In the field of application of these sets, we often meet serious problems of abrasion and corrosion. So parts of the screws are made of tempered - steel, or HIP or Vanadis 10 which,due to different blendings of powders entering their formula , give those elements a longer life - span.The barrel sections are fitted with internal, interchangeable liners made of bi-metal alloys to allow swift and efficient repairs. EUROVITI also offers a range of screws immediately available.