Technical solutions of vibration safety cold riveting performed ship repair

2020 ◽  
pp. 172-179
Author(s):  
A.Ya. Rozinov
Keyword(s):  
Aluminum Alloy ◽  
Cold Shock ◽  
Vibration Disease ◽  
Shock Absorbers ◽  
Heating And Cooling ◽  
The Press ◽  
Press Equipment ◽  
Technical Solutions ◽  
Ship Repair ◽  
Reverse Methods

The parameters of heating and cooling of rivets made of steel and aluminum alloy, as well as data of fi lling holes with these rivets during hot and cold riveting are compared. The features of the process of performing cold impact riveting by direct and reverse methods, as well as the possibility of reducing the force of this riveting by improving the closing heads and constructive transformation of the rivets themselves are considered. Features of physiological infl uence of cold shock riveting on hands, elbows and shoulders of workers are determined. Describes the construction of riveting hammers and supports with spring shock absorbers that prevent the disease of workers vibration disease, portable riveting presses of pneumatic and hydraulic action. A description of the press equipment and technology of bolt-riveting connections, allowing mechanizing the process of cold riveting is given.

The analysis of an intense and deformation condition of shaving and glue mix in a rolling zone

2016 ◽  
Author(s):  
В.В. Сергеевичев ◽  
А.В. Сергеевичев ◽  
А.Е. Михайлова
Keyword(s):  
Deformation Condition ◽  
Composition Material ◽  
Continuous Change ◽  
Contact Points ◽  
Processed Material ◽  
The Press ◽  
Dangerous Place ◽  
Variable Tension ◽  
Press Equipment ◽  
Width Reduction

При прохождении стружечноклеевой массы по ленточному прессу и формования ее в изделие под вальцами происходит постоянное изменение свойств материала. От несвязной сыпучей композиции материал в результате пьезотермообработки должен преобразоваться в монолитное фасонное изделие. Силовое и температурные воздействия в процессе обработки вызывают в материале, а затем и в готовом изделии переменное напряженное состояние, которое в значительной степени определяет целостность и окончательные механические свойства готовой продукции. В настоящей статье исследуются напряженные состояния в наиболее опасном месте пресса – под профилирующим вальцом. Основная цель исследования заключается в попытке объяснить появление дефектов изделия и наметить конструктивные и технологические мероприятия по их устранению или хотя бы смягчению. При проведении предварительных экспериментов по изготовлению погонажных изделий из стружечноклеевой массы был обнаружен ряд основных недостатков. Большинство дефектов связано с процессом профилирования и возникают под профилирующим барабаном. Очевидно, причиной всех отмеченных дефектов являются экстремальные условия деформирования материала под барабаном и несоответствие термомеханического состояния обрабатываемого материала характеру деформирования. На основании проведенных исследований можно сделать основные выводы: продольный изгиб при прокатке изделий из стружечноклеевой массы представляет существенную опасность и может быть причиной расслоения изделий по ширине; уменьшение вредного влияния продольного изгиба по ширине изделия может быть достигнуто за счет его интенсивного разогрева и ограничения отверждения связующего под вальцами; диаметры профилирующих барабанов необходимо делать максимальными по конструктивным соображениям; оптимальным вариантом является профилирование на прямолинейных участках, где радиус равен бесконечности; необходимо обеспечить жесткую синхронизацию линейных скоростей по всем точкам контакта изделия с рабочими органами прессового оборудования. Такие условия автоматически удовлетворяется в гусеничном прессе, что дополнительно характеризует его достоинства. When shaving and glue mix passing through a tape press and its formations to product under rollers there is a continuous change of properties of material. From incoherent loose composition material as a result of a pyezoterm processing has to be transformed to a monolithic shaped product. Power and temperature influences in processing cause in material, and then and in a finished product a variable tension which substantially defines integrity and final mechanical properties of finished goods. In the present article intense states in the most dangerous place of a press – under the main roller are investigated. The main objective of research consists in attempt to explain emergence of defects of a product and to plan constructive and technological actions for their elimination or at least to mitigation. When carrying out preliminary experiments on production wooden materials from shaving and glue mix has been found a number of the main shortcomings. The majority of defects is connected with process of profiling and arise under a main drum. Obviously, extreme conditions of deformation of material under a drum and discrepancy of a thermomechanical condition of the processed material to nature of deformation are the reason of all noted defects. On the basis of the conducted researches it is possible to draw the main conclusions: the longitudinal bend when rolling products of shaving and glue mix constitutes essential danger and can be the cause of stratification of products on width; reduction of an adverse effect of a longitudinal bend on width of a product can be reached at the expense of its intensive warming up and restriction of curing binding under rollers; diameters of main drums need to be done maximum for constructive reasons; an optimal variant is profiling on straight sections where radius is equal to infinity; it is necessary to provide rigid synchronization of line speeds on all contact points of a product with operating parts of the press equipment. Such conditions it is automatically satisfied in a truck press that in addition characterizes its advantages.

