Chlorine in lubricating oils

In the first  methods the  sample  is oxidized  by  combustion  in a  bomb  containing  oxygen  under  pressure. The  chlorine  compounds thus  liberated  are  absorbed  in a  sodium carbonate  solution and  the amount  of  chlorine  present is determined gravimetrically  by  precipitation  as  silver  chloride.

With the second method, the sample, dissolved in a low boiling hydrocarbon mixture, is boiled under reflux with metallic sodium and n-butyl   alcohol. Under  these  conditions the  chlorine  is converted  to sodium  chloride which  is then  extracted  with  water. The  chloride in  the  extract is  determined  volumetrically  by  titration  with silver in the  presence of  thiocyanate.

  

Sulfur in Gear Oils

In this method  the sample is vaporized  and  burned in a  stream of air, and  the  oxidation completed  by passing  over  quartz particles  maintained  at a temperature  of 950 to 1000 degree C. The combustion  products are then  passed  through hydrogen  peroxide  which  absorbs  the  sulfur  as sulfuric  acid  and  the  chlorine  as hydrochloric  acid. The  absorbent  is then  analyzed  for total  acidity  and  for chloride ion. The  procedure for  the  determination  of  chlorine  is  included  only  for  correcting   the  sulfur  content  and  the  method is not  recommended  for the  determination  of chlorine  alone. 

Lubrication of Special steels

If special alloys are used in one or both members of a gear set, special consideration may be necessary in choosing a lubricant.  The supplier of the equipment will no doubt have the answer since, as Forbes et al. ^20 states:

“The choice  of  metals  that will operate together in a particular type of  reduction  gear is based on practical  data  that have been secured by trial  and error methods  over a period of years.”

It is known that some steels are more difficult to lubricate than others. Stainless steel is very important in this time. Some alloys will not react readily with certain EP elements. Chromium  is  practically  inert  to  sulfur  compounds  but will react  with most chlorine  compounds. Therefore, with high nickel-chrome-molybdenum alloy steels it is important that an EP lubricant contain chlorine additives as well as sulfur compounds.