PAPER PUBLICATION ARTICLE Annealing Effect On The Microstructure Toward Tensile Strength And Fatigue Strength Of Motorcycle Wheel Shaft Of Low Carbon Steel.

1 PAPER

PUBLICATION ARTICLE

ANNEALING EFFECT ON THE MICROSTRUCTURE TOWARD

TENSILE STRENGTH AND FATIGUE STRENGTH OF

MOTORCYCLE WHEEL SHAFT OF LOW CARBON STEEL

The Paper of Final Project Seminar is submitted as a requirement to follow Final Project Examination in Automotive/Motorcycle Engineering Muhammadiyah

University of Surakarta

Arranged by: ACHMAD FAUZAN

D200 090 209

MECHANICAL ENGINEERING DEPARTMENT

INTERNATIONAL PROGRAM

IN AUTOMOTIVE/MOTORCYCLE ENGINEERING

MUHAMMADIYAH UNIVERSITY OF SURAKARTA

3

ANNEALING EFFECT ON THE MICROSTRUCTURE TOWARD TENSILE STRENGTH AND FATIGUE STRENGTH OF MOTORCYCLE WHEEL SHAFT OF

LOW CARBON STEEL Ir. Pramuko IP, MT.

Mechanical Engineering Department of Muhammadiyah University of Surakarta Jln. A. Yani Pabelan-Kartasura. Tromol Pos I Telp. (0271) 715448 Surakarta

Wijianto, ST.M.Eng.Sc

Mechanical Engineering Department of Muhammadiyah University of Surakarta Jln. A. Yani Pabelan-Kartasura. Tromol Pos I Telp. (0271) 715448 Surakarta

Achmad Fauzan

Automotive Department of Muhammadiyah University of Surakarta Jln. A. Yani Pabelan-Kartasura. Tromol Pos I Telp. (0271) 715448 Surakarta

E-mail : colomadu007@gmail.com

ABSTRACT

The Objective of this research is to determine the effect of annealing on physical and mechanical properties of the motorcycle wheel shaft. The tests conducted are testing the chemical composition, hardness, tensile strength, fatigue strength, and microstructure.

The methods to conduct in this study apart from literature, the authors also conducted the test. The material to be studied is a low carbon steel, specimens will be used are without heat treatment and with heat treatment. The annealing processes was conducted by heating the material up to 9000C with holding time for 60 minutes and then cooling it slowly in the furnace. Physical properties of the specimens tested by testing the chemical composition and microstructure observation, while the mechanical properties determined by hardness testing, tensile testing, and fatigue testing.

The results showed that the chemical composition of the material shaft wheel motorcycle included in the low-carbon steel (C < 0.2 %). Microstructure observations, the specimens before annealing obtained ferrite and pearlite phase with a small grain size. Whereas, after annealing has a bigger grain size and dominated by ferrite. Hardness test results before annealing has the highest value 205.69 Kg/mm2but after the annealing has the highest value 93.81 Kg/mm2. Tensile strength test results before annealing has the highest value 56.18 Kg/mm2 but after the annealing have the highest value 39.76 Kg/mm2. And for fatigue strength testing maximum load that can be imposed before annealing 33.30 Kg/mm2 whereas after annealing the maximum load that can be imposed 17.93 Kg/mm2.

4 Background of the study

In the material industries steel is described on mechanical property like toughness, hardness, endurance, and so on. To meet the requirements of the mechanical properties of the steel can be improved. Improved mechanical properties can be done by adding the chemical element, forging material, and heat treatment. Heat treatment on steel has a very important role in order to obtain certain properties are desirable as needed.

Steel is metal alloy between ferrous as a basic element carbon as the main alloying element. Carbon steel is an alloy between Fe and C, with C levels up to 2%. Mechanical properties of carbon steel depend on levels of carbon contains. Each steel including carbon steel is actually a multi-component alloys besides Fe necessarily contain other elements such as Mn, Si, S, P, N, H, which can affect its properties. Carbon steel can be classified into three parts according to the carbon content it contains, namely low carbon steel with a carbon content less than 0.20%, medium carbon steel containing 0.20 to 0.50% carbon and high-carbon steel containing 0.5 - 2% carbon.

