Carburizing, and Carbo-Nitriding or Nitrocarburising: These well-established high-temperature atmosphere heat treating processes for the surface or "case" hardening of steel.

Carburizing, and Carbo-Nitriding or Nitrocarburising: These well-established high-temperature atmosphere heat treating processes for the surface or "case" hardening of steel utilize some or all of a variety of Marathon products - Our Magnum, Carbonseer, or AACC zirconia oxygen sensors and the complete line of 10 Pro, DualPro, and CarbPro instruments have been leaders in the industry and enabled increasingly more precise control of the heat treatment process.

Nitriding: Gas Nitriding is an alternative to ion or plasma nitriding and improves wear and fatigue resistance with low distortion. The technology runs at a lower temperature than carburizing or carbonitriding, and is characterized by extremely long cycles, often exceeding 100 hours.

Vacuum: The vacuum process is used for a variety of metallurgical uses such as Bright Annealing, Solution Heat Treating, Brazing, Tempering, Stress Relieving, etc. When atmosphere control is important, for example to avoid de-carburization, Marathon's carbon probes (Magnum and Carbonseer), DualPro or MultiPro instruments will have a significant role to play in the success of the operation. The 10Pro line of instruments are used in a large number of vacuum furnace installations.

ReDox: Marathon's VersaPro ReDox Setpoint Controller is often used in conjunction with an oxygen probe for ReDox applications including brazing, sintering, glass-metal or glass-ceramic sealing, and neutral hardening in N2-H2 or exothermic atmospheres. Depending on the amount of enrichment gas that is required, an on-off solenoid valve may be sufficient. In some cases, a proportional control valve is necessary to maintain consistent conditions within the furnace or retort.

Sintering and Brazing: Powder metal sintering can be applied to both ferrous and non-ferrous metals, and can utilize either a neutral or a carburizing atmosphere. In all cases, a reducing atmosphere must be maintained during the process to prevent oxidation. The reducing gas atmosphere is usually created and maintained by the addition of hydrogen to an inert gas such as nitrogen or argon. The process typically runs at a high temperature, between 2000ºF to 2100ºF. Zirconia probes like Marathon's Magnum and Carbonseer can be used in a sealed "reheat well" to control the dew point of the process and maintain a reducing atmosphere at all times. Or the unique Piccolo probe, with a faster reaction time than a typical reheat well, can be used.

Annealing: Although often not suited for control by means of traditional high-temperature zirconia oxide carbon probes, Marathon has annealing solutions including simple "recipe control" using our DualPro and CarbPro instruments.