Residual Deformation of a Hard-Coated Valve Seat Subjected to Thermal Shocks

2010 ◽  
Author(s):  
Jean-Philippe Mathieu ◽  
Jean-Franc¸ois Rit ◽  
Je`roˆme Ferrari ◽  
David Hersant
Keyword(s):  
Welding Process ◽  
Residual Deformation ◽  
The Body ◽  
Dominant Effect ◽  
Welding Temperature ◽  
Physical Test ◽  
Physical Testing ◽  
A Chain ◽  
Globe Valve ◽  
Thermal Shocks

Most safety related valves in EDF’s nuclear plant must prove their ability to sustain thermal shocks of approximately 240K amplitude. This paper evaluates the simulation of a globe valve tested for thermal shocks. Since the physical test campaign showed inadequate internal sealing, the simulation focuses on the residual deformation of the hard alloy, planar seat, welded on successive body designs. This deformation is the result of the thermal loadings first induced by the welding process, then by fluid flow inside the valve. A chain of 3D simulations successively computes: a welding temperature transient in the body, the resulting strain hardening — especially in the seat vicinity —; temperature transients in the flow and the valve parts, and the resulting strains in the body causing a bump deformation of the seat surface. This end result agrees with measurements on the tested valve specimen. We show that inaccurate results are obtained on simpler assumptions, such as no welding, and we give insights on the dominant effect of the first hot, cold, hot transient over other profiles. Finally, the agreement we obtain on deformation predictions is toned down by an unsatisfactory sealing prediction, as well as the complexity and duration of the simulation chain compared with physical testing.

On the Influence of Flows in Clearances for Thermal Shocks in a Globe Valve

2017 ◽  
Author(s):  
Sébastien Meunier ◽  
Jérôme Ferrari ◽  
Jean-François Rit ◽  
David Hersant ◽  
Jean-Philippe Mathieu
Keyword(s):  
Nuclear Power ◽  
Simulation Models ◽  
Operating Conditions ◽  
The Body ◽  
Hot Water ◽  
Entire Height ◽  
Simulation And Experiment ◽  
Globe Valve ◽  
Thermal Shocks ◽  
Good Agreement

In a nuclear power plant, the functionality of valves must be proven under severe operating conditions. Thermal shocks of approximately 225°C are part of the qualification tests, that fulfill this demonstration. Such shocks are studied here on a large globe valve (nominal diameter: 150 mm), experimentally and numerically. The experimental campaign is carried out on the testing loop “CYTHERE” of EDF. 14 thermal shocks are performed successively in pressurized cold and hot water. The tested valve is equipped with 37 thermocouples distributed over its entire height. The 12 studs of the body-bonnet flange are instrumented with strain gauges, which allow the tracking of the clamping forces evolution in the flange. A 3D numerical simulation of such a shock in the valve is performed. It is carried out by a chained multiphysics simulation: fluid, heat conduction and finally mechanics. The mechanical simulation models around 40 different parts with numerous contacts. Two versions of this simulation are presented, the second one takes into account a heat transfer taking place in clearances. A good agreement between simulation and experiment is shown for temperature in the studs. For clamping forces, only the second simulation manage to reproduce tightening variations observed experimentally at the beginning of cold and hot shocks.

Experimental Investigations on Aluminium Ultrasonic Welding Parameters

2014 ◽  
Vol 657 ◽  
pp. 306-310
Author(s):  
Lăcrămioara Apetrei ◽  
Vasile Rață ◽  
Ruxandra Rață ◽  
Elena Raluca Bulai
Keyword(s):  
Microstructural Analysis ◽  
Base Material ◽  
Welding Process ◽  
Ultrasonic Welding ◽  
Experimental Investigations ◽  
Welding Parameters ◽  
Material Structure ◽  
Welding Temperature ◽  
Wide Range ◽  
Made In

Research evolution timely tendencies, in the nonconventional technologies field, are: manufacture conditions optimization and complex equipments design. The increasing of ultrasonic machining use, in various technologies is due to the expanding need of a wide range materials and high quality manufacture standards in many activity fields. This paper present a experimental study made in order to analyze the welded zone material structure and welding quality. The effects of aluminium ultrasonic welding parameters such as relative energy, machining time, amplitude and working force were compared through traction tests values and microstructural analysis. Microhardness tests were, also, made in five different points, two in the base material and three in the welded zone, on each welded aluminium sample. The aluminum welding experiments were made at the National Research and Development Institute for Welding and Material Testing (ISIM) Timişoara. The ultrasonic welding temperature is lower than the aluminium melting temperature, that's so our experiments reveal that the aluminium ultrasonic welding process doesn't determine the appearance of moulding structure. In the joint we have only crystalline grains deformation, phase transformation and aluminium diffusion.

