Analysis of Damage of Solder Joint of Heat Exchanger

2017 ◽  
Vol 270 ◽  
pp. 63-67
Author(s):  
Pavel Gejdoš ◽  
Lenka Klakurková ◽  
Martin Juliš ◽  
Miroslava Horynová ◽  
Lucie Páleníková ◽  
...  
Keyword(s):  
Heat Exchanger ◽  
Solder Joint ◽  
Austenitic Steel ◽  
Metallographic Analysis ◽  
High Alloy ◽  
Pressure Test ◽  
The Subject ◽  
Microstructure Of The Material ◽  
Soldered Joint ◽  
Eds Microanalysis

The paper focus on the metallographic analysis of damaged heat exchanger made of high‑alloy austenitic steel by soldering. The object in question is a soldered joint of main mounting plate of the heat exchanger and first heat exchanging plate of it. In this part of the heat exchanger after the vibration and pressure test crack appeared. The subject of the analysis is the evaluation of the microstructure of the solder joint (high-alloy austenitic steel and copper), and evaluation of the appeared crack. The problematic is solved with aid of metallographic analysis of the microstructure of the material, using light microscopy and scanning electron microscopy and the EDS microanalysis of chemical composition.

Analysis of Coupling Segment of Belt Conveyor

2015 ◽  
Vol 647 ◽  
pp. 210-215
Author(s):  
Lenka Klakurková ◽  
Ladislav Čelko ◽  
Martin Juliš ◽  
David Jech ◽  
Jiří Švejcar
Keyword(s):  
Base Material ◽  
Design Solution ◽  
Metallographic Analysis ◽  
Component Part ◽  
Belt Conveyor ◽  
High Alloy ◽  
The Subject ◽  
Microstructure Of The Material ◽  
Eds Microanalysis

The paper focuses on the metallographic analysis of damaged belt-conveyor coupling segments made of high-alloy austenitic steel. The object in question is a weldment – a bar with a ring welded on it at either end. The subject of the analysis is the evaluation of the microstructure of the base material of the two components (weldment and weld metal), the quality of the execution of the weld joints, subsequent heat treatment of the weldment, and the overall state of the component part after operational loading. The suitability of the design solution of the whole weldment is also discussed. The problematic is solved with the aid of a metallographic analysis of the microstructure of the material, using light microscopy, scanning electron microscopy inclusive of the EDS microanalysis of chemical composition, and microhardness measurement.

Metallographic Analysis of Stainless Steel Inner Shaft of Centrifugal Pump

2020 ◽  
Vol 405 ◽  
pp. 223-228
Author(s):  
Pavel Gejdoš ◽  
Lenka Klakurková ◽  
Martin Juliš
Keyword(s):  
Electron Microscopy ◽  
Stainless Steel ◽  
Centrifugal Pump ◽  
Metallographic Analysis ◽  
Transmitted Power ◽  
Magnetic Clutch ◽  
Routine Work ◽  
Microstructure Of The Material ◽  
Eds Microanalysis ◽  
Scanning Electron

The paper focuses on the metallographic analysis of the damaged inner shaft of a centrifugal pump with a magnetic clutch. This pump was used for the pumping of viscous suspensions. The damaged part of the centrifugal pump was made of stainless steel and transmitted power from the magnetic clutch to the impeller of the pump. The pump was overhauled by the Manufacturer after ten years of routine work. Slightly worn parts of the pump, including the inner stainless steel shaft, were replaced by the Manufacturer according to the preserved documentation. The overhauled pump failed after two days of running in the original conditions. The problematic is solved by an analysis of three used inner shafts with the aid of a metallographic analysis of the microstructure of the material, using light microscopy and scanning electron microscopy, and an EDS microanalysis of the chemical composition and hardness measurements.

