Tensile experiment

Although each tube tensile testing machine factory in baotou fluid are familiar with, but really can be put behind the standard and reasons to understand factory is not much, in guiding the user through each machine factory is currently in baotou commonly when fluid tube tensile test is the power to their own devices, with the most simple way to complete the test, such as full at the rate of displacement of the beam to complete the whole test process. There are a lot of details about the tension test of baotou fluid tube.

The first is the problem of stretch velocity. In the elastic deformation stage, the deformation of the baotou fluid tube is small and the tensile load increases rapidly. At this point, if the tensile test is carried out by the beam displacement control, the velocity will be too fast and the entire elastic section will be rushed. With common elastic modulus of 200 gpa baotou fluid pipe, for example, if the range of 50 mm material, in elastic segment, such as tensile experiment was carried out at the rate of 10 mm/min, then the actual stress rate is 200000 n/x 10 mm2S – 1 mm/min * 1 min / 60 s * 1/50 = 666 n/mm mm2S – 1 general baotou fluid tube yield strength is less than 600 mpa, so need to pull the sample 1 second only to yield, the rate was obviously too fast. Therefore, stress rate control or load control is generally adopted in elastic section. Good plastic material sample after elastic segment of load increase, and the deformation increase quickly, so in order to prevent the stretching speed too fast, generally USES the strain or displacement of the beam control. So in GB228-2002 suggested, “on the elastic range and until the yield strength, testing machine chuck separation rate should be kept constant and within the prescribed scope of stress rate (material elastic modulus E/(N/was) < 150000, stress rate control range is 2 – (N/was), 20 s – 1, baotou fluid pipe elastic modulus E/(N/was) 150000 or higher, stress rate control range of 6 to 60 (N/was), s – 1 =. If the yield strength is determined only, the strain rate should be between 0.00025/s~0.0025/s during the yield of the sample’s parallel length. The strain rate in the parallel length should be as constant as possible.