Characterization of laser metal deposited 17-4 PH stainless steel and tungsten composite for surface engineering applications
- Authors: Adeyemi, A.A.
- Date: 2018
- Subjects: Pulsed laser deposition , Metal coating , Metals - Mechanical properties , Lasers - Industrial applications , Stainless steel
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/284734 , uj:30767
- Description: Abstract: 17-4 PH Stainless steel is a martensitic characterized precipitation hardened stainless steel with excellent mechanical properties that has been tailored to industrial applications such as aerospace, automobile, marine, food processing equipment, oil and gas industries and chemical processing industries. Despite the growth experienced in the use of this material, 17-4 PH stainless steels are prone to degradation due to long service use in applications that required extreme hardness and wear resistance. This limitation led to the research of property enhancement of the material using modern fabrication technique called laser metal deposition additive manufacturing technology. Laser metal deposition is a modern additive manufacturing technique used in fabricating physical components from the configuration of a 3D CAD data model using a high intensity laser beam while depositing metallic powder on a substrate one layer at a time. This process is flexible in its use as it allows addition of reinforcing particles to improve surface properties of a metallic material such as hardness and wear amongst others. This research study presents the use of laser metal deposition process to investigate the property enhancement of 17-4 PH stainless steel through various characterization process such as microstructural evaluation, microhardness and wear test. The deposition process was carried out using Rofin Sinar Ytterbium fibre laser system of laser capacity of 3.0 kW. The reinforcement material was 17-4 PH stainless steel and tungsten metallic powder deposited on 316 stainless steel substrate. The deposition process commenced firstly with a trial-run deposition of 5 samples with multiple-track of 17-4 PH stainless steel at 50% overlapping percentage on 316 stainless steel substrate to establish process window. The reason for the trial-run was to achieve a deposition with no defects such as pores and cracks. After this was achieved, 17-4 PH stainless steel metallic powder and tungsten metallic powder were now deposited in form of multiple track at 50% overlapping percentage at high laser power and low laser power of 2600 W and 1500 W at varied tungsten powder flow rate on 316 stainless steel substrate. The microstructural evaluation, geometrical analysis, microhardness profiling and wear resistance characteristics of the deposited composites were investigated. The microstructural evolution investigation was carried out using optical microscopy (OM), scanning electron microscopy (SEM) equipped with energy dispersive spectroscopy (EDS) and x-ray diffraction (XRD). Geometrical analysis was carried out on the deposited composite samples both at high and low laser power to investigate the extent of laser... , M.Ing. (Mechanical Engineering)
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- Authors: Adeyemi, A.A.
- Date: 2018
- Subjects: Pulsed laser deposition , Metal coating , Metals - Mechanical properties , Lasers - Industrial applications , Stainless steel
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/284734 , uj:30767
- Description: Abstract: 17-4 PH Stainless steel is a martensitic characterized precipitation hardened stainless steel with excellent mechanical properties that has been tailored to industrial applications such as aerospace, automobile, marine, food processing equipment, oil and gas industries and chemical processing industries. Despite the growth experienced in the use of this material, 17-4 PH stainless steels are prone to degradation due to long service use in applications that required extreme hardness and wear resistance. This limitation led to the research of property enhancement of the material using modern fabrication technique called laser metal deposition additive manufacturing technology. Laser metal deposition is a modern additive manufacturing technique used in fabricating physical components from the configuration of a 3D CAD data model using a high intensity laser beam while depositing metallic powder on a substrate one layer at a time. This process is flexible in its use as it allows addition of reinforcing particles to improve surface properties of a metallic material such as hardness and wear amongst others. This research study presents the use of laser metal deposition process to investigate the property enhancement of 17-4 PH stainless steel through various characterization process such as microstructural evaluation, microhardness and wear test. The deposition process was carried out using Rofin Sinar Ytterbium fibre laser system of laser capacity of 3.0 kW. The reinforcement material was 17-4 PH stainless steel and tungsten metallic powder deposited on 316 stainless steel substrate. The deposition process commenced firstly with a trial-run deposition of 5 samples with multiple-track of 17-4 PH stainless steel at 50% overlapping percentage on 316 stainless steel substrate to establish process window. The reason for the trial-run was to achieve a deposition with no defects such as pores and cracks. After this was achieved, 17-4 PH stainless steel metallic powder and tungsten metallic powder were now deposited in form of multiple track at 50% overlapping percentage at high laser power and low laser power of 2600 W and 1500 W at varied tungsten powder flow rate on 316 stainless steel substrate. The microstructural evaluation, geometrical analysis, microhardness profiling and wear resistance characteristics of the deposited composites were investigated. The microstructural evolution investigation was carried out using optical microscopy (OM), scanning electron microscopy (SEM) equipped with energy dispersive spectroscopy (EDS) and x-ray diffraction (XRD). Geometrical analysis was carried out on the deposited composite samples both at high and low laser power to investigate the extent of laser... , M.Ing. (Mechanical Engineering)
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Influence of laser power on microstructure of laser metal deposited 17-4 ph stainless steel
- Adeyemi, A.A., Akinlabi, Esther Titilayo, Mahamood, R.M., Sanusi, K.O., Pityana, S., Tlotleng, M.
- Authors: Adeyemi, A.A. , Akinlabi, Esther Titilayo , Mahamood, R.M. , Sanusi, K.O. , Pityana, S. , Tlotleng, M.
