The Experts below are selected from a list of 261 Experts worldwide ranked by ideXlab platform

P Bhandhubanyong - One of the best experts on this subject based on the ideXlab platform.

  • study on the effects of pulsed tig welding parameters on delta ferrite content shape factor and bead quality in orbital welding of aisi 316l stainless steel plate
    Journal of Materials Processing Technology, 2001
    Co-Authors: Gobboon Lothongkum, Ekkarut Viyanit, P Bhandhubanyong
    Abstract:

    Abstract The TIG pulse welding parameters of AISI 316L stainless steel plate of 3 mm thickness at the welding positions of 6–12 h were investigated. The weld bead profiles corresponded to DIN 8563 class BS. The studied parameters were welding speed, pulse/base currents, pulse frequency, and % on time. Pure argon and argon with nitrogen contents of 1–4 vol.% were used as shielding gas with a flow rate of 8 l/min at both the top and the back sides of welds. Preliminary welding results at the 6 h welding position showed that the appropriate parameters were: base current of 61 A, pulse frequency of 5 Hz, and 65% on time. With these constant parameters the effects of welding speeds of 2–8 mm/s and nitrogen contents of 0–4 vol.% in argon shielding gas on pulse currents were examined to attain acceptable weld bead profile corresponding to DIN 8563 class BS with complete penetration. The results showed that the lowest pulse currents were observed at the 9 h welding position. Increasing nitrogen content in argon gas decreases the pulse currents. At the welding positions of 6 and 12 h, the maximum welding speed is limited to 6 mm/s, and with a welding speed of 7 mm/s the formation of Slag Inclusion at the top of weld metal was observed. The maximum welding speed of 5 mm/s is found for the welding positions of 8, 9, 10 h, but the welding speed of 6 mm/s is not applicable because of incomplete filled groove. The depth/width ratios ( D / W ) are between 0.34 and 0.40. Increasing welding speed decreases in the weld width and increases in the D / W ratio. The delta-ferrite contents of the weld metal are about 6–10 vol.%, and are minimum at the welding position of 9 h, because of the high nitrogen content of the cover gas and lowest pulse currents compared to all other welding positions. Radiography showed acceptable weld beads free of porosity.

Gobboon Lothongkum - One of the best experts on this subject based on the ideXlab platform.

  • study on the effects of pulsed tig welding parameters on delta ferrite content shape factor and bead quality in orbital welding of aisi 316l stainless steel plate
    Journal of Materials Processing Technology, 2001
    Co-Authors: Gobboon Lothongkum, Ekkarut Viyanit, P Bhandhubanyong
    Abstract:

    Abstract The TIG pulse welding parameters of AISI 316L stainless steel plate of 3 mm thickness at the welding positions of 6–12 h were investigated. The weld bead profiles corresponded to DIN 8563 class BS. The studied parameters were welding speed, pulse/base currents, pulse frequency, and % on time. Pure argon and argon with nitrogen contents of 1–4 vol.% were used as shielding gas with a flow rate of 8 l/min at both the top and the back sides of welds. Preliminary welding results at the 6 h welding position showed that the appropriate parameters were: base current of 61 A, pulse frequency of 5 Hz, and 65% on time. With these constant parameters the effects of welding speeds of 2–8 mm/s and nitrogen contents of 0–4 vol.% in argon shielding gas on pulse currents were examined to attain acceptable weld bead profile corresponding to DIN 8563 class BS with complete penetration. The results showed that the lowest pulse currents were observed at the 9 h welding position. Increasing nitrogen content in argon gas decreases the pulse currents. At the welding positions of 6 and 12 h, the maximum welding speed is limited to 6 mm/s, and with a welding speed of 7 mm/s the formation of Slag Inclusion at the top of weld metal was observed. The maximum welding speed of 5 mm/s is found for the welding positions of 8, 9, 10 h, but the welding speed of 6 mm/s is not applicable because of incomplete filled groove. The depth/width ratios ( D / W ) are between 0.34 and 0.40. Increasing welding speed decreases in the weld width and increases in the D / W ratio. The delta-ferrite contents of the weld metal are about 6–10 vol.%, and are minimum at the welding position of 9 h, because of the high nitrogen content of the cover gas and lowest pulse currents compared to all other welding positions. Radiography showed acceptable weld beads free of porosity.

David A. Wood - One of the best experts on this subject based on the ideXlab platform.