Low carbon steel with carbon content less than 0.20% C is used to industries components such as a car body, frame building construction, ship construction applications, including vehicle frame wheels. Use of low carbon steel is widely used in the material industry and the automotive industry, due to the low carbon steels have high ductility and machine ability.

Although carbon steel has so many excellent mechanical properties that used in the industries, but carbon steel has many flaws, one of them is not fire resistant, although steel is the material not flammable, but if there is a fire at high temperatures would reduce the strength of steel drastically.

Each metals has a physical nature and a good mechanic, as well as with steel, although steel impressed so tough but still has shortcomings, one of which is fatigue failure, fatigue failure is a very dangerous thing, because there is no early indication. The

resulting fatigue fracture that looks fragile, because no deformation on the fracture. At the macroscopic scale, fracture surface can usually be identified from the shape of the field of fracture, there are smooth parts caused by friction that occurs when the crack propagates and the rough area.

Fatigue failure, perhaps due to the generally occurs after long usage. Fatigue failure more obvious with the development of technology equipment such as: cars, airplanes, compressors, pumps, turbines and others. All of them sustained recurrent load and vibration. Until now often expressed that covers at least 90% of all failures are caused by things are mechanical.

Based on the description above, in this study the authors will conduct research on how much the influence of heat treatment on the physical and mechanical properties of carbon steel, here the author uses a low carbon steel in the study. The process to be performs are give in the form of heat treatment temperature annealing up to 900 0C and then the next process is to examine the form of changes in the steel microstructure before and after annealing, to prove the effect of annealing the material strength then performed testing of hardness testing, tensile strength testing and fatigue rotary bending testing on carbon steel before and after annealing.

Objective of the Study

The purpose of this study that are:

1. To know the chemical composition of material used.

2. To determine the effect of heat treatment to the hardness of material.

3. To determine the effect of heat treatment to the tensile strength of material.

4. To determine the effect of heat treatment to the fatigue strength of material.

5. To determine the effect of heat treatment to the microstructure of material.

5 Problem Limitation

To further focus the problem of this research, the writer needs to limit the problem. The extent of the problem is;

1. The material used is low carbon steel ASTM and AISI tube steels A254 class or I ASTM and API pipe steels A381 class Y52.

2. Treatment options include: heat treatment such as annealing, microstructure testing, hardness testing, tensile testing, and fatigue rotary bending testing.

3. Effect of roughness material and environmental variation is negligible.

Literature Review

Gatot setyawan (2003), the research on Pengaruh proses quenching dan annealing terhadap struktur mikro dan kekerasan sprocket Toyota kijang, hardness results for the raw material that the material which has the highest hardness value at the end of which the value obtained hardness is 203.4 kg/mm2. In the middle 177 kg/mm2, and on the main is 159.9 kg/mm2. Meanwhile, after a process of quench and anneal value of hardness to be down when compared to the raw material. Based on the observation of microstructure for without and with the process of quenching and annealing obtained microstructure of ferrite and pearlite, where for quenching and annealing process material obtained larger grain structure of the raw material so that the hardness down.

Ahmad Fahrur Rozaq dan Soeharto (2009) on their research Pengaruh Waktu Temper Perlakuan Panas Quench- Temper terhadap Umur Lelah Baja St 41 pada Pembebanan Lentur Putar Siklus Tinggi, conclude that fatigue life highest generated by the raw material. With the longer time tempering the martensite formed more and more, it will cause the material hardness decreased. With the decline in hardness followed the increase ductility of the material would cause material fatigue life lower.

Fundamental Theory Carbon Steel

Carbon steel is an alloy between Fe and C with higher levels of C to 2%. Mechanical properties of carbon steel depending on levels of C it contains. Each steels including carbon steels is actually a multi-component alloy Fe besides always contains other elements there are Mn, Si, S, P, N, H which may affect its properties. Carbon steel can be classified into three parts according to the carbon level it contains, namely low carbon steel with a carbon content of less than 0.20%, medium carbon steel content 0.20 – 0.50 % of carbon, and high carbon steels containing 0.50 – 2% of carbon.

