Electrical and heat treatment of materials
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Metal will slow heating to a certain temperature, sufficient time to keep, and then to an appropriate rate of cooling metal heat treatment process. Stainless steel bright annealing furnace hot back into full annealing to deal with, not to stress annealing and annealing. Annealing mechanical properties can be used to detect the tensile test, hardness test can also be used to detect. Annealing the metal is slowly heated to a certain temperature, sufficient time to keep, and then to an appropriate rate of cooling metal heat treatment process. Bright annealing furnace heat treatment into full annealing, annealing and not to stress annealing. Stainless steel bright annealing furnace with the mechanical properties can be used to detect the tensile test, hardness test can also be used to detect. Many are steel annealing heat treatment to a state of supply, steel hardness testing Rockwell hardness tester can be used to test the hardness of HRB, for the thin steel plate, steel and thin-walled steel pipe can be used on the surface Rockwell hardness tester, hardness testing HRT . Annealing is aimed at: ① to improve or eliminate the iron and steel casting, forging, welding and rolling process caused by a variety of organizational shortcomings, as well as residual stress to prevent deformation of the workpiece, the cracking. ② softening workpiece for machining. ③ grain refinement to improve the organization in order to improve the mechanical properties of the workpiece. ④ for the final heat treatment (quenching and tempering) make preparations for the organization. Annealing process commonly used are: ① complete annealing. To refine, as low-carbon steel casting, forging and welding after the poor mechanical properties of large organizations overheating. Will be heated to work all the ferrite into the austenitic temperature above 30 ~ 50 ℃, insulation for a period of time, and then with the stainless steel annealing furnace to cool slowly, in the process of cooling austenite change from happening again, to make steel Thinning. ② continuous annealing furnace of the ball. To reduce the tool steel and bearing steel after the forging of high hardness. Steel work will be heated to the temperature began to take shape more than austenitic 20 ~ 40 ℃, after the heat to cool slowly, in the cooling of pearlitic in the process of layered film into a spherical cementite, which reduces the hardness. ③ isothermal cover-bright annealing furnace. To reduce some of the nickel, chromium alloy with a high level of structural steel high-hardness, for cutting. General before cooling to a more rapid pace of the most unstable austenite temperature, proper heat preservation, occasional austenite into or sorbite's hardness can be reduced. ④ recrystallization hood-type annealing furnace. For the elimination of metal wire, sheet in the cold drawing, cold-rolled in the process of hardening phenomenon (increased hardness, plastic drop). Heating temperature is generally austenitic steel began to take shape following the temperature 50 ~ 150 ℃, is the only way to eliminate the effect of hardening metal to soften. ⑤ graphite annealing. To make cementite contains a lot of cast iron into a good plastic malleable iron. Operation will be casting process is heated to around 950 ℃, the heat after a certain period of time due to cool, so that cementite decomposition group floc formation of graphite. ⑥ the proliferation of annealing. Alloy castings used to make chemical composition homogenization, to improve their performance. In no way is melting under the premise of casting will be heated to temperatures as high as possible, and heat for a long time, to be in a variety of alloy elements tend to the proliferation of uniformly distributed relief after the cold. ⑦ to stress annealing. In order to remove the iron and steel casting and welding pieces of the stress. The iron and steel products began to take shape when heated to temperatures below austenitic 100 ~ 200 ℃, after the heat in the air cooling, with zinc to the elimination of internal stress.