Application of Appropriate Coatings on Extrusion Dies and Evaluation of Their Performance During Hot Extrusion of Aluminum

Author(s):  
Antonios Lontos ◽  
George Demosthenous ◽  
Filippos Soukatzidis

The aim of this paper is to study the effect of extrusion parameters (extrusion speed and temperature), die geometry, and the application of appropriate coating materials on the extrusion dies in order to extend their working life. To achieve the above goal FEM techniques and experimental tests adopted and simulating and experimental results evaluated. In this way, special FEM software was used to set up the finite element model of the aluminum extrusion. As a billet material the 6061 aluminum was used, with a specific diameter and length. The extrusion process was modeled as isothermal, which means that the billet material preheated at the specific temperature and then it was pressured into the two different dies, with a specific extrusion ratio. The extrusion speed was varied between 0.5 to 1 mm/sec and the extrusion temperature varied between 400 °C to 500 °C. The extrusion angle of the two different dies was 9° degrees. The fillet radius at the top surfaces was selected to be 1 mm. The friction between aluminum material (billet) and the extrusion equipment was i) aluminum material and die 0.3, ii) aluminum material and ram 0.9 and iii) aluminum material and container equal to 0.96. Optimized algorithms of extrusion parameters were proposed regarding to the concluded simulating results. The results obtain from the simulation procedure help to the better understanding of the specific extrusion process, leading to better modification of the experimental procedure. In this way, experimental tests were conducted on special laboratory extrusion press using the two different die geometries coated with three different PVD coatings. By means of these experimental tests the additional working life of the coated dies, during hot extrusion process, was able to be evaluated. In addition, the three different coatings where tested by established quality procedures in order to determine their behavior on the material of the extrusion die.

2014 ◽  
Vol 622-623 ◽  
pp. 111-118
Author(s):  
Jing Yang ◽  
Qing Jun Zhou ◽  
Chao Yang Sun ◽  
Dong Liu

A 2D axi-symmetric finite element model for tube hot extrusion process has been established by consideration of the billet transfer, glass lubrication, constitutive equation of IN690 superalloy and modified Archard wear model. The influence of extrusion process parameters on the stress state and wear conditions of the mandrel surface has been investigated. The results show that under the optimal extrusion process parameters of the extrusion speed of 250 mm/s, the friction factor of 0.05 and the billet preheating temperature of 1250 ̊C, the mandrel can be reused 200 times when it is fixed and 500 times when it moves with the ram.


Author(s):  
Nooman Ben Khalifa ◽  
A. Erman Tekkaya

A new innovative direct extrusion process, helical profile extrusion (HPE) is presented, which increases the flexibility of aluminum profile manufacturing processes. The application fields of such profiles can be seen in screw rotors for compressors and pumps. The investigations concentrate on experimental and numerical analyses by 3D-FEM simulations to analyze the influence of friction and the material flow on the twisting angle and contour accuracy. By means of finite-element method (FEM), the profile shape could be improved by modifying the die design. The numerical results were validated by experiments. For these investigations, a common aluminum alloy AA6060 was used. Mainly, the friction in the die influences the twist angle and the shape of the helical profile. Two die coatings were analyzed, but the friction was not substantially decreased in any of these cases. Although there is no efficient practical solution for reducing the friction in extrusion dies using tested die coatings, the required profile contour could be achieved by new die designing and by modifying the material flow. However, increasing the twist angle is limited due to geometrical aspects of this technology, namely, by the ratio of the volume to the contact area with the die for the displaced metal.


2013 ◽  
Vol 585 ◽  
pp. 13-22 ◽  
Author(s):  
Alessandro Selvaggio ◽  
Thomas Kloppenborg ◽  
Martin Schwane ◽  
Ramona Hölker ◽  
Andreas Jäger ◽  
...  

A bridge die was designed for the simultaneous extrusion of two rectangular profiles and used in a strictly monitored aluminum extrusion process. Experimental investigations aimed at the measurement of the mandrel deflection, the local die temperature, and the pressure inside the welding chamber by means of special measurement equipment. AA6082 alloy was used as extrusion material. The influence of the extrusion speed on the aforementioned objectives is reported. The experiments were repeated at least three times under the same conditions in order to achieve a statistical validation of the acquired data. These data are provided as reference for the 2013 edition of the Extrusion Benchmark.


2012 ◽  
Vol 166-169 ◽  
pp. 896-901
Author(s):  
Lei Xu ◽  
Guang Ze Dai ◽  
Xing Min Huang ◽  
Jun Wen Zhao ◽  
Jing Han ◽  
...  

