At Michigan Seamless tube, tight control of the process is the key to our competitiveness. Raw material in the form of solid round billets arrives in over 100 grades. Heated in a rotary hearth furnace, each billet is indented in the exact center before entering the rotary piercing mill where a hydraulic ram feeds the billet between heavy rollers that drive it over a piercing point to produce a tube shell. While still hot, the tubes are reduced in size in a stretch reducing mill. This produces tubes shells of superior concentricity. After cooling, the tube shell is cold worked. The draw bench pulls it over the stationary die and over a mandrel improving grain structure and surface condition, increasing hardness and reducing the tubes to the desired size and thickness with in very close tolerance. The production process supports small quantity runs that are customized to customer specifications. After cold working, the tubes go to the annealing furnace where variations of temperature, time and the number of cycles produces a wide range of hardness and tensile strength to meet the standards and customer requirements. After straightening to desired tolerances the tubes are cut to length, checked by eddy current and demagnetized. Through out the process the tubes receive minimal handling which ensures excellent surface finishes. Before being shipped, the tubes are extensively tested for quality and a test report is then provided to the customer with each shipment. © Michigan Seamless Tube 2006