- Date: 2017
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/244692 , uj:25306 , Citation: Adeyemi, A.A. et al. 2017. Influence of laser power on microstructure of laser metal deposited 17-4 ph stainless steel.
- Description: Abstract: The influence of laser power on the microstructure of 17-4 PH stainless steel produced by laser metal deposition was investigated. Multiple-track of 17-4 stainless steel powder was deposited on 316 stainless steel substrate using laser metal deposition, an additive manufacturing process. In this research, laser power was varied between 1.0 kW and 2.6 kW with scanning speed fixed at 1.2 m/s. The powder flow rate and the gas flow rate were also kept constant at values of 5 g/min and 2 l/min respectively. The microstructure was studied under optical microscope and it revealed that the microstructure was dendritic in structure with finer and lesser δ-ferrite at low laser power while the appearance of coarse and more δ-ferrite are seen at higher laser power.
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- Authors: Adeyemi, A.A. , Akinlabi, Esther Titilayo , Mahamood, R.M. , Sanusi, K.O. , Pityana, S. , Tlotleng, M.
- Date: 2017
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/244692 , uj:25306 , Citation: Adeyemi, A.A. et al. 2017. Influence of laser power on microstructure of laser metal deposited 17-4 ph stainless steel.
- Description: Abstract: The influence of laser power on the microstructure of 17-4 PH stainless steel produced by laser metal deposition was investigated. Multiple-track of 17-4 stainless steel powder was deposited on 316 stainless steel substrate using laser metal deposition, an additive manufacturing process. In this research, laser power was varied between 1.0 kW and 2.6 kW with scanning speed fixed at 1.2 m/s. The powder flow rate and the gas flow rate were also kept constant at values of 5 g/min and 2 l/min respectively. The microstructure was studied under optical microscope and it revealed that the microstructure was dendritic in structure with finer and lesser δ-ferrite at low laser power while the appearance of coarse and more δ-ferrite are seen at higher laser power.
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Microstructural evolution of laser metal deposited 17-4 PH SS-tungsten composite with varying volume percent tungsten
- Adeyemi, A.A., Akinlabi, Esther Titilayo, Mahamood, R.M.
- Authors: Adeyemi, A.A. , Akinlabi, Esther Titilayo , Mahamood, R.M.
- Date: 2018
- Subjects: Laser Metal Deposition , Laser Power , Microstructure
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/290972 , uj:31595 , Citation: Adeyemi, A.A., Akinlabi, E.T. & Mahamood, R.M. 2018. Microstructural evolution of laser metal deposited 17-4 PH SS-tungsten composite with varying volume percent tungsten.
- Description: Abstract: This study investigates the influence of quantity of tungsten powder on the microstructural evolution of 17-4 PH stainless steel-tungsten composite produced using laser metal deposition process. The 17-4 PH stainless steel and tungsten powders were deposited on 316 stainless steel substrate at laser power of 2600 W. The tungsten powder flow rate was varied between 0.5 rpm and 2.0 rpm while 17-4 PH stainless steel powder flow rate, the scanning speed, the gas flow rate and the laser spot size were fixed at 2.0 rpm, 0.5 m/s, 2.5 l/min and 2.0 mm respectively. Five (5) multiple track of 17-4 PH stainless steel and tungsten powder were deposited on 316 stainless steel of thickness 10 mm from different hopper at 50% overlapping percentage to produce 17-4 PH SS-W composite. During the microstructural study, it was observed that tungsten carbide has been precipitated in-situ and evenly dispersed in the 17-4 PH SS-W composite produced. SEM and EDS analysis also revealed the presence of BCC alpha (α) ferrite and FCC gamma (δ) ferrite with the presence of sigma (σ) phase precipitates.
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- Authors: Adeyemi, A.A. , Akinlabi, Esther Titilayo , Mahamood, R.M.
- Date: 2018
- Subjects: Laser Metal Deposition , Laser Power , Microstructure
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/290972 , uj:31595 , Citation: Adeyemi, A.A., Akinlabi, E.T. & Mahamood, R.M. 2018. Microstructural evolution of laser metal deposited 17-4 PH SS-tungsten composite with varying volume percent tungsten.
- Description: Abstract: This study investigates the influence of quantity of tungsten powder on the microstructural evolution of 17-4 PH stainless steel-tungsten composite produced using laser metal deposition process. The 17-4 PH stainless steel and tungsten powders were deposited on 316 stainless steel substrate at laser power of 2600 W. The tungsten powder flow rate was varied between 0.5 rpm and 2.0 rpm while 17-4 PH stainless steel powder flow rate, the scanning speed, the gas flow rate and the laser spot size were fixed at 2.0 rpm, 0.5 m/s, 2.5 l/min and 2.0 mm respectively. Five (5) multiple track of 17-4 PH stainless steel and tungsten powder were deposited on 316 stainless steel of thickness 10 mm from different hopper at 50% overlapping percentage to produce 17-4 PH SS-W composite. During the microstructural study, it was observed that tungsten carbide has been precipitated in-situ and evenly dispersed in the 17-4 PH SS-W composite produced. SEM and EDS analysis also revealed the presence of BCC alpha (α) ferrite and FCC gamma (δ) ferrite with the presence of sigma (σ) phase precipitates.
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