green laser pointer needs more time for preheating

green laser pointer needs more time for preheating especially in the winter
Some of the austenitic stainless steel welded joints welded joints to intergranular corrosion, localized corrosion along the grain boundaries may work for some time in the corrosive medium,

generally referred to such corrosion is intergranular corrosion, 0Cr18Ni9 stainless steel to intergranular corrosion as shown in Figure 3 shows. According to the type of parent material and the use

of welding materials and welding, the welded joints of austenitic stainless steel is likely to occur in the weld zone, HAZ sensitized to (600 to 1000 ° C) and fusion zone. An intergranular

corrosion (1) intergranular corrosion because 0Cr18Ni9 stainless steel to intergranular corrosion. Austenitic stainless steel weld and HAZ sensitization to intergranular corrosion, grain boundary

related to the formation of chromium depleted layer and the process of sensitization. The final inspection of green laser pointer is listed in the manual.
Weld to produce intergranular corrosion can have two situations: one is already welded Cr23C6 precipitation, such as multi-layer welds repeated heating region; another joint welded chromium

depletion layer, but after welding sensitization temperature range, and thus has a tendency to intergranular corrosion. 16 Harbin Institute of Technology austenitic stainless steel is heated to 450

~ 850 ℃, the intergranular corrosion of the most sensitive to this temperature range, said sensitizing temperature zone. This is because when the temperature is below 450 ° C, the carbon atomic

activity is weak and does not Cr23C6 precipitation difficult the formation of chromium depleted layer; kinetic energy when the temperature higher than 850 ° C, obtained inside the grains of

chrome, extended to the crystal sector, so that the formation of chromium depletion layer disappears. The good quality laser chip of green laser pointer has the long life time.
In the temperature range of 450 ~ 850 ℃, both beneficial Cr23C6 precipitation inside the grains of chromium atoms can not diffuse to grain boundaries, most likely to form a chromium depletion

layer, the most sensitive to intergranular corrosion. Of course, if heated 450 ~ 850 ℃ temperature range long enough period of time, the intragranular chromium atoms can diffuse to the grain

boundary chromium depletion layer disappears. (2) to prevent the welded joint measures to intergranular corrosion process measures to select the appropriate welding method, choose the minimum heat

input welding method, the welded joints as much as possible to shorten the time to stay in the sensitization temperature range. Welded joints for thin, small rules, you should use the energy of the

focused laser welding. Forced rapid cooling of the weld zone.