Powder metallurgy process for making lead free brass alloys

A method of producing a workable graphite-containing brass alloy billet having less than 0.25 wt. % lead, the method comprising:

• mixing a brass powder comprising copper and zinc with an acid solution comprising one or more of sulfuric acid, hydrochloric acid, nitric acid, and phosphoric acid;
• rinsing the brass powder with an aqueous solution until the pH of the brass-powder exceeds 6.5;
• mixing the brass powder with greater than or equal to 0.05 wt. % to less than or equal to 2.0 wt. % of a graphite powder and greater than or equal to 0.02 wt. % to less than or equal to 1 wt. % of one or more organic binders to form a brass-powder mixture, wherein the one or more organic binders are selected from the group consisting of:
• squalene, mineral spirits, kerosene, isoparaffinic fluids, and polyethers;
• compacting the brass-powder mixture to form an initial billet, the initial billet having a diameter greater than or equal to 127 mm to less than or equal to 381 mm;
• heating the initial billet to a first temperature range and holding the first temperature range for a first time period to remove the one or more organic binders, wherein the first time period is greater than or equal to 60 seconds per 25.4 mm of billet diameter;
• and
• heating the binder-free billet to a second temperature range that is greater than the first temperature range to sinter the binder-free billet and form the workable graphite-containing brass alloy billet wherein the first temperature range is greater than or equal to 100 degrees C. to less than or equal to 400 degrees C.;
• and wherein the second temperature range is greater than or equal to 650 degrees C. to less than or equal to 900 degrees C.