IMPROVEMENT OF THE PROCESS OF OPERATION OF THE GUIDE MOVING CROSSBARS OF HYDRAULIC PRESSES

2020 ◽  
Author(s):  
K.O. Kobzev ◽  
◽  
S.A. Vyalov ◽  
E.S. Bozhko ◽  
I.A. Zolotuhina ◽  
...  
Keyword(s):  
Service Life ◽  
Hydraulic Press ◽  
Operating Conditions ◽  
The Press ◽  
Technical Solutions

This article deals with the problem of operating conditions of guide moving crossbars of hydraulic presses. Based on the study of hydraulic press operation processes, the need to develop and implement measures to ensure reliable and trouble-free operation of the press was identified. The conclusion justifies the idea that if these technical solutions are implemented, the service life of hydraulic presses will increase

The durability of press-formed paperboard trays – Effects of sealing and drying

BioResources ◽  
2020 ◽  
Vol 16 (1) ◽  
pp. 236-248
Author(s):  
Arvo Niini ◽  
Ville Leminin ◽  
Panu Tanninen ◽  
Juha Varis ◽  
Teija Laukala
Keyword(s):  
Dimensional Stability ◽  
Food Processing ◽  
Positive Impact ◽  
Processing Conditions ◽  
Optical Analysis ◽  
Heating And Cooling ◽  
The Press ◽  
Heat Sealing ◽  
Dimensional Measurements ◽  
The Impact

Dimensional measurements were recorded to observe the durability of press-formed paperboard trays used for food processing via heating and cooling of the paperboard trays containing oatmeal. A set of the studied press-formed paperboard trays were dried before being heated, and a set of the paperboard trays were heat-sealed before being cooled to compare the effects of drying and sealing on the durability of the tray. In addition, empty trays were heated to observe the impact of food processing conditions on its durability via leak tests with a colouring solution as well as optical analysis of the material coating on the surface of the trays. The drying process of the trays was observed to improve the dimensional stability of the trays while being heated, and heat-sealing the trays yielded a major positive impact on the dimensional stability of the trays while being cooled. The leak tests and optical analysis results on the heated empty trays showed a negative durability impact from the food processing conditions. It was concluded that adjusting the heat-sealing parameters and food processing conditions is necessary in order to achieve improved durability of the press-formed paperboard trays for food processing purposes.

Residual Stresses due to Deep-Drawing of Pre-Coated Aluminum-Alloy Sheets

2005 ◽  
Vol 490-491 ◽  
pp. 358-363 ◽  
Author(s):  
Masatoshi Sudo ◽  
Tomohiko Iwase ◽  
Yoshiyuki Hattori ◽  
Madoka Nakajima
Keyword(s):  
Residual Stress ◽  
Aluminum Alloy ◽  
Residual Stresses ◽  
Sheet Metal ◽  
Direct Contact ◽  
Volatile Oil ◽  
The Press ◽  
The Face ◽  
Coated Layer ◽  
Press Formability

In this study, we examined how the press formability of A1 alloys sheets and the generation of residual stresses was influenced by pre-coating resins, lubricants, die shoulder radius, the punch shoulder radius, and so on. The use of a pre-coated layer offers advantages by preventing direct contact between sheet metal and the face of the die, and also by enabling the use of volatile oil lubricants that keep the factory environment cleaner. The circumferential residual stress (σC ) of a cup becomes lower when the lubricant is less effective, and when the die shoulder radius is smaller.

