An apparatus for thermally treating and coloring a plurality of curved suture needles. The apparatus includes a conveyer for transferring the plurality of curved suture needles from a source of curved suture needles to a receiver, a housing positioned adjacent the conveyer, the housing having a first end, a second end, and an opening running from the first end to the second end, the opening aligned with the conveyer to enable the plurality of curved suture needles to pass therethrough, a heat source located within the housing for heating the plurality of curved suture needles as the plurality of curved suture needles are transferred by the conveyer from the first end of the housing to the second end of the housing and a system for providing a gas mixture containing a fractional concentration of oxygen to oxidize and colorize the surfaces of the plurality of curved suture needles as the plurality of suture needles pass through the housing. A process for thermally treating and coloring a plurality of curved suture needles to colorize and enhance the stiffness and yield moment of the curved suture needles is also provided.