Rianti Dewi Sulamet-Ariobimo | Trisakti University (original) (raw)

Papers by Rianti Dewi Sulamet-Ariobimo

Materials Science Forum, Mar 1, 2017

Sugarcane bagasse has demonstrated its ability to act as a reductor in iron-reduction process. As... more Sugarcane bagasse has demonstrated its ability to act as a reductor in iron-reduction process. As a reductor, bagasse has specialties as double-acting reductor equiped with volatile matter. This is the first study of the use of bagasse as reductor in iron-reduction process. The parameter concluded from this study was used for the second study which report has been submitted for publication. The aim of this study is to discuss the effect of reduction process parameter to the use of bagasse as reductor. This study was divided into 2 step. The first step is determining the optimum reduction process temperature and weight ratio. The reduction temperature varied as 700, 800, 900 and 1000 °C and the weight ratio are 1:2 and 1:4. The process duration is 30 minutes. The second stape is determining the process duration. The process duration will be varied as 30, 45 and 60 minutes. The condition of bagasse is air dried basis. The result shows that the reduction process produced wustite (FeO).

IOP conference series, Aug 1, 2019

Austempering process was carried out on thin wall ductile iron (TWDI) connecting rod produced by ... more Austempering process was carried out on thin wall ductile iron (TWDI) connecting rod produced by the design built in previous research. Austempering process was applied to improve the mechanical properties of the component, so it will be equal to forged steel. The aim of this work is to study the effects of austempering holding time to microstructure and mechanical properties of TWDI connecting rod. The process was applied to all connecting rods resulting from the vertical casting. The austenitising temperature was 960 0 C with 35 minutes holding time and the austempering temperature was 350 0 C with varied austempering holding time, that were 15, 30, 45 and 60 minutes. The process was held in fluidized bed furnace. Metallographic examination, tensile and compression stress-strain test were conducted directly to the connecting rod. The results showed that austempering process improved the mechanical properties of TWDI connecting rod and the result of the compression stress-strain test showed that the austempered TWDI connecting rod met its requirements.

Materials Science Forum, Aug 1, 2018

Cooling rate plays an important role in the formation of thin wall ductile iron microstructure du... more Cooling rate plays an important role in the formation of thin wall ductile iron microstructure due to their thickness, which is 3 mm below based on Stefanescu. Cooling rate is closely related to casting design and determines the microstructure. This paper discusses the effect of casting design modification to casting yield and microstructures. Modification was made on a patented design used previously to produce thin wall ductile iron plates. The design was minimized and casting simulation was used to analyze castability of the design. After that, the design were casted in several pouring temperatures. Improvement was made to casting design based on the failure during the experiment. Casting process took place after simulation analysis. The casting product was fully casted as shown by the simulation. The casting yield has improved to 28%. When all plates were examined for microstructure, the result showed that all the microstructure of the plates was not graphite in ferrite matrix as occurred in the patented design but it was graphite in pearlite matrix.

Advanced Materials Research, 2013

Indonesia due its archipelago has so many kinds of rocks which contain ores. With the finding in ... more Indonesia due its archipelago has so many kinds of rocks which contain ores. With the finding in technology iron source is not iron ore alone like it use to be in the past. This research is conducted to see availability of mineral rocks in Indonesia as iron source. Four different kinds of mineral rocks are used. They are: limonite, saprolite, malachite, and chalcopyrite. Separation of limonite is done by magnetic separation process while saprolite, malachite, and chalcopyrite are done by washing separation methods. Analysis on Fe content is done at origin and roasting condition for all rocks. The results show that other mineral rocks can become iron source, separation will enhance Fe content, and lateritic nickel rocks especially limonite can be new other iron source.

Applied Mechanics and Materials, Apr 1, 2015

Cooling rate plays an important role in thin wall ductile iron solidification, due to their thick... more Cooling rate plays an important role in thin wall ductile iron solidification, due to their thickness. Casting simulation is use as a tool to estimate the cooling rate. In the other hand, every microstructure has its own cooling rate. This paper explores the similarity of solidification mechanism between simulation and graphite characteristics. Three types of casting design simulated and produced. Solidification mechanism is analyzed based on cooling rate sequence and trend line matching. Temperature gradient and thermocouple function represent simulation while graphite characteristic represent experiment. The result shows that similarity in solidification mechanism is not found between simulation with experiment due to lack of parameters in both sides.