Effects of structural inhomogeneities on the steel balls resistance to loading

2020 ◽  
pp. 29-38
Author(s):  
O. B. Berdnik ◽  
I. N. Tsareva ◽  
L. A. Krivina ◽  
S. V. Kirikov ◽  
S. I. Gerasimov ◽  
...  
Keyword(s):  
Brittle Fracture ◽  
Bearing Steel ◽  
Metallographic Analysis ◽  
Structural Factors ◽  
Steel Shkh15 ◽  
Maximum Hardness ◽  
High Shock ◽  
Steel Balls ◽  
Plasticity Coefficient ◽  
Microstructure Of The Material

When conducting impact tests of protective glasses, nonunique cases of destruction of balls made of bearing steel ShKh15 were recorded. The causes of their destruction were determined. The state of the material was studied by fractographic and metallographic analysis, hardness and microhardness measurement. In the structure of the metal of all the balls, no critical defects were found such as flockens, shells and microcracks, but adverse factors were detected in the microstructure of the material, namely, the presence of fineneedle martensite with excessive carbides. It is established that the detected structural factors lead to liability to brittle fracture, an increase in the hardness of the material, a decrease in plasticity. To prevent brittle fracture of the balls and provide a reserve of plasticity of steel ShKh15 at high shock loads assessment calculations of ductility coefficient were made; and it was recommended to limit the maximum hardness of the material critical value HV=5.70 HPa (54 HRC), with the corresponding plasticity coefficient equal to 0.8.

scholarly journals Semi-Hybrid CO2 Laser Metal Deposition Method with Inter Substrate Buffer Zone

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 720
Author(s):  
Bogdan Antoszewski ◽  
Hubert Danielewski ◽  
Jan Dutkiewicz ◽  
Łukasz Rogal ◽  
Marek St. Węglowski ◽  
...  
Keyword(s):  
Structural Steel ◽  
Co2 Laser ◽  
Hybrid Method ◽  
Steel Substrate ◽  
Metal Deposition ◽  
Inconel 625 ◽  
Metallographic Analysis ◽  
Deposition Method ◽  
High Alloy ◽  
Powder Deposition

This article presents the results of the metal deposition process using additive materials in the form of filler wire and metal powder. An important problem in wire deposition using a CO2 laser was overcome by using a combination of the abovementioned methods. The deposition of a multicomponent alloy—Inconel 625—on a basic substrate such as structural steel is presented. The authors propose a new approach for stopping carbon and iron diffusion from the substrate, by using the Semi-Hybrid Deposition Method (S-HDM) developed by team members. The proposed semi-hybrid method was compared with alternative wire and powder deposition using laser beam. Differences of S-HDM and classic wire deposition and powder deposition methods are presented using metallographic analysis, within optic and electron microscopy. Significant differences in the obtained results reveal advantages of the developed method compared to traditional deposition methods. A comparison of the aforementioned methods performed using nickel based super alloy Inconel 625 deposited on low carbon steel substrate is presented. An alternative prototyping approach for an advanced high alloy materials deposition using CO2 laser, without the requirement of using the same substrate was presented in this article. This study confirmed the established assumption of reducing selected components diffusion from a substrate via buffer layer. Results of metallographic analysis confirm the advantages and application potential of using the new semi-hybrid method for prototyping high alloy materials on low alloy structural steel substrate.

scholarly journals Numerical and experimental investigation of alumina-based nanofluid effects on double-pipe heat exchanger thermal performances

2021 ◽  
Vol 3 (2) ◽  
Author(s):  
A. Bendaraa ◽  
My. M. Charafi ◽  
A. Hasnaoui
Keyword(s):  
Heat Exchanger ◽  
Volume Fraction ◽  
Convective Heat Transfer Coefficient ◽  
Deionized Water ◽  
Comsol Multiphysics ◽  
Exchange Coefficient ◽  
The Subject ◽  
Double Pipe ◽  
Pipe Heat ◽  
Thermoelectric Power Plant

AbstractIn this study, we investigate the thermal behaviour of nanofluids in a double-pipe heat exchanger. It is about a counterflow configuration, designed to cool a lubrication unit of a thermoelectric power plant. The subject of this work is to evaluate the thermal performances of the exchanger by using a nanofluid based on alumina suspension comparing with deionized water. In order to evaluate the thermal performance of the studied configuration, we carried out numerical experiments in an application developed on COMSOL Multiphysics environment, these experiments are utilized to show the feasibility of this application. As result, we found that the nanofluid with an increase in its volume fraction leads to an increase in the overall exchange coefficient, the convective heat transfer coefficient, as well as the efficiency and the power of the exchanger. It is noted that an increase of 1% in volume fraction, can enhance the overall exchange coefficient, the power and the effectiveness of the exchanger by 17.62%, 1.473% and 10.80% respectively. Besides, it is noted that the increase in the concentration of nanofluids leads to a narrowing of the pinch points of the inlet and outlet temperatures, which means that nanofluids are more efficient in cooling temperatures than conventional fluids.

