The effect of heat input, shielding gas, and welding technique on the structure of the weld metal... more The effect of heat input, shielding gas, and welding technique on the structure of the weld metal has been investigated in all weld multipass test plates produced by flux cored arc welding using 1.2 mm diameter boron microalloyed rutile, metal cored, and rutile flux cored wires. Linear and areal measurement techniques have been used on cross-sections of seventeen test plates welded using three different consumables to determine the volume fraction of reheated (at least partially reaustenitised) region and as solidified weld metal. Using the simplifying assumption that the structural gradient in the heat affected zone of reheated weld metal can be characterised in terms of the grain coarsened, grain refined, and intercritical regions, the volume fractions of these regions were also determined. Some of the reheated regions evolve under the thermal influence of a second overlapping weld bead, resulting in doubly reheated weld metal structures that can be defined in terms of nine subzon...
This is an overview of a current three-year project for the Cooperative Research Centre for Welde... more This is an overview of a current three-year project for the Cooperative Research Centre for Welded Structures entitled "Integrity of High Energy Piping". The results of a performance evaluation conducted on an emergency cold weld (controlled deposition temperbead, TB) repair applied to a 2.25Cr-1Mo steel header using the manual metal arc welding (MMAW) process are described. With repair rather than replace being a far more viable option, welding is increasingly used for performing repairs, replacements, retrofits and modifications to elevated temperature plants. However, with the considerable cost and time involved with performing conventional post weld heat-treatment (PWHT) repairs, in today's economic environment utility owners are increasingly forced to turn toward other alternatives, such as cold weld repairs. These require no PWHT and rely on a controlled deposition process - precise weld bead placement and heat inputs etc to achieve tempering of the HAZ. However,...
ABSTRACT Stellite 6 was deposited by laser cladding on a P22 steel substrate with energy inputs o... more ABSTRACT Stellite 6 was deposited by laser cladding on a P22 steel substrate with energy inputs of 1 kW (P22-1) and 1.8 kW (P22-1.8). The chemical compositions and microstructures of these coatings were characterized by atomic absorption spectroscopy, optical microscopy and scanning electron microscopy. The microhardness of the coatings was measured and the wear mechanism of the coatings was examined using a pin-on-plate (reciprocating) wear testing machine. The results showed less cracking and pore development for Stellite 6 coatings applied to the P22 steel substrate with the lower heat input (P22-1). Further, the Stellite coating for P22-1 was significantly harder than that obtained for P22-1.8. The wear test results showed that the weight loss for P22-1 was much lower than for P22-1.8. It is concluded that the lower hardness of the coating for P22-1.8, markedly reduced the wear resistance of the Stellite 6 coating.
ABSTRACT Stellite 6 was deposited by laser cladding on a nickel superalloy substrate (NIS) with e... more ABSTRACT Stellite 6 was deposited by laser cladding on a nickel superalloy substrate (NIS) with energy inputs of 1 kW (NIS 1) and 1.8 kW (NIS 1.8). The chemical compositions and microstructures of these coatings were characterized by atomic absorption spectroscopy, optical microscopy and scanning electron microscopy. The microhardness of the coatings was measured and the wear mechanism of the coatings was examined using a pin-on-plate (reciprocating) wear testing machine. The results showed less cracking and pore development for Stellite 6 coatings applied to the nickel superalloy substrate with the lower heat input (NIS 1). Further, the Stellite coating for NIS 1 was significantly harder than that obtained for NIS 1.8. The wear test results showed that the weight loss for NIS 1 was much lower than for NIS 1.8. It is concluded that the lower hardness of the coating for NIS 1.8, together with the softer underlying substrate structure, markedly reduced the wear resistance of the Stellite 6 coating.
ABSTRACT The development of two low cost, corrosion resistant Fe-Mn-Si based shape memory alloy s... more ABSTRACT The development of two low cost, corrosion resistant Fe-Mn-Si based shape memory alloy systems: Fe-Mn-Si-Al-Cu and Fe-Mn-Si-Cr-Cu is discussed. The new alloys exhibited a shape memory capacity wh ich is clearly superior to traditional Fe-Mn-Si ternary alloys. Corrosion test results indicated that the new alloys have good corrosion resistance in acid solutions. In addition, anodic polarisation measurements established that alloying with copper increases the passivity of the corrosion film formed in the passive potential range and improves the general corrosion resistance.