Advanced Materials Research, Jul 1, 2011

In the general rule of casting design the thickest part of the cast should be placed near to the ... more In the general rule of casting design the thickest part of the cast should be placed near to the ingate. This arrangement was meant to guarantee the completion of filling process. An unusual vertical casting design to produce plates with different thicknesses was established based on the idea that the heat from molten metal will always warm up its entire runner. In this design the thinnest plate is placed near to the ingate. The design was made for producing thin wall ductile iron. This research was conducted to see the effects of reverse thickness arrangement in casting design to the microstructure and mechanical properties of the plates. Plates produced by this design were compared to plates produced by the same design with general casting arrangement. Thicknesses of the plates produced in this casting were 1, 2, 3, 4, and 5 mm. The moulds used were made from furan sand. Beside experiment, casting design simulation with Z-Cast was also conducted to ensure the completion of filling process and to see the manner of solidification. Casting simulation showed that arrangement of plates gave different filling and solidification manners. Although there were some differences, the filling was successful for both arrangements of plates. Skin effect was found in both designs. Nodule counts and nodularity were higher in the new design while average nodule diameters were lower. The result gained in tensile and hardness test did not follow the correlations in the characteristic of graphite. Mechanical properties showed that position of plate, ignoring the thickness, influence tensile strength and hardness.

Advanced Materials Research, Feb 1, 2014

Quality molten metal needed to produce thin wall ductile iron (TWDI). Pig iron, as the major base... more Quality molten metal needed to produce thin wall ductile iron (TWDI). Pig iron, as the major base material to produce quality molten metal, due to its high price, has been change with scraps. The use of scrap as major base material associates with more cleaning and chemical composition adjustment. The ITmk3 technology in iron making has successfully produced iron nugget. Iron nugget can be use to substitute pig iron due to its quality that is comparable to pig iron but lower in price. This research conducted to see the effects of carbon content in producing iron nugget. Limonite iron ores used in this research are part of laterite rocks taken from Sebuku Island in South Kalimantan, Indonesia. Variation made to weight of carbon mixed with laterite. Heating temperatures of direct reduction process are 700°C, 900°C, and 1000°C. The process times are 10, 20, and 30 minutes. XRF used in analysing Fe content in laterite and XRD is used in analysing result of direct reduction process. The result shows that increasing carbon content to certain condition will increase the rate of gasification process during direct reduction. The increase of gasification rate will result to higher Fe formation.

Applied Mechanics and Materials, 2012

In producing thin wall ductile iron (TWDI) cooling rate must be strictly maintained to prevent ca... more In producing thin wall ductile iron (TWDI) cooling rate must be strictly maintained to prevent carbide formation. There are many ways to control cooling rate BUT the most independent one is by casting design. By choosing this parameter major changes in equipment and raw material used in the foundry can be avoided. This paper discusses the effect of gating system design on microstructure and mechanical properties of 5 mm TWDI plate. A casting design based on vertical gating system is made to produce 1, 2, 3, 4, and 5 mm TWDI plates. Plate with 5 mm thickness becomes an interesting subject due to its position as the thickest and furthest from ingate in casting design with a new concept. There are three designs coded as T1, T2, and T3. These three designs were also used in making 1 and 3 mm TWDI plates of which the result has been published. The plate with 5 mm thickness will be used for automotive components. Casting design simulation for filling flow and solidification were conducted with Z-Cast. Result of flow simulation shows that the filling flow happens in two kinds. Result of solidification shows that T3 has the highest solidification rate. In the experiment, the moulds used were furan sand. Experiment result shows that all the designs have microstructure consisting of nodule graphite in ferrite matrix, no trace of carbide and skin effect are formed. Skin effect length is various for all designs. The highest nodularity is only 72% and nodule count shows only 700 nodules/mm2. Brinell hardness number for all design is beyond standard given by JIG G5502. As for UTS and elongation none of the designs exceed the minimal standard. Experiment results confirms simulation result. Compared to the previous result nodularity and nodule count decrease and curve trends for every result are not similar.