Phase Diagram Fe-Fe3C

A phase diagram is a graphic representation of the phases in a material on a variation of temperature, pressure and composition. This diagram is the basis of understanding for all heat treatment operations. In general, the phase diagram constructed in a state of equilibrium (the condition is a very slow cooling). This diagram is used to identify and predict many aspects of the nature of the material.

6

Figure 1. Fe-Fe3c diagram

Basic Theory of Testing Hardness Test

Hardness is important property of material, probably the quality most often considered is connected with the ability of a material to resist indentation. However, resistance to being scratched also is

common connotation. Clearly these two abilities are not exactly the same. Hardness is measure by number of well-standardized tests, but the entire test to do not measure precisely the same phenomenon. As a consequence, there is no exact correlation between the results, or hardness measure, obtained from the various tests.

HV = 1.854 d=

7 Tensile Test

The experiment was conducted, by providing tensile load on the specimen slowly until it broke. An event experienced by the test object is a change in shape, elongated in the direction of flow is directly proportional to the increase in force. Deformation at this level is called elastic deformation. When released (P = 0 ton), then the length of the specimen will return to its original size, as before given loading namely Lo. In the area of Hooke's law is valid:

E = = Constants,

Whereas,

σ =

ε=σ/L0 = (L0 – Li)/L0

Where:

E = Modulus Elasticity

σ = Tensile Stress

ε = Elongation

A0 = Initial cross-sectional area

P = Load on the specimen

L0 = Initial length

Li = Length after loading

Figure 3. Tensile test machine

Tensile Test Specimen

Specimens used in this study refers to the standard JIS Z 2201 year 1981 No.10 Test Piece, in this study the load attached to the machine is equal to 10 tons. Tensile testing was carried out in the laboratory materials, majoring in mechanical engineering and industrial Gajah Mada University.

Fatigue Rotary Bending Test

If metals are subjected to large numbers of large variations of applied stress, they may fail at stress levels far below the maximum stress they would withstand in a normal static test. This phenomenon is known as metal fatigue.

D L P R

8

Consequently, when metals fail due this phenomenon such failures are known as fatigue failures. Unfortunately, the- appearance of fractures where fatigue was a major factor is the same as other factor wherein fatigue may be only a significant factor. The correct name for all fractures having this appearance is progressive fractures. When fractures of this type are examined closely, it usually can be seen that the failure started at some type of a discontinuity (stress raiser). Such discontinuities may take the form of a fine surface crack, or a sharp corner, or they are metallurgical notches in the form of serve changes in the crystal structure of a metal.

Figure 4. Fatigue rotary bending machine

S-N curve

Fatigue data is usually presented in a stress curves and cycles, where the stress is S and the cycle is N. The number of cycles is the cycle starting from nucleation crack until crack propagation.

When the stress drops, the number of cycles to failure is rise, whereas when the stress rises, the number of cycles is reduced. On steel as a ferrous alloy, there is a stress limit where fatigue failure does not occur or occurs in very long cycles (infinite). The Limit value is seen as a point of showing the value of the fatigue limit or endurance limit. Endurance limit is

the stress where no failure or fracture in the range of 107 cycles. Unlike the nonferrous materials such as aluminum and other alloys do not have a fatigue limit.

Figure 5. S-N Curve

Fatigue Rotary Bending Test Specimen

Specimens used in this study refers to the standard JIS Z 2201 year 1981 No 1 Test Piece, and load taken in fatigue testing, is the result of the tensile test, taken < 0.7 yield from tensile test result.

Do shall, as a rule, be 8, 12, or 15 mm.

Heat Treatment

Heat Treatment is a combination of heating and cooling operations at a certain speed, which made the metal or alloy in the solid state, as an attempt to acquire certain properties. Heat Treatment Process itself is one of the processes to change the

Symbol d (mm) R L

1-6 1-8 1-10 1-12

6 8 10 12

3 d or more

2 d or more

9

structure of the metal by heating the specimen at furnace in the recrystallization temperature over a period of time and then cooled on a cooling medium, such as air, water, brine, and oil respectively have different densities, and if necessary followed by repeated heating and cooling.

