Blackening Chemical

EVERBLACK-FCB

 

(CHEMICAL BLACKENING PROCESS – HOT)

 

PRODUCT

 

Blackening process converts clean iron and steel surface to uniform glossy black film of Iron oxide, when oiled coating exhibits good corrosion resistance.

 

BENEFITS

1. Blackening coating does not affect dimension.
2. A good uniform coating can be obtained over threads, blind holes etc., and its suitable for small machined components.

 BATH PARAMETERS

 

1. Concentration               :   65 Kegs of EVERBLACK-FCB & 65 kegs of water for every 100 liters of working volume.

 

2. Chemical Strength           : 130 - 140 points

 

3. Temperature                  ; 135 Celsius to 140 Celsius.

 

4. Dipping time                   : 10-15 min (The dip time will depend upon the nature of    steel treated. Hard alloys and case hardened work will require longer immersion time, soft low carbon steel will require short time.)

                                                     

BATH MAKE UP

 

1.      Partially fill the tank with water and add 65 kegs of EVERBLACK-FCB for every 100 liters of bath.

2.      Fill the bath up to its operating level with water and stir the solution thoroughly.

 

BATH CONTROL

 

            EVERBLACK-FCB concentration can be determined more accurately by titration method.

a)      Take 1 ml of EVERBLACK-FCB bath solution into a conical flask.

b)      Add 5 to 6 drops of phenolphthalein indicator solution.

c)      Titration against N/10 Sulphuric acid standard solution.

 

END POINT: Pink to Colorless

 

No. Of. Ml of N/10 Sulphuric acid standard solution required = point.

 

 

 

 

BATH MAINTANANCE

 

It is important to maintain the above temperature which represents the boiling range of the initial bath made as recommended.

 

If the bath becomes concentrated the boiling temperature will be elevated above 150 degree Celsius. This will lead to brown stains on the work.

 

If the bath becomes weak, the boiling point will be lowered below 140 degree Celsius this is lead to transparent color.

 

The bath level should be carefully maintained while the bath is boiling by water drip feed arrangement.

 

 

REPLENISHMENT

 

            Add 460 gms of EVERBLACK-FCB per 100 liters of bath for each point below 130.