ABSTRACT Stellite 6 coatings were produced using laser cladding of two different steel substrates... more ABSTRACT Stellite 6 coatings were produced using laser cladding of two different steel substrates (martensitic and austenitic stainless steels). The chemical composition and microstructure of these coatings were characterized by atomic absorption spectroscopy, optical microscopy and scanning electron microscopy. The microhardness of the coatings was measured and the wear mechanism of the coatings was examined using a pin-on-plate (reciprocating) wear testing machine. The results showed less cracking and pore development for Stellite 6 coatings applied to the martensitic stainless steel (SS) substrate. The wear test results showed that the weight loss for the coating on martensitic SS was significantly lower than for the austenitic SS substrate. It is concluded that the higher hardness of the coating on the martensitic SS, together with the harder and more rigid substrate increase the wear resistance of the Stellite 6 coating.
ABSTRACT The development of two low cost, corrosion resistant Fe-Mn-Si based shape memory alloy s... more ABSTRACT The development of two low cost, corrosion resistant Fe-Mn-Si based shape memory alloy systems: Fe-Mn-Si-Al-Cu and Fe-Mn-Si-Cr-Cu is discussed. The new alloys exhibited a shape memory capacity wh ich is clearly superior to traditional Fe-Mn-Si ternary alloys. Corrosion test results indicated that the new alloys have good corrosion resistance in acid solutions. In addition, anodic polarisation measurements established that alloying with copper increases the passivity of the corrosion film formed in the passive potential range and improves the general corrosion resistance.
Polished tiles (7x7x2 mm3) of Nd-bearing zirconolite were fabricated and then some were irradiate... more Polished tiles (7x7x2 mm3) of Nd-bearing zirconolite were fabricated and then some were irradiated on both large faces with 3 MeV or 2 MeV Au2+ ions (total fluence of {approx} 1 x 1015 ions/cm2) in order to render the zirconolite amorphous and so simulate displacement ...
The effect of heat input, shielding gas, and welding technique on the structure of the weld metal... more The effect of heat input, shielding gas, and welding technique on the structure of the weld metal has been investigated in all weld multipass test plates produced by flux cored arc welding using 1.2 mm diameter boron microalloyed rutile, metal cored, and rutile flux cored wires. Linear and areal measurement techniques have been used on cross-sections of seventeen test plates welded using three different consumables to determine the volume fraction of reheated (at least partially reaustenitised) region and as solidified weld metal. Using the simplifying assumption that the structural gradient in the heat affected zone of reheated weld metal can be characterised in terms of the grain coarsened, grain refined, and intercritical regions, the volume fractions of these regions were also determined. Some of the reheated regions evolve under the thermal influence of a second overlapping weld bead, resulting in doubly reheated weld metal structures that can be defined in terms of nine subzon...
This is an overview of a current three-year project for the Cooperative Research Centre for Welde... more This is an overview of a current three-year project for the Cooperative Research Centre for Welded Structures entitled "Integrity of High Energy Piping". The results of a performance evaluation conducted on an emergency cold weld (controlled deposition temperbead, TB) repair applied to a 2.25Cr-1Mo steel header using the manual metal arc welding (MMAW) process are described. With repair rather than replace being a far more viable option, welding is increasingly used for performing repairs, replacements, retrofits and modifications to elevated temperature plants. However, with the considerable cost and time involved with performing conventional post weld heat-treatment (PWHT) repairs, in today's economic environment utility owners are increasingly forced to turn toward other alternatives, such as cold weld repairs. These require no PWHT and rely on a controlled deposition process - precise weld bead placement and heat inputs etc to achieve tempering of the HAZ. However,...
