scholarly journals Analysis of Thermal Stresses and Strains Developing during the Heat Treatment of Windmill Shaft

2017 ◽  
Vol 62 (2) ◽  
pp. 459-471 ◽  
Author(s):  
A. Cebo-Rudnicka ◽  
Z. Malinowski ◽  
T. Telejko
Keyword(s):  
Heat Treatment ◽  
Stress Field ◽  
Thermal Stresses ◽  
Stress Fields ◽  
Axially Symmetric ◽  
The Finite Element Method ◽  
Temperature Changes ◽  
Incremental Method ◽  
Heating And Cooling ◽  
The Mathematical Model

AbstractIn the paper the results of evaluation of the temperature and stress fields during four cycles of the heat treatment process of the windmill shaft has been presented. The temperature field has been calculated from the solution to the heat conduction equation over the whole heat treatment cycles of the windmill shaft. To calculate the stress field an incremental method has been used. The relations between stresses and strains have been described by Prandtl-Reuss equation for the elastic-plastic body. In order to determine the changes in the temperature and stress fields during heat treatment of the windmill shaft self-developed software utilizing the Finite Element Method has been used. This software can also be used to calculate temperature changes and stress field in ingots and other axially symmetric products. In the mathematical model of heating and cooling of the shaft maximum values of the strains have been determined, which allowed to avoid the crack formation. The critical values of strains have been determined by using modified Rice and Tracy criterion.

Design Optimisation of a Ferritic Ring Weld Specimen Using FE Modelling

2009 ◽  
Author(s):  
Christopher M. Gill ◽  
Paul Hurrell ◽  
John Francis ◽  
Mark Turski
Keyword(s):  
Heat Treatment ◽  
Residual Stress ◽  
Finite Element ◽  
Neutron Diffraction ◽  
Stress Field ◽  
Finite Element Modelling ◽  
Post Weld Heat Treatment ◽  
Stress Fields ◽  
Element Modelling ◽  
Weld Heat

This paper describes the design optimisation of an SA508 ferritic steel ring weld specimen using FE modelling techniques. The aim was to experimentally and analytically study the effect of post weld heat treatment upon a triaxial residual stress field. Welding highly constrained geometries, such as those found in some pressure vessel joints, can lead to the formation of highly triaxial stress fields. It is thought that application of post weld heat treatments will not fully relax hydrostatic stress fields. Therefore a ferritic multi-pass ring weld specimen was designed and optimised, using 2D finite element modelling, to generate a high magnitude triaxial stress field. The specimen thickness and weld-prep geometry was optimised to produce a large hydrostatic stress field and still allow efficient use of neutron diffraction to measure the residual stress. This paper reports the development of the test specimen geometry and compares the results of welding FE analysis and neutron diffraction measurements. Welding residual stresses were experimentally determined using neutron diffraction; both before post weld heat treatment. Three dimensional moving heat source weld finite element modelling has been used to predict the residual stresses generated by the welding process used. Finite element modelling examined the effect of phase transformation upon the residual stress field produced by welding. The relaxation of welding stresses by creep during post weld heat treatment has also been modelled. Comparisons between the modelled and measured as-welded residual stress profiles are presented. This work allows discussion of the effect of post weld heat treatment of triaxial stress fields and determines if finite element modelling is capable of correctly predicting the stress relaxation.

scholarly journals Thermal Stresses in the Wall Connections of Cast Grate Structures

2016 ◽  
Vol 16 (4) ◽  
pp. 11-16 ◽  
Author(s):  
A. Bajwoluk ◽  
P. Gutowski
Keyword(s):  
Heat Treatment ◽  
Cross Section ◽  
Hot Spots ◽  
Thermal Stresses ◽  
Cooling Process ◽  
Temperature Variations ◽  
Temperature Changes ◽  
Different Types ◽  
The Difference ◽  
The Impact