Jurnal Abdi Masyarakat Indonesia, Apr 3, 2022

DEStech Transactions on Engineering and Technology Research, Jun 26, 2017

Finding iron sources from other ores is important because of the depletion of iron ore. One such ... more Finding iron sources from other ores is important because of the depletion of iron ore. One such source is lateritic rocks. Lateritic rocks are a nickel source, but owing to their high iron content, they are promoted as an iron source. This research was conducted to investigate the effect of reduction parameters on lateritic rock behaviour. Lateritic limonite rock is used. Process parameters include particle size, temperature, holding time and ratio of carbon. Particle size is varied in 120, 170, 200 and 270 meshes. Temperatures are 600, 800, 1000, 1100 and 1200 o C. Holding times used are 60 and 90 minutes. The variable ratios of carbon to ore are 1:1, 2:1, and 3:1. The results show that among all the parameters, temperature has a significant effect and holding time displays the weakest effect.

InTech eBooks, May 2, 2018

The use of austempered ductile iron (ADI) as an alternative material has increased, and it is pre... more The use of austempered ductile iron (ADI) as an alternative material has increased, and it is predicted that it will reach 300,000 tons by the year of 2020 due to its characteristics especially design flexibility. When the reduction in weight is considered as a parameter for energy saving, ADI is presented as thin wall austempered ductile iron (TWADI). To produce a good quality TWADI, a good quality thin wall ductile iron (TWDI) must be used as a raw material. Good quality TWDI is produced by casting design. This chapter discusses the production of thin wall ductile iron, including its characterisation and defect. The discussion includes the background of thin wall casting (TWC) and TWDI, applying TWC in general casting, the problems in producing TWDI, characterisation of the TWDI and specific defects.

Advanced Materials Research, Dec 1, 2011

The problem occurs in producing thin wall ductile iron (TWDI) is high cooling rate due to its thi... more The problem occurs in producing thin wall ductile iron (TWDI) is high cooling rate due to its thickness. Cooling rate must be strictly maintained to prevent carbide formation. There are many ways to control cooling rate. Casting design is one of these, especially gating system design. This parameter is often chosen because of its independence. Major changes in equipment and raw material used in the foundry are not needed when a casting design is chosen to deal with cooling rate. This paper discusses the effect of gating system design on microstructure and mechanical properties of 3 mm TWDI plate. A casting design based on gating system design is made to produce 1, 2, 3, 4, and 5 mm TWDI plates. There are three designs coded as T1, T2, and T3. These three designs were also used in making 1 mm TWDI plates of which the result has been published. The plate with thickness of 3 mm will be used for automotive component like the crankshaft made by Martinez. The moulds used were furan sand. Beside the experiment, casting design simulation with Z-Cast was also conducted to see the behaviour of solidification in 3 mm TWDI plate. Simulation result showed every design has its own solidification behaviour for 3 mm TWDI plate, especially for T2. Experiment result showed that all the designs have microstructure consisting of nodule graphite in ferrite matrix, no trace of carbide and skin effect are formed. Skin effect length is various for all designs. Nodularity exceeded 75% and nodule count exceeded 900 nodules/mm2. Brinell hardness number for all design is beyond standard given by JIG G5502. As for UTS and elongation none of the designs exceed the minimal standard. Experiment results confirmed simulation result. Compared to the previous result nodularity and nodule count decrease and curve trends for every result are not the same.

Advanced Materials Research, Feb 1, 2014

Many parameters are involved in reduction process but carbon availability, process temperature an... more Many parameters are involved in reduction process but carbon availability, process temperature and process time hold the role. This research conducted to find the relation effects of three main factors mention previously. This research used lateritic rocks from Sebuku Island as the iron source and coal as carbon source. Particle size with the highest Fe content is used for reduction process. Variations in reduction process made in mass ratio, process temperature, and process time. The mass ratios are 1:4 and 1:5. The process temperatures are 900OC and 1000OC. Process times are 10, 20, and 30 minutes. Characterization process used XRD and XRF. The results show that carbon availability is important and combinations of higher carbon supplies and process temperature are able to prevent further oxidation.

