Research on the grain refinement method of cylindrical parts by power spinning

Abstract Magnesium alloy is one of the structure metals of great potential. The hcp structure makes its plasticity is poor at room temperature, which severely limits the development of magnesium alloy. Magnesium alloy plastic problem can be resolved through grain refinement method, and equal channel angular processing is one of the more effective methods of grain refinement. In this paper, two-dimensional dynamic simulation of equal channel angular processing for magnesium alloy were done with the finite element software. The deformation of magnesium alloy was analyzed when die angle and die corner angle were different. The results show that: in the main deformation zone, when die angles were different, the sample deformation in the horizontal direction is very uniform. But in the sample longitudinally direction, the greater the die angle, the more uniform the sample deformation. Die corner angle has no significant effect on the uniformity of the longitudinally deformation of the sample, but its affects the size of the dead zone and sample warpage.

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Research on Formation Conditions of the Ultrafine-Grained Structure of the Cylindrical Parts Manufactured by Power Spinning Based on Small Strains

Materials ◽

10.3390/ma11101891 ◽

2018 ◽

Vol 11 (10) ◽

pp. 1891 ◽

Cited By ~ 1

Author(s):

Gangfeng Xiao ◽

Qinxiang Xia ◽

Xiuquan Cheng ◽

Weiping Chen

Keyword(s):

Dislocation Density ◽

Lath Martensite ◽

Recrystallization Annealing ◽

Second Phase ◽

Power Spinning ◽

Small Strains ◽

Ultrafine Grained ◽

Cylindrical Parts ◽

Formation Conditions ◽

Storage Energy

Two different methods, power spinning and annealing (PSA), quenching and power spinning followed by annealing (QPSA), for manufacturing the cylindrical parts with ultrafine-grained (UFG) structure were reviewed, the dislocation density and microstructural evolution during the two different processes of PSA and QPSA were further studied. The results show that the required strains for obtaining the UFG structure by power spinning is only 0.92 when the initial microstructure of the material is in the phase of lath martensite. The dislocation density and storage energy are increased to 10 times that of the blank after quenching and power spinning and decreased to the level of the blank after recrystallization annealing. Microstructures with fine grain size after quenching, storage energy of 1.8 × 105 kJ/m3 obtained after power spinning and second phase particle with nano-scale precipitated during annealing are the necessary formation conditions for manufacturing the cylindrical parts with UFG structure based on small strains. Compared with the original tubular blank, the mechanical properties of the spun parts with UFG structure improves significantly. The tensile strength and hardness of the spun parts manufactured by QPSA method is 815 MPa and 305 HV, respectively, and the elongation is 17.5%.

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