Heat Treat (SDB) Ovens

Heat treat ovens are very common in the heat treat industry and are commonly referred to as Companion Draw Furnaces or Draw Batch Furnace.
Hartley Corp. offers 40 standard SDB heat treat oven models.

Ten (10) standard sizes
Four (4) temperature ranges. Standard maximum continuous temperature ratings are 800°F (425°C), 1000°F (540°C), 1250°F (675°C), and 1400°F (760°C).
Each SDB heat treat oven model can be heated by either a direct gas fired burner (Natural or Propane), or with electric heating elements. We can also provide indirect gas fired units if required.

When specified, the equipment can be designed to meet even the most stringent standards (i.e. AMS-2750, AMS-2770, or BAC-5602, to name a few).


  • Tempering
  • Solution Treating
  • Aging
  • Annealing
  • Normalizing Stress Relieving

The standard furnaces are designed to accept the most common heat treat oven baskets and load sizes (please reference chart). If your basket size isn’t listed, please contact us so we can discuss your application.

Model Basket Dimensions
Width Height Depth
SDB-436 24″ 18″ 36″
SDB-446 24″ 24″ 36″
SDB-448 24″ 24″ 48″
SDB-558 30″ 30″ 48″
SDB-658 36″ 30″ 48″
SDB-668 36″ 36″ 48″
SDB-6612 36″ 36″ 72″
SDB-8612 48″ 36″ 72″
SDB-888 48″ 48″ 48″
SDB-101010 60″ 60″ 60″

Heavy Duty Construction

Wisconsin Oven’s draw batch ovens feature heavy duty construction, which includes a plate steel outer shell, a reinforced steel plate oven front, a lined inner shell, and exterior structural reinforcements as required. The following chart shows a breakdown of these components by maximum temperature rating.

Maximum Temperature Ratings
800°F (425°C) 1,000°F (540°C) 1,250°F (675°C) 1,400°F (760°C)
Oven Front 3/8″ Plate Steel 3/8″ Plate Steel 1/2″ Plate Steel 1/2″ Plate Steel
Outer Shell 3/16″ Plate Steel 3/16″ Plate Steel 3/16″ Plate Steel 3/16″ Plate Steel
Inner Shell 20 gauge aluminized 18 gauge aluminized 18 gauge 304 SS 18 gauge 309 SS
Insulation 6″ semi-rigid mineral wool 4″ mineral wool & 2″ N-Block 4″ mineral wool & 2″ N-Block 4″ mineral wool & 4″ N-Block

Standard Features

  • Maintenance free door gaskets
  • High pressure air distribution ducts
  • Heavy duty exterior plate construction
  • Corrosion resistant aluminized or stainless steel interior (depending upon model)
  • Non-settling batt type insulation
  • Air operated vertical lift door

Wisconsin Oven’s heat treating ovens also include combination air flow through the work chamber, a pier rail hearth, disconnect switch and NEMA 12 controls.


We offer a wide variety of standard options to satisfy most applications, including special temperature controllers, chart & paperless temperature recorders (as well as other data acquisition equipment), process timers, and 7-day timers. Our heat treat ovens can be supplied with Quench Tanks or powered or non-powered load tables.
Traveling loaders (as shown below) are also available.

Hearths & Work Support

Many different hearth designs can be supplied with our equipment. As a standard, we provide a pier-rail hearth, which is used when the baskets or products are loaded either by hand, or by fork truck. Other hearth designs we offer as options include: full width rollers, split roller, wheel or roller rail (with or without chain guides). Hearths are available in either carbon steel, stainless steel, or alloy, depending on the temperature and your needs. We can design the equipment with a bridge and chain guides, to allow loading and unloading from an existing charge car.