1. Roller Hearth Furnace for Stainless Steel Tubes and Bars

Roller Hearth Furnace for Stainless 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.

Pipes, bars and other semi-finished products made from high grade steel are becoming increasingly important throughout industry.

Roller hearth furnace plants can be used to treat a very wide range of products which are used in all industrial sectors. Economical, energy-efficient heat treatment plants are essential to meet the growing requirements faced by materials, such as corrosion resistance in the offshore industry, increased cleanliness in the pharmaceutical industry and weight reduction without sacrificing strength and other properties in the automobile industry, and to produce large quantities of materials required throughout the world.

The heat treatment is an essential stage in the production and processing of pipes and bars made from high grade steel. This heat treatment is mainly carried out in roller hearth furnaces, which may either be electrically heated or gas-fired. The main heat treatment processes under protective gas atmosphere in a roller hearth furnace plant are bright annealing in combination with

  • Stress relief
  • Recrystallization
  • Normalizing
  • Tempering
  • Spheroidizing
  • Solution Annealing
  • Subcritical Annealing
  • Isothermal Annealing

Tenova LOI roller hearth furnace plants with a protective controlled atmosphere are used to prevent unwanted reactions such as the oxidation or nitrification of the charge material in air or waste gas and therefore achieve the highest requirements. Especially the high annealing temperatures up to 1200° C, the jet cooling between 900° C to 400° C and the 100% H2 atmosphere are the features for the treatment of high grade steel. LOI designs such kind of furnaces as 100% continuous lines without any vacuum or purging locks if required.

The controlled atmospheres consist of neutral or inert constituents. However, they may contain reactive components for process reasons.

The neutral or inert component is mainly nitrogen, although argon or helium may be used in special cases. The active or reactive components are mainly hydrogen.

  • 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


    • Centravis Group
    • Jiuli Hi-Tech Metals Co., Ltd.
    • Salzgitter Mannesmann Group
    • Sandvik Group
    • Tubacex Group (including SchöllerBleckmann Edelstahlrohr, Austria, and Salem Tube, USA)
    • Vallourec Group
  • Value for Money

    Value for Money

    • Recuperative burner system
    • Energy recovering systems, e.g. waste gas 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