Abstract: An Sn—Zn lead-free solder alloy according to the present invention is constructed in a manner such that it is an Sn-based solder alloy indispensably containing 6 to 10 wt % zinc at least, and further containing 0.0015 to 0.1 wt % magnesium, said magnesium content being effective quantity for forming a protective magnesium oxide film on the solder surface and also for destroying said oxide film during soldering. When solder paste is preserved, the inside of solder particle is protected by the protective magnesium oxide film formed on the surface of solder particle, and a reaction between zinc and an activator is suppressed, so that preservation stability is improved, and at elevated temperature during soldering, a state where said protective oxide film is easily destroyed is obtained, so that good wettability is held.

Abstract: An Sn—Zn lead-free solder alloy according to the present invention is constructed in a manner such that it is an Sn-based solder alloy indispensably containing 6 to 10 wt % zinc at least and further containing 0.0015 to 0.03 wt % magnesium and 0.0010 to 0.006 wt % aluminum. Upon preservation of solder paste not only under refrigeration but also at a room temperature or higher, the inside of solder particle is protected by the protective magnesium/aluminum oxide film formed on the solder particle surface, and a reaction between zinc and an activator is suppressed, so that preservation stability is improved, and at the elevated temperature during soldering, the solder alloy enters a state where said protective oxide film is easily destroyed, so that good wettability is held.

Abstract: An Sn—Zn lead-free solder alloy according to the present invention is constructed in a manner such that it is an Sn-based solder alloy indispensably containing 6 to 10 wt % zinc at least, and further containing 0.0015 to 0.1 wt % magnesium, said magnesium content being effective quantity for forming a protective magnesium oxide film on the solder surface and also for destroying said oxide film during soldering. When solder paste is preserved, the inside of solder particle is protected by the protective magnesium oxide film formed on the surface of solder particle, and a reaction between zinc and an activator is suppressed, so that preservation stability is improved, and at elevated temperature during soldering, a state where said protective oxide film is easily destroyed is obtained, so that good wettability is held.

Abstract: An Sn—Zn lead-free solder alloy according to the present invention is constructed in a manner such that it is an Sn-based solder alloy indispensably containing 6 to 10 wt % zinc at least, and further containing 0.0015 to 0.1 wt % magnesium, said magnesium content being effective quantity for forming a protective magnesium oxide film on the solder surface and also for destroying said oxide film during soldering. When solder paste is preserved, the inside of solder particle is protected by the protective magnesium oxide film formed on the surface of solder particle, and a reaction between zinc and an activator is suppressed, so that preservation stability is improved, and at elevated temperature during soldering, a state where said protective oxide film is easily destroyed is obtained, so that good wettability is held.

Abstract: An Sn—Zn lead-free solder alloy according to the present invention is constructed in a manner such that it is an Sn-based solder alloy indispensably containing 6 to 10 wt % zinc at least and further containing 0.0015 to 0.03 wt % magnesium and 0.0010 to 0.006 wt % aluminum. Upon preservation of solder paste not only under refrigeration but also at a room temperature or higher, the inside of solder particle is protected by the protective magnesium/aluminum oxide film formed on the solder particle surface, and a reaction between zinc and an activator is suppressed, so that preservation stability is improved, and at the elevated temperature during soldering, the solder alloy enters a state where said protective oxide film is easily destroyed, so that good wettability is held.

Abstract: An Sn—Zn lead-free solder alloy according to the present invention is constructed in a manner such that it is an Sn-based solder alloy indispensably containing 6 to 10 wt % zinc at least and further containing 0.0015 to 0.03 wt % magnesium and 0.0010 to 0.006 wt % aluminum. Upon preservation of solder paste not only under refrigeration but also at a room temperature or higher, the inside of solder particle is protected by the protective magnesium/aluminum oxide film formed on the solder particle surface, and a reaction between zinc and an activator is suppressed, so that preservation stability is improved, and at the elevated temperature during soldering, the solder alloy enters a state where said protective oxide film is easily destroyed, so that good wettability is held.

Abstract: A process for the production of a metal sheet having a multi-layered structure and a fine composite structure, which process comprises stacking at least two kinds of thin sheets selected from thin sheets of pure metals and thin sheets of alloys alternately so as to have multiple layers in total, integrating the stacked sheets by circumferential welding or placing the stacked sheets in a steel or stainless steel box to integrate these, and then, bonding all the layers of the integrated sheets metallically by hot rolling, and a metal sheet obtained thereby.

Abstract: A method and an apparatus for simply disposing medical waste from a medical institution on site. The method comprises crushing medical waste in a closed container, exhausting air out of the container, sterilizing the air before releasing it into the atmosphere, and filling the container with a high-pressure steam having a temperature between 110.degree. C. and 150.degree. C. to sterilize the crushed medical waste. The apparatus is equipped with a pressure container having at least one air-tight seal, an internal waste crushing mechanism such as blades, an internal supply of steam, a valve for exhausting air from the container, and an air sterilizer for the exhausted air.

Abstract: The present invention provides a process for producing a clad plate which comprises a first step of forming a coil by taking up two or more metal sheets as clad materials and a thin sheet of heat-resistant steel which works as a separator material while these members are overlaid on one another and a second step of vacuum heat-treating the resultant coil.

Abstract: This invention provides the following stainless steels called invention steel 1 and invention steel 2.Invention steel 1 is a subzero treatment hardening type martensitic stainless steel characterized by comprising not more than 0.4% by weight of C, not more than 0.4% by weight of N, not more than 15% by weight of Mn, not more than 12% by weight of Ni, 10 to 23% by weight of Cr, not more than 3.0% by weight of Mo, not more than 5.0% by weight of Cur, not more than 2.0% by weight of Si, and the remaining portion consisting of inevitable impurities and Fe and satisfying the following formaulae (1), (2) and (3),[Cr %]+1.5[Si %]+[Mo %]-[Mn %)]-1.3[Ni %]-[Cu %]-19 [C %]-19[N %].ltoreq.12.0 Formula (1)27.5.ltoreq.[Cr %]+1.3[SDi %]+1.3[Mn %]+1.5[Ni %]+[Cu %]+[Mo %]+15[C %]+20[N %].ltoreq.32.0 Formula (2)and1.3[Ni %]+[Mn %]+[Cu %]>4.0 Formula (3)Invention steel is a subzero treatment hardening type martensitic stainless characterized by comprising not more than 0.4% by weight of C, not more than 0.

Abstract: Manufacturing apparatus for continuous casting of sheet metal includes a pair of chill rolls and a vessel containing molten metal. One of the rolls is of a larger diameter, on which the other roll of a smaller diameter is arranged at a position corresponding to a clock position of 12-3 O'clock. The vessel has an open forward end and is arranged to contact the larger roll or leave a gap as narrow as possible. The smaller roll is partially disposed in molten metal in the vessel. When the two rolls are driven at the same peripheral velocity in the opposite direction, molten metal is fed between the rolls to form a sheet metal which may be continuously peeled from the larger roll surface.