Press-Formability of Aluminum Alloy Sheets of Solution-Hardening Type

1983 ◽  
Vol 105 (4) ◽  
pp. 235-242 ◽  
Author(s):  
N. Kawai ◽  
T. Mori ◽  
T. Nozaki
Keyword(s):  
Aluminum Alloy ◽  
Fracture Behavior ◽  
Plastic Anisotropy ◽  
Weight Ratio ◽  
High Strength ◽  
Solution Hardening ◽  
Solution Type ◽  
Metal Sheets ◽  
The Press ◽  
Press Formability

Recently, formable metal sheets with a high strength-to-weight ratio have been developed especially to conserve energy and resources. For this purpose, two conditions are necessary: the strengthening of the sheet metal and improvement of the press-formability, which are difficult to obtain together. In the present study, the conditions necessary for this are examined using solid-solution type aluminum alloy sheets. Moreover, a new measure to assess press-formability is proposed in terms of the strain-hardening capability and plastic-anisotropy based on fracture behavior of sheet metals.

scholarly journals Effects of press-forming parameters on the dimensional stability of paperboard trays

BioResources ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. 4876-4890
Author(s):  
Arvo Niini ◽  
Panu Tanninen ◽  
Juha Varis ◽  
Ville Leminen
Keyword(s):  
Dimensional Stability ◽  
Dwell Time ◽  
Outer Wall ◽  
Tool Temperature ◽  
Pressing Force ◽  
Heating And Cooling ◽  
Press Forming ◽  
Forming Parameters ◽  
The Press ◽  
Blank Holding Force

The dimensional stability of press-formed paperboard trays was investigated during heating and cooling of trays packed with oatmeal. Female mold tool temperature, dwell time, pressing force, and blank holding force were altered in the press-forming of the trays to observe their impacts on the dimensional stability. Dimensional measurements of the trays showed reduced tray width, and the trays exhibited distortions on the tray flange and outer wall. The results showed smaller effects on the tray length, parallel to the machine direction of the material. Improved dimensional stability of the trays was found with a 180 °C female mold tool temperature, a 600-ms dwell time, a 150-kN pressing force, and a 1.44-kN blank holding force. The optimal press-forming parameters were concluded to enhance bonding of the paperboard fibers during the press-forming. The optimization of the press-forming parameters was found necessary to reduce the observed negative response of the material to the challenging environmental conditions in the production of prepared food.

Feasibility Study on Die Quenching of AA2024 Aluminum Alloy Billet Using Servo Press

2014 ◽  
Vol 922 ◽  
pp. 286-291 ◽  
Author(s):  
Jae Yeol Jeon ◽  
Ryo Matsumoto ◽  
Hiroshi Utsunomiya
Keyword(s):  
Aluminum Alloy ◽  
Motion Control ◽  
Solution Heat Treatment ◽  
Precipitation Hardening ◽  
Peak Hardness ◽  
Precipitation Kinetics ◽  
Aging Behavior ◽  
Servo Press ◽  
Die Quenching ◽  
The Press

Die quenching of an AA2024 aluminum alloy billet was carried out using a servo press with ram motion control of WC-20mass%Co dies directly after solution heat treatment (SHT). The cylindrical billets were heated in an electric furnace and transferred to the press, then subjected to uniaxial compression with a reduction in height (Δh/h0) of 2%, 5% or 10% after SHT at 773 K or 823 K. The die quenching was successfully carried out without the precipitation hardening only on the billet after SHT at 823 K by sandwiching for 8 s. The subsequent artificial aging behavior at 463 K in an oil bath was investigated. It is found that the precipitation kinetics is accelerated in the die-quenched billets after SHT at 823 K. The peak hardness of the billet processed with 5% after SHT at 823 K is as high as that of the water-quenched billet, HV 149.0.

