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Technical Report
Failure Analysis of
Shaft Com Gear Shift
By Integrated Master Student Team
BangkitIndriyana (1106154274)
M. Ekaditya Albar (1106154305)
RhidiyanWaroko (0806331935)
StefannoWidyYunior (0806332004)
YudiPrasetyo (0806455950)
Department of Metallurgy and Materials EngineeringUniversity of Indonesia
October2012
Technical Report
Failure Analysis of
Shaft Com Gear Shift
By Integrated Master Student Team
BangkitIndriyana (1106154274)
M. Ekaditya Albar (1106154305)
RhidiyanWaroko (0806331935)
StefannoWidyYunior (0806332004)
YudiPrasetyo (0806455950)
Department of Metallurgy and Materials EngineeringUniversity of Indonesia
October2012
Technical Report
Failure Analysis of
Shaft Com Gear Shift
By Integrated Master Student Team
BangkitIndriyana (1106154274)
M. Ekaditya Albar (1106154305)
RhidiyanWaroko (0806331935)
StefannoWidyYunior (0806332004)
YudiPrasetyo (0806455950)
Department of Metallurgy and Materials EngineeringUniversity of Indonesia
October2012
Failure Analysis Assignment
2
1. Background
Component of a motorcycle that is "Gear Shift Shaft Com" produced by PT. Y
which acts as a supplier of automotive components for PT. ISI has been damaged during
use. Observations indicated that the damage occurred in the weld joint where the welds are
not fused between the plates with the shaft. This causes the transmissioncannot move the
gearshift from position 1 to position 2, 3 and 4. The next component is submitted to the
Department of Metallurgy and Materials UI to analyze the cause of the damage these
components.
2. Fish Bone Diagram (Root Cause Analysis)
The fish bone diagram is perform during the performance of the analysis work in
order to get more acquaint of the specimen to be tested. The interim results of the fish bone
diagram as shown below:
Manufacture is a critical phase which has important roles for the quality of Gear
Shift Shaft Com, in this case, assembly process, material has been chosen, operating
condition of the sample (the environment during the performance of the sample), and the
maintenance are properly done by the operator and the user. So, the analysis is going to be
focused on manufacturing phase.
Failure Analysis Assignment
2
1. Background
Component of a motorcycle that is "Gear Shift Shaft Com" produced by PT. Y
which acts as a supplier of automotive components for PT. ISI has been damaged during
use. Observations indicated that the damage occurred in the weld joint where the welds are
not fused between the plates with the shaft. This causes the transmissioncannot move the
gearshift from position 1 to position 2, 3 and 4. The next component is submitted to the
Department of Metallurgy and Materials UI to analyze the cause of the damage these
components.
2. Fish Bone Diagram (Root Cause Analysis)
The fish bone diagram is perform during the performance of the analysis work in
order to get more acquaint of the specimen to be tested. The interim results of the fish bone
diagram as shown below:
Manufacture is a critical phase which has important roles for the quality of Gear
Shift Shaft Com, in this case, assembly process, material has been chosen, operating
condition of the sample (the environment during the performance of the sample), and the
maintenance are properly done by the operator and the user. So, the analysis is going to be
focused on manufacturing phase.
Failure Analysis Assignment
2
1. Background
Component of a motorcycle that is "Gear Shift Shaft Com" produced by PT. Y
which acts as a supplier of automotive components for PT. ISI has been damaged during
use. Observations indicated that the damage occurred in the weld joint where the welds are
not fused between the plates with the shaft. This causes the transmissioncannot move the
gearshift from position 1 to position 2, 3 and 4. The next component is submitted to the
Department of Metallurgy and Materials UI to analyze the cause of the damage these
components.
2. Fish Bone Diagram (Root Cause Analysis)
The fish bone diagram is perform during the performance of the analysis work in
order to get more acquaint of the specimen to be tested. The interim results of the fish bone
diagram as shown below:
Manufacture is a critical phase which has important roles for the quality of Gear
Shift Shaft Com, in this case, assembly process, material has been chosen, operating
condition of the sample (the environment during the performance of the sample), and the
maintenance are properly done by the operator and the user. So, the analysis is going to be
focused on manufacturing phase.
