The metal flaring test is a method for testing the deformation characteristics of the ends of metal pipes. When performing the expansion test, press the upper core with a certain taper (for example, 1:10, 1:15) into one end of the metal tube sample so that it can be uniformly expanded to the expansion ratio (%) specified in the relevant specification, then check the presence of cracks and other defects in the flaring to determine whether it is qualified or not.
To give everyone a better visualization, the next two pictures
I played with mud as a child
I played with mud as a child
The mouth expansion test made me think about playing in the mud, shaping the mouth, and then there was a big crack, let's see who made the sound
The flaring test is suitable for determining the plastic deformation capacity of flaring round metal pipes with an outer diameter of metal pipes not more than 150mm (non-ferrous metal pipes not more than 100mm) and a pipe wall thickness of not more than 10mm.
The sample must be cut from any part of the visually inspected metal pipe. When cutting the sample, damage to the surface of the sample and change in its characteristics due to heating or cold working should be avoided. The two ends of the test specimen shall be perpendicular to the axis of the pipe. The edges of the test end may be rounded or beveled with a file or other means. When testing a welded pipe, the reinforcement of the weld on the inner wall of the pipe may be removed. The sample length depends on the angle of inclination of the upper rod. When the core angle is equal to or less than 30°, the sample length should be approximately 2D; when the core angle is greater than 30°, the sample length should be approximately 1.5D.
According to the relevant specification or agreement between the two parties, various conical cores are selected, and the recommended core angles are 30°, 45°, and 60°.
In general, testing should be done at room temperature. For tests with strict temperature requirements, it should be controlled within (23 ± 5) ° C.
Gently apply pressure to the tapered top core to push it into the end of the specimen for uniform flaring until the desired outside diameter is reached. The maximum outer diameter or expansion ratio of the specimen after expansion shall be specified in the relevant product standards. The expansion rate Xd is calculated using the following formula:
In the formula, D0 and D are respectively the maximum outside diameter and the original outside diameter in mm after the test.
The speed at which the top rod is pressed into the specimen is usually not specified, but in the event of disputes or arbitration tests, the speed at which the top rod is pressed into the specimen should not exceed 50 mm/min. The results of the combustion test shall be evaluated in accordance with the requirements of the relevant product standards. Unless special requirements are specified, a test specimen with no visible cracks shall be accepted, and only minor cracks at the edge of the specimen shall not be considered defective.