Temperature Field Simulation for Aluminum Alloy Surface Modification by Scanning Electron Beam

2010 ◽  
Vol 97-101 ◽  
pp. 1404-1407
Author(s):  
Pei Xin Sun ◽  
Rong Wang ◽  
De Qiang Wei
Keyword(s):  
Surface Modification ◽  
Aluminum Alloy ◽  
Electron Beam ◽  
Element Model ◽  
Melting Zone ◽  
Scanning Electron Beam ◽  
Heating And Cooling ◽  
Axis Length ◽  
Aluminum Alloy Surface ◽  
Scanning Electron

According to the actual experimental condition and theoretical analysis, a finite element model was established to describe the surface modification process of scanning electron beam of 6A02 aluminum alloy. The phase change process and thermal radiation were considered in the simulation. The temperature simulation revealed the ultrahigh rate of the heating and cooling, rapid melting and re-solidification within seconds in the range of millimeters in depth. The calculated melting zone was an irregular semicircle, the x-axis length was about 2.9mm, and the axial depth was about 1.4mm. This research will predict the melting condition.

scholarly journals Fabrication of Two-Layered Aluminum Foam with Closed-Cell and Open-Cell Structures and Shaping of Closed-Cell Layer by Press Forming Immediately after Foaming

Metals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 140
Author(s):  
Yoshihiko Hangai ◽  
Mizuki Ando ◽  
Masataka Ohashi ◽  
Kenji Amagai
Keyword(s):  
Aluminum Alloy ◽  
Melting Point ◽  
Aluminum Foam ◽  
Cell Layer ◽  
Open Cell ◽  
Press Forming ◽  
Cell Structures ◽  
Closed Cell ◽  
The Press

Two-layered aluminum foam consisting of both closed and open cells is expected to improve the functionality of aluminum foam, because the cells have different morphologies and characteristics. In this study, press forming of the closed-cell layer of the two-layered aluminum foam immediately after foaming was performed to shape the closed-cell layer. By measuring the temperatures of the two layers during foaming, we found that it is necessary to use aluminum alloy with a higher melting point for the open-cell layer than that for the closed-cell layer to foam the closed-cell layer. In the press forming experiments, the closed-cell layer could be shaped by press forming while the shape of the open-cell layer was maintained.

A Vortex Jet Device Applied in the Development of Active Hydro-Pneumatic Dampers Used in Rehabilitation Equipment

2021 ◽  
pp. 185-204
Author(s):  
A.Yu. Uss ◽  
A.V. Chernyshev
Keyword(s):  
High Reliability ◽  
Current Status ◽  
Design And Development ◽  
Technical Literature ◽  
Advantages And Disadvantages ◽  
Shock Absorbers ◽  
Damping Control ◽  
Working Environments ◽  
Valve Assembly ◽  
Technical Solutions

The paper overviews and analyses the current status of the development and research of active hydro-pneumatic dampers, which are used in rehabilitation equipment, where vortex jet devices can be applied as control valves. The study focuses on a vortex jet device whose distinctive feature is the absence of mechanically moving parts, describes the principle of its operation, and gives the rationale for using it in the active hydro-pneumatic damper of the knee module prosthesis. From a review of scientific and technical literature, a conclusion is drawn that active hydro-pneumatic dampers are used not only in rehabilitation equipment but also in vehicle shock absorbers. The experience gained in the design and development of active hydro-pneumatic dampers for vehicle shock absorbers was applied in the design and development of an active hydro-pneumatic damper for the knee module. In order to identify the advantages and disadvantages, we examined some designs of active hydro-pneumatic dampers for vehicle shock absorbers. Analysis of technical solutions showed the advantage of vortex jet devices, e.g. high reliability, the ability to work with various working environments, low manufacturing and operating costs; enabled us to recommend a vortex jet device to be used as an actuator, i.e., a vortex valve, in the valve assembly of an active hydro-pneumatic damper. The use of a vortex jet device increases the reliability of the structure and reduces the energy consumption for the control of the structure. The proposed design of the hydro-pneumatic damper allows the use of interactive damping control. The study is the first to introduce the concept and describe the principle of operation of an active hydro-pneumatic damper using a vortex jet device

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