Failure Analysis Assignment
3
It is obvious that the failure occur in the weld area, this fact endorsed the probability
that the failure root cause ascribeto the welding process. The other processes during the
performance of the manufacturing process widely open to be envisaged in this analysis. The
welding root cause fish bone diagram as shown below:
There are five possible processes which can leads to the failure of the component. To
ascertain and provision the cause of the failure of the component, a number of investigations
is perform in order to get data (or information) and acquaint to the problem.
3. Scope of Investigation
The scope of the testing performed to investigate the sample "Gear Shift Shaft Com"
produced by PT. Y is as follows:
Visual examination
Chemical composition using OES
Hardness testing
Metallography testing (macrostructure and microstructure)
Fractographyexamination using Scanning Electron Microscope (SEM)
Micro chemical composition test by EDS
Failure Analysis Assignment
3
It is obvious that the failure occur in the weld area, this fact endorsed the probability
that the failure root cause ascribeto the welding process. The other processes during the
performance of the manufacturing process widely open to be envisaged in this analysis. The
welding root cause fish bone diagram as shown below:
There are five possible processes which can leads to the failure of the component. To
ascertain and provision the cause of the failure of the component, a number of investigations
is perform in order to get data (or information) and acquaint to the problem.
3. Scope of Investigation
The scope of the testing performed to investigate the sample "Gear Shift Shaft Com"
produced by PT. Y is as follows:
Visual examination
Chemical composition using OES
Hardness testing
Metallography testing (macrostructure and microstructure)
Fractographyexamination using Scanning Electron Microscope (SEM)
Micro chemical composition test by EDS
Failure Analysis Assignment
3
It is obvious that the failure occur in the weld area, this fact endorsed the probability
that the failure root cause ascribeto the welding process. The other processes during the
performance of the manufacturing process widely open to be envisaged in this analysis. The
welding root cause fish bone diagram as shown below:
There are five possible processes which can leads to the failure of the component. To
ascertain and provision the cause of the failure of the component, a number of investigations
is perform in order to get data (or information) and acquaint to the problem.
3. Scope of Investigation
The scope of the testing performed to investigate the sample "Gear Shift Shaft Com"
produced by PT. Y is as follows:
Visual examination
Chemical composition using OES
Hardness testing
Metallography testing (macrostructure and microstructure)
Fractographyexamination using Scanning Electron Microscope (SEM)
Micro chemical composition test by EDS
Failure Analysis Assignment
4
4. Examinations
4.1. Visual Examination
Figure 1. Sample Shaft Com Gear Shift as received
Figure 2. Sample Failed Shaft Com Gear Shift as received
4.2. Chemical Composition by OES
Gear Shift Shaft Com was subjected to chemical composition test using Optical Emission
Spectrometer (OES). Table 1 shows the chemical composition test result of samples.
Table 1.Chemical composition results on as received components
Material C(%)
Si(%)
Mn(%)
S(%)
P(%)
Cr(%)
Ni(%)
V(%)
Mo(%)
Cu(%)
Al(%)
AISI1045M(S45C)
0.42-0.48
0.15-0.35 0.6-0.9 0.035
max 0.03 - - - - - -
SHAFT 0.50 0.197 0.661 0.010 0.015 0.067 0.057 0.001 0.025 0.134 0.006
SPCC 0.12max -- 0.5 max 0.045
max0.04max -- -- -- -- -- --
PLATE 0.10 0.009 0.348 0.013 0.005 0.023 0.020 0.001 0.005 0.044 0.045
Failure Analysis Assignment
4
4. Examinations
4.1. Visual Examination
Figure 1. Sample Shaft Com Gear Shift as received
Figure 2. Sample Failed Shaft Com Gear Shift as received
4.2. Chemical Composition by OES
Gear Shift Shaft Com was subjected to chemical composition test using Optical Emission
Spectrometer (OES). Table 1 shows the chemical composition test result of samples.