Abstract The purpose of this study was to establish a relationship between the type of wall connection used in the cast grates, which are part of the equipment operating in furnaces for heat treatment and thermal-chemical treatment, and stresses generated in these grates during the process of rapid cooling. The places where the grate walls are connected to each other are usually characterized by the thickness larger than the remaining parts of walls. Temperature variations in those places are responsible for the formation of hot spots, and in the hot spots temperature changes much more slowly. The type of wall connection shapes the temperature gradient in the joint cross-section, and hence also the value of thermal stresses generated during cooling. In this study, five different designs of the grates were compared; the difference in them was the type of the designed wall connection. The following design variants were adopted in the studies: X connections with and without holes, T connections with and without technological recesses, and R (ring) connection. Numerical analysis was performed to examine how the distribution of temperature changes in the initial phases of the cooling process. The obtained results served next as a tool in studies of the stress distribution in individual structures. The analysis were carried out by FEM in Midas NFX 2014 software. Based on the results obtained, the conclusions were drawn about the impact of different types of wall connections on the formation of thermal stresses in cast grates.

scholarly journals Numerical analysis of thermal stresses in welded joint smade of steels X20 and X22

2014 ◽  
Vol 18 (suppl.1) ◽  
pp. 121-126 ◽  
Author(s):  
Sasa Mladenovic ◽  
Vera Sijacki-Zeravcic ◽  
Gordana Bakic ◽  
Jasmina Lozanovic-Sajic ◽  
Marko Rakin ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Finite Element Method ◽  
Thermal Stresses ◽  
Welded Joint ◽  
Dissimilar Materials ◽  
Post Weld Heat Treatment ◽  
The Finite Element Method ◽  
Steam Pipeline ◽  
Transition Piece ◽  
Critical Regions

Stress calculation of steam pipeline is presented, focused on the welded joint. Numerical calculation was performed using the finite element method to obtain stress distribution in the welded joint made while replacing the valve chamber. Dissimilar materials were used, namely steel 10CrMoV9-10 according to EN 10216-2 for the valve chamber, the rest of steam pipeline was steel X20, whereas the transition piece material was steel X22. Residual stresses were calculated, in addition to design stresses, indicating critical regions and necessity for post-weld heat treatment.

Analysis of Thermal Conduction Effects on Thermoelastic Temperature Measurements for Composite Materials

1992 ◽  
Vol 59 (3) ◽  
pp. 552-558 ◽  
Author(s):  
S. A. Dunn
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Mathematical Model ◽  
Composite Materials ◽  
Surface Stress ◽  
Thermal Conduction ◽  
Dissimilar Materials ◽  
Stress Fields ◽  
Temperature Changes ◽  
The Mathematical Model

Measurement of the temperature changes which occur as a body undergoes a change in stress is becoming a widely used technique for the analysis of surface stress fields. In this paper, an investigation into the effects of thermal conduction on surface thermoelastic temperature changes for composite materials is reported. A mathematical model which shows the effects of thermal conduction is developed, and the results from this model are compared with experimental data. The mathematical model is then extended to solve for heat transfer between two thermally dissimilar materials. It is shown how this model can be used to account for the effects of a surface epoxy layer on the observed thermoelastic temperature changes.

scholarly journals Effect of the heat treatment mode of high chrome iron rolling mills on chrome redistribution in the stress field

2021 ◽  
pp. 113
Author(s):  
Olena Popova ◽  
Nataliia Lalazarova ◽  
Оlga Afanasieva
Keyword(s):  
Heat Treatment ◽  
Residual Stresses ◽  
Cooling Rate ◽  
Uniform Distribution ◽  
Temperature Difference ◽  
Thermal Stresses ◽  
Stress Gradient ◽  
Working Layer ◽  
Heating And Cooling ◽  
Uneven Heating

