Takao Funamoto

Development of A New High-Frequency, High-Peak Current Power Source for High Constricted Arc Formation

A new power source, able to generate high-frequency, up to 20 kHz, and high-peak pulse current, up to 500 A, has been developed. By using the new power source, arc pressure and bead depth 3 times as high and twice as deep as those obtained from the DC power source were obtained. The new power source achieved a stable arc in a narrow groove with high aspect ratio due to high constriction. Welding speeds using the new power source are twice as fast as the DC arc.

Characteristics of press soldered joints by using resistance heating

In order to increase the strength of soldered joints, a novel press-soldering method was investigated. In this method, materials with low melting points and low strengths (mainly Pb) were discharged from the joint interface, and an alloyed layer of high strength was left. Copper-to-copper lap joints were press-soldered using a resistance heating apparatus. In this process, heating and pressure were applied simultaneously. The copper plate was presoldered using Pb-50Sn solder and the alloyed layer was formed. The tensile strength increased at a pressure above 45 N, and fracturing occurred in the copper base metal above a 75-N pressure load. The joints fractured in the copper base metal during 150 degrees C and 250 degrees C tensile testing and showed excellent thermal resistance. Changes in joint strengths after high-temperature heating (150 degrees C, 250 degrees C for 1000 h) were also considered.<<ETX>>

Characteristics of press-soldered joints by using resistance heating

In order to increase the strengths of soldered joints, a novel press-soldering method was investigated. In this method, materials of low melting points and low strengths (mainly Pb) were discharged from the joint interface and an alloyed layer of high strength was left. Copper-to-copper lap joints were press-soldered using a resistance heating apparatus. In this process, heating and pressure were applied simultaneously. The copper plate was presoldered using Pb-50 Sn solder, and the alloyed layer was formed. The tensile strengths increased at a pressure above 45 N, and fracturing occurred in the copper base metal above a 75-N pressure load. The joints fractured in the copper base metal during the 150 degrees C and 250 degrees C tensile testing and showed excellent thermal resistance. Changes in joint strengths after high-temperature heating (150 degrees C, 250 degrees C, 1000 h) are also considered. >

Durability evaluation of press-soldered joints.

Copper to copper lap joint was made by the resistance heating apparatus by which heating and pressure was applied simultaneously. The copper plate was pre-soldered and the alloyed layer was pre-formed by using Pb-50Sn solder.Tensile test of the joints was carried out at room temperature after heat test at 150°C or 250°C for 1000h, heat cycle test from -55°C to +150°C by 1000 cycles or salt spray test at 35°C for 1000h.All of these joints were fractureed at the base metal, copper.The strengths of the joints were as those of the joints which were brazed by using BAg-6.Although the joints made by press-soldering were heated at 150°C or 250°C the thickness of the alloyed layer was constant.