Welding Stress Numerical Simulation and Analysis of High-Pressure Pipeline

2014 ◽  
Vol 912-914 ◽  
pp. 890-894
Author(s):  
Lei Zhang ◽  
Jin Zhou Zhang ◽  
Xiao Ming Li
Keyword(s):  
High Pressure ◽  
Welding Process ◽  
Source Model ◽  
Heat Source Model ◽  
Welding Stress ◽  
Welding Temperature ◽  
Welding Arc ◽  
Pressure Pipeline ◽  
Pipeline Welding ◽  
High Pressure Pipeline

Welded stress has an important impact on quality and life of of high-pressure pipeline. Based on pipeline material performance, considered welding arc force and its mining action, selected double ellipsoidal heat source model, simulated welding process of of high-pressure pipeline, analysised welding temperature field and stress field, determined the distribution disciplines of welding stress, provides useful help on exploring the disciplines of pipeline welding.

scholarly journals Effect of Trailing Intensive Cooling on Residual Stress and Welding Distortion of Friction Stir Welded 2060 Al-Li Alloy

2018 ◽  
Vol 37 (5) ◽  
pp. 397-403 ◽  
Author(s):  
Shude Ji ◽  
Zhanpeng Yang ◽  
Quan Wen ◽  
Yumei Yue ◽  
Liguo Zhang
Keyword(s):  
Residual Stress ◽  
Friction Stir Welding ◽  
Plastic Strain ◽  
Welding Process ◽  
Butt Joint ◽  
Welding Distortion ◽  
Welding Temperature ◽  
Friction Stir ◽  
Numerical Simulation Methods ◽  
Conventional Cooling

AbstractTrailing intensive cooling with liquid nitrogen has successfully applied to friction stir welding of 2 mm thick 2060 Al-Li alloy. Welding temperature, plastic strain, residual stress and distortion of 2060 Al-Li alloy butt-joint are compared and discussed between conventional cooling and trailing intensive cooling using experimental and numerical simulation methods. The results reveal that trailing intensive cooling is beneficial to shrink high temperature area, reduce peak temperature and decrease plastic strain during friction stir welding process. In addition, the reduction degree of plastic strain outside weld is smaller than that inside weld. Welding distortion presents an anti-saddle shape. Compared with conventional cooling, the reductions of welding distortion and longitudinal residual stresses of welding joint under intense cooling reach 47.7 % and 23.8 %, respectively.

scholarly journals Research Regarding Physical Testing in the Military Pentathlon at the 50 M Race with Obstacles

2019 ◽  
Vol 24 (1) ◽  
pp. 29-37
Author(s):  
Ioan Sabin Sopa ◽  
Marcel Pomohaci
Keyword(s):  
Research Methods ◽  
Statistical Significance ◽  
Control Group ◽  
Military Students ◽  
Physical Test ◽  
Two Samples ◽  
Physical Testing ◽  
Experiment Method ◽  
The Military

Abstract The research started from the necessity of finding new ways to physical test the military students that are part of the military pentathlon 50 m race with obstacles team. The research methods used was the experiment method, using two groups: the first group was the control group and the second the experiment group. The experiment consisted in testing the students at: 50 m speed running, 800 m resistance running, push-ups, and specific testing like: 50 m swimming with obstacles, 8 km run in varied terrain. The results of our investigation showed that calculation of the statistical significance of the differences between the averages of the two samples showed significant values at p>0.05, n-1, at the following parameters: running 800 m (t = 2.71> 2.13 - p = 0.05); push-ups (t = 3.01> 2.95 - p = 0.05); freestyle swimming 50m (t = 2.81> 2.13 - p = 0.05).

