Erosion Corrosion Of Materials In A Marine Environment Biology Essay

On

Erosion-Corrosion of Materials in a Marine Environment

By,

Gikku Kurian Joy

Banner ID: 00579401-3

BEng Hons. Mechanical Engineering

Supervisor: Dr Mark S. Bingley

University of Greenwich at Medway

Chatham Maritime, Kent

Acknowledgement

I would like to express my sincere gratitude and appreciation to all who gave me encouragement to successfully complete this final year project. Special thanks to my project supervisor Dr Mark S. Bingley, whose help, stimulating suggestions and valuable thoughts helped me to coordinate this project.

I would also like to acknowledge the assistance by Dr Sabuj Mallik, who helped me in generating microscopic images using SEM, during analysis part for this project. Special thanks to assessor Dr Michael I. Okereke whose, findings and suggestions during presentation which improved the standard of this project. Also to thank is the staff of Mechanical laboratory in Hawke, who gave the permission to use the required tools to work with the experiments.

Last but not least, many thanks to University of Greenwich faculty for providing laboratory and library facilities for the success and completion of this report.

Table of Contents

Abstract

Erosion-Corrosion is the complex phenomenon of solid particle erosion and electrochemical process of corrosion. One of the main areas it’s been seen is the marine industry where the pipes, valves and vessels are exposed to the process leading them to wear and later to damage completely. A wide range of issues are thereby affected when selecting the appropriate materials for this specific use. When selecting a particular material the designer has to consider a number of constraints and parameters which solves the problems. Some of among them are slurry pot test rigs and submerged test conditions which will provide enough data to work with the selection of appropriate material.

The aim of this work is to examine the wear rate caused in engineering materials like Copper, Brass and Stainless Steel. The study reveals the particle wear rate caused in the materials to classify them according to resistance to Erosion-Corrosion. The slurry pot tester is run at different speeds under different Erosive-Corrosive media to acquire test results which will accompany an SEM analysis to conclude the resistance levels.

Chapter 1

1.1 Aim of the Project

The fundamental am of this project is to investigate the effect of Erosion and Corrosion in materials used in marine environments. Therefore, materials like Copper, Brass and Stainless Steel are tested and examined using a slurry pot tester under different particle-fluid conditions. The susceptibility is differed according to the type of material being used. The process will reveal the safe-unsafe flow conditions for the test materials used in marine environments.

1.2 Objectives

To develop a theoretical understanding about Erosion-Corrosion processes.

Identifying the required equipment and resources for the test conditions.

Conduct an experiment involving different materials undergoing Erosion, Corrosion and Erosion-Corrosion process.

Investigating the role of different parameters (flow velocity, sand size, test solution etc.) influencing Erosion-Corrosion.

Collection of data to identify the variation of wear rate in materials undergone tests in different fluid-particle concentrations.

Determining the synergy levels for each material and classifying them relative to its Erosion-Corrosion resistance.

Microscopic analysis (SEM) to generate images which shows any spatial variations and surface roughening happened to the material.

Concluding safe-unsafe flow conditions for the use of test specimen under flow conditions.

1.3 Project Deliverables

Project proposal report

Experimental and analytical data

Determining safe-unsafe flow conditions for engineering materials

A detailed documented literature review on the project

Project logbook

Poster for presentation

Chapter 2

2.1 Introduction

In the recent years, studies related to particle wear in engineering materials have received a substantial attention due to the rigorousness of problems created in relevant fields. Among them is the solid particle erosion-corrosion which affects the marine industry very much due to the damage caused to components like pipelines, valves, turbines, pumps etc. (Rajahram, Harvey, & Wood, 2009)

The constant requirement for water to cool the heat exchangers in plants thereby uses the pipelines to supply flowing seawater at a specific rate. The sand particles in a particular shape and size which are carried by a stream of seawater through the pipes are then combined to cause wear to the material exposed. The application of erosion-corrosion process starts from here as the sand particles acts as an erosive media whereas, the seawater normally with a pH of 7.8 to 8.2 and 3% NaCl acts as a corrosive media. The combined action of both the mediums results in the inner wall of pipes to degrade the material thus resulting in a failure after an average lifetime of 7 years. (Wood, Puget, Trethewey, & Stokes, 1998)