Table 1.Chemical composition results on as received components
Material C(%)
Si(%)
Mn(%)
S(%)
P(%)
Cr(%)
Ni(%)
V(%)
Mo(%)
Cu(%)
Al(%)
AISI1045M(S45C)
0.42-0.48
0.15-0.35 0.6-0.9 0.035
max 0.03 - - - - - -
SHAFT 0.50 0.197 0.661 0.010 0.015 0.067 0.057 0.001 0.025 0.134 0.006
SPCC 0.12max -- 0.5 max 0.045
max0.04max -- -- -- -- -- --
PLATE 0.10 0.009 0.348 0.013 0.005 0.023 0.020 0.001 0.005 0.044 0.045
Failure Analysis Assignment
4
4. Examinations
4.1. Visual Examination
Figure 1. Sample Shaft Com Gear Shift as received
Figure 2. Sample Failed Shaft Com Gear Shift as received
4.2. Chemical Composition by OES
Gear Shift Shaft Com was subjected to chemical composition test using Optical Emission
Spectrometer (OES). Table 1 shows the chemical composition test result of samples.
Table 1.Chemical composition results on as received components
Material C(%)
Si(%)
Mn(%)
S(%)
P(%)
Cr(%)
Ni(%)
V(%)
Mo(%)
Cu(%)
Al(%)
AISI1045M(S45C)
0.42-0.48
0.15-0.35 0.6-0.9 0.035
max 0.03 - - - - - -
SHAFT 0.50 0.197 0.661 0.010 0.015 0.067 0.057 0.001 0.025 0.134 0.006
SPCC 0.12max -- 0.5 max 0.045
max0.04max -- -- -- -- -- --
PLATE 0.10 0.009 0.348 0.013 0.005 0.023 0.020 0.001 0.005 0.044 0.045
Failure Analysis Assignment
5
Based on the test result, the chemical composition of shaft sample is close to AISI 1045M
(S45C) and the chemical composition of plate sample is closed to SPCC.
4.3. Hardness Testing
Hardness testing was conducted by Vickers micro-hardness. It is found that the hardness of
weld area, HAZ, and fusion line respectively 367 HV, 396 HV, 689 HV. The hardness of
base metal for plate material is 166 HV and for shaft material 243 HV.
Table 2.Hardness testing results on welding components
Location Location Hardness ofSample 1 (HV)
1. Base Metal 1 1662. Plate surface 6133. Base Metal 2 2434. Weld Metal 3675. Fusion Line 6896. HAZ 396
Figure 3.Scheme of hardness testing on welding components
Failure Analysis Assignment
6
4.4. Metallography Testing
4.4.1. Macrostructure
Figure 4. Macroscopic of shaft com gear shift (good sample), magnification 7X, 2% nital etch
Figure 5. Macroscopic of shaft com gear shift on the left side (good sample), magnification 10X, 2% nital etch
Figure 6. Macroscopic of shaft com gear shift on the right side (good sample), magnification 10X,
2% nital etch
Failure Analysis Assignment
7
Figure 7. Macroscopic of failedshaft com gear shift (rejected), magnification 10X, 2% nital etch
Figure 4 shows proper penetration of the good sample with the presence of huge porosity
(left weld-Fig. 5). Figure 6 shows a good weld joint area without any evidence of defects.
Fig.7 shows the weld penetration is not good on the shaft and plate material. Fig. 7 also
indicated that the weld design use a gap that serves as ventilate of the gas of zinc produced
by welding process.
