Effects of thread rolling processing parameters on mechanical properties and microstructures of high-strength bolts

2020 ◽  
Vol 62 (10) ◽  
pp. 1017-1024
Author(s):  
Serkan Aktas ◽  
Yasin Kisioglu
2020 ◽  
Vol 62 (10) ◽  
pp. 1017-1024
Author(s):  
Serkan Aktas ◽  
Yasin Kisioglu

Abstract Bolt production with a grade of 10.9 class quality made from AISI4140 material with a low thread rolling index is usually implemented in accordance with the thread rolling method (cold forming) in industrial applications. In this method, the effects of die revolutions and multiple passes are unknown in the thread forming process as the devices are usually operated with respect to geometrical dimensions but not the mechanical properties and microstructures of the material. In the literature there are few studies on microstructures of low-carbon steel having a higher thread rolling index in bolt production. This study experimentally examined the effects of the processing parameters on the mechanical properties and microstructures. Parameters such as forming speed and single or multi-pass influences were considered in the production of M12 × 1.75 and M20 × 2.5 fasteners widely used in industrial applications. The experiments identified the behavior of the mechanical properties, microstructures and micro-hardness of the AISI4140 material at two forming speeds (rpm) and three passes in the thread rolling process. Thus, significantly sensible outcomes as a function of processing parameters were obtained considering the thread strength viewpoints.


2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Le Van Long ◽  
Dinh Van Hien ◽  
Nguyen Truong Thanh ◽  
Nguyen Chi Tho ◽  
Van Thom Do

The low carbon steel has good ductility that is favorable for forming process, but its low strength leads to limiting their application for forced structures. This paper studied improving strength of low-carbon steel via rolling deformation and dual-phase treatment. The results showed that the dual-phase treated steel had a combination of high strength and good ductility; its tensile ultimate strength reached 740 MPa with elongation at fracture of over 15%, while that of the cold-rolled steel only reached 700 MPa with elongation at fracture of under 3%. Based on the obtained results, relationships between mechanical properties and dual-phase processing parameters were established to help users choose suitable-processing parameters according to requirements of products.


2021 ◽  
Vol 3 (1) ◽  
pp. 29
Author(s):  
Lai Dang Giang ◽  
Nguyen Anh Tuan ◽  
Dao Van Luu ◽  
Nguyen Vinh Du ◽  
Nguyen Manh Tien

The mechanical properties of thixoextrusion components can be improved by controllable processing parameters such as the solid fraction of alloy, holding time, punch velocity, heat treatment and die temperature. In this study, the effects of thixoforming parameters on the microstructures and mechanical properties of thixoextrusion ADC12 alloy Aptomat Contact are studied. ADC12 has excellent castability with high fluidity and low shrinkage rate, so it is widely used in industry, especially in automotive and motorcycle engine part casting. It is a near eutectic alloy with high strength and low ductility (1%). The optimization parameters mechanical properties were investigated by changing the punch velocity, specimen temperature and holding time. The results also indicated optimal value at punch velocity (15 mm/s), specimen temperature (560 °C) and holding time (5 min) which was changed microstructure from eutectic dendrite to globular grain, increasing the ductility (3.3%) of this alloy during the semi-solid forming process while the remaining mechanical properties lead to an increase in the quality of finished parts.


2018 ◽  
Vol 53 (6) ◽  
pp. 719-730 ◽  
Author(s):  
Weiyuan Ma ◽  
Dong Zhang

A novel structural supercapacitor is assembled with graphene electrodes and the magnesium phosphate cement separator. Magnesium phosphate cement acts as separator material for the first time due to its high strength and relatively high porosity. Magnesium phosphate cement is synthesized by acid-based reaction between phosphate and magnesia. Effects of processing parameters of magnesium phosphate cement, including M/P ratio and the curing time, on the electrochemical and mechanical properties are investigated. The maximum specific capacitance is as high as 46.38 F g−1 with M/P ratio of 3 at the curing time of 1 day. Moreover, the structural supercapacitor exhibits a specific capacitance of 40.92 F g−1 and simultaneously a compressive strength of 24.59 MPa with the M/P ratio of 3 at the curing time of 28 days. Thus, the optimal M/P ratio is 3 regarding the multifunctionality of structural supercapacitor.


2014 ◽  
Vol 788 ◽  
pp. 115-121
Author(s):  
Rong Wang ◽  
Xiu Rong Zhu ◽  
Zhi Wen Shao ◽  
Yong Dong Xu ◽  
Jun Wang ◽  
...  

Magnesium wrought alloys are of special interest for structural components owing to their improved microstructures and mechanical properties by comparison with Mg cast parts. However, the market of Mg wrought alloys is still relatively small and one of the most important limitations for their application in areas such as aviation and spaceflight is that their strength is still not high enough to be widely used. Currently, more and more attention are paid to hydrostatic extrusion of Mg alloys because the extruded Mg alloys which exhibit extremely fine grains and high strength can be easily obtained by hydrostatic extrusion process. This review detailed the microstructures and mechanical properties of various wrought Mg alloys subjected to hydrostatic extrusion. Furthermore, numerical simulations and processing parameters optimization of the hydrostatic extrusion were also discussed. Finally, the current problems and development trends of hydrostatic extrusion of high-strength Mg alloys were also put forward.