Journal of materials science & engineering, Mar 30, 2011

Airiti Library華藝線上圖書館.

Applied Mechanics and Materials, Jun 1, 2016

Iron ores should be separated from oxygen and impurities which are coming along during the mining... more Iron ores should be separated from oxygen and impurities which are coming along during the mining process. The separation process is known as reduction. There are two types of reduction process, and the most common is direct reduction process (DRP). There are several parameters in DRP which will determine the quantities of the product known as direct reduction iron (DRI). This worked discussed the effect of reduction temperature and pellet heap to the quantities of DRI using single conveyer belt Hearth furnace. The worked was done in laboratory scale using composite pellets with 14 mm in diameter. The ratio of iron ore to coal in the composite pellet is 1 to 1. The reduction process temperatures are 500oC, 700oC and 900oC. The reduction time is 25 minutes. While the pellets heap are also varied to 1, 3, 5, 7, 8 and 9 layers. The results show that DRI was formed in 700OC and the quantities of DRI are in line with the reduction temperatures and layers of composite pellets heap.

Advanced Materials Research, May 1, 2013

Casting design is chosen by Soedarsono et al to maintain cooling rate in producing thin wall duct... more Casting design is chosen by Soedarsono et al to maintain cooling rate in producing thin wall ductile iron (TWDI). Cooling rate should be maintained to prevent carbide formation. This paper discusses the effect of gating system design on microstructure and mechanical properties of 4 mm TWDI plate. A casting design based on vertical gating system is made to produce TWDI plates with the thickness of 1, 2, 3, 4, and 5 mm. This vertical system allows plates to function as runner which will helps in preventing premature solidification. Three designs were made. These designs are coded as T1, T2, and T3. These three designs were also used in making 1, 2, 3, and 5 mm TWDI plates of which the result has been published. Z-Cast is used to conduct a casting design simulation for filling flow and solidification. The result of flow simulation shows that the filling flow is resulted in two kinds. The result of solidification specifies that the 4 mm TWDI plates solidify in the third place. The result of the experiment highlights that in all of the designs, which have microstructure and consisted of nodule graphite in ferrite matrix, no trace of carbide and skin effect are formed. The length of skin effect varies in all of the designs. The highest nodularity is only 80% while nodule count is 931 nodules/mm2. Brinell hardness number for all of the design is beyond the standard given by JIG G5502. As for UTS, yield strength and elongation none of the designs exceeds the minimal standard. The result of the experiment does not confirm the result of the simulation. In sum, compared to the previous result, the curve trends of 4 mm TWDI plates look similar to 2 mm TWDI plates.

1ST INTERNATIONAL SEMINAR ON ADVANCES IN METALLURGY AND MATERIALS (i-SENAMM 2019), 2020

This study reports isothermal crystallization of Zr60Cu25Ni5Al10 (at%) amorphous alloy. The speci... more This study reports isothermal crystallization of Zr60Cu25Ni5Al10 (at%) amorphous alloy. The specimens used for the study was prepared by arc melting and induction melting. Experiments using isothermal method used Differential Scanning Calorimetry (DSC) to obtain parameters for crystallization kinetics which describe the transformation mechanism during crystallization process. The analysis of crystallization kinetics was performed using Kolmogorov-Johnson-Mehl-Avrami (KJMA) equation. Avrami exponent, n, obtained for Zr60Cu25Ni5Al10 varied between 4.1 and 4.3. This value of Avrami exponent can be interpreted as that the transformation mechanism for Zr60Cu25Ni5Al10 is interface-controlled growth with increasing nucleation rate.