2.2 Marine Environment

Figure 2.1: Corrosion damage to iron rods under a bridge

The marine industry can be broadly categorized into three different sections. Above water (ships and boats), under water (submarines, pipelines) and fixed main structures (wind mills). All the above three are exposed to factors which affects the degradation of materials. The main process to look out for is the corrosion damage which is occurred by the influence of saline water. Most of the engineering materials in marine industry are damaged as a result of corrosion mechanism. The vehicles and other components that are mostly used in seashore areas are exposed to the flowing saline water which gradually starts this process. The electrochemical process of corrosion thus starts in a specific area unless protected by coatings spreads to the other parts gradually thereby wearing out the material completely. [1] http://cce.engr.oregonstate.edu/structural/images/corrosion_1.JPG

Unlike other industries, marine departments have only one thing in common, namely, that they operate in, or upon the surface of, a body of water. Also, the continuous requirement in supply of water in these areas exposes the materials to the process of erosion and corrosion. Components such as pipes, valves and other fittings are highly affected by this process and leads to failure after average lifetime. Therefore materials in these areas have to be clearly identified according to its resistance to erosion and corrosion.

2.3 Applications

The research, experimental and analytical data recorded in this project aids to classify the engineering materials according to their erosion-corrosion resistance. Materials like copper, brass and stainless steel are mostly seen and used in marine fields. Especially copper components like valve fittings are pipes which are more likely to affect the process of both erosion and corrosion. The high resistive features for copper and brass in some cases are less likely to be seen in mechanisms of this kind.

Stainless steel, however being more strong and stiff is nowadays used for components which are subjected to degradation techniques. The results generated in the study are enough to examine the hardness levels of the above materials which are subjected to three different test conditions.

The fields most often seen with erosion and corrosion damage is marine industry where the flowing seawater combined with particles affecting the exposed material. Thus, both processes are examined and evaluated thoroughly to identify the factors affecting wear rates and flow concentrations which may have a role in the process.

Chapter 3

3.1 Theory of Erosion-Corrosion

Material

Direction of fluid flow

Corrosion film

Impingement corrosion pits

Original surface

Figure 3.1: The Erosion-Corrosion process

The mechanical process of erosion and electrochemical process of corrosion are combined to known as Erosion-Corrosion in engineering materials. It occurs in materials when solid particles interact with a corrosive liquid. Erosion occurs when solid particles carried by a stream of liquid or gas hits a target material causing it to deform or fracture. Corrosion on the other hand is the gradual destruction of material when it undergoes a chemical reaction with its environment. The process is most powerful in soft alloys such as, copper, aluminium, lead etc.

The phenomenon is commonly seen in industries like oil and gas, mining, chemical and power where there is an interaction between both erosive and corrosive media resulting in the damage of components. Typical wear of components leads to either repair or replacements which is a liability for industries.(Rajahram, 2010)

Turbulent flow process can destroy the protective films on a material and cause high corrosion rates, otherwise high resistant under static conditions. In a laminar flow, fluid flow rate has variable effect depending on the material. Cavitation is special factor in erosion-corrosion and is caused by formation and collapse of bubbles in liquid near to the material. It removes protective scales on the surface by the implosion of gas bubbles in a fluid causing the material to undergo corrosion.

3.2 Synergism

The material which is subjected to the process of erosion-corrosion experiences an additional wear rate which is normally higher than the sum of wear caused by pure erosion and flow corrosion. This additional wear rate is termed as synergy. Synergism can be expressed as follows; (Rajahram, 2010)

……….…………………………… [Eqn. 3.1]

…………………………………… [Eqn. 3.2]

Where,

T = Total wear due to erosion-corrosion

S = Additional wear caused due to synergistic effects

E = Wear due to pure erosion

C = Wear due to flow corrosion

3.2.1 Positive/Negative Synergy

The additional wear rate caused in materials due to synergistic effects can be either positive or negative depending on the rates of total wear rate (T), pure erosion (E) and flow corrosion (C). Positive synergism is often seen when the total wear rate of the material is higher than the sum of wear rates due to pure erosion and flow corrosion.