The properties metal mechanical are primarily strongly influenced by micro structure beside of its chemical, for example, a metal or alloy will have different mechanical properties vary when modified micro structure. With the heating or cooling to a certain speed the metals and alloys exhibit changes in structure.

Figure 6. Annealing furnace

Annealing Processes

Annealing process is done to reduce the hardness and improve ductility, which will bring re-structured phase change, the atomic structure is stable, and the grains are slightly distorted.

In this annealing process, the test specimen is inserted in a furnace, and then the furnace performed temperature adjustment. In this test the temperature used was 9000C, with the holding time of 60 minutes, and then cooled in the furnace to room temperature. This process is carried out in the laboratory materials,

majoring in mechanical engineering and industrial Gajah Mada University.

Microstructure Test

This test was conducted to observe and compare the physical microstructure of materials, which saw the composition of the existing metal forming. This structure will be obvious when the specimen surface is really flat, smooth, and shiny without scratches.

Chemical Composition Test

This test is to determine the amount (percentage) content of alloy elements on the specimen, especially the levels of the elements carbon (C). This testing is done in laboratory materials, PT. ITOKOH CEPERINDO in Klaten, this test using test equipment FSQ Spectrovac Foundary. Spectrometer has the following work system, after the specimens are placed over the hole in the table above, both the table attached to ensure no light coming into the combustion chamber and the work piece is clamped. Then the electrodes with argon gas assisted fire blasts into the test object and light arose. Light has some physical properties, such as color and intensity of light, which is used to determine the chemical composition. Each chemical element has a light color different combustion.

10 Flowchart of the Study

Figure 7. Flowchart of the study

Study of literature and field

Preparation for materials testing

Heat treatment Raw material

Chemical composition

test

Annealing 9000C

Microstructure testing

Microstructure testing

Fatigue rotary bending testing Tensile

strength testing Fatigue rotary

bending testing Tensile

strength testing

The result of study

Discussion

Conclusion Done

11 Analysis and Discussion of Data Result 1. Chemical Composition Tests

Table 1. The data results chemical composition test

Discussion of the Chemical Composition Test Results

From the research results of the chemical composition test carried out, based on the percentage of carbon element, the steel including low carbon steel, it

contains <0.2% C, by the ASM Committee on metallographic of plate, tube and pipe steel, this material is included in the category of ASTM and AISI tube steels A254class I or ASTM and API pipe steels A381 class Y52. Which the chemical composition, according to ASTM and AISI tube steels A254class I contains 0.05-0.15 C, 0.27-0.63Mn, 0.050 max P, 0.060 max S. whereas according to ASTM and API pipe steels A381 class Y52 contains 0.26 max C, 1.40 max Mn, 0.040 max P, 0.05 max S.

2. Hardness test

Table 2. The data results of hardness test of raw material (without annealing)

Point 1 2 3

Diagonal 1 (mm)

0.52 0.52 0.52

Diagonal 2 (mm)

0.52 0.52 0.52

Table 3. The data results of hardness test of annealing material

Point 1 2 3

Diagonal 1 (mm)

0.52 0.52 0.52

Diagonal 2 (mm)

0.52 0.52 0.52

Point 1 2 3

Average diagonal (mm)

0.77 0.78 0.78

VHN (kg/mm2)

93.81 91.42 91.42 No Element

Name

Levels of elements

(%)

1 Fe 99.2349

2 C 0.0945

3 Si 0.1520

4 Mn 0.3444

5 P 0.0208

6 S 0.0257

7 Ni 0.0255

8 Cr 0.0506

9 Mo 0.0008

10 Cu 0.0345

11 Al 0.0002

12 N 0.0186

13 V 0.002

14 W <0.0016

15 Ti 0.0010

Point 1 2 3

Average diagonal (mm)

0.52 0.52 0.52

VHN (kg/mm2)

12

Figure 8.Histogram average hardness test value

Discussion of Hardness Test Results

From the test results data using a Vickers hardness tester, it can be seen that the value of hardness is owned by low carbon steel ASTM and AISI tube steels A254 class or I ASTM and API pipe steels A381 class Y52 prior to heat treatment, has high hardness which is equal to 205.6 HVN, but after heated by annealing the steel hardness being dropped drastically, amounting to 92.21 HVN. This is caused by grain size changes in the steel after annealing.

