HEATING TEST

PURPOSE:To enable continuous observation of cracking due to aging with the same heating test piece by applying a heating or cooling to a test piece comprising a hetero weld joint with a section containing two matrixes and a weld part exposed. CONSTITUTION:A cracking is generated in the weld part of a hetero joint due to difference in thermal expansion of material of different kinds to observe. For example, a metal 1 of austenite system is welded with a plate-shaped material made of a metal 2 of carbon steel or a metal 1' of austenite system to form a test piece horizontally symmetrical with sections 5 and 5' of the joint made of a welding metal 3 exposed and this is used to generate a cracking in a weld part depending on difference of thermal expansion of the hetero material by heating or cooling it. The horizontally symmetrical form of the test piece enables the modeling of the stress condition of a pipe material and when the thermal stress of the weld metal 3 section is large, cracking is generated in the surface of a high carbon steel side material 2 made of two kinds of metals 1 and 2 as shown by the dotted line. This facilitates the follow-up observation of crackings 8 and 8' at the sample point with one test piece.