Heat treatment is an important stage in the technology of rolling rolls, due to the fact that the thermal stresses that occur during rapid or uneven heating summing up with the rather high residual stresses after casting, create a risk of cracking. Goal. The aim is improving the quality of rolling rolls by varying the modes of heat treatment. Therefore, it is important to assess the level of thermal stress. Method. Evaluation of thermal stresses arising in heating and cooling in the heat treatment process that summing up to the relatively high residual stresses after casting, creates the risk of fractures. The profile of the distribution of chromium in the cross section of the working layer at each time under the action of the stress gradient that occurs during heat treatment of the roll is obtained by calculation. Results To ensure a minimum temperature difference between the surface and the core, it is necessary to reduce the heating and cooling rate, as well as increase the duration of exposure at a given temperature. Reducing the cooling rate from 17 to 3.7°C/h decreases the temperature difference at the surface and in the center of the roll and the intensity of thermal stresses from 29 to 7 MPa. It is established that the rate of heating and cooling should not exceed 10– 15° C/h, and exposure to annealing should be at least 5–7 hours. Scientific novelty. The modes of heat treatment of rolling rolls with a high-chromium cast iron working layer are designed by estimating the level of thermal stresses. The profile of distribution of chromium after various modes of heat treatment is calculated analytically and its mode at which the most uniform distribution of chromium on section of a working layer remains is offered. Practical significance. The developed technique allows to calculate analytically the profile of distribution of chromium after various modes of heat treatment and to choose such a mode at which the most uniform distribution of chromium remains on the section of a working layer.

Numerical Analysis of Super Drill of Shaft Well Boring Machine in the Stress Field

2012 ◽  
Vol 468-471 ◽  
pp. 2287-2291
Author(s):  
Wei Guo Zhu ◽  
Ya Wang ◽  
Ke Ren Zhang
Keyword(s):  
Mathematical Model ◽  
Finite Element Method ◽  
Stress Field ◽  
Theoretical Basis ◽  
Material Model ◽  
Element Model ◽  
The Finite Element Method ◽  
Linear Elastic ◽  
Nonlinear Features ◽  
The Mathematical Model

We research the super two-stage rapid drill of shaft well boring machine, taking the mathematical model of the drill in the stress field of shaft bottom as theoretical basis. Taking linear elastic and nonlinear features of element material into consideration, we establish element model in the stress field of shaft bottom and material model of stratum rock. Furthermore, we use the finite element method to numerically simulate the fragment intake effect of the super drills with diameter of 400mm and 800mm respectively. The result can be applied in the field of mine exploiting and tunnel advancement.

INFLUENCE THE QUENCHING AND TEMPERING ON THE MICROSTRUCTURE, MECHANICAL PROPERTIES AND SURFACE ROUGHNESS, OF MEDIUM CARBON STEEL

2018 ◽  
Vol 18 (1) ◽  
pp. 125-135
Author(s):  
Sattar H A Alfatlawi
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Surface Roughness ◽  
Carbon Steel ◽  
Cold Water ◽  
Medium Carbon Steel ◽  
Medium Carbon ◽  
Heating And Cooling ◽  
Treatment Processes ◽  
Quenching And Tempering

One of ways to improve properties of materials without changing the product shape toobtain the desired engineering applications is heating and cooling under effect of controlledsequence of heat treatment. The main aim of this study was to investigate the effect ofheating and cooling on the surface roughness, microstructure and some selected propertiessuch as the hardness and impact strength of Medium Carbon Steel which treated at differenttypes of heat treatment processes. Heat treatment achieved in this work was respectively,heating, quenching and tempering. The specimens were heated to 850°C and left for 45minutes inside the furnace as a holding time at that temperature, then quenching process wasperformed in four types of quenching media (still air, cold water (2°C), oil and polymersolution), respectively. Thereafter, the samples were tempered at 200°C, 400°C, and 600°Cwith one hour as a soaking time for each temperature, then were all cooled by still air. Whenthe heat treatment process was completed, the surface roughness, hardness, impact strengthand microstructure tests were performed. The results showed a change and clearimprovement of surface roughness, mechanical properties and microstructure afterquenching was achieved, as well as the change that took place due to the increasingtoughness and ductility by reducing of brittleness of samples.