3. Tensile Test

Table 3. The data result of tensile test

Figure 9.Histogram average tensile test value

Figure 10. Tensile stress graph

Discussion of Tensile Test Results

From the tensile strength test data, for test specimen before annealing process, the ultimate tensile strength values on average, which is equal to 526.69 N/mm2, and from these data, indicate that the material before annealing has a higher tensile strength than the material after annealing, with an average of 389.16 N/mm2. As well as the steel yield stress, where the specimen before annealing had an average yield strength higher is equal to 471.25 N/mm2 while steel after annealing has a yield stress, the amount of 243.75 N/mm2.

205.69 92.21 0 50 100 150 200 250

Raw m at erial annealing

v ic k e rs h a rd n e ss v a lu e ( H V N ) 56.18 39.76 0 10 20 30 40 50 60

Raw m at erial annealing

T e n si le st re ss (K g /m m 2) 0 47.59 56.18 0 24.61 47.59 0 10 20 30 40 50 60

0 10 20 30

raw m at e rial anne aling te n si le st re ss (K g /m m 2)

elongat ion (%)

Raw D

(mm)

y

(Kg/mm2)

u

(Kg/mm2)

(%)

1 8 47.47 53.27 11.67

2 8 45.70 50.12 8.33

3 8 49.61 56.18 10

Annealing material

D (mm) y

(Kg/m m2)

u

(Kg/ mm2)

(%)

1 8 24.49 39.51 23.33

2 8 24.99 38.63 21.66

13 4. Fatigue Rotary Bending Test

Fatigue rotary bending test results using Shimadzu machine at the lab materials, majoring in mechanical engineering and industrial Gajah Mada University, obtained the following data:

Table 4. The data result of fatigue rotary test

Discussion of Fatigue Test Results

By taking the load, amounting to 0.7 from stress yield of tensile stress for the raw material, and the material that has been annealed, from the fatigue testing research data, it can be seen that the maximum load for the amount of raw material is 329.8 N/mm2, while for the material after annealing at 177.6 N/mm2 therefore it can be said that the material that has been heat-treated have a lower strength in the loading.

Raw material

Load (Kg/mm2)

Log N (Cycle)

Time (minute)

1 23 4.6138 20

2 20 4.7435 35

3 16 5.3496 60

4 14 6.4242 240

Anne aling

Load (Kg/mm2)

Log N (Cycle)

Time (minute)

1 15 4.3242 30

2 12 5.2003 60

3 10 5.6049 150

4 8 6.5106 270

14 5. Microstructure Test

Captured through microscope Olympus photo micrographic system, photograph obtained as follows:

(a)

(b)

a. Microstructure of raw material, with magnification 200

b. Microstructure of annealing material, with magnification 200

Discussion of Microstructure Test

Captured pictures pass through microscope Olympus photo micrographic system, resulting specimen without annealing and with annealing process. From the photos that can be analyzed prior to the annealing process appears the phase ferrite and pearlite, Ferrite phase appears whitish, and perlite was

colored black. Pearlite which has hardened properties, spread evenly and homogeneously. After the annealing process produced larger grain structure consisting of ferrite and pearlite phase, larger grain structure and growth of ferrite which cause hardness decreases. This is due to the elements carbon

Ferrit e Pearlit e

Pearlit e

50

15

(C) diffuses to the grain boundaries, so that the hardness decreases.

Conclusions

Conclusions are taken based on the observations, the results of research and analysis that has been done. Possibility of lack of accurate data obtained can occur, among others: the lack of accuracy in specimen process making, any defects on the specimen, as well as other mistakes (human error). But cultivated specimens as possible in order to conform to the dimensions specified standards and that research results can be used as a reference for future studies.

