1. HPH® Bell-type Annealing Furnaces for Wire
  2. HPH® Bell-type Annealing Furnaces for Wire
  3. HPH® Bell-type Annealing Furnaces for Wire

HPH® Bell-type Annealing Furnaces for Wire

LOI Thermprocess, with its predecessors Matthias Ludwig and Nassheuer, has been building bell-type annealing plants for more than 60 years. Throughout the world, more than 8500 LOI annealing bases have been installed. About 5000 of these bases operate with HNx controlled atmospheres. More than 3500 bases use HPH® annealing technology, with a proven atmosphere of pure hydrogen.

The bell-type furnaces product line for wire coils is based on LOI Nassheuer technology, which in 1996 after the merger between LOI Nassheuer and LOI Thermprocess was added to the HPH bell-type annealing lines division.

For spheroidization and recristallization annealing of rod and drawn wire bell-type annealing plants are used.

The object of heat treatment of hot rolled wire (spheroidizing) is to obtain the low strength which is essential for subsequent cold forming as well as a defined crystalline structure with a share of at least 90% spheroidal cementite. This type of annealing is characterized by a heating-up phase to transformation temperature Ac1 followed by a soaking phase and controlled slow cooling with the heating hood to a temperature significantly below the Ac1 transformation temperature.

Drawn wire is subjected to one or more recrystallization processes (depending on the reduction required in order to achieve the final thickness). The objective of the final annealing of drawn wire products is to obtain a recrystallization structure of specified hardness, tensile strength and forming properties.

Depending on the surface condition of the material to be treated, the atmosphere gas consists either of hydrogen or nitrogen.

  • Value for Money

    Value for Money

    • Solid annealing equipment design
    • Low operational costs
  • Efficiency


    • Excellent temperature uniformity
    • Very uniform mechanical properties of the annealed wire
    • High convective heat transfer
    • High efficient burners
    • Individual recuperators
  • Safety


    • TÜV proven safety strategy
    • Sophisticated process control
    • O2 concentration monitoring
  • Service


    • Long service life
    • Sturdy cast diffusor system
  • Reference


    • > 60 years of experience in Bell-type Annealing
    • > 8,500 annealing bases worldwide (>3,500 HPH®)
  • Environment


    • Selection of alternative cooling systems
  • Digitalization


    • Fully automated control system
    • Various software modules for optimization
  • Technical Excellence

    Technical Excellence

    • World's first fully automated BAF plant
    • HPH®-Flameless combustion technology
  • ContactContact PersonPositionLegal EntityDepartmentPhoneFaxE-mailAddress
    LOI Thermprocess GmbH
    +49 201 1891-1
    +49 201 1891-321

    Am Lichtbogen 29

    45141 Essen


Wire and Rods