Wyniki wyszukiwania - BazTech

1

Inverter DC resistance spot welding of magnesium alloy AZ31

Hwang I., Kim D., Kang M.

Archives of Materials Science and Engineering

|

2011

|

Vol. 48, nr 2

112-117

EN

The welding lobes of AC resistance spot welding and inverter DC resistance spot welding for the magnesium alloy sheet AZ31 were compared and analyzed.

2

Weldability of 440 MPa galvanized steel with inverter DC resistance spot welding process

Hwang I., Yoon H., Kang M., Kim D.

Archives of Materials Science and Engineering

|

2010

|

Vol. 42, nr 1

37-44

EN

Purpose: This paper comparatively analyzes resistance spot weldability depending on whether or not 440 MPa-grade steel is galvanized at inverter DC spot welding. Design/methodology/approach: To compare the resistance spot weldability depending on whether or not the steel is galvanized, an inverter DC welding system was designed. Then, using this system, both tensile strength testing and macro-section testing were conducted on SPRC440 (uncoated steel) and SGARC440 (galvanized steel), and weldability was evaluated. Suitable welding conditions were calculated using the resistance spot welding variables such as electrode force, welding time and lobe diagram on the welding current. The low limit of the lobe diagram was set to the low limit of the tensile strength of 440 MPa-grade steel while the high limit was set depending on whether or not expulsion was detected. Findings: Compared to uncoated steel, galvanized steel had lower suitable welding current conditions and a narrower lobe diagram. Research limitations/implications: This paper compared resistance spot weldability and lobe diagram depending on whether or not 440 MPa-grade steel is galvanized. Practical implications: This paper confirms the weldability of galvanized steel by comparing resistance spot weldability depending on whether or not steel is galvanized. Originality/value: For analysis of resistance spot weldability depending on whether or not steel is galvanized, weldability was compared between SPRC440 (uncoated steel) and SGARC440 (galvanized steel) under the same welding conditions. As a result, compared to uncoated steel, galvanized steel had lower suitable welding current conditions and a narrower lobe diagram.

3

Resistance spot welding of aluminium alloy sheet 5J32 using SCR type and inverter type power supplies

Kim D., Park H., Hwang I., Kang M.

Archives of Materials Science and Engineering

|

2009

|

Vol. 38, nr 1

55-59

EN

Purpose: A characteristic was compared and analyzed between the lobe diagram of SCR type resistance spot welding and that of inverter type resistance spot welding of the aluminum alloy sheet 5J32 for the car body. Design/methodology/approach: Using the lobe diagram on the electrode force, weld time, and weld current which are process variables of the resistance spot welding, the range of optimal welding condition was determined. The low limit of the range of the optimal welding condition was decided by the lower limit of the tensile strength of the aluminum alloy sheet 5J32, and the upper limit was decided by whether an expulsion occurs or not. Findings: It was found that the range of the optimal welding condition of the inverter type resistance spot welding was larger than the SCR type resistance welding and that the nugget size of inverter type resistance spot welding was larger in the same welding condition. Research limitations/implications: A comparison was between the lobe diagram at the SCR type on the aluminum alloy sheet 5J32 and the lobe diagram at the inverter type resistance spot welding. Practical implications: In this study, by comparing the range of the appropriate welding condition of the resistance spot welding between SCR type and inverter type power supplies, the characteristic of the appropriate welding range by the power supply characteristic could be confirmed. Originality/value: This study compared the characteristic of the resistance spot welding between the SCR type and inverter type power supply using lobe diagram. It was confirmed that the range of appropriate welding conditions of the inverter type resistance spot welding was large.