scholarly journals THE INFLUENCE OF METISEVIT AND METIFEN ON THE INTENSITY OF LIPID PER OXIDATION IN THE BLOOD OF BULLS ON NITRATE LOAD

2016 ◽  
Vol 18 (3(70)) ◽  
pp. 67-71 ◽  
Author(s):  
B.V. Gutyj ◽  
D.F. Hufriy ◽  
V.M. Hunchak ◽  
I.I. Khariv ◽  
N.D. Levkivska ◽  
...  
Keyword(s):  
The Body ◽  
Oxidation Products ◽  
Depressing Effect ◽  
Chain Reaction ◽  
Diene Conjugates ◽  
Inactive Compound ◽  
Nitrite Toxicity ◽  
Nitrate Load ◽  
Young Cattle ◽  
A Chain

The level of primary and secondary lipid per oxidation products were investigated: diene conjugates and malondialdehyde in conditions of nitrate loading. It was established that at bulls feeding with sodium nitrite at a dose of 0.2 hNO3ˉ/kg of body weight, the level of diene conjugates and malondialdehyde in their was increased during the entire the experiment. On the 30thday of the experiment the level of diene conjugates in blood of bull, which were conducted with nitrate load was 7.44 ± 0.15 mmol/l, and the level of malondialdehyde – 0.305 ± 0.014 mmol/l.Under conditions of nitrate load , young cattle was used a new integrated drug «Metisevit», which consists of sodium selenite, vitamin E and metifen. It was found the stimulating effect of metifen and metisevit on antioxidant system of the body of young cattle. Depressing effect of metifen and metisevit on the processes and lipid per oxidation in the blood of bulls under conditions of chronic nitrate–nitrite toxicity. Metifen and metisevit interact with radicals of fatty acids and delay the development of a chain reaction of oxidative stress, reduce the oxidation of phospholipids and form a biologically inactive compound with products of per oxidation of fats. Obtained results of the research indicate antioxidant drugs «Metisevit» and «Metifen» in the application of their young cattle.The mentioned changes are occurring through the comprehensive action of the drug components «Medisvit», that leads to the normalization of metabolic processes and free radical in the body of bulls. Obtained results of the research indicate the antioxidant action of the drugs «Metisevit» and «Metifen» in the application of their young cattle and the reasonableness of their administration to improve the antioxidant status of the organism according to nitrate loading.

scholarly journals Endoscopic removal of metal foreign bodies by magnet: case report

2020 ◽  
Vol 10 (4) ◽  
pp. 467-472
Author(s):  
Vladimir I. Petlakh ◽  
Vladimir A. Borovitsky ◽  
Alexander K. Konovalov ◽  
Natalya N. Strogova
Keyword(s):  
Case Report ◽  
Conservative Therapy ◽  
Foreign Bodies ◽  
Intestinal Wall ◽  
The Body ◽  
Surgical Interventions ◽  
Number Of Children ◽  
The Past ◽  
A Chain ◽  
The Right

The number of children swallowing magnetic foreign bodies has been a significantly high for the past decades, increasingly needing endoscopic or surgical interventions. Case report. In our observation, a 12-year-old girl swallowed magnetic balls from childrens designer 10 days prior to hospital admission. Foreign bodies (5 balls) were found during X-ray examination in the projection of the cecum. Conservative therapy carried out for 4 days had no success, thus colonoscopy was performed to remove foreign bodies. Foreign bodies were fixed to the intestinal wall, and attempts to separate them were unsuccessful. When a medical magnet was placed outside the body in the right iliac region, a chain of magnetic balls detached from the intestinal wall and made it possible to be captured in a trap loop and be removed. The girl avoided a laparotomy with an opening of the colon. Conclusion. External use of a medical magnet is effective for navigation and assistance during colonoscopic extraction when magnetic foreign bodies are found in the colon.

