scholarly journals Experimental and Finite Element Investigation of Annealing on the Torsional Aspects of Carbon Steel St35

2012 ◽  
Vol 2 (6) ◽  
pp. 135-139
Author(s):  
Hani Aziz Ameen ◽  
Khairia Salman Hassan ◽  
Muwafaq Mahdi Salah
Keyword(s):  
Author(s):  
Ali Keshavarz ◽  
Andrew K. Ali ◽  
Randy K. Lall

Flow-accelerated corrosion (FAC) is a phenomenon that results in metal loss from piping, vessels and equipment made of carbon steel. This metal loss can lead to stress to occur at the steam inlet nozzle side, where it is located at the side of the deaerator. This paper presents a method to find the thickness critical of the steam inlet nozzle. A Finite Element (FE) model of the pressure vessel head was created to perform a stress analysis using NX Nastran 5.0. By applying materials properties, loads and constraints to the model, the results obtained are required to satisfy the following criterion: vonMises≥SySy=YieldStrength The results obtained from the stress analysis were analyzed to obtain a corrosion allowance and it was compared to the recommended value from a normal deaerator design, which is roughly 0.25 inches. From the FE model, and by continuously reducing the thickness of the nozzle, it was determined that the corrosion allowance is 0.229 inches, and that the percentage error was 8.4%.


Author(s):  
Warren Brown

In previous papers, practical limits on the maximum applied load for standard ASME B16.5 and B16.47 carbon steel, weld neck pipe flanges were examined. A new code equation for the tangential (hoop) stress at the small end of the hub for a weld neck flange was developed to facilitate calculation of the limits using elastic analysis. The results were verified against elastic-plastic Finite Element Analysis (FEA). In this paper, the work is extended to include other flange configurations, including loose ring flanges, slip-on flanges and flat plate flanges. This paper is a continuation of the papers presented during PVP 2006 and PVP 2007 (Brown [1, 2]) and it extends the scope of the proposed methodology for determining flange stress limits in determining the maximum allowable bolt load for any given flange size and configuration.


Author(s):  
Joginder Singh ◽  
M. R. Tyagi ◽  
Abdul Ahad ◽  
Abhinav Chawla ◽  
Dinesh Kashyap ◽  
...  

Author(s):  
Fadi Al-Badour

Abstract Hybrid Friction Diffusion Bonding (HFDB) is a solid-state welding process that proved its capability of producing sound tube-tubesheet joints, but with limitations on tube thickness (up to 1mm) and tube-tubesheet materials. In the petrochemical industry, there is a great demand for the use of carbon steel shell and tube heat exchangers. To investigate the feasibility of HFDB techniques in joining thicker tube (i.e 2.1 mm) on tubesheet joint, a three-dimensional thermo-mechanical finite element model (FEM) was developed and solved using ABAQUS (commercial finite element analysis (FEA) software). The model was used to predict the temperature distribution and developed stresses during and after welding. The model considered temperature dependent material properties while Johnson-cook model was used to govern material plastic flow behavior. In this paper,19 mm (¾ in) ASTM 179 cold-drawn carbon steel tube into an ASTM A516 Grade 70 tubesheet joints was simulated. Results are validated based on temperature measurements, which was found in good agreement with experimental results. The developed model can be used to optimize processing parameters (i.e. tool rotational speed, dwell time “holding time”, and forging force.. etc) and study their effect on material flow and developed stresses.


Author(s):  
Cameron Ewing

Abstract Stress Intensification Factors or SIFs allow piping to be analyzed using beam theory, with a SIF representing local effects of specific piping geometry. However, the current piping codes do not explicitly provide SIFs for collared type piping joints for use in pipe stress calculations. The objective of this paper is to describe the methodology on how a finite element analysis (FEA) was to model the behavior of collared joints, and to ultimately develop appropriate SIFs that can be used in pipe stress analyses. This paper describes a real-life analysis example on collared joints installed on a set of existing fuel transfer lines. The lines, which ranged in size from DN200 to DN350, were concrete lined carbon steel with the collars fillet welded to the carbon steel section of the piping. Test coupons cut from existing pipe-collar sections were tested in a laboratory to determine the forces required to break the collar welds. Using FEA, the same test coupons were modelled to replicate the failure tests. Multiple iterations were undertaken to determine an appropriate bi-linear stress-strain curve fit for the weld material. The curves of different weld electrode materials were considered. The curve which lead to results similar to those observed in physical testing was selected. From this, a failure stress across the weld could be determined. This stress, 435MPa was then used in subsequent models to determine the point at which the weld fails under bending loads. Multiple tests were analyzed to allow for possible effects of inclusions and voids. Finite element models of the collar geometries were constructed and non-linear analyses were undertaken using the weld strengths determined from the coupon testing data. A simple cantilever type arrangement with a point load at one end was analyzed, inducing a bending moment across the collar. The peak stress resulting from the bending moment across the collar weld at the center of the cantilevered pipe arrangement, was investigated across various pipe diameters, wall thicknesses, weld sizes and collar geometries. Based on the results, a relationship between the pipe geometry and SIF was developed. Hence a pipe stress model of the transfer lines could ultimately be developed using these SIFs to predict the behavior of the piping.


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