TOWARD ADAPTIVE RESEARCH AND TECHNOLOGY DEVELOPMENT FOR FUTURE LIFE

INTERNATIONAL CONFERENCE ON MECHANICAL ENGINEERING FOR EMERGING TECHNOLOGIES (ICOMEET 2021)

Materials Science Forum, Mar 1, 2017

Sugarcane bagasse has demonstrated its ability to act as a reductor in iron-reduction process. As... more Sugarcane bagasse has demonstrated its ability to act as a reductor in iron-reduction process. As a reductor, bagasse has specialties as double-acting reductor equiped with volatile matter. This is the first study of the use of bagasse as reductor in iron-reduction process. The parameter concluded from this study was used for the second study which report has been submitted for publication. The aim of this study is to discuss the effect of reduction process parameter to the use of bagasse as reductor. This study was divided into 2 step. The first step is determining the optimum reduction process temperature and weight ratio. The reduction temperature varied as 700, 800, 900 and 1000 °C and the weight ratio are 1:2 and 1:4. The process duration is 30 minutes. The second stape is determining the process duration. The process duration will be varied as 30, 45 and 60 minutes. The condition of bagasse is air dried basis. The result shows that the reduction process produced wustite (FeO).

IOP conference series, Aug 1, 2019

Austempering process was carried out on thin wall ductile iron (TWDI) connecting rod produced by ... more Austempering process was carried out on thin wall ductile iron (TWDI) connecting rod produced by the design built in previous research. Austempering process was applied to improve the mechanical properties of the component, so it will be equal to forged steel. The aim of this work is to study the effects of austempering holding time to microstructure and mechanical properties of TWDI connecting rod. The process was applied to all connecting rods resulting from the vertical casting. The austenitising temperature was 960 0 C with 35 minutes holding time and the austempering temperature was 350 0 C with varied austempering holding time, that were 15, 30, 45 and 60 minutes. The process was held in fluidized bed furnace. Metallographic examination, tensile and compression stress-strain test were conducted directly to the connecting rod. The results showed that austempering process improved the mechanical properties of TWDI connecting rod and the result of the compression stress-strain test showed that the austempered TWDI connecting rod met its requirements.

Materials Science Forum, Aug 1, 2018

Cooling rate plays an important role in the formation of thin wall ductile iron microstructure du... more Cooling rate plays an important role in the formation of thin wall ductile iron microstructure due to their thickness, which is 3 mm below based on Stefanescu. Cooling rate is closely related to casting design and determines the microstructure. This paper discusses the effect of casting design modification to casting yield and microstructures. Modification was made on a patented design used previously to produce thin wall ductile iron plates. The design was minimized and casting simulation was used to analyze castability of the design. After that, the design were casted in several pouring temperatures. Improvement was made to casting design based on the failure during the experiment. Casting process took place after simulation analysis. The casting product was fully casted as shown by the simulation. The casting yield has improved to 28%. When all plates were examined for microstructure, the result showed that all the microstructure of the plates was not graphite in ferrite matrix as occurred in the patented design but it was graphite in pearlite matrix.

Advanced Materials Research, 2013

Indonesia due its archipelago has so many kinds of rocks which contain ores. With the finding in ... more Indonesia due its archipelago has so many kinds of rocks which contain ores. With the finding in technology iron source is not iron ore alone like it use to be in the past. This research is conducted to see availability of mineral rocks in Indonesia as iron source. Four different kinds of mineral rocks are used. They are: limonite, saprolite, malachite, and chalcopyrite. Separation of limonite is done by magnetic separation process while saprolite, malachite, and chalcopyrite are done by washing separation methods. Analysis on Fe content is done at origin and roasting condition for all rocks. The results show that other mineral rocks can become iron source, separation will enhance Fe content, and lateritic nickel rocks especially limonite can be new other iron source.

Applied Mechanics and Materials, Apr 1, 2015

Cooling rate plays an important role in thin wall ductile iron solidification, due to their thick... more Cooling rate plays an important role in thin wall ductile iron solidification, due to their thickness. Casting simulation is use as a tool to estimate the cooling rate. In the other hand, every microstructure has its own cooling rate. This paper explores the similarity of solidification mechanism between simulation and graphite characteristics. Three types of casting design simulated and produced. Solidification mechanism is analyzed based on cooling rate sequence and trend line matching. Temperature gradient and thermocouple function represent simulation while graphite characteristic represent experiment. The result shows that similarity in solidification mechanism is not found between simulation with experiment due to lack of parameters in both sides.