2021 ◽  
pp. 095400832110036
Author(s):  
Bin Hu ◽  
Zehua Xing ◽  
Weidong Wu ◽  
Xiaojun Zhang ◽  
Huamin Zhou ◽  
...  

Short-carbon-fiber (SCF)–reinforced poly-ether-ether-ketone (PEEK) is a promising polymer composite material with good biocompatibility, a high strength-to-weight ratio, and low friction properties. In artificial-bone fabrication and other applications with more flexible fabrication demands, fused-deposition modeling (FDM) technology enables the rapid and low-cost fabrication of SCF/PEEK parts with sophisticated structures. Owing to the high viscosity of melting PEEK composites, great challenges, associated with the poor internal interface, need to be overcome before enhanced mechanical properties can be obtained. In this study, key processing parameters and various SCF amounts were studied to investigate their effects on the mechanical properties of PEEK composites. It was revealed that the existence of voids and gaps between the SCF and PEEK led to a decrease in the strength of the composite systems. The FDM processing parameters were tuned to eliminate these defects in the PEEK composites. The tensile strength of the 2% SCF/PEEK sample reached 96.4 MPa, which is comparable to that of PEEK parts prepared by injection molding. Meanwhile, its elastic modulus reached 2.6 GPa, which is 169% higher than that of the bare PEEK sample.


2010 ◽  
Vol 148-149 ◽  
pp. 253-258
Author(s):  
Hai Na Lu ◽  
Xiu Hua Gao ◽  
Zheng Yi Jiang ◽  
Dong Bin Wei ◽  
Xiang Hua Liu

This paper investigates the effects of normal hot rolling and high rate cooling (NHR+HRC) on microstructure and mechanical properties of the rolled EH 36 hull plate. Double-hit tests were carried out to study the effect of process parameters such as the deformation temperature and soaking time on microstructures of the tested steel, and explore optimal processing parameters. Single-hit compression with various parameters was developed and the microstructures of the tested steel are analyzed to determine the cooling rate and the final cooling temperature of the normal hot rolling and high rate cooling. This study will provide experimental and theoretical base on high-temperature rolling control system. Industrial trial was performed to produce regular products. The results show that the NHR+HRC is an effective and promising method to improve the product quality of high-strength hull plate.


Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 356
Author(s):  
Chengpeng Huang ◽  
Mingxin Huang

Deformed and partitioned (D&P) medium Mn steels exhibiting high strength, large ductility, and excellent fracture toughness have been developed recently. The ultra-high dislocation density and transformation-induced plasticity (TRIP) effect are the main mechanisms for their exceptional mechanical properties. The simple processing route to manufacturing D&P steel makes it promising for large-scale industrial applications. However, the exact effect of each processing step on the final mechanical properties of D&P steel is not yet fully understood. In the present work, the effects of processing parameters on the mechanical properties of D&P steels are systematically investigated. The evolution of microstructure, tensile behavior and austenite fraction of warm rolled samples and D&P samples are revealed. Two D&P steels, with and without the intercritical annealing process, are both produced for comparison. It is revealed that the intercritical annealing process plays an insignificant role to the mechanical properties of D&P steel. The partitioning process is extremely important for obtaining large uniform elongation via slow but sustaining strain hardening by the TRIP effect in the partitioned austenite. The cold rolling process is also significant for acquiring high strength, and the cold rolling thickness reduction (CRTR) is extremely critical for the strength–ductility synergy of D&P steels.


2017 ◽  
Vol 873 ◽  
pp. 54-59 ◽  
Author(s):  
Young Sin Choi ◽  
Chang Lim Kim ◽  
Gun Hee Kim ◽  
Byoung Soo Lee ◽  
Chang Woo Lee ◽  
...  

The Electron Beam Melted (EBM) method is one of the attractive attention thing additive manufacturing methods. By using an EBM additive manufacturing method, CP Ti and Ti-6Al-4V specimen were fabricated with a certain processing parameters. The mechanical properties such as fatigue limit, tensile properties including microstructural characteristics of CP Ti and Ti-6Al-4V specimens fabricated by EBM were confirmed and were compared with the conventional Ti alloys. Additive manufacturing was obtained high strength by creating martensite due to rapid cooling. On the other hand, void occurrence cannot be avoided by the method of using powder, accordingly it had a low fatigue strength value. Therefore, this study focused on that the values of fatigue characteristics of the EBM specimens and conventional specimens were compared and analyzed. EBM CP Ti had good mechanical properties such as yield strength, ultimate tensile strength, elongation and fatigue limits, approximately as same as casting CP Ti. EBM Ti-6Al-4V showed good mechanical properties, but fatigue limits were lower than wroughtTi-6Al-4V. That resulted from the formation of several kinds of internal pores which caused to increase the crack initiation and propagation.


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