4.4.2. Microstructure
Figure 8.The microstructure of base metal plate.Nital etch
Failure Analysis Assignment
8
Figure 9.The microstructure of base metal shaft.Nital etch
Figure 10.The microstructure of carbonitided plate surface.Nital etch
Figure 11.The microstructure of weld metal.Nital etch
Failure Analysis Assignment
9
Figure 12. The microstructure of HAZ, Nital etch
Figure 13. The microstructure of fusion line, Nital etch
Figure 14. Macrostructure of failed shaft com gear shift, magnification 10X, 2% nital etch
The microstructure of base metal of the plate sample shows typical of ferrite-pearlite
structures (Figure 8). The diffusion of carbon is occurs due to the different level of
concentration of carbon in shaft sample. It is obvious that during the performance of the
welding process, the carbon concentration on the surface of the shaft is higher than the inner
Failure Analysis Assignment
10
area of the shaft. Bainite structure in HAZ area (Figure 12) and bainite structure in weld area
(Figure 11)are imposed by the observation. The hardness of weld area and HAZ are
approximately 367 and 396 HV, which indicated the range of hardness of bainite
structure.There is no indication of thepresence of micro-inclusions at grain boundaries and
defects in microstructure. Figure 10 and 13 indicates the formation of nitrides and carbide in
the fusion line. These phasesare produced by carbonitrided process during manufacture of
the plate and ascertained by the hardness of the area, approximately 689 HV(see table 2),
that value of hardness tend to be large and is brittle.
4.5. FractographyExamination using Scanning Electron Microscope (SEM)
Figure 15. SEM image in weld area (good sample) with Quadrant Back Scattering Detector (QBSD), 45X
Failure Analysis Assignment
11
Figure 16. SEM image in weld area (good sample) with Secondary Electron Detector (SE1), 80X
Figure 17. SEM image in weld area (good sample) with Secondary Electron Detector (SE1), 100X
Failure Analysis Assignment
12
Figure 18. SEM image in weld area (good sample) with Secondary Electron Detector (SE1), 30X
Figure 19. SEM image in weld area (good sample) with Secondary Electron Detector (SE1), 200X
The figure 15, 16, 17, and 18 are show that the specimen contains porosity in the weld area.
The gap between the specimen is prepared to allows the gas resulted by vaporization zinc to
out from the weld. The porosity, spread uniformly in the welding area. This causesthe
mechanical properties of the material decreases significantlyand failure occurs during utilize
the material. Figure 19 shows porosity at higher magnification.
Failure Analysis Assignment
13
4.6. Micro chemical composition test by EDS
Table 3.EDS results on welding components
Element Element %C 1.71O 41.62Si 0.47Cl 2.20Ca 0.23Ti 0.95Fe 27.66Zn 25.16
5. Results and Discussions
Galvanized steel is widely used for car bodies due to its corrosion resistance.
However, it is associated with serious problems related to the welds quality when welding is
applied as a process to a joint without gaps. In the plate used for gear shaft com, material is
galvanized. It may cause defects in weld area. Zn has higher vapor pressure than Fe, the
higher value of vapor pressure of Zn are tend to have contributed to the explosion. The
problem of welding continued-zinc coated products lies in the different of vaporization and
melting point of Zn compared to steel. Arc can be contaminated by zinc in its vapor state,
results in an unstable and erratic arc and produced a few of porosity in the weld bead,
because zinc in its vaporized state cannot escape or trapped in the weld area.The pores
resulting from the aforementioned processinfluence the mechanical characteristics, leading to
defectivewelds. Accordingly, they should be prevented in advance.Zn also have poor
weldability, highly reactive, easy to form intermetallic compounds at temperatures close to
the melting temperature of zinc brittle.The presence of zinc is indicated in EDX (Table 3).
Figure. ????
Failure Analysis Assignment
13
4.6. Micro chemical composition test by EDS
Table 3.EDS results on welding components
Element Element %C 1.71O 41.62Si 0.47Cl 2.20Ca 0.23Ti 0.95Fe 27.66Zn 25.16
5. Results and Discussions
Galvanized steel is widely used for car bodies due to its corrosion resistance.