Advanced Materials Research, Jul 1, 2011

In the general rule of casting design the thickest part of the cast should be placed near to the ... more In the general rule of casting design the thickest part of the cast should be placed near to the ingate. This arrangement was meant to guarantee the completion of filling process. An unusual vertical casting design to produce plates with different thicknesses was established based on the idea that the heat from molten metal will always warm up its entire runner. In this design the thinnest plate is placed near to the ingate. The design was made for producing thin wall ductile iron. This research was conducted to see the effects of reverse thickness arrangement in casting design to the microstructure and mechanical properties of the plates. Plates produced by this design were compared to plates produced by the same design with general casting arrangement. Thicknesses of the plates produced in this casting were 1, 2, 3, 4, and 5 mm. The moulds used were made from furan sand. Beside experiment, casting design simulation with Z-Cast was also conducted to ensure the completion of filling process and to see the manner of solidification. Casting simulation showed that arrangement of plates gave different filling and solidification manners. Although there were some differences, the filling was successful for both arrangements of plates. Skin effect was found in both designs. Nodule counts and nodularity were higher in the new design while average nodule diameters were lower. The result gained in tensile and hardness test did not follow the correlations in the characteristic of graphite. Mechanical properties showed that position of plate, ignoring the thickness, influence tensile strength and hardness.

Advanced Materials Research, Feb 1, 2014

Quality molten metal needed to produce thin wall ductile iron (TWDI). Pig iron, as the major base... more Quality molten metal needed to produce thin wall ductile iron (TWDI). Pig iron, as the major base material to produce quality molten metal, due to its high price, has been change with scraps. The use of scrap as major base material associates with more cleaning and chemical composition adjustment. The ITmk3 technology in iron making has successfully produced iron nugget. Iron nugget can be use to substitute pig iron due to its quality that is comparable to pig iron but lower in price. This research conducted to see the effects of carbon content in producing iron nugget. Limonite iron ores used in this research are part of laterite rocks taken from Sebuku Island in South Kalimantan, Indonesia. Variation made to weight of carbon mixed with laterite. Heating temperatures of direct reduction process are 700°C, 900°C, and 1000°C. The process times are 10, 20, and 30 minutes. XRF used in analysing Fe content in laterite and XRD is used in analysing result of direct reduction process. The result shows that increasing carbon content to certain condition will increase the rate of gasification process during direct reduction. The increase of gasification rate will result to higher Fe formation.

Applied Mechanics and Materials, 2012

In producing thin wall ductile iron (TWDI) cooling rate must be strictly maintained to prevent ca... more In producing thin wall ductile iron (TWDI) cooling rate must be strictly maintained to prevent carbide formation. There are many ways to control cooling rate BUT the most independent one is by casting design. By choosing this parameter major changes in equipment and raw material used in the foundry can be avoided. This paper discusses the effect of gating system design on microstructure and mechanical properties of 5 mm TWDI plate. A casting design based on vertical gating system is made to produce 1, 2, 3, 4, and 5 mm TWDI plates. Plate with 5 mm thickness becomes an interesting subject due to its position as the thickest and furthest from ingate in casting design with a new concept. There are three designs coded as T1, T2, and T3. These three designs were also used in making 1 and 3 mm TWDI plates of which the result has been published. The plate with 5 mm thickness will be used for automotive components. Casting design simulation for filling flow and solidification were conducted with Z-Cast. Result of flow simulation shows that the filling flow happens in two kinds. Result of solidification shows that T3 has the highest solidification rate. In the experiment, the moulds used were furan sand. Experiment result shows that all the designs have microstructure consisting of nodule graphite in ferrite matrix, no trace of carbide and skin effect are formed. Skin effect length is various for all designs. The highest nodularity is only 72% and nodule count shows only 700 nodules/mm2. Brinell hardness number for all design is beyond standard given by JIG G5502. As for UTS and elongation none of the designs exceed the minimal standard. Experiment results confirms simulation result. Compared to the previous result nodularity and nodule count decrease and curve trends for every result are not similar.

