Thermal Process Technology (Isıl Proses Teknolojisi)

Martempering Furnaces using Neutral Salts

WB 30 with charging aid

Salt-bath hardening in practice

Double martempering bath

WB 10 - WB 400

WB 10 - WB 400 martempering furnaces are filled with neutral salt and offer remarkably rapid and intensive heat transmission to the workpiece while ensuring optimum temperature uniformity. For working temperatures at between 180 °C and 500 °C these furnaces are ideal for quenching or cooling with minimal workpiece distortion, retempering, austempering for optimal toughness, recrystallization annealing after electrical discharge machining (EDM) and for blueing. The quenching or cooling process is applied in order to achieve an even temperature uniformity throughout the workpiece's entire cross-section before the formation of martensite and to avoid distortion and formation of cracks in valuable mechanical components during the subsequent hardening process. Tempering in a martempering bath is the same as the tempering process in air circulation furnaces and is used to reduce a previously hardened workpiece to a desired hardness, to increase toughness and reduce stress within the workpiece. Austempering is a good choice to achieve a high level of toughness and dimensional accuracy in oil hardened low-alloy steels. Workpieces subject to austempering have high tensile strength and good elasticity.

  • Tmax 500 °C
  • Optimal temperature uniformity
  • Martemper bath temperature control
  • Over-temperature limiter controller with adjustable cutout temperature for thermal protection class 2 in accordance with EN 60519-2 as temperature limiter for furnace and product
  • Heating with immersion heating elements
  • Charging basket

Additional Equipment

  • Charging aid mounted on side of furnace
Article no.ModelTmaxInner dimensions in mmVolumeOuter dimensions in mmSupplyElectricalWeight
  °Cwdhin lWDHpower/kWconnection*in kg
001305100WB 10500220200300105504505701.01-phase60
001305200WB 20500300210460206105809202.61-phase110
001305300WB 30500300210580306105809203.21-phase140
001305700WB 70500400300680707506809807.53-phase240
001305800WB 200500540520880200900900120018.03-phase660
001305900WB 40050073072098040011001100130024.03-phase1150
*Please see page 32 for more information about mains voltage
Information about salts by Petrofer and Durferrit and their application

SaltApplicationWorking temperatureComment
  in °C 
AS 135/140Salt-bath hardening, tempering, austempering180 - 500Not for use with workpieces which are heated up to above 950 °C and salts which contain more than 13 % KCN
AS 220/225Tempering, austempering250 - 500 
AS 200/235Tempering, austempering280 - 500Nitrite-free in the as-received condition
AS 200/235Tempering340 - 500