Negative synergy is recorded when the sum of pure erosion and flow corrosion is higher than the total wear rate caused. This is termed as antagonism. (Rajahram, 2010)

3.2.2 Components of Synergism

The additional wear rate termed as synergy also consists of two main components which are as follows;

………………………………………. [Eqn. 3.3]

Where,

S = Synergy

∆E = Corrosion enhanced erosion

∆C = Erosion enhanced corrosion

R.J.K. Wood [1] and S.P. Hutton [2] who carried out researches on synergism later went on to publish the two groups of synergy, which are medium and high synergy. Below equations are obtained for these two groups. (Rajahram, 2010)

Medium Synergy group

……………………….. [Eqn. 3.4]

High Synergy group

……………………….. [Eqn. 3.5]

3.2.3 Corrosion enhanced erosion (∆E)

Corrosion enhanced erosion is the phenomenon of cracking a material in pieces when multiple erodent impacts were subjected. A jet impingement test was used to conduct the corrosion enhanced erosion rate which was proposed by Y. Li, G.T. Burstein and I.M. Hutchings [3]. The study showed how corrosion enhances the erosion rates by attacking local targets which leads to propagation of the crack, making the surface susceptible to detachment.(Rajahram, 2010)

Similar researches and findings were proposed by A. Toro, A. Sinatora, D.K. Tanaka A.P. Tschiptschin [4] and A. Neville, T. Hodgkiess, H. Xu [5]. who approached the process experimentally. He performed tests on erosion-corrosion subjecting grey cast iron which strengthened the theory by F. Aiming, L. Jinming and T.Ziyun [6].

3.2.4 Erosion enhanced corrosion (∆C)

Like the process of corrosion enhanced erosion, erosion enhanced corrosion affects a material at a particular region which is subjected to corrosion. The erosion wear affected to the material tend to favour the corrosion rate by destroying the surface continuously. The works put forward by M.M. Stack, S. Zhou and R.C. Newman [7] established an erosion-corrosion map which aided to detect the transition between erosion-corrosion regimes. The study figured the role of passive current density increased with higher velocity in the existence of erosive mediums. As the speed was increased, the passive current was then increased to rupture the surface of the material.

Chapter 4

4.1 Solid Particle Erosion

The process of erosion reflects the contact between solid particles and a carrier fluid which can normally be a stream of liquid or a gas. The erosive media here referred to as solid particles are suspended in the carrier fluid which then on goes to impinge the material surface. The material is then subjected to continuous erosion by damaging the outer surface. This leads the material to either rupture completely or depending on several factors such as velocity of impact, size of particle etc.

The main researches conducted on solid particle erosion are based on the above factors namely, size and shape of solid particles, type and nature of flowing fluid and the type of material characteristics (Rajahram, 2010). Early researches and studies put forward by I.M. Hutchings [8] relates to the forces acting on a solid particle when it is contact with the material surface.

Figure 4.1 below, shows the different forces acting on a solid particle which travels through a stream of liquid media. On contact with the surface of the material the particle experiences forces such as drag, gravitational and forces which results from flowing liquid. Forces are also created when surrounding particles comes into contact with each other. Of all the forces, the significant one is force exerted by surface due to gravity (Rajahram, 2010).

Direction of fluid flow

Surface contact force

Inter particle contact force

Figure 4.1: Forces acting on a solid particle when in contact with a material

Weight

Drag Force

4.2 Flow Corrosion

P. Roberge, B.C. Syrett [9] proposed flow corrosion as the increase in rate of corrosion by the motion of the flowing corrosive fluid. Flow corrosion, a component of synergy, advances the rate of material being corroded from the surface. Thus the exposed surface gets damaged very quickly which then leads to repair or replacement in material.

There are four different types of flow corrosion. In 1996, Heitz [10] recognized and classified them as follows;

Mass transport controlled

Phase transport controlled

Erosion-Corrosion

Cavitation

The picture below best describes the above four processes of flow corrosion.

Direction of fluid flow

Material

Material

Aggressive liquid phase

Collapsing liquid phase

Figure 4.3: Phase transport controlled flow corrosion

Figure 4.2: Mass transport controlled flow corrosion

Material

Particles

Figure 4.4: Erosion-Corrosion phenomenon

Cavitation bubbles

Figure 4.5: Cavitation corrosion in materialsMaterial

Collapsing liquid

4.3 Material removal mechanisms

During the mid of last century, I. Finnie [11] conducted studies on several erosion mechanisms to investigate the different types of material removal techniques. The materials subjected to experiments were ductile and brittle in nature. This revealed the process of displacement and cutting in ductile material, while combination and propagation of cracks in brittle materials lead to subsequent wear (Rajahram, 2010). This research however was not enough to define the erosion rates at normal impact angles.