Hot extrusion process of Al-Zn-Mg-Cu alloy billet had been simulated under different temperature of billet and container. It was proposed that due to large deformation and friction, maximum temperature of the billet occurs on the skin near extrusion export and is under three direction tension stress state, where surface is likely to crack if temperature surpassed the incipient melting point. The right temperature of the billet and container is 425°C~450°C and 400°C respectively with the constant extrusion speed 0.8mm/s


2017 ◽  
Vol 9 (7) ◽  
pp. 168781401771241
Author(s):  
Changyong Liu ◽  
Renji Zhang ◽  
Yongnian Yan ◽  
Changshi Lao

Extrusion container is the most important tooling for steel hot extrusion process. Conventional design using large castings and forgings is very difficult to execute due to high cost and risk. Steel wire wound containers have many advantages over conventional designs. However, conventional wire wound containers are developed for use at room temperature which are not applicable to steel hot extrusion process. In this article, the impacts of preheating on the design of steel wire wound containers are discussed in detail. A finite element model was established to examine the preheating temperature distribution, and a 1:10 scaled extrusion container was manufactured to verify the effectiveness of the finite element model. Based on the finite element model–computed temperature field, thermal stress analysis was performed. The thermal impacts on the stress of extrusion container and steel wire were obtained. Results showed that insufficient stability of internal cylinder and greatly enhanced steel wire stress may lead to the failure of extrusion container. To solve the problems, an improved design was put forward by increasing the stability factor of internal cylinder, reducing the prestress factor and lowering the allowable stress of steel wire. Results showed that the improved design can meet the requirements and counteract the thermal impacts.


2014 ◽  
Vol 788 ◽  
pp. 127-133 ◽  
Author(s):  
Zhi Wen Shao ◽  
Xiu Rong Zhu ◽  
Jun Wang ◽  
Rong Wang ◽  
Yong Dong Xu ◽  
...  

The hot backward extrusion process of the Mg-Gd-Y-Zn-Zr magnesium alloy was investigated by both numerical simulation and experiments. An axisymmetric 2D rigid-plastic finite element model (FEM) was established to simulate the material flow during the extrusion process. The shapes of the dies were optimized in order to avoid severe stress concentration and obtain uniform deformation of the workpiece. After hot extrusion, the microstructures of the alloys were obviously refined, and the secondary phases which included many long-period stacking order (LPSO) phases precipitated in the matrix. The optimal comprehensive mechanical properties of the alloy have been obtained after extrusion and ageing at 200°C for 48h with the ultimate tensile strength of 434MPa, tensile yield strength of 375MPa and elongation of 4.5%, respectively. The good mechanical properties were mainly attributed to the fine microstructures and numerous precipitates in the matrix.


Author(s):  
Frank F. Kraft ◽  
Jonathan Kochis

This paper presents the development of a unique, net shape, hot-extrusion process to produce precision, thin-wall, multichannel copper profiles for high efficiency heat-exchangers. This process is a departure from conventional copper extrusion, which is a nonisothermal process used primarily to produce simple semifinished products and hollow profiles requiring cold drawing after hot extrusion. A lab-scale apparatus was developed to simultaneously extrude multiple heated billets through a porthole type hollow die to form the multi-channel profiles. The process is performed at 700–750 °C, essentially at isothermal extrusion conditions. Temperature and tooling strength considerations necessitated the use of superalloys for the apparatus (which included dies, container, ram stems, and support tooling). A 250 kN computer controlled servo-hydraulic MTS® machine was used to provide the extrusion ram force. Two part designs were extruded to demonstrate process feasibility and versatility. A two-channel design with 0.2 mm wall thicknesses and an 11-channel design with wall-thicknesses of 0.3 mm were extruded. The extrusion ratios for these profiles are 67 and 25, respectively. Experimental data and an approach to analytically model the process are presented. Because solid-state welds in the tube walls are necessitated by the use of hollow extrusion dies, the microstructure in these regions is also presented.


Alloy Digest ◽  
1967 ◽  
Vol 16 (4) ◽  

Abstract Mustang-LC is a tungsten-molybdenum high-speed steel specially developed for hot work applications requiring long die life. It is recommended for hot forming and swaging dies, hot extrusion dies, hot punches, etc. This datasheet provides information on composition, physical properties, hardness, and elasticity. It also includes information on forming, heat treating, machining, and joining. Filing Code: TS-192. Producer or source: Jessop Steel Company.


Alloy Digest ◽  
1989 ◽  
Vol 38 (2) ◽  

Abstract UNS T20819 is a hot-work tool and die steel that is characterized by excellent resistance to shock and abrasion at elevated temperatures. This steel provides relatively high toughness and outstanding resistance to heat checking and softening at elevated temperatures. Among its many applications are hot-punch tools, forging dies and inserts, brass extrusion dies, permanent molds for brass casting and hot-extrusion die inserts for steel. This datasheet provides information on composition, hardness, and tensile properties as well as fracture toughness. It also includes information on high temperature performance as well as forming, heat treating, machining, and joining. Filing Code: TS-496. Producer or source: Tool steel mills.


Author(s):  
A. Damodar Reddy ◽  
P.N. Karthikeyan ◽  
S. Krishnaraj ◽  
Adarsh Ajayan ◽  
K. Sunil Kumar Reddy ◽  
...  

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