--- title: "Tempering" url: "https://uptonindustries.com/application/tempering/" description: "Upton tempering furnaces: box, car bottom, bell, belt and pit types, plus ceramic, internally heated and externally heated salt bath furnaces." site: "Upton Industries" updated: "2026-09-25T04:24:43+00:00" breadcrumbs: "Home > Applications > Tempering" --- # Tempering Upton tempering furnaces: box, car bottom, bell, belt and pit types, plus ceramic, internally heated and externally heated salt bath furnaces. 8 Upton systems · Salt Bath · Batch · Specialty · Pit ## Which furnace should I use for tempering? That depends on the material, load arrangement, atmosphere and production pattern. Upton lists eight systems for tempering: box, car bottom, bell, belt and pit-type furnaces, electric or gas fired, plus ceramic, internally heated and externally heated salt bath furnaces. Send those four details and we’ll talk through which furnace fits your tempering. - **Process:** Tempering - **Equipment types:** [Salt bath furnaces](https://uptonindustries.com/application/tempering/#route-salt) [Batch, specialty & pit furnaces](https://uptonindustries.com/application/tempering/#route-other) - **Systems:** 8 [Request a quote for a tempering system](https://uptonindustries.com/contact/?need=equipment&ref=Tempering) ## Salt bath furnaces ### [Ceramic Salt Bath Furnaces](https://uptonindustries.com/products/salt-bath-furnaces/ceramic/) U-ABCD Only the faces of Upton’s submerged electrodes touch the salt, so the electrodes take up none of the bath space. ### [Externally Heated Salt Pot Furnaces](https://uptonindustries.com/products/salt-bath-furnaces/externally-heated/) Externally heated salt pot furnaces with carbon-steel or stainless-steel liners, electric resistance heaters or Upton Hurricane gas burners, for intermittent service. ### [Internally Heated Salt Bath Furnaces](https://uptonindustries.com/products/salt-bath-furnaces/internally-heated/) Internally heated salt bath furnaces for non-chloride salts, with carbon-steel or stainless-steel liners. ## Externally or internally heated Link: https://uptonindustries.com/application/tempering/#compare-salt-heating Both are steel-lined salt bath furnaces. They differ in where the heat enters the salt: through the wall of a pot, or directly in the bath. *Fig. 1 Where the heat enters the salt. Section views, not to scale.* *Externally Heated Salt Pot Furnaces & Internally Heated Salt Bath Furnaces compared* | | [Externally Heated Salt Pot Furnaces](https://uptonindustries.com/products/salt-bath-furnaces/externally-heated/) | [Internally Heated Salt Bath Furnaces](https://uptonindustries.com/products/salt-bath-furnaces/internally-heated/) | | --- | --- | --- | | Heat enters | From outside the pot, through its wall | In the salt, from heat sources immersed in the bath | | Electric | Electric resistance heaters | Immersion heaters for lower-temperature work; air- or water-cooled electrodes with transformers at elevated temperatures | | Gas | Upton Hurricane tangential burners, designed to minimize flame impingement on the salt pot | Radiant tubes | | Suited to | Intermittent service | Non-chloride salt applications | | Liner | Carbon steel or stainless steel, selected for the operating conditions | Carbon steel or stainless steel, selected for the operating conditions | | Drawings (PDF) | [Round: Upton Externally Heated Salt Pot Furnace (Round)](https://uptonindustries.com/wp-content/uploads/2018/04/externally-heated-salt-pot-furnace-round.pdf); [Square: Upton Externally Heated Salt Pot Furnace (Square)](https://uptonindustries.com/wp-content/uploads/2018/04/externally-heated-salt-pot-furnace-square.pdf) | [Electrodes: Internally Heated Salt Bath Furnaces (Electrodes)](https://uptonindustries.com/wp-content/uploads/2018/04/upton-internally-heated-salt-bath-furnace.pdf); [Heaters: Internally Heated Salt Bath Furnaces (Heaters)](https://uptonindustries.com/wp-content/uploads/2018/04/upton-internally-heated-salt-bath-furnace-heaters.pdf) | To quote either furnace, send us: - Part sizes - Load weight - Process temperature - The salt you plan to run ## Batch, specialty & pit furnaces ### [Box Furnaces](https://uptonindustries.com/products/batch-furnaces/box-furnaces/) Batch · U-BE · U-BCE Electric or gas-fired box furnaces with fan recirculation; a charge-table model is available as the U-BCE. ### [Car Bottom Furnaces](https://uptonindustries.com/products/batch-furnaces/car-bottom-furnaces/) Batch · U-CBE Electric or gas-fired car-bottom furnaces with fan recirculation and a ColdCar loading hearth. ### [Bell Furnaces](https://uptonindustries.com/products/specialty-furnaces/bell-furnaces/) Specialty · U-LBE Electric or gas-fired lift-off bell furnaces with fan recirculation and ball-screw actuators in the lifting system. ### [Belt Furnaces](https://uptonindustries.com/products/specialty-furnaces/belt-furnaces/) Specialty · U-CONT Electric or gas-fired continuous belt furnaces with fan recirculation and variable-speed belt drives. ### [Pit Type Furnaces](https://uptonindustries.com/products/pit-type-furnaces/) Pit · U-PE Electric or gas-fired pit furnaces with stainless-steel retorts and bottom-mounted circulation fans. ## Related processes - [Drawing 8 shared systems](https://uptonindustries.com/application/drawing/) - [Annealing 6 shared systems](https://uptonindustries.com/application/annealing/) - [Stress Relieving 6 shared systems](https://uptonindustries.com/application/stress-relieving/) - [Spheroidizing 5 shared systems](https://uptonindustries.com/application/spheroidizing/) - [Atmosphere Processing 4 shared systems](https://uptonindustries.com/application/atmosphere-processing/) - [Normalizing 4 shared systems](https://uptonindustries.com/application/normalizing/) ## Need a custom thermal solution? Send us your process details to start a quote. [Request a quote](https://uptonindustries.com/contact/?need=equipment&ref=Tempering)