After doing various tests and analyzes, the data obtained in the form of figures, graphs, and images, it can be concluded as follows:

1. Chemical Composition Test

From the analysis of the chemical composition test results, based on the percentage of carbon element, The materials include low carbon steel, its contains of <0.2% C, by the ASM Committee on metallographic of plate, tube and pipe steel, this material is included in the category of ASTM and AISI tube steels A254class I or ASTM and API pipe steels A381 class Y52. 2. Hardness Test

From the test results data using a Vickers hardness tester, it can be seen that the value of hardness is owned by low carbon steel ASTM and AISI tube steels A254 class or I ASTM and API pipe steels A381 class Y52 prior to heat treatment has a high hardness, which is equal to 205.6 HVN, but after heated by annealing, hardness being dropped drastically, which is equal to 92.21 HVN. This is caused by grain size changes in the steel after annealing.

3. Tensile Test

From the tensile strength test data, for test specimen before annealing process, the

ultimate tensile strength values on average, which is equal to 526.69 N/mm2, and from these data, indicate that the material before annealing has a higher tensile strength than the material after annealing, with an average 389.16 N/mm2. As well as the steel yield stress, where the specimen before annealing had an average yield strength higher is equal to 471.25 N/mm2, while steel after annealing has a yield stress, the amount of 243.75 N/mm2. It can be concluded that the material after annealing will reduce its strength.

4. Fatigue Rotary Bending Test

From fatigue testing research data can be known, that the maximum load for the raw material, the amount of 329.8 N/mm2, while for the material after annealing at 177.6 N/mm2, therefore it can be said, that the material that has been heat-treated have a lower strength in the loading And from the research it can be seen that the higher stress given to the material, so the material has a low cycle, and if the lower the stress that given to the material, so it has high cycle. 5. Microstructure Test

Based on the test results of microstructure observation it can be concluded that appears the ferrite and pearlite phase, the annealing process resulting structure ferrite and pearlite grain size are larger. That can affect the value of hardness, especially in the ferrite which can lead to decreased hardness.

Suggestion

From the experiment that has been done by researcher, here researcher want to give some suggestions for the better in the next experiment:

1. The machine that used in the experiment should be in normal condition to get the accurate data.

2. The specimen that used in the experiment should be in room temperature, in order to keep the physic and mechanic properties

16 BIBLIOGRAPHY

Amstead, B.H., Djaprie, S. (Alih Bahasa), 1995, Teknologi Mekanik, Edisi ke-7, Jilid I, PT. Erlangga, Jakarta

De Garmo, P., 1969, Materials and Processes in Manufacturing, Mac Millan Company, New York

Dieter, G.E., Djaprie, S. (Alih Bahasa), 1990, Metalurgi Mekanik, Jilid I, Edisi ke-3, PT. Erlangga, Jakarta

Risman., 2007., “ Analisa Pengaruh Annealing Terhadap Sifat Fisis dan Mekanis Dari Material Tabung Freon’’ Tugas Akhir S-1, Teknik

Mesin, Universitas

Muhammadiyah, Surakarta.

Setyawan Piyarto, Dwi., 2008, “ Pengaruh Quenching dan Tempering Pada

Material SCMnCr 2 Untuk

Memenuhi Standar JIS G 5111’’ Tugas Akhir S-1, Teknik Mesin,

Universitas Muhammadiyah,

Surakarta.

Surdia, T. & Chijiwa., 1996, Teknik Pengecoran Logam, Edisi ke-2, cetakan ke-7, PT. Pradnya Paramita, Jakarta

Surdia, T.; Shinroku, S., 1999, Pengetahuan Bahan Teknik, PT. Pradnya Paramita, Jakarta

Tarmanegara, T., 2003, “ Proses Pengaruh Annealing Terhadap Sifat Fisis dan Mekanis Spacer Pada Front Axle Sepeda Motor Produk Jepang’’ Tugas Akhir S-1, Teknik Mesin,

Universitas Muhammadiyah,

Surakarta.

