A highly conductive exothermic solder powder suitable for use in acidic soils

Abstract

A high-conductivity exothermic solder powder suitable for use in acidic soil, the solder powder includes the following components in parts by weight: copper oxide: 15-20 parts, aluminum powder: 20-25 parts, copper powder: 35 parts -50 parts, alloy powder: 5-15 parts, molybdenum: 3-8 parts, oxygen scavenger: 1-2 parts, slagging agent 1-2 parts, rare earth 1-2 parts, the weight of chromium in the alloy powder The percentage is 25-35%, the weight percentage of manganese is 20-25%, the weight percentage of manganese nitride is 15-25%, and the balance is aluminum. The exothermic solder powder involved in the present invention will not crystallize in acidic soil. Inter-corrosion, good conductivity.

Description

technical field [0001] The invention relates to the technical field of welding, in particular to a high-conductivity exothermic welding powder suitable for use in acidic soil. Background technique [0002] In order to protect the safety of workers, transformers usually need to be grounded through a grounding grid. In order to obtain higher electrical conductivity, corrosion resistance, and from the perspective of environmental protection, a variety of new grounding grid materials have been developed in China. For example, China Electric Power Research Institute has developed a new type of corrosion-resistant steel - stainless steel clad steel composite material. Stainless steel clad steel is composed of high-quality carbon steel special wire and special special stainless steel tube, and is manufactured with special technology and technology. The basic material of stainless steel clad steel is high-quality carbon steel, the basic material of hot-dip galvanized round steel is...

AI Technical Summary

Problems solved by technology

In addition, the production and manufacture of stainless steel clad steel all adopt physical processes, eliminate the use of chemical processes, and will not cause secondary pollution to the atmosphere, water, and soil. It is austenitic stainless steel) Compared with general structural steel, it is easy to produce hot cracks when welding with conventional solder, and the joints are prone to embrittlement and stress corrosion cracking after welding, especially in acidic soil. Serious, it will have a serious impact on the normal use of the entire grounding grid, and the welding of the grounding grid needs better conductivity to reduce the step voltage of the grounding grid to ensure personnel safety

[0003] The Chinese invention patent with the notification number CN104043913B discloses a thermite welding powder for welding new grounding grid materials, which is composed of the following substances by weight percentage: copper oxide 45-60%, aluminum powder 8-13%, copper powder 20-30%, copper-phosphorus alloy powder 5-15%, tin powder 1-5%, fluorite powder 2-6%, borax powder 1-4%, and the balance is alloy powder; the alloy powder consists of the following weight percentages Material composition: Ca: 8-12%, Si: 40-47%, Ba: 28-32%, and the rest are impurities. The raw materials of this invention are cheap and easy to get, and solve the problems of pores, slag inclusions, and hot cracks that are easy to occur in thermite welding powder welding and other problems, effectively reducing the connection cost of the new grounding grid material, but the conductivity is low (when the content of tin powder is greater than 1%, the conductivity of copper is greatly reduced)

[0004] The Chinese invention patent with the publication number CN108326466A discloses a high-conductivity thermite welding powder. 500-550 parts of powder, 5-15 parts of lithium fluoride, 20-40 parts of borax, 4-10 parts of cryolite, 2-5 parts of rare earth, 1-5 parts of copper alloy, 5-10 parts of magnesium diboride and 2-6 parts of boron slag. After welding with this welding powder, the conductivity of the welding place is good, but the corrosion resistance is poor. When the heat-affected zone of the weld seam reaches the sensitization temperature region (600-1000°C) before the seam, chromium carbides are easily precipitated on the grain boundary, forming a chromium-poor grain boundary. If this area is just exposed on the weld surface And in contact with acidic soil, intergranular corrosion will occur, and intergranular corrosion will penetrate deep into the weld along the grain boundary, causing the reduction of the mechanical properties and corrosion resistance of the entire welding point, which is a dangerous form of corrosion