1. Roller Hearth Furnace for Carbon Steel Tubes and Bars

Roller Hearth Furnace for Carbon Steel Tubes and Bars

LOI Thermprocess, with its predecessors Matthias Ludwig and Nassheuer, has been building Continuous roller hearth furnace plants under protective gas atmosphere for tubes, bars, wire coils and semi-finished annealing goods for more than 60 years. Throughout the world, more than 350 LOI roller hearth furnace plants under protective gas atmosphere have been installed.

Carbon and low-alloy steel is annealed at temperatures up to 1,050 °C in a process gas atmosphere. Bright annealing combined with

  • stress relieving annealing
  • recrystallization annealing
  • normalizing
  • tempering
  • soft annealing
  • solution annealing
  • isothermal annealing

is the most important heat treatment procedure in roller hearth furnaces.

In the process gas, nitrogen is mainly used as carrier gas. Hydrogen e.g. is added to it, which reduces, among other things, the oxide layers on the material surface and thus achieves the blank annealing effect.

We apply a process technology particularly for the carbon-neutral annealing of steel that precisely regulates the proportion of carbon in the atmosphere by measuring the dew point. The so-called C-level control creates the optimal conditions for the heat treatment of the material surface. Under certain conditions, this technology is also applicable for carburizing annealing.

Depending on the process requirements or the local availability of the reaction gas – such as e.g. endogas, monogas, exogas or split ammonia – our experts optimize the process parameters with which the desired product properties are reliably achieved.

In contrast to stainless steel, the annealing good must not be cooled too quickly downstream the furnace chamber in order to ensure a uniform distribution of the structure and minimal distortion of the final products.

Individually adapted to the customer's needs, we apply various cooling concepts. Since these concepts mainly focus on efficiently using the “waste heat”, the low-temperature and high-temperature cooling sections are not only equipped with heat recovery units, but they are additionally coupled with each other. In addition, the energy from the exhaust gas of the burner device can optimally complement and round off the heat recovery. Furthermore, the energy from the burner waste gas can optimally complete and round off the heat recovery.

The different types of jet cooling are integrated at appropriate places in the segments of the radiation cooling section to implement a particularly small construction length of the entire furnace.
Up to twelve tons of heating good are treated per hour in our roller hearth furnaces for normal steel. Leading steel pipe manufacturers apply our furnace plant technology throughout the world. We design furnaces higher throughput in accordance with our customers’ requirements.

  • Value for Money

    Value for Money

    • High reliability
    • Long durability
    • Customized design
    • Chainable design
  • Efficiency


    • Data reception from higher-level systems, e.g. ERP or MES
    • Process and capacity optimization
    • Consumption optimization and analysis
    • Easy production line integration
    • High efficiency heating systems
  • Safety


    • According to DIN EN 746
    • Safety analysis and risk assessment
    • Redundant Atmosphere Control System
    • Protective gas flow metering
    • Safety Flow Control
    • Furnace Pressure
    • Failsafe Design
    • Consistent with local requirements
  • Service


    • Low-wear
    • High reliability
    • Maintenance Assistance System
    • Alarm - Management via e-mail/sms/app
    • Remote maintenance
  • Reference


    • More than 350 furnace plants all over the world
    • Benteler Group
    • Baosteel Group
    • Boehler Group
    • Salzgitter Mannesmann Group
    • Sandvik Group
    • Tenaris Group
    • Tubacex Group
    • Vallourec Group
  • Environment


    • Recuperative burner system
    • Energy recovering systems, e.g. waste gas heat exchanger, high temperature cooling section with heat exchanger
  • Digitalization


    • Industry 4.0
    • DMC (Data Management Center)
    • CQI 9 conformity
    • Production data recording and analyse at everytime
    • Level 0, 1, 2 design by LOI
  • Technical Excellence

    Technical Excellence

    • Customized design
    • Customized programming and visualization
    • 100% continuous roller hearth furnace plant under 100% H2 without lock systems
    • Different jet cooling systems
    • Arbitrary sub suppliers
    • After sales service with know-how in modification and modernization
  • ContactContact PersonPositionLegal EntityDepartmentPhoneFaxE-mailAddress
    LOI Thermprocess GmbH
    +49 201 1891-1
    +49 201 1891-321

    Am Lichtbogen 29

    45141 Essen


Tubes and Bars