However, it is associated with serious problems related to the welds quality when welding is
applied as a process to a joint without gaps. In the plate used for gear shaft com, material is
galvanized. It may cause defects in weld area. Zn has higher vapor pressure than Fe, the
higher value of vapor pressure of Zn are tend to have contributed to the explosion. The
problem of welding continued-zinc coated products lies in the different of vaporization and
melting point of Zn compared to steel. Arc can be contaminated by zinc in its vapor state,
results in an unstable and erratic arc and produced a few of porosity in the weld bead,
because zinc in its vaporized state cannot escape or trapped in the weld area.The pores
resulting from the aforementioned processinfluence the mechanical characteristics, leading to
defectivewelds. Accordingly, they should be prevented in advance.Zn also have poor
weldability, highly reactive, easy to form intermetallic compounds at temperatures close to
the melting temperature of zinc brittle.The presence of zinc is indicated in EDX (Table 3).
Figure. ????
Failure Analysis Assignment
13
4.6. Micro chemical composition test by EDS
Table 3.EDS results on welding components
Element Element %C 1.71O 41.62Si 0.47Cl 2.20Ca 0.23Ti 0.95Fe 27.66Zn 25.16
5. Results and Discussions
Galvanized steel is widely used for car bodies due to its corrosion resistance.
However, it is associated with serious problems related to the welds quality when welding is
applied as a process to a joint without gaps. In the plate used for gear shaft com, material is
galvanized. It may cause defects in weld area. Zn has higher vapor pressure than Fe, the
higher value of vapor pressure of Zn are tend to have contributed to the explosion. The
problem of welding continued-zinc coated products lies in the different of vaporization and
melting point of Zn compared to steel. Arc can be contaminated by zinc in its vapor state,
results in an unstable and erratic arc and produced a few of porosity in the weld bead,
because zinc in its vaporized state cannot escape or trapped in the weld area.The pores
resulting from the aforementioned processinfluence the mechanical characteristics, leading to
defectivewelds. Accordingly, they should be prevented in advance.Zn also have poor
weldability, highly reactive, easy to form intermetallic compounds at temperatures close to
the melting temperature of zinc brittle.The presence of zinc is indicated in EDX (Table 3).
Figure. ????
Failure Analysis Assignment
14
Figure 20. Fillet weld or lapped joint of continued-zinc product
Figure21. Vapor pressure of several metals as a function of temperature
The test result shows the presence of carbide hardness in fusion line, with hardness
approximately 689 HV. The fusion line contained nitride and carbide phasethat cause high
hardness and brittle materials. This causes the material have high sensitivity to crack.The
carbon equivalents of each parent material are:
CE =% C + (% Mn / 6) + Si/24 + Cr / 5 + Mo / 4 + Ni/15
Failure Analysis Assignment
15
CE Shaft : 0.5 + 0.11 + 0,008 + 0.0134 + 0.00625 + 0.0038 = 0.64
CE Plate : 0.1 + 0,058 + 0.000375 + 0.0046 + 0.00125 + 0.00133 = 0.16
Value of Carbon Equivalent (CE) shaft material is quite high, it is above 0.35, it is required
to do an additional treatment in areas other than the plate, the treatment such as preheats,
interpass temperature and post heat treatment to release stress and prevent cracking due to
welding. All heat treatment must do at temperature under melting point of Zn.
6. Conclusion and Recommendation
Zn vapor trapped in the area of weld metal makes the porosity in the weld metal, coupled
with the phase carbida and brittle nitrides at the fusion line area, making a broken component
on the connection between shaft and plate. When the product receives load, the connection
between the shaft and the plate contained porosity and brittle phase in, will instantly broken.
The recommendations we conduct in this case are:
Galvanizing steel should have special surface preparation, such as grinding the area
subjected to be welded to remove the zinc layer on the surface, that is because of melting
point of Zn is far lower than Fe. Zinc vaporizes at 902oC. So, when Fe in melt state, Zn in
vapor state. Zn vapor can contaminate the molten metal. That condition can make a few
of porosity in weld metal because of Zn in vapor state cannot escape.
