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"Dry" Tunnel Furnace Roll Assemblies
Tunnel furnaces (or roller hearth slab reheat
furnaces) provide one of the toughest environments for
cast steel fabrications. With temperatures over 2300o F, these rolls are expected to carry the full weight of the slab being heated to rolling temperatures. Duraloy's patented dry rolls, manufactured in our proprietary alloy Super 22H®, have proven themselves to be some of the best rolls in the world.
Dry rolls provide several advantages over "wet" or water-cooled rolls. First, in a tunnel furnace transfer car, they eliminate the need for flexible water hoses to be hanging from the shuttle. And they minimize the heat loss in the furnace, reducing the energy consumption when compared to water-cooled rolls.
Now, with the introduction of Duraloy's proprietary
MO-RE 2150®, dry rolls are used throughout the furnace.
Click
here
for more information on MO-RE 2150® dry rolls.
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Water Cooled Tunnel Furnace Roll Assemblies
These water cooled rolls are the type of rolls most typically found in tunnel furnaces around the world. The rolls are fabricated from a shaft that is made from carbon steel tubing and has a stainless steel "corebuster" installed in the shaft to direct water flow through the roll. Cast tyres are then welded to the shaft to provide the carrying surface for the slabs in the furnace. The areas between the tyres is then covered with a castable ceramic material to insulate and protect the shaft.
Duraloy has supplied hundreds of these rolls around the world, both with the castable installed, but, more typically, without castable ceramic installed.
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Nickel Aluminide Plate Hardening Rolls
These roller hearth plate hardening furnace rolls have barrels that are cast in patented Nickel Aluminide alloy and Duraloy's proprietary alloy MO-RE-1® end bells. The Nickel Aluminide resists carburization while operating at high temperatures.
The barrels and ends are joined by welding using a new welding technique developed by Duraloy.
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Continuous
Annealing Line (CAL) Rolls
Duraloy produces a these large diameter rolls, typically used in continuous annealing or continuous galvanizing lines. The rolls are produced with centrifugally cast bodies up to 54" (1370 mm) in diameter. The ends are statically cast and the shafts are typically wrought materials. All the parts are fabricated in house and finish machined to customer specifications. The rolls can