In the production of large-diameter flanges, there are many factors that affect the performance of large flanges. Let’s talk about the common factors below.
The first is the annealing temperature (the annealing temperature is the temperature parameter when the primer and template are combined. When 50% of the primer and The temperature at which the complementary sequence appears as a double-stranded DNA molecule. It is a more important factor affecting the specificity of PCR. Ideally, the annealing temperature is low enough to ensure that the primer anneals effectively to the target sequence and high enough to reduce Non-specific binding. The reasonable annealing temperature is from 55°C to 70°C. The annealing temperature is generally set 5°C lower than the Tm of the primer.
Whether the specified temperature is reached Large-scale flange treatment generally adopts solution heat treatment, which is usually called “annealing”, and the temperature range is 1040~1120°C (Japanese standard). You can also observe through the observation hole of the annealing furnace. The large flanged pipe fittings in the annealing area should be in an incandescent state, but there is no softening and sagging.
The second is the sealing of the furnace body (the shell is welded by steel plate and section steel, the trolley is welded by section steel and steel plate, the trolley reduces heat radiation and convection loss through soft contact with the furnace lining and sand sealing mechanism, and effectively ensures the airtightness of the furnace body. ), the bright annealing furnace should be closed and isolated from the outside air; if hydrogen is used as the protective gas, only one exhaust port is open (used to ignite the exhausted hydrogen). The inspection method can be to use soapy water to wipe the gaps of the joints of the annealing furnace to see if there is air leakage; the places where the air is most likely to escape are the place where the annealing furnace enters the pipe and the place where the pipe exits. The sealing ring in this place is particularly easy to wear. Always check and change frequently.
The second is the protective gas pressure. In order to prevent micro-leakage, the protective gas in the furnace should maintain a certain positive pressure. If it is hydrogen protective gas, it generally requires more than 20kBar. Annealing atmosphere: Generally, pure hydrogen is used as the annealing atmosphere. The purity of the atmosphere is preferably above 99.99%. If the other part of the atmosphere is an inert gas, the purity can be lower, but it must not contain too much oxygen or water vapor.