| 摘要 |
PROBLEM TO BE SOLVED: To easily mold a cavity with constant depth using a simple means, in the case of testing the quality of a metal pipe by applying the cavity with a constant depth to the surface of the metal pipe. SOLUTION: A ball test piece consists of a sphere 1 for applying a cavity with a constant depth to the surface of a metal pipe 3 and a support 2 having the sphere 1 formed on its surface in a protruded state to support the same. The protruding quantity of the sphere 1 from the support 2, set to a quantity where the surface of the support 2 comes into contact with the surface of the metal pipe 3, when the sphere 1 is pressed in the surface of the metal pipe 3 to form a cavity 4 with constant depth and the support 2 has the contact surface coming into contact with the surface of the metal pipe 3, when the cavity 4 with constant depth is formed in the surface of the metal pipe 3 to disperse the press-in stresses.
|
