Ningbo Superior Machinery and over 30-year-old factory with ISO 9001:2008 certificated, manufacturing screws, barrels for injection and extrusion processing. Specifications of our Ni-based bimetallic barrel: Basic Material for body: superior pre-hardening material 4140 Alloy powder: Nickle-based self-melting alloy powder from American Wall Colmonoy Corporation Processing: vacuum sintering cladding ( we're the first and unique Chinese factory applying this technology to barrel production since 2009!) Hardness: 56-60 HRC Service life: 3~6 times than bimetallic barrels processed by high temperature centrifugal casting Application: halogen-free plastic, the high abrasion, corrosion materials adding high fibre, carbon fiber, mineral fiber, ceramic, magnetic powder, metal powder etc. Advantage: more stable molecular structure, higher density of the alloy power than common bimetallic barrels.