ASTM D524 Ramsbottom Carbon Residue of Petroleum Products
This test measures the coke-forming propensity of oils under extreme temperatures causing cracking and pyrolysis. The sample is placed in a glass bulb and heated in a furnace at 550°C for 20 minutes to evaporate and reduce the material to a coke residue or 'carbon residue'. Ash forming additives can give erroneous indication of coke-forming tendencies by adding to the weight of residue formed. Carbon residue is a useful guide in the manufacture of oils and finished lubricants. Results differ from those obtained by ASTM D189.