The Potential Danger of Fire in Gas Turbine Heat Exchangers

1969 ◽  
Author(s):  
C. F. McDonald
Keyword(s):  
Heat Exchanger ◽  
Gas Turbine ◽  
Heat Exchangers ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Engine Operation ◽  
Exhaust Heat ◽  
The Subject ◽  
Gas Turbine Cycle

Increased emphasis is being placed on the regenerative gas turbine cycle, and the utilization of waste heat recovery systems, for improved thermal efficiency. For such systems there are modes of engine operation, where it is possible for a metal fire to occur in the exhaust heat exchanger. This paper is intended as an introduction to the subject, more from an engineering, than metallurgical standpoint, and includes a description of a series of simple tests to acquire an understanding of the problem for a particular application. Some engine operational procedures, and design features, aimed at minimizing the costly and dangerous occurrence of gas turbine heat exchanger fires, are briefly mentioned.

Analysis of the Gasket Damage and Sealing Performance for the Thread Ring Block Heat Exchanger

2019 ◽  
Author(s):  
Fakun Zhuang ◽  
Wen Sui ◽  
Guoshan Xie ◽  
Shanshan Shao ◽  
Zhiyuan Han ◽  
...  
Keyword(s):  
High Temperature ◽  
Heat Exchanger ◽  
Metallographic Analysis ◽  
Tube Sheet ◽  
Operational Conditions ◽  
Term Operation ◽  
High Temperature And Pressure ◽  
Sealing Performance ◽  
Temperature And Pressure ◽  
Gasket Material

Abstract The thread ring block heat exchangers, served at the high temperature and pressure, are the key equipment in the petrochemical industry. Due to the severe operational conditions and unsuitable assemble, internal leakage problem commonly occurs, especially for the seal gasket between the tube sheet and shell. Many failed gaskets are collected. Through a series of experiments including chemical composition, metallographic analysis, SEM and fracture analysis, the gasket damage and leakage causes are analyzed. For further interpretation, the gasket stress analysis is completed by the finite element method. It shows that the gasket stress is a main factor that affects the sealing performance for the thread ring block heat exchanger. Under long term operation at high temperature and pressure, the gasket stress between the tube sheet and shell becomes loose and creep. The gasket material also deteriorates with increasing time. Therefore, in order to prevent the internal leakage, the stress should be controlled in an appropriate range. And periodical inspection must be performed.

Study on the Mechanical Bend Fatigue of Micro-Joining Soldered Joint with Lead-Free Solder

2007 ◽  
Vol 353-358 ◽  
pp. 2573-2576 ◽  
Author(s):  
Fang Juan Qi ◽  
Li Xing Huo ◽  
Ya Ping Ding ◽  
Zhan Lai Ding
Keyword(s):  
Solder Joint ◽  
Failure Modes ◽  
Lead Free ◽  
Joint Interface ◽  
Similar Data ◽  
Lead Free Solder ◽  
Fatigue Reliability ◽  
Free Solder ◽  
Halogen Free ◽  
Soldered Joint

In recent years, several electronics manufacturers have been working toward introducing lead-free solder and halogen-free print circuit boards (PCBs) into their products. The key drivers for the change in materials have been the impending environmental legislations, particularly in Europe and Japan as well as the market appeal of ‘green’ products. The reliability of the new materials is an important determinant of the pace of adoption. Fairly extensive mechanical fatigue reliability data is also available for micro-joining soldered joint such as Ball Grid Array (BGA) with tin-lead solder. However, similar data is not available for BGAs assembled with lead-free solder. Mechanical reliability is a critical indicator for phone and BGA survival during repeated keypress, and to some extent during drop. In this paper, the mechanical bend fatigue of BGAs with tin-lead and lead-free solders on halogen-free substrates are examined respectively. A tin-silver-copper alloy was used as lead-free solder due to its increasing acceptance, and the results were compared to those from samples assembled with Sn63Pb37 solder. The reliability was examined at both low cycle and high cycle fatigue. Results show that the mechanical bend fatigue reliability of BGA assemblies with lead-free solder is higher than that of BGA assembly with tin-lead solder. Cross section and failure analysis indicated two distinct failure modes - solder joint and PCB failure. A 3-D parametric finite element model was developed to correlate the local PCB strains and solder joint plastic strains with the fatigue life of the assembly. The intermetallic compoumd (IMC) of micro-joining joint interface was analysised in the future in order to study on the effect of IMC on the reliability.

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