Jurnal Abdi Masyarakat Indonesia, Apr 3, 2022

DEStech Transactions on Engineering and Technology Research, Jun 26, 2017

Finding iron sources from other ores is important because of the depletion of iron ore. One such ... more Finding iron sources from other ores is important because of the depletion of iron ore. One such source is lateritic rocks. Lateritic rocks are a nickel source, but owing to their high iron content, they are promoted as an iron source. This research was conducted to investigate the effect of reduction parameters on lateritic rock behaviour. Lateritic limonite rock is used. Process parameters include particle size, temperature, holding time and ratio of carbon. Particle size is varied in 120, 170, 200 and 270 meshes. Temperatures are 600, 800, 1000, 1100 and 1200 o C. Holding times used are 60 and 90 minutes. The variable ratios of carbon to ore are 1:1, 2:1, and 3:1. The results show that among all the parameters, temperature has a significant effect and holding time displays the weakest effect.

InTech eBooks, May 2, 2018

The use of austempered ductile iron (ADI) as an alternative material has increased, and it is pre... more The use of austempered ductile iron (ADI) as an alternative material has increased, and it is predicted that it will reach 300,000 tons by the year of 2020 due to its characteristics especially design flexibility. When the reduction in weight is considered as a parameter for energy saving, ADI is presented as thin wall austempered ductile iron (TWADI). To produce a good quality TWADI, a good quality thin wall ductile iron (TWDI) must be used as a raw material. Good quality TWDI is produced by casting design. This chapter discusses the production of thin wall ductile iron, including its characterisation and defect. The discussion includes the background of thin wall casting (TWC) and TWDI, applying TWC in general casting, the problems in producing TWDI, characterisation of the TWDI and specific defects.

Advanced Materials Research, Dec 1, 2011

The problem occurs in producing thin wall ductile iron (TWDI) is high cooling rate due to its thi... more The problem occurs in producing thin wall ductile iron (TWDI) is high cooling rate due to its thickness. Cooling rate must be strictly maintained to prevent carbide formation. There are many ways to control cooling rate. Casting design is one of these, especially gating system design. This parameter is often chosen because of its independence. Major changes in equipment and raw material used in the foundry are not needed when a casting design is chosen to deal with cooling rate. This paper discusses the effect of gating system design on microstructure and mechanical properties of 3 mm TWDI plate. A casting design based on gating system design is made to produce 1, 2, 3, 4, and 5 mm TWDI plates. There are three designs coded as T1, T2, and T3. These three designs were also used in making 1 mm TWDI plates of which the result has been published. The plate with thickness of 3 mm will be used for automotive component like the crankshaft made by Martinez. The moulds used were furan sand. Beside the experiment, casting design simulation with Z-Cast was also conducted to see the behaviour of solidification in 3 mm TWDI plate. Simulation result showed every design has its own solidification behaviour for 3 mm TWDI plate, especially for T2. Experiment result showed that all the designs have microstructure consisting of nodule graphite in ferrite matrix, no trace of carbide and skin effect are formed. Skin effect length is various for all designs. Nodularity exceeded 75% and nodule count exceeded 900 nodules/mm2. Brinell hardness number for all design is beyond standard given by JIG G5502. As for UTS and elongation none of the designs exceed the minimal standard. Experiment results confirmed simulation result. Compared to the previous result nodularity and nodule count decrease and curve trends for every result are not the same.

Advanced Materials Research, Feb 1, 2014

Many parameters are involved in reduction process but carbon availability, process temperature an... more Many parameters are involved in reduction process but carbon availability, process temperature and process time hold the role. This research conducted to find the relation effects of three main factors mention previously. This research used lateritic rocks from Sebuku Island as the iron source and coal as carbon source. Particle size with the highest Fe content is used for reduction process. Variations in reduction process made in mass ratio, process temperature, and process time. The mass ratios are 1:4 and 1:5. The process temperatures are 900OC and 1000OC. Process times are 10, 20, and 30 minutes. Characterization process used XRD and XRF. The results show that carbon availability is important and combinations of higher carbon supplies and process temperature are able to prevent further oxidation.