Investigation on the Allowable Temperature During Electrofusion Welding of Polyethylene Pipe

2012 ◽  
Author(s):  
Sijia Zhong ◽  
Jianfeng Shi ◽  
Weican Guo ◽  
Jinyang Zheng
Keyword(s):  
Molecular Weight ◽  
Thermal Degradation ◽  
Carbon Number ◽  
Welding Process ◽  
Gel Permeation Chromatography ◽  
Degradation Process ◽  
Pipe Material ◽  
Welding Temperature ◽  
Lower Temperature ◽  
Allowable Temperature

Polyethylene (PE) pipe material may degrade into lower carbon number volatiles quickly during the electrofusion welding process when the welding temperature rises up to more than about 370°C. Meanwhile, PE may also degrade into lower molecular weight (MW) polymer when subject to a lower temperature. As a result, the allowable temperature during electrofusion welding is uncertain. In this paper, a typical PE100 material was chosen to conduct thermogravimetic analysis (TGA) and Gel permeation chromatography (GPC) test. The thermal degradation behavior of PE100 was investigated in Dynamic and isothermal mode. And the composition of the thermal degradation residue was determined through MW and molecular weight distribution (MWD) measurements of the residue. Based on the experimental results, the initial temperature of thermal degradation with volatilization was derived and the thermal degradation process was studied in detail. To limit the thermal degradation degree of PE in a required range in thermal welding process, the preliminary allowable welding temperature for typical commercial PE100 material was determined. In addition, some regular information was obtained, which could promote the ultimate determination of the allowable welding temperature.

CAE Data Management Using Traditional PDM Systems

2004 ◽  
Author(s):  
Alhad A. Joshi
Keyword(s):  
Data Management ◽  
Product Design ◽  
Data Model ◽  
Process Management ◽  
Low Cost ◽  
Data Types ◽  
Physical Test ◽  
Design Alternatives ◽  
Physical Testing ◽  
Warranty Costs

Over the past decade, Computer Aided Engineering (Simulation) has experienced explosive growth being a significant enabler for: 1. Validating product design; 2. Providing low-cost methods for exploring a variety of product design alternatives; 3. Optimizing parts for better service performance; 4. Reducing dependence on physical testing; 5. Reducing warranty costs; 6. Achieving faster time to market. This rapid growth in the number of simulations performed and the amount of data generated in the absence of any significant data and process management initiatives has led to considerable inefficiencies in the CAE domain. Many companies now recognize the need to manage their CAE process and data as well as their desire to leverage their existing PDM systems as the primary repositories of CAE data. Some major issues are: 1. There is a need for a PDM data model to support CAE; 2. The CAE data model can be very complex; 3. There is an immense variety of CAE applications and data types; 4. Many CAE simulations require access to physical test data for input and correlation; 5. Data management discipline is not typically part of the CAE culture today. Despite the unique challenges posed by bringing PDM into the CAE world, the transition could occur faster than it has in the CAD world. This presentation will showcase an approach for managing CAE data in traditional PDM systems. Two working examples of CAE process automation software solutions integrated with CAD and PDM will be discussed. In particular, these applications will show how CAE users can leverage established PDM infrastructure and interact with EDS’ Teamcenter/Enterprise, Teamcenter/Engineering and Dassault Systeme’s SmarTeam through seamless integrations with their CAE systems.

Temperature Field and Residual Stress Analysis of the Gear on CO2 Laser Welding Process

2011 ◽  
Vol 86 ◽  
pp. 670-673
Author(s):  
Jian Luo ◽  
Fei Li ◽  
Ke Liang Xue ◽  
De Jia Liu ◽  
Hai Wei Zhang
Keyword(s):  
Residual Stress ◽  
Temperature Field ◽  
Laser Welding ◽  
Welding Process ◽  
Welding Residual Stress ◽  
Temperature Cycle ◽  
Residual Tensile Stress ◽  
Welding Seam ◽  
Welding Temperature ◽  
Laser Welding Process

The welding technique is one of important technologies on the gear manufacturing process. The special welding temperature cycle is the basic conditions of the welding residual stress appearance in the gear. The large welding residual stress will create the large deformation after the gear welding, which will affect the gear service behavior. In this paper, the finite element method has used to simulate the gear laser welding process. The temperature field and residual stress has described. The research results show that the biggest residual compressive stress appears on the transverse direction of welding region. In the longitudinal direction, the biggest residual tensile stress appears on both sides of the welding seam line. When the laser welding power is 2.4 kW and welding speed is 20mm/s, the no apparent welding deformation’s 20CrMnSi gear can be achieved really.

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