Rolling Resistance Calculation Procedure Using the Finite Element Method

2019 ◽  
Vol 48 (3) ◽  
pp. 224-248
Author(s):  
Pablo N. Zitelli ◽  
Gabriel N. Curtosi ◽  
Jorge Kuster
Keyword(s):  
Finite Element ◽  
Energy Dissipation ◽  
Rolling Resistance ◽  
Element Model ◽  
The Finite Element Method ◽  
Temperature Changes ◽  
Rubber Compounds ◽  
Different Temperatures ◽  
Materials Used ◽  
Account Temperature

ABSTRACT Tire engineers are interested in predicting rolling resistance using tools such as numerical simulation and tests. When a car is driven along, its tires are subjected to repeated deformation, leading to energy dissipation as heat. Each point of a loaded tire is deformed as the tire completes a revolution. Most energy dissipation comes from the cyclic loading of the tire, which causes the rolling resistance in addition to the friction force in the contact patch between the tire and road. Rolling resistance mainly depends on the dissipation of viscoelastic energy of the rubber materials used to manufacture the tires. To obtain a good rolling resistance, the calculation method of the tire finite element model must take into account temperature changes. It is mandatory to calibrate all of the rubber compounds of the tire at different temperatures and strain frequencies. Linear viscoelasticity is used to model the materials properties and is found to be a suitable approach to tackle energy dissipation due to hysteresis for rolling resistance calculation.

Analysing Mechanical Systems in Domestic and Foreign CAD Systems

2018 ◽  
pp. 10-17
Author(s):  
V. A. Martynyuk ◽  
V. A. Trudonoshin ◽  
V. G. Fedoruk
Keyword(s):  
Sheet Material ◽  
The Finite Element Method ◽  
Cad Systems ◽  
Cad System ◽  
Software Products ◽  
Foreign Products ◽  
Nonlinear Algebraic Systems ◽  
Software Product ◽  
Pipeline Design ◽  
The Mathematical Model

The article considers applications of foreign CAD-systems in creating the challenging projects at domestic enterprises and design bureaus. As stated in the article "... presently, there is no domestic CAD-system that could completely replace such foreign products as NX, CATIA, Credo". Besides, due to international cooperation in creating the challenging projects (for example, the project to create a modern wide-body aircraft, proposed jointly with China), it makes sense to use the worldwide known and popular CAD systems (the aforementioned NX, CATIA, Credo). Therefore, in the foreseeable future, we will still have to use foreign software products. Of course, there always remains a question of the reliability of the results obtained. Actually, this question is always open regardless of what software product is used - domestic or foreign. This question has been haunting both developers and users of CAD systems for the last 30 to 40 years. But with using domestic systems, it is much easier to identify the cause of inaccurate results and correct the mathematical models used, the methods of numerical integration applied, and the solution of systems of nonlinear algebraic systems. Everything is much more complicated if we use a foreign software product. All advertising conversations that there is a tool to make the detected errors available to the developers, remain only conversations in the real world. It is easily understandable to domestic users, and, especially, to domestic developers of similar software products. The existing development rates and competition for potential buyers dictate a rigid framework of deadlines for releasing all new versions of the product and introducing the latest developments into commercial product, etc. As a result, the known errors migrate from version to version, and many users have accepted it long ago. Especially, this concerns the less popular tools rather than the most popular applications (modules) of a CAD system. For example, in CAD systems, the "Modeling" module where geometric models of designed parts and assembly units are created has been repeatedly crosschecked. But most of the errors are hidden in applications related to the design of parts from sheet material and to the pipeline design, as well as in applications related to the analysis of moving mechanisms and to the strength or gas dynamic analysis by the finite element method.The article gives a concrete example of a moving mechanism in the analysis of which an error was detected using the mathematical model of external influence (a source of speed) in the NX 10.0 system of Siemens.

POTOMAC

Alloy Digest ◽  
1975 ◽  
Vol 24 (8) ◽  
Keyword(s):  
Fracture Toughness ◽  
High Temperature ◽  
Heat Treating ◽  
General Purpose ◽  
Low Carbon ◽  
Repeated Heating ◽  
Temperature Changes ◽  
Heating And Cooling ◽  
Temperature Performance ◽  
Heat Checking

Abstract POTOMAC is a general-purpose, low-carbon, chromium-molybdenum-tungsten hot-work steel. It has excellent resistance to shock and heat checking after repeated heating and cooling. Potomac is suitable for hot-work applications involving severe conditions of shock and sudden temperature changes. This datasheet provides information on composition, physical properties, hardness, and tensile properties as well as fracture toughness. It also includes information on high temperature performance as well as forming, heat treating, and machining. Filing Code: TS-290. Producer or source: Allegheny Ludlum Corporation.

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