RESEARCH OF COUPLER OF Fe-Mn-Si-Cr-Ni SHAPE MEMORY ALLDYS

Under analyzing the research achievements of Fe-Mn-Si-Cr-Ni alloy, a new developed Fe-based shape memory alloy since the eighties, this paper put forward three problems existing in Fe-based SMA coupler: the shape recovery ratio and the recovery strain are low; the research of magnitude and stabilization of recovery stress are scarce; the research of the performance of Fe-based SMA coupler and its engineering application are scarce. This paper deals with not only the effects of expanding ratio of coupler, recovery annealing temperature, thermal-mechanical cycle training on the performance of coupler, but also study on the temperature-field of linking system of coupler by using ANSYS finite element software. Some creative research achievements have been made:The quenching temperature has a remarkable effect on SME. When the quenching temperature is 650 慍 ?50 慍, the SME is the best. The higher of quenching temperature, the greater effect of different quenching media on the SME. The SME will be the best when quenched in water. This research achievement lays the foundation of engineering application.Both the shape recovery ratio and the recovery strain ~ can be remarkably improved through the thermal-mechanical cycle training. For the improving of the recovery strain, improve the recovery stress ar. Because the difference of deformation model, the shape recovery ratio of coupler is higher than fihiform sample when its deformation ratio axe same. The thermal-mechanical cycle training has more remarkable effect SME of coupler than filiform sample.DG-3S epoxy adhesive pad improve the sealing performance of SMA coupler in essence. The expanding ratio and the coordinated gap effect sealing performance because its different combination can be change the thickness of epoxy adhesive pad. The suitable thickness of epoxy adhesive pad is 0.2?-0.3mm.IIIThe suitable coordinated gap is only O.3--O.4mm, that is difficult for its engineering application. Improving the SME of coupler is the key to solve this problem. Thermal-mechanical cycle training can be remarkably improve the SME of coupler, that can be obtain the suitable thickness of pad when the coordinated gap is large in engineering application.In this paper, the pulling test and leakage test result show that the coupler have 8500kg joint strength and 3OMP resistance to pressure, that are suitable for engineering application.For the first time, we simulate the temperature-field of the linking system of coupler by using ANSYS finite-element Software. We find that the epoxy adhesive pad has a hot-resistance effect well in temperature-field. Changing the thickness of pad, that can be solve the contradiction of requiring high temperature for SMA coupler and limiting low temperature for seamless steel tube.