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Disc spring black processing technology

Number of visits: Date:1/3/2017

Spring black process
Alkaline chemical oxidation treatment is black, is the processing of qualified spring into the concentrated alkali solution containing heat treatment, the spring surface to obtain a layer of meager dense oxide film, the oxide film has anti-corrosion effect.

     Spring in the heated solution, due to alkali corrosion of the surface of the spring, resulting in iron ions (ferrous compounds) in the alkali by adding oxidant - sodium nitrite can make the oxidation process is changed in the spring surface to produce dense oxide film Iron oxide). This oxide film is mainly composed of magnetic iron oxide, oxide film generation time of 30 to 60 minutes. If the time and then extended, can not improve the thickness of the oxide film.

1, the process:

To the oil - (to copper) - pickling - cleaning - oxidation (or secondary oxidation) - cleaning - hot water cleaning - saponification - immersion film device oil change - storage.

2, the process requirements

(1) to the oil

     1. Chemical to the oil NaoH100 ~ 150 g / l + Na2CO320-27 g / l heated to the boiling point of the barrel by adding a small amount of waste acid and iron quiet

    2. Wash oil with gasoline or diesel.

    3. Remove the oil and rust with sandblasting or shot peening

    4. Quenching and tempering the spring can be used to oil and rust barrels

(2) to copper

    With chromic acid 250 ~ 300 g / l + ammonium sulfate 80 ~ 100 g / l without copper can save this process

Add water for 1 to 2 minutes, and then rinse in water

(3) pickling

With 30% of industrial hydrochloric acid dip 1 to 2 minutes to remove oil and rust pickling time can not be too long

(4) cleaning, cleaning in the weak base tank and to prevent the acid into the oxidation tank

(5) oxidation

Sodium hydroxide 650 to 700 g / l + sodium nitrite 100 to 150 g / l Heating to 140 to 144 ° C for 30 to 60 minutes NaOH: NaNO2 = 5 to 8: 1

(6) cleaning, after oxidation in the flow of water rinse

(7) hot water cleaning, hot water 90 ~ 100 ℃, cleaning 1 to 2 minutes

(8) saponification

    10 ~ 20% industrial soap or triethanol soap heated 50 ~ 60 ℃ 1 ~ 2 minutes, the temperature can not be too high

(9) oil, immersion MS-1 water film replacement rust-proof oil

(10) storage

Black procedure operation procedure

   (1) daily after the start of the power supply will be heated to the boiling point of the bath, Pa to the tank in the iron oxide (sediment);

   (2) Pa to the precipitate after adding about 0.5kg of yellow blood salt (potassium ferrocyanide)

   (3) according to the black technology requirements to join a certain amount of sodium nitrite (in line with 5 ~ 8: 1);

   (4) with a thermometer to measure the black bath humidity, to ensure that the bath temperature 140 ~ 144 ℃, if the temperature is too high to add water, and control the heating power;

   (5) before the black, the spring must be fully pickled and cleaned, the tension spring must be vertical frame, easy to clean;

   (6) black must be strictly enforced technical requirements, the liquid surface of the slag to be caught in time, the tank should be added in time;

   (7) after the black spring to be washed by high pressure water, washed by boiling water, saponification temperature control in the 50 ~ 60 ℃;

   (8) spring by leaking off the amount of oil after the frame, storage. Pour the spring of the iron frame to be washed by high pressure water and then re-use;

   (9) to get off work, add a certain amount of sodium hydroxide in the oxidation tank (in line with 5 ~ 8: 1), turn off the power, clean up, clean the workplace, keep the venue clean.

TypeInfo: Industry news

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