Search results
Results From The WOW.Com Content Network
Spot welding (or resistance spot welding [1]) is a type of electric resistance welding used to weld various sheet metal products, through a process in which contacting metal surface points are joined by the heat obtained from resistance to electric current.
Spot welding is a resistance welding method used to join two or more overlapping metal sheets, studs, projections, electrical wiring hangers, some heat exchanger fins, and some tubing. Usually power sources and welding equipment are sized to the specific thickness and material being welded together.
Apocalyptic fiction is a subgenre of science fiction that is concerned with the end of civilization due to a potentially existential catastrophe such as nuclear warfare, pandemic, extraterrestrial attack, impact event, cybernetic revolt, technological singularity, dysgenics, supernatural phenomena, divine judgment, climate change, resource depletion or some other general disaster.
In general, resistance welding methods are efficient and cause little pollution, but their applications are somewhat limited and the equipment cost can be high. [51] Spot welder. Resistance spot welding is a popular method used to join overlapping metal sheets of up to 3 mm thick. [51]
In friction stir spot welding, individual spot welds are created by pressing a rotating tool with high force onto the top surface of two sheets that overlap each other in the lap joint. The frictional heat and the high pressure plastify the workpiece material, so that the tip of the pin plunges into the joint area between the two sheets and ...
"Idiot Stick" is a science fiction short story by American writer Damon Knight. It first appeared in a 1958 issue of Star Science Fiction and has been reprinted a number of times, including in Star Science Fiction Stories No. 4 (1958) and Far Out (1961).
Many of the most enduring science fiction tropes were established in Golden Age literature. Space opera came to prominence with the works of E. E. "Doc" Smith; Isaac Asimov established the canonical Three Laws of Robotics beginning with the 1941 short story "Runaround"; the same period saw the writing of genre classics such as the Asimov's Foundation and Smith's Lensman series.
In spot welding, metal surfaces that are held in contact are joined by the heat from resistance to electric current flow. It is common for a spray of sparks in the form of molten metal droplets to be ejected from the parts being joined. [12] or the resistance heating of spot welding. [13]