Thermal International Co.,Ltd

Closing the loop on thermal Solutions

How to deal with the electric heating element once it is corroded?
- Jan 16, 2018 -

How to deal with the electric heating element once it is corroded?

       Metal electric heating element, especially in the long-term immersion in liquid work, its stainless steel surface will appear due to have different degrees of corrosion, even will be different severity, the electric heating element due to corrosion will gradually expand and then lead to the leakage of the final result is that the electric heating element shall be damaged and  can not be used.

       The electric heating element can usually be corrected by brazing. Before brazing to completely clean the surface of rust, oil, oxide and sediment, etc., and then use flux to further clean the sand hole or microcrack, and then drop the molten solder into the sand hole or crack, after the solder condensation is welded firmly, the casting will not leak.

       The leakage part of the casting is positioned at the lowest position, the metal leakage mending agent is dissolved in water, and the solution pressure is increased to about 1.5 times of the working pressure of the casting by using a hydraulic test method, so that water rich in the leakage mending agent blocks the adhesive in the sand hole through the filtering effect of the sand hole, and the more the adhesive in the sand hole is gathered, and finally the sand hole is blocked. After stopping the leakage, adhere to the pressure for 20 min, then let go of the leakage supplement, let stand for 24 - 28 h, let its natural dry and adhesive curing. From the beginning to do the test, no leakage can be used.

       The defects such as pores, holes and cracks were eliminated by the method of HCL.Particular way is, the box body wash clean with gasoline, and then pumped into the 5% - 5% hydrochloric acid solution soak a day and night, let the hydrochloric acid and casting abundant chemical reaction, because of the substitution effect, the generated ferrous chloride can fill tiny sand holes, cracks and pores.However, after corrosion, it is necessary to take part in a small number of 0.5% to 10% sodium hydroxide alkaline solution to clean, to remove the residual hydrochloric acid solution of the atraz air compressor accessories.

       As for electric heat pipe hydraulic test, and find out the leakage site, and then use chisel along the crack open a small groove depth of not less than 1.5 mm, for degreasing treatment, place the groove surface level, can use AR - 4 glue to fill plugging;In addition to filling the groove, a part of the adhesive can enter into the sand hole under the effect of gravity to complete the leak.

Note: this method should be used to make the casting boring before adding. After curing, the water pressure test should be conducted to see if it can leak.