The breakthrough experiment, which defined both deformation and cutting in materials was conducted by J.G.A. Bitter [12]. The research concluded that both the mechanisms appear in ductile materials. Compared to Finnie’s model, Bitters’ work was able to predict the erosion wear rate in ductile material at normal impact angles [13].

Considering Bitters’ work related to cutting of ductile material, I. M. Hutchings [8] extended proposed three types of mechanisms which removes material at 30O impact angle. They are given below as follows;

Figure 4.6: Ploughing mechanism

Un-eroded area

Eroded area

Crater

Figure 4.7: Type I cutting

Lip formation

Un-eroded area

Eroded area

Figure 4.8: Type II cutting

Eroded area

Un-eroded area

4.4 Factors influencing Erosion rates

The table below serves as a key to identify the general factors that affect the erosion mechanisms in engineering materials. The terms noted are irrespective of the type, size and shape etc. of material being used.

Erodent

Material characteristics

Flow condition

Fluid characteristics

Hardness

Hardness

Fluid velocity

Viscosity

Size

Fracture toughness

Impact angle

Temperature

Shape

Ductility

Flow trajectory

Density

Mass

Surface roughness

Particle interactions

-

Concentration

Microstructure

-

-

Table 4.1: General factors influencing erosion rates in materials

Chapter 5

5.1 Different types of Erosion models

There were different types of models created by researchers to predict the rate of erosion. The types of experiments and other factors which may have a possible effect in predicting erosion in materials differed among them. Among the studies conducted, latter part described the equations for many types of wear. A huge number of equations were monitored by H.C. Meng and K.C. Ludema [14] in a survey. The study went to figure the problems created with wear modelling and suggestions were put forward to overcome them.

Four major erosion models by different researchers are accounted below, which shows the variance in erosion rates for engineering materials.

5.1.1 J.G.A. Bitter’s Erosion model

The erosion models bitter put forwarded underlined the two basic kinds of erosion wear happening to materials. As the particle flows pass the material, it will start to deform due to the impinging which eventually turns to failure. This was the first model he proposed. The second model involves the action of free moving particles in stream which cuts the material surface leading to failure. The experiments J.G.A. Bitter worked out was mainly based on factors like impact angle, mass and velocity of erodent which joined with properties of type of material being subjected.

The difference in which he treats his cutting model compared to Finnie’s model lies in the fact that unlike Finnie who assumes the material strength determines the energy absorption during cutting, Bitter relates the energy absorption (elastic and elastic-plastic) to the integrated product of the stress-strain curve.

5.1.2 I. Finnie’s Erosion model

5.1.3 I.M. Hutching’s Erosion model

5.1.4 M. Hashish’s Erosion model

Chapter 6

6.1 Experimental

This part of the project covers the experimental approach to the project which has been taken. Typical sections include the materials used, speeds they are subjected, type of tests selected, factors which favoured a particular process etc. The different parameters and constraints which were a crucial part of the study are also noted down in the latter part of this section.

6.1.1 Materials

6.1.2 Experimental Rig

6.1.3 Erosive and Corrosive media

6.1.4 Velocity

6.1.5 SEM Analysis

6.1.6 Methodology

Chapter 7

7.1 Experimental data

The project method, as described on Chapter 6 [2] was the combination of selecting a range of materials in marine environment which are prone to the process of erosion and corrosion. The identification of appropriate test method helped to generate the rates of mass loss for each of the processes. Suitable velocity rates were then selected to subject the materials to undergo erosion, corrosion and erosion-corrosion. Selection of appropriate erosive and corrosive media was put forward to start the tests, which are a crucial part of the experiments. The last stage of project lifecycle was to analyse the samples through an SEM analysis, which helped in generating high magnification images to identify the rates of material loss from the surface of the specimen.

Details below, account for the experimental and technical data received during the different stages of this particular project.

7.1.1 Determined speeds for the tests

Rotating shaft

Figure 7.1: Schematic diagram/Top view of slurry pot tester

97.7 mm

Insert position for specimens

Direction of rotation

The speeds were derived using the following equation;

……………………………………… [Eqn. 7.1]

Where,

r = Distance between the insert positions. (Center to center length)

ꙍ = Rotational speed

Distance between the two insert positions were measured using a Vernier Calliper and found out to be 97.7 mm.

