Cylinder Construction and Reparation

Barrel construction can be done following samples or drawings in various materials: standard nitrided, hardened steel (for small dimensions barrels), bimetallic, where there are moulding materials with high abrasion and corrosion. Material choice is in accordance to customer request.

As soon as the used barrels are received, a complete dimensional check is carried out (inner bore, threading conditions, cooling circuit, thermocouple holes condition, etc) in order to provide an offer.

  • Standard nitrited and hardened steel barrels:
    Basic purpose is to restore the correct tolerance between barrel, screw and screw-tip in order to bring back the moulding to the original level.
  • Internal bushing:
    The overlay (partial or total) is carried out in X155CrV121.
    We always propose an offer for a new barrel in standard nitrited steel and bimetallic as an alternative.
  • Bimetallic barrels:
    If barrels are in Bimetallic material, the only way to proceed is to increase the inner bore with the renewing or supply of the screw and of a series of valves (interchangeable with the existing) suitable for the cylinder. In such case the feasibility of this type of renewing is based on moulding material.


Nitrided Standard – (41CrAlMo7) – 60 HRC
Characteristics: hardened and tempered steel, containing alloying elements such as aluminium, chromium Molybdenum, which during heat treatment (Nitriding), form particularly resistant nitrides, reaching hardnesses of around 1050 HV.
Suitable for: those who have no particular problems with wear and corrosion.

Hardened material – (X155CrMoV121) – 58-60 HRC
Characteristics: hardening steel with a high percentage of chromium, resulting in good toughness and high wear resistance.
Suitable for: those with significant wear problems.
Durability: 2-3 times the nitrided standard

Bimetal (wear and corrosion resistant) – 62-69 HRC
Properties: cylinders internally coated with a hard, approx. 5 mm thick, highly wear and corrosion resistant state reaching a hardness of approx. 65 HRC.
Suitable for: major wear and corrosion problems.
Durability: 4-5 times the nitrided standard