ABSTRACT Stellite 6 was deposited by laser cladding on a P22 steel substrate with energy inputs o... more ABSTRACT Stellite 6 was deposited by laser cladding on a P22 steel substrate with energy inputs of 1 kW (P22-1) and 1.8 kW (P22-1.8). The chemical compositions and microstructures of these coatings were characterized by atomic absorption spectroscopy, optical microscopy and scanning electron microscopy. The microhardness of the coatings was measured and the wear mechanism of the coatings was examined using a pin-on-plate (reciprocating) wear testing machine. The results showed less cracking and pore development for Stellite 6 coatings applied to the P22 steel substrate with the lower heat input (P22-1). Further, the Stellite coating for P22-1 was significantly harder than that obtained for P22-1.8. The wear test results showed that the weight loss for P22-1 was much lower than for P22-1.8. It is concluded that the lower hardness of the coating for P22-1.8, markedly reduced the wear resistance of the Stellite 6 coating.
ABSTRACT Stellite 6 was deposited by laser cladding on a nickel superalloy substrate (NIS) with e... more ABSTRACT Stellite 6 was deposited by laser cladding on a nickel superalloy substrate (NIS) with energy inputs of 1 kW (NIS 1) and 1.8 kW (NIS 1.8). The chemical compositions and microstructures of these coatings were characterized by atomic absorption spectroscopy, optical microscopy and scanning electron microscopy. The microhardness of the coatings was measured and the wear mechanism of the coatings was examined using a pin-on-plate (reciprocating) wear testing machine. The results showed less cracking and pore development for Stellite 6 coatings applied to the nickel superalloy substrate with the lower heat input (NIS 1). Further, the Stellite coating for NIS 1 was significantly harder than that obtained for NIS 1.8. The wear test results showed that the weight loss for NIS 1 was much lower than for NIS 1.8. It is concluded that the lower hardness of the coating for NIS 1.8, together with the softer underlying substrate structure, markedly reduced the wear resistance of the Stellite 6 coating.
ABSTRACT The development of two low cost, corrosion resistant Fe-Mn-Si based shape memory alloy s... more ABSTRACT The development of two low cost, corrosion resistant Fe-Mn-Si based shape memory alloy systems: Fe-Mn-Si-Al-Cu and Fe-Mn-Si-Cr-Cu is discussed. The new alloys exhibited a shape memory capacity wh ich is clearly superior to traditional Fe-Mn-Si ternary alloys. Corrosion test results indicated that the new alloys have good corrosion resistance in acid solutions. In addition, anodic polarisation measurements established that alloying with copper increases the passivity of the corrosion film formed in the passive potential range and improves the general corrosion resistance.
ABSTRACT Stellite 6 coatings were produced using laser cladding of two different steel substrates... more ABSTRACT Stellite 6 coatings were produced using laser cladding of two different steel substrates (martensitic and austenitic stainless steels). The chemical composition and microstructure of these coatings were characterized by atomic absorption spectroscopy, optical microscopy and scanning electron microscopy. The microhardness of the coatings was measured and the wear mechanism of the coatings was examined using a pin-on-plate (reciprocating) wear testing machine. The results showed less cracking and pore development for Stellite 6 coatings applied to the martensitic stainless steel (SS) substrate. The wear test results showed that the weight loss for the coating on martensitic SS was significantly lower than for the austenitic SS substrate. It is concluded that the higher hardness of the coating on the martensitic SS, together with the harder and more rigid substrate increase the wear resistance of the Stellite 6 coating.
ABSTRACT The development of two low cost, corrosion resistant Fe-Mn-Si based shape memory alloy s... more ABSTRACT The development of two low cost, corrosion resistant Fe-Mn-Si based shape memory alloy systems: Fe-Mn-Si-Al-Cu and Fe-Mn-Si-Cr-Cu is discussed. The new alloys exhibited a shape memory capacity wh ich is clearly superior to traditional Fe-Mn-Si ternary alloys. Corrosion test results indicated that the new alloys have good corrosion resistance in acid solutions. In addition, anodic polarisation measurements established that alloying with copper increases the passivity of the corrosion film formed in the passive potential range and improves the general corrosion resistance.
Polished tiles (7x7x2 mm3) of Nd-bearing zirconolite were fabricated and then some were irradiate... more Polished tiles (7x7x2 mm3) of Nd-bearing zirconolite were fabricated and then some were irradiated on both large faces with 3 MeV or 2 MeV Au2+ ions (total fluence of {approx} 1 x 1015 ions/cm2) in order to render the zirconolite amorphous and so simulate displacement ...
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