Now, d = 97.7 mm therefore, r = d/2.

Thus, r = 48.85 mm

Since, the rate is applied in the form of mm/s the equation is thus transformed into the following version.

………………………………………. [Eqn. 7.2]

………………………………………. [Eqn. 7.3]

Speed 1: 1 m/s

1 m/s = 1000 mm/s r = 48.85 mm

Now, the controller on the slurry pot is systemised in a way that the actual rate per minute is divided by 30 times of the original value.

Thus, the machine setting is found out as;

Speed 2: 2.5 m/s

2.5 m/s = 2500 mm/s

Hence,

Speed 3: 5 m/s

5 m/s = 5000 mm/s

Hence,

Velocity (m/s)

Velocity (mm/s)

Rotational Speed (rpm)

Machine setting

1

1000

195.6

6.52

2.5

2500

489

16.3

5

5000

978.

32.6

Table 7.1: Comprehensive data for determined velocities

7.2 Erosion tests performed

The following data aids a comprehensive evaluation for the test specimens used. The information relates to the erosion tests performed on the 3 different materials. Each of material is subjected to 3 different tests namely, Erosion, Corrosion and Erosion-Corrosion.

7.2.1 Copper

The mass loss is the main factor that reflects phenomenon like erosion. So, two specimens of the same material are subjected to experiments to obtain the rates of mass loss. The weights of both the specimens are recorded after the tests are finished. Average of both the pre and post weights are then recorded to further evaluation.

Type of test

Type of result

Speeds used

1 m/s

2.5 m/s

5 m/s

Erosion

Pre-experiment weight (gms)

18.94696

18.90264

19.08890

19.15134

18.95158

18.74300

Post-experiment weight (gms)

18.94634

18.90168

19.07942

19.15040

18.95036

18.73380

Table 7.2: Erosion test results for Copper

The difference in average of pre-experiment weight and post-experiment are then recorded. This value shows the amount of material lost from the surface of the specimen.

Speeds used

Average of mass loss

Total mass loss (gms)

Pre-experiment

Post-experiment

1 m/s

19.04915

19.04837

0.00078

2.5 m/s

18.92711

18.92602

0.00109

5 m/s

18.91595

18.90661

0.00934

Table 7.3: Mass loss during Erosion for Copper

7.2.2 Brass

Type of test

Type of result

Speeds used

1 m/s

2.5 m/s

5 m/s

Erosion

Pre-experiment weight (gms)

17.90284

17.66979

17.76147

17.55803

18.02770

17.73571

Post-experiment weight (gms)

17.90281

17.66875

17.75333

17.55792

18.02666

17.72620

Table 7.4: Erosion test results for Brass

Speeds used

Average of mass loss

Total mass loss (gms)

Pre-experiment

Post-experiment

1 m/s

17.73044

17.73037

0.000007

2.5 m/s

17.84875

17.84771

0.00104

5 m/s

17.74859

17.73977

0.008825

Table 7.5: Mass loss during Erosion for Brass

7.2.3 Stainless Steel

Type of test

Type of result

Speeds used

1 m/s

2.5 m/s

5 m/s

Erosion

Pre-experiment weight (gms)

16.67353

16.57920

16.69584

16.57564

16.57113

16.65066

Post-experiment weight (gms)

16.67300

16.57887

16.69157

16.57538

16.57068

16.64705

Table 7.6: Erosion test results for Stainless Steel

Speeds used

Average of mass loss

Total mass loss (gms)

Pre-experiment

Post-experiment

1 m/s

16.62459

16.62419

0.000395

2.5 m/s

16.57517

16.57478

0.00039

5 m/s

16.67325

16.66931

0.00394

Table 7.7: Mass loss during Erosion for Stainless Steel

7.3 Corrosion tests performed

7.3.1 Copper

Type of test

Type of result

Speeds used

1 m/s

2.5 m/s

5 m/s

Corrosion

Pre-experiment weight (gms)

18.89733

19.03883

18.68717

18.88307

19.00692

18.80293

Post-experiment weight (gms)

18.89608

19.03796

18.68563

18.88208

19.00544

18.80183

Table 7.8: Corrosion test results for Copper

Speeds used

Average of mass loss

Total mass loss (gms)