Van Vlack, L., 1994, Ilmu dan Teknologi Bahan, Terjemahan, Sriati Djaprie, Edisi ke-5, PT. Erlangga, Jakarta

Analysis and Discussion of Data Result 1. Chemical Composition Tests

Table 1. The data results chemical composition test

Discussion of the Chemical Composition Test Results

From the research results of the chemical composition test carried out, based on the percentage of carbon element, the steel including low carbon steel, it

contains <0.2% C, by the ASM Committee on metallographic of plate, tube and pipe steel, this material is included in the category of ASTM and AISI tube steels A254class I or ASTM and API pipe steels A381 class Y52. Which the chemical composition, according to ASTM and AISI tube steels A254class I contains 0.05-0.15 C, 0.27-0.63Mn, 0.050 max P, 0.060 max S. whereas according to ASTM and API pipe steels A381 class Y52 contains 0.26 max C, 1.40 max Mn, 0.040 max P, 0.05 max S.

2. Hardness test

Table 2. The data results of hardness test of raw material (without annealing)

Point 1 2 3

Diagonal 1 (mm)

0.52 0.52 0.52

Diagonal 2 (mm)

0.52 0.52 0.52

Table 3. The data results of hardness test of annealing material

Point 1 2 3

Diagonal 1 (mm)

0.52 0.52 0.52

Diagonal 2 (mm)

0.52 0.52 0.52

Point 1 2 3

Average diagonal (mm)

0.77 0.78 0.78

VHN (kg/mm2)

93.81 91.42 91.42 No Element

Name

Levels of elements

(%)

1 Fe 99.2349

2 C 0.0945

3 Si 0.1520

4 Mn 0.3444

5 P 0.0208

6 S 0.0257

7 Ni 0.0255

8 Cr 0.0506

9 Mo 0.0008

10 Cu 0.0345

11 Al 0.0002

12 N 0.0186

13 V 0.002

14 W <0.0016

15 Ti 0.0010

Point 1 2 3

Average diagonal (mm)

0.52 0.52 0.52

VHN (kg/mm2)

Figure 8.Histogram average hardness test value

Discussion of Hardness Test Results

From the test results data using a Vickers hardness tester, it can be seen that the value of hardness is owned by low carbon steel ASTM and AISI tube steels A254 class or I ASTM and API pipe steels A381 class Y52 prior to heat treatment, has high hardness which is equal to 205.6 HVN, but after heated by annealing the steel hardness being dropped drastically, amounting to 92.21 HVN. This is caused by grain size changes in the steel after annealing.

3. Tensile Test

Table 3. The data result of tensile test

Figure 9.Histogram average tensile test value

Figure 10. Tensile stress graph

Discussion of Tensile Test Results

From the tensile strength test data, for test specimen before annealing process, the ultimate tensile strength values on average, which is equal to 526.69 N/mm2, and from these data, indicate that the material before annealing has a higher tensile strength than the material after annealing, with an average of 389.16 N/mm2. As well as the steel yield stress, where the specimen before annealing had an average yield strength higher is equal to 471.25 N/mm2 while steel after annealing has a yield stress, the amount of 243.75 N/mm2.

205.69 92.21 0 50 100 150 200 250

Raw m at erial annealing

v ic k e rs h a rd n e ss v a lu e ( H V N ) 56.18 39.76 0 10 20 30 40 50 60

Raw m at erial annealing

T e n si le st re ss (K g /m m 2) 0 47.59 56.18 0 24.61 47.59 0 10 20 30 40 50 60

0 10 20 30

raw m at e rial anne aling te n si le st re ss (K g /m m 2)

elongat ion (%)

Raw D (mm)

y (Kg/mm2)

u (Kg/mm2)

(%)

1 8 47.47 53.27 11.67

2 8 45.70 50.12 8.33

3 8 49.61 56.18 10

Annealing material

D (mm) y

(Kg/m m2)

u (Kg/ mm2)

(%)

1 8 24.49 39.51 23.33

2 8 24.99 38.63 21.66

4. Fatigue Rotary Bending Test

Fatigue rotary bending test results using Shimadzu machine at the lab materials, majoring in mechanical engineering and industrial Gajah Mada University, obtained the following data:

Table 4. The data result of fatigue rotary test

Discussion of Fatigue Test Results

By taking the load, amounting to 0.7 from stress yield of tensile stress for the raw material, and the material that has been annealed, from the fatigue testing research data, it can be seen that the maximum load for the amount of raw material is 329.8 N/mm2, while for the material after annealing at 177.6 N/mm2 therefore it can be said that the material that has been heat-treated have a lower strength in the loading.