To avoid the porosity and leak of penetration of the material, the laser-arc hybrid welding
process can be applied. The combination of laser welding power and arc welding power
simultaneously to compose a single weld, utilizing the advantages of both methods. This
process allows preheat and post heat treatments on the welds through the arrangement of
the laser and arc.
Failure Analysis Assignment
16
Use special filler offor weld the galvanized component, such astitanium or any other filler
which needs low weld energy.
Do preheat before weld the materials. The relationship between carbon equivalent and
preheat and interpass temperatures are recommended is shown in Table 4.All heat
treatment must do at temperature under melting point of Zn. Because of carbon
equivalent in shaft 0.64, preheat and interpass temperature should do between 250-300oC
in areas other than the plate.
Table 4. The relationship between carbon equivalent and preheat and interpass temperatures are recommended
The price comparisons of the recommendation given above are as shown in Tabel 5.
Table 5.list of material which can remove abrasively carbonitrided, with hardness value and the price
Material Hardness Value (Hv) Price (USD) / kg powder
Carbon Boron Nitride 6000 200 – 2000
Boron Carbide 3700 10 – 50
Titanium Carbide 3200 10 – 60
Vanadium Carbide 2800 60 – 65
Tungsten Carbide 2400 35 – 80
Chromium Carbide 1400 10 – 40
Boron Carbide is very recommended because the price as cheap as chromium carbide but
boron carbide has more hardness value than chromium carbide, so the longer times it takes to
wear boron carbide than to wear chromium carbide. Then, The powder form of boron nitride
Failure Analysis Assignment
17
can be fabricated by casting to become a wheel, like figure 23 below. In market, price of a
wheel is about USD 100 - 500.
Figure 23. Super abrasive wheel
Failure Analysis Assignment
17
can be fabricated by casting to become a wheel, like figure 23 below. In market, price of a
wheel is about USD 100 - 500.
Figure 23. Super abrasive wheel
Failure Analysis Assignment
17
can be fabricated by casting to become a wheel, like figure 23 below. In market, price of a
wheel is about USD 100 - 500.
Figure 23. Super abrasive wheel
Failure Analysis Assignment
18
7. References
Sperko Engineering Services, Inc. 1999. Welding Galvanized Steel – Safely.
http://www.nakedwhiz.com/weldinggalvanized.pdf.Accessedseptember 25 2012, 11.14
WIB.
http://www.slbgroup.com/pdf/balltinfotech/thrustballtech.pdf.Accessed September 25th
2012, 12.01 WIB.
JIS S45C composition. http://www.meadinfo.org/2010/03/s45c-jis-mechanical-
properties.html. Accessed September 25th 2012, 11.30 WIB.
Welding Handbook. 2009. Kobe Steel, Ltd.
http://www.kobelcowelding.com/20100119/handbook2009.pdf. Accessed September
16th 2012, 15.30 WIB.
Cheolhee Kim, Woongyong Choi, Jeonghan Kim, and Sehun Rhee. 2008. Relationship
between the Weldability and the Process Parameters for Laser-TIG Hybrid Welding of
Galvanized Steel Sheets.Materials Transactions, Vol. 49, No. 1 (2008) pp. 179 to 186.
M. Pouranvari. 2011. Analysis of Fracture Mode of Galvanized Low Carbon Steel
Resistance Spot Welds. International Journal of Multidisciplinary sciences and
engineering, vol.2, No.6, September 2011.
HongpingGu and Boris Shulkin. Remote laser welding of zinc-coated sheet metal;
component in a lap configuration utilizing humping effect. Stronach Centre for
Innovation, Magna International Inc. Aurora, Ontario, L4G 7G6, Canada.
http://astralloy.infomedia.net/pdf/plate_outwear.pdf. Accessed October 6th 2012, 23.00
WIB.
http://www.3m.com/product/information/Superabrasive-Wheels.html. Accessed October
7th 2012, 00.11 WIB.
http://www.alibaba.com.