Pre-experiment

Post-experiment

1 m/s

18.8902

18.88908

0.00112

2.5 m/s

19.02288

19.0217

0.001175

5 m/s

18.74505

18.74373

0.00132

Table 7.9: Mass loss during Corrosion test for Copper

7.3.2 Brass

Type of test

Type of result

Speeds used

1 m/s

2.5 m/s

5 m/s

Corrosion

Pre-experiment weight (gms)

17.86996

17.73638

17.70100

17.89113

17.63458

18.00210

Post-experiment weight (gms)

17.86916

17.73540

17.69858

17.89027

17.63304

17.99770

Table 7.10: Corrosion test results for Brass

Speeds used

Average of mass loss

Total mass loss (gms)

Pre-experiment

Post-experiment

1 m/s

17.88055

17.87972

0.00083

2.5 m/s

17.68548

17.68422

0.00126

5 m/s

17.85155

17.84814

0.00341

Table 7.11: Mass loss during Corrosion test for Brass

7.3.3 Stainless Steel

Type of test

Type of result

Speeds used

1 m/s

2.5 m/s

5 m/s

Corrosion

Pre-experiment weight (gms)

16.58480

16.60366

16.64730

16.66245

16.76633

16.69420

Post-experiment weight (gms)

16.58470

16.60349

16.64700

16.66222

16.76624

16.69393

Table 7.12: Corrosion test results for Stainless Steel

Speeds used

Average of mass loss

Total mass loss (gms)

Pre-experiment

Post-experiment

1 m/s

16.62363

16.62346

0.000165

2.5 m/s

16.685

16.68487

0.00013

5 m/s

16.67075

16.67047

0.000285

Table 7.13: Mass loss during Corrosion test for Stainless Steel

7.4 Erosion-Corrosion tests performed

7.4.1 Copper

Type of test

Type of result

Speeds used

1 m/s

2.5 m/s

5 m/s

Erosion-Corrosion

Pre-experiment weight (gms)

18.90020

18.82269

18.92295

18.77993

18.64560

19.12122

Post-experiment weight (gms)

18.89920

18.82030

18.91465

18.77876

18.64368

19.11294

Table 7.14: Erosion-Corrosion test results for Copper

Speeds used

Average of mass loss

Total mass loss (gms)

Pre-experiment

Post-experiment

1 m/s

18.84007

18.83898

0.001085

2.5 m/s

18.73415

18.73199

0.002155

5 m/s

19.02209

19.0138

0.00829

Table 7.15: Mass loss during Erosion-Corrosion test for Copper

7.4.2 Brass

Type of test

Type of result

Speeds used

1 m/s

2.5 m/s

5 m/s

Erosion-Corrosion

Pre-experiment weight (gms)

17.78252

18.02080

17.91481

17.50880

18.02983

17.57378

Post-experiment weight (gms)

17.78185

18.01874

17.90260

17.50816

18.02755

17.56160

Table 7.16: Erosion-Corrosion test results for Brass

Speeds used

Average of mass loss

Total mass loss (gms)

Pre-experiment

Post-experiment

1 m/s

17.64566

17.64501

0.000655

2.5 m/s

18.02532

18.02315

0.00217

5 m/s

17.7443

17.7321

0.012195

Table 7.17: Mass loss during Erosion-Corrosion test for Brass

7.4.3 Stainless Steel

Type of test

Type of result

Speeds used

1 m/s

2.5 m/s

5 m/s

Erosion-Corrosion

Pre-experiment weight (gms)

16.60385

16.65706

16.59143

16.47436

16.64864

16.52830

Post-experiment weight (gms)

16.60360

16.65678

16.58740

16.47403

16.64825

16.52450

Table 7.18: Erosion-Corrosion test results for Stainless Steel

Speeds used

Average of mass loss

Total mass loss (gms)

Pre-experiment

Post-experiment

1 m/s

16.53911

16.53882

0.00029

2.5 m/s

16.65285

16.65252

0.000335

5 m/s

16.55987

16.55595

0.003915

Table 7.19: Mass loss during Erosion-Corrosion test for Stainless Steel

7.5 Additional Work

Composite

Type of test

Type of result

Speeds used

2.5 m/s

Erosion

Pre-experiment weight (gms)

4.29465

4.30742

Post-experiment weight (gms)

4.29385

4.30740

Table 7.20: Additional work carried out on Composite

Speeds used

Average of mass loss

Total mass loss (gms)

