Ipsen Delivers Three-Row Pusher Furnace with Small Footprint to Mercedes-Benz

Ipsen recently created and delivered a special atmosphere heat-treating system to Mercedes-Benz for the thermal processing of gearbox parts, crown wheels and drive pinion wheels. The three-row Pusher system requires comparatively less floor space and power consumption, upholding Ipsen's reputation for high performance.

This new Ipsen heat treatment system provided quite the challenge during installation at Mercedes. To start, there was limited space surrounding the area where the customer planned to install the furnace. However, Ipsen utilized the available space by carefully linking the high- and low-temperature furnaces, cleaning systems and quenching equipment into complex units, which provided flexibility for various types of parts and minimized the space needed. In the end, Ipsen used a highly integrated transfer mechanism to service the entire system and required components in the compact area.  

System Operation and Configuration

This three-row Pusher atmosphere furnace utilizes semi-automatic powered roller tracks for loading and unloading parts. These roller tracks feed the parts into the system before passing them into automatic load storage conveyors. The load in the pre-oxidation furnace is preheated to 842 °F (450 °C). An intermediate transfer system then moves loads into the entrance vestibule of the high-temperature furnace. Upon leaving the entrance vestibule, the parts enter the three-row heat treatment chamber where they are heated to a carburizing temperature of over 1,652 °F (900 °C).  

High-temperature furnace

The three-row heating zone then carburizes the parts of multiple loads until the surface reaches the required carbon specifications. Using three-rows means multiple loads can be treated at the same time, which helps increase both production capacity and profitability.  

At the end of the carburizing zone, the loads are transferred to a single-row pre-quench soak zone. On exiting the pre-quench soak zone, loads are either free quenched in oil or passed through a fully automatic press quenching system. This produces a distortion-free finish for large parts - such as crown wheels with a diameter of over 11.8 in (30 cm) - and ensures the finished components are true to size.

After quenching, a fully automated transfer system transports all the parts for any further processing they might need to undergo. This typically includes efficient cleaning in the subsequent three-zone post-washing machine, after which they are dried. Alternatively, if needed, the parts may also be removed for straightening or other processes before being returned to the two-row tempering furnace. After tempering and cooling, the parts are then moved through the load handling system for final cooling and storage.  

This complete Ipsen heat-treating system includes the following units:

  • Oil bath with two separate immersion baths
  • Fully automatic Heess press-hardening system
  • Three-zone post-washing machine
  • Tempering furnace
  • Various transport units
  • Pre-oxidation furnace with an operating temperature of 842 °F (450 °C)
  • High-temperature heat treatment furnace with a maximum operating temperature of 1,742 °F (950 °C), containing the following equipment:
    • Entry gate
    • Three-row heating zone
    • Three-row carburizing zone
    • Single-row hardening zone
    • Gas-tight intermediate doors
    • Discharge station for individual, press-hardened parts

New Features and Benefits

This atmosphere heat-treating Pusher furnace utilizes three rows in all its main operating zones and is the first continuous heat treatment furnace from Ipsen to feature the new, patented Lock up system. This system features an entrance vestibule and an oil bath, both of which are separated from the Pusher furnace's heat treatment chamber by gas-tight doors.

The use of special gas-guiding systems means that it is now possible to feed all loads in and out of the furnace without disturbing the furnace's atmosphere. The furnace atmosphere thus fluctuates less in terms of temperature and carbon potential, resulting in precise, straight-line characteristics which are easy to monitor and can be adjusted accurately.  

Another benefit of this atmosphere system, due to the gas-tight separation of the working chambers in the furnace, is the reduced requirement for protective atmosphere. This results from maintaining a constant pressure in the heat treatment chamber while the load is being fed in and out. The pressure only has to be adjusted in the vestibules before the parts continue on the transport belts.  

A further advantage is the intergranular oxidation (IGO) on the parts is minimized. This is essential, as these parts are primarily high-quality precision gearbox components - such as axles, crown wheels and drive pinion wheels - all of which are designed for a service life of several decades.   

Control cabinet

EcoFire Creates High Efficiency  

A process known as EcoFire, which Ipsen has patented, takes a significant step forward in terms of improving energy efficiency. This particularly innovative process means the endogas used to fill the furnace chamber is not lost by burning it off. In the past, burning off exhausted process atmosphere was standard procedure in heat treatment furnace systems similar to the Pusher, resulting in both high temperatures around the furnace and large bills for process gases.  

Now, though, EcoFire uses the exhausted endogas from the preheating furnace as a combustion gas via strictly controlled process steps, meaning the process gas is recycled in a way that allows it to be used again. The main benefit of this process is seen in the costs. Depending on the size of the furnace, this system allows for significant savings within the span of only a few years.  

Advanced Circulation Ensures Temperature Uniformity 

Furnishing the entire system with sophisticated circulation equipment ensures both the homogeneous distribution of protective gas in the heat treatment chambers and a generous flow of reactive gases around the parts. The improved airflow characteristics and the use of the latest burner technology ensure excellent temperature uniformity and outstanding reproducibility of specific heat treatment results.   

Insulation Aids Economical Operation  

Another supporting measure that aids in the economical operation of the atmosphere furnace system is Ipsen's new insulation technology. Time-tested, durable Ipsen masonry consisting of refractory bricks continues to be used as hot face insulation for the walls, floor and ceiling. The support components are made of high-strength silicon carbide materials and provide an exceptionally long service life.  

With a wall thickness of 16 in. (40 cm) to 20 in. (50 cm) in the main sections of the furnace system, microporous material is used as backup insulation as it surpasses all previous materials in terms of its insulation effect. The principle behind this material is that, with its high temperature resistance of up to 2,012 °F (1,100 °C), very few air molecules remain insulated within the tiny chambers. Compared to conventional designs, this results in up to a 30 percent reduction of waste heat, as demonstrated by comparatively lower process costs.   

A Continuous Source of Solutions

No matter your challenges or needs, Ipsen is a source you can rely on to produce particularly demanding, innovative solutions, as well as reduce the running costs of these systems. To learn more about Ipsen's atmosphere heat-treating Pusher furnace, as well as our other products, visit us online at www.IpsenUSA.com/Products.