Metal coating process and compositions

In an aqueous acidic lubricant coating composition useful as is or when diluted with water for treating metal surfaces prior to metal forming operations, which composition is an aqueous emulsion which contains:

• (a) at least about 0.2 wt. % phosphate ions;
• (b) from about 0.3 to about 16 wt. % of an emulsified organic lubricant selected from the group consisting of C.sub.8 to C.sub.40 carboxylic acids and alcohols including esters, mono and polyamine salts, mono and polyalkyl (C.sub.1 -C.sub.18) amine salts thereof as well as mixtures thereof;
• (c) from about 0.1 to about 10 wt. % of a cationic emulsifying agent;
• (d) at least about 0.1 wt. % of metal other than alkali metal ions;
• and
• (e) water,
• and is characterized by the formation therein, during use, of an adherent wax scale which builds up on the apparatus in which the composition is used, the improvement which comprises incorporating in said composition from about 0.05 to 5.0 weight % of at least one scale prevention additive selected from the group consisting of naphthalene sulfonic acid/formaldehyde condensation products and the alkali metal or ammonium salts thereof, which agent is effective in preventing the formation of said wax scale.