Pre-experiment

Post-experiment

2.5 m/s

4.301035

4.300625

0.00041

Table 7.21: Mass loss during Erosion test for Composite

Chapter 8

8.1 Analytical data

Chapter 9

9.1 Discussion

9.2 Conclusion

9.3 Future work

Chapter 10

10.1 Project Management

10.2 Gantt Chart

References

R.J.K. Wood, ‘Erosion-Corrosion synergism for multi-phase flowline material’, Institution of Mechanical Engineers C, C453/011, (1992), 151-158

R.J.K. Wood, S.P. Hutton, ‘The synergistic effect of erosion-corrosion: trends in published results’, Wear, 140, (1990), 387-394

Y. Li, G.T. Burstein and I.M. Hutchings, ‘The influence of corrosion on the erosion of aluminium by aqueous silica slurries’, Wear, 186-187, (1995), 515-522

A. Toro, A. Sinatora, D.K. Tanaka and A.P. Tschiptschin, ‘Corrosion-Erosion of nitrogen bearing martensitic stainless steels in seawater-quartz slurry’, Wear, 251, (2001), 1257-1264

A. Neville, T. Hodgkiess and H.Xu, ‘An electrochemical and microstructural assessment of erosion-corrosion of cast iron’, Wear, 233-235, (1999), 523-534

F. Aiming, L. Jinming and T. Ziyun, ‘An investigation of the corrosive wear of stainless steel in aqueous slurries’, Wear, 193, (1996), 73-77

M.M. Stack, S. Zhou and R.C. Newman, ‘Identification of transitions in erosion-corrosion regimes in aqueous environments’, Wear, 186-187,(1995), 523-532

I.M. Hutchings, ‘Tribology – Friction and wear of engineering materials’, (1992), Edward Arnold, UK

P. Roberge, B.C. Syrett, ‘Erosion-Corrosion’, Corrosion Testing Made Easy Series, NACE International, (2004)

E. Heitz, ‘Mechanistically based prevention strategies of flow induced corrosion’, Electrochimica Acta, 41, No. 4, (1996), 503-509

I. Finnie, ‘Erosion of surface by solid particles’, Wear, 3, (1960), 87-103

J.G.A. Bitter, ‘A study of erosion phenomena-Part I’, Wear, 6, (1963), 5-21

J.G.A. Bitter, ‘A study of erosion phenomena-Part II’, Wear, 6, (1963), 169-190

H.C. Meng, K.C. Ludema, ‘Wear models and predictive equations: Their form and content’, Wear, 181-183, (1995), 443-457

Bibliography

K.R. Trethewey, J. C. (1995). Corrosion for Science and Engineering (2nd ed.). Longman Singapore Publishers (Pvt.) Ltd.

R.C. Barik, J. W. (2009). Electro-mechanical interactions during erosion-corrosion.

R.J.K Wood, Y. P. (1998). The Performance of marine coatings and pipe materials under fluid-borne sand erosion.

Rajahram, S. (2010). Erosion-Corrosion mechanisms of stainless steel UNS S31603. University of Southampton, Department of Engineering, Science and Mathematics. Southampton: Research repository, ePrints Soton.

S.S. Rajahram, T. H. (2009). Erosion-Corrosion resistance of engineering materials in various test conditions.

S.S. Rajahram, T. H. (2009). Evaluation of a semi-empirical model in predicting erosion-corrosion.

Wood, R. J. (2006). Erosion–corrosion interactions and their effect on marine and offshore materials.

List of Figures and Tables

Figure 2.1: Corrosion damage to iron rods under a bridge……………………………………7

Figure 3.1: The Erosion-Corrosion process…………………………………………………...9

Figure 4.1: Forces acting on a solid particle when in contact with a material……………….12

Figure 4.2: Mass transport controlled flow corrosion………………………………………..13

Figure 4.3: Phase transport controlled flow corrosion……………………………………….13

Figure 4.4: Erosion-Corrosion phenomenon…………………………………………………14

Figure 4.5: Cavitation corrosion in materials………………………………………………...14

Figure 4.6: Ploughing mechanism……………………………………………………………15

Figure 4.7: Type I cutting…………………………………………………………………….15

Figure 4.8: Type II cutting…………………………………………………………………...16

Table 4.1: General factors influencing erosion rates in materials……………………………16