groove region to be gradually distant from a joint position joined with the second projection so as to be closer to an outer surface of the first projection, and
• wherein removing the second part forms a second inclined surface in the second projection facing the groove region to be gradually distant from the joint position joined with the first projection so as to be closer to an outer surface of the second projection.