Journal of materials science & engineering, Mar 30, 2011

Airiti Library華藝線上圖書館.

Applied Mechanics and Materials, Jun 1, 2016

Iron ores should be separated from oxygen and impurities which are coming along during the mining... more Iron ores should be separated from oxygen and impurities which are coming along during the mining process. The separation process is known as reduction. There are two types of reduction process, and the most common is direct reduction process (DRP). There are several parameters in DRP which will determine the quantities of the product known as direct reduction iron (DRI). This worked discussed the effect of reduction temperature and pellet heap to the quantities of DRI using single conveyer belt Hearth furnace. The worked was done in laboratory scale using composite pellets with 14 mm in diameter. The ratio of iron ore to coal in the composite pellet is 1 to 1. The reduction process temperatures are 500oC, 700oC and 900oC. The reduction time is 25 minutes. While the pellets heap are also varied to 1, 3, 5, 7, 8 and 9 layers. The results show that DRI was formed in 700OC and the quantities of DRI are in line with the reduction temperatures and layers of composite pellets heap.

Advanced Materials Research, May 1, 2013

Casting design is chosen by Soedarsono et al to maintain cooling rate in producing thin wall duct... more Casting design is chosen by Soedarsono et al to maintain cooling rate in producing thin wall ductile iron (TWDI). Cooling rate should be maintained to prevent carbide formation. This paper discusses the effect of gating system design on microstructure and mechanical properties of 4 mm TWDI plate. A casting design based on vertical gating system is made to produce TWDI plates with the thickness of 1, 2, 3, 4, and 5 mm. This vertical system allows plates to function as runner which will helps in preventing premature solidification. Three designs were made. These designs are coded as T1, T2, and T3. These three designs were also used in making 1, 2, 3, and 5 mm TWDI plates of which the result has been published. Z-Cast is used to conduct a casting design simulation for filling flow and solidification. The result of flow simulation shows that the filling flow is resulted in two kinds. The result of solidification specifies that the 4 mm TWDI plates solidify in the third place. The result of the experiment highlights that in all of the designs, which have microstructure and consisted of nodule graphite in ferrite matrix, no trace of carbide and skin effect are formed. The length of skin effect varies in all of the designs. The highest nodularity is only 80% while nodule count is 931 nodules/mm2. Brinell hardness number for all of the design is beyond the standard given by JIG G5502. As for UTS, yield strength and elongation none of the designs exceeds the minimal standard. The result of the experiment does not confirm the result of the simulation. In sum, compared to the previous result, the curve trends of 4 mm TWDI plates look similar to 2 mm TWDI plates.

1ST INTERNATIONAL SEMINAR ON ADVANCES IN METALLURGY AND MATERIALS (i-SENAMM 2019), 2020

This study reports isothermal crystallization of Zr60Cu25Ni5Al10 (at%) amorphous alloy. The speci... more This study reports isothermal crystallization of Zr60Cu25Ni5Al10 (at%) amorphous alloy. The specimens used for the study was prepared by arc melting and induction melting. Experiments using isothermal method used Differential Scanning Calorimetry (DSC) to obtain parameters for crystallization kinetics which describe the transformation mechanism during crystallization process. The analysis of crystallization kinetics was performed using Kolmogorov-Johnson-Mehl-Avrami (KJMA) equation. Avrami exponent, n, obtained for Zr60Cu25Ni5Al10 varied between 4.1 and 4.3. This value of Avrami exponent can be interpreted as that the transformation mechanism for Zr60Cu25Ni5Al10 is interface-controlled growth with increasing nucleation rate.

TOWARD ADAPTIVE RESEARCH AND TECHNOLOGY DEVELOPMENT FOR FUTURE LIFE

INTERNATIONAL CONFERENCE ON MECHANICAL ENGINEERING FOR EMERGING TECHNOLOGIES (ICOMEET 2021)