  • Reducing welding repair requirements in refinery pressure vessel manufacturing: a case study applying six sigma principles
    International Journal on Interactive Design and Manufacturing (IJIDeM), 2019
    Co-Authors: Ahmadreza Rezaei, Mohammad Ehsanifar, David A. Wood
    Abstract:

    High welding intensity is an integral part of the refinery pressure vessel manufacturing process. Weld defects are also responsible for a substantial part of the rework requirements, waste and operating costs associated with such manufacturing. Seeking ways to reduce welding defects and improve the efficiency of the manufacturing process is therefore critical for profitability and fulfills customer expectations of product reliability. A problem-solving project applying six sigma principles, and specifically its define, measure, analysis, improve and control methodology, successfully identified, quantified and reduced weld defects in pressure vessel manufacture for the Machine Sazi Arak Company leading to ongoing process improvement gains. Failure modes and effect analysis and customized experiments were able to quantify the impacts of identified root causes on the Slag Inclusion, lack of fusion and porosity weld defects. This lead to improvement solutions being successfully tested and implemented. These improvement initiatives significantly reduced the average number of the welding repairs required, increased the sigma level of weld defects by up to 19% reduced welding process costs by up to 350% and increased process yield by 1.12%. Consequently, the profitability and efficiency of pressure vessel manufacture was much improved by adopting the six-sigma problem-solving approach.

Ekkarut Viyanit - One of the best experts on this subject based on the ideXlab platform.

  • study on the effects of pulsed tig welding parameters on delta ferrite content shape factor and bead quality in orbital welding of aisi 316l stainless steel plate
    Journal of Materials Processing Technology, 2001
    Co-Authors: Gobboon Lothongkum, Ekkarut Viyanit, P Bhandhubanyong
    Abstract:

    Abstract The TIG pulse welding parameters of AISI 316L stainless steel plate of 3 mm thickness at the welding positions of 6–12 h were investigated. The weld bead profiles corresponded to DIN 8563 class BS. The studied parameters were welding speed, pulse/base currents, pulse frequency, and % on time. Pure argon and argon with nitrogen contents of 1–4 vol.% were used as shielding gas with a flow rate of 8 l/min at both the top and the back sides of welds. Preliminary welding results at the 6 h welding position showed that the appropriate parameters were: base current of 61 A, pulse frequency of 5 Hz, and 65% on time. With these constant parameters the effects of welding speeds of 2–8 mm/s and nitrogen contents of 0–4 vol.% in argon shielding gas on pulse currents were examined to attain acceptable weld bead profile corresponding to DIN 8563 class BS with complete penetration. The results showed that the lowest pulse currents were observed at the 9 h welding position. Increasing nitrogen content in argon gas decreases the pulse currents. At the welding positions of 6 and 12 h, the maximum welding speed is limited to 6 mm/s, and with a welding speed of 7 mm/s the formation of Slag Inclusion at the top of weld metal was observed. The maximum welding speed of 5 mm/s is found for the welding positions of 8, 9, 10 h, but the welding speed of 6 mm/s is not applicable because of incomplete filled groove. The depth/width ratios ( D / W ) are between 0.34 and 0.40. Increasing welding speed decreases in the weld width and increases in the D / W ratio. The delta-ferrite contents of the weld metal are about 6–10 vol.%, and are minimum at the welding position of 9 h, because of the high nitrogen content of the cover gas and lowest pulse currents compared to all other welding positions. Radiography showed acceptable weld beads free of porosity.

Rajesh Prasad - One of the best experts on this subject based on the ideXlab platform.

  • experimental analysis of dissimilar metal weld joint ferritic to austenitic stainless steel
    Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2015
    Co-Authors: Dinesh W Rathod, Sunil Pandey, P. K. Singh, Rajesh Prasad
    Abstract:

    Abstract The dissimilar metal weld (DMW) joint between SA508Gr.3Cl.1 ferritic steel and SS304LN using Inconel 82/182 consumables was required in the nuclear power plants. The joint integrity assessment of these welds requires mechanical and metallurgical properties evaluation in weldment regions. The joint was subjected to 100% radiography test and bend test and transverse tensile test. Welding and testing were carried out as per the requirements of ASME Sec-IX and acceptance criteria as per ASME Sec-III. The transverse tensile test results indicated the failure from the weld metal although it satisfies the minimum strength requirement of the ASME requirements; therefore, the DMW joint was analyzed in detail. Straight bead deposition technique, fine Slag Inclusion, less reliable radiograph technique, plastic instability stress, yield strength ratio and metallurgical deteriorations have been contributed to failure of the DMW joint from the weld region. In the present work, the factors contributing to the fracture from weld metal have been discussed and analyzed.