Raw material

Load (Kg/mm2)

Log N (Cycle)

Time (minute)

1 23 4.6138 20

2 20 4.7435 35

3 16 5.3496 60

4 14 6.4242 240

Anne aling

Load (Kg/mm2)

Log N (Cycle)

Time (minute)

1 15 4.3242 30

2 12 5.2003 60

3 10 5.6049 150

4 8 6.5106 270

5. Microstructure Test

Captured through microscope Olympus photo micrographic system, photograph obtained as follows:

(a)

(b)

a. Microstructure of raw material, with magnification 200

b. Microstructure of annealing material, with magnification 200

Discussion of Microstructure Test

Captured pictures pass through microscope Olympus photo micrographic system, resulting specimen without annealing and with annealing process. From the photos that can be analyzed prior to the annealing process appears the phase ferrite and pearlite, Ferrite phase appears whitish, and perlite was

colored black. Pearlite which has hardened properties, spread evenly and homogeneously. After the annealing process produced larger grain structure consisting of ferrite and pearlite phase, larger grain structure and growth of ferrite which cause hardness decreases. This is due to the elements carbon

Ferrit e Pearlit e

Pearlit e

50

(C) diffuses to the grain boundaries, so that the hardness decreases.

Conclusions

Conclusions are taken based on the observations, the results of research and analysis that has been done. Possibility of lack of accurate data obtained can occur, among others: the lack of accuracy in specimen process making, any defects on the specimen, as well as other mistakes (human error). But cultivated specimens as possible in order to conform to the dimensions specified standards and that research results can be used as a reference for future studies.

After doing various tests and analyzes, the data obtained in the form of figures, graphs, and images, it can be concluded as follows:

1. Chemical Composition Test

From the analysis of the chemical composition test results, based on the percentage of carbon element, The materials include low carbon steel, its contains of <0.2% C, by the ASM Committee on metallographic of plate, tube and pipe steel, this material is included in the category of ASTM and AISI tube steels A254class I or ASTM and API pipe steels A381 class Y52. 2. Hardness Test

From the test results data using a Vickers hardness tester, it can be seen that the value of hardness is owned by low carbon steel ASTM and AISI tube steels A254 class or I ASTM and API pipe steels A381 class Y52 prior to heat treatment has a high hardness, which is equal to 205.6 HVN, but after heated by annealing, hardness being dropped drastically, which is equal to 92.21 HVN. This is caused by grain size changes in the steel after annealing.

3. Tensile Test

From the tensile strength test data, for test specimen before annealing process, the

ultimate tensile strength values on average, which is equal to 526.69 N/mm2, and from these data, indicate that the material before annealing has a higher tensile strength than the material after annealing, with an average 389.16 N/mm2. As well as the steel yield stress, where the specimen before annealing had an average yield strength higher is equal to 471.25 N/mm2, while steel after annealing has a yield stress, the amount of 243.75 N/mm2. It can be concluded that the material after annealing will reduce its strength.

4. Fatigue Rotary Bending Test

From fatigue testing research data can be known, that the maximum load for the raw material, the amount of 329.8 N/mm2, while for the material after annealing at 177.6 N/mm2, therefore it can be said, that the material that has been heat-treated have a lower strength in the loading And from the research it can be seen that the higher stress given to the material, so the material has a low cycle, and if the lower the stress that given to the material, so it has high cycle. 5. Microstructure Test

Based on the test results of microstructure observation it can be concluded that appears the ferrite and pearlite phase, the annealing process resulting structure ferrite and pearlite grain size are larger. That can affect the value of hardness, especially in the ferrite which can lead to decreased hardness.

Suggestion

From the experiment that has been done by researcher, here researcher want to give some suggestions for the better in the next experiment:

1. The machine that used in the experiment should be in normal condition to get the accurate data.

2. The specimen that used in the experiment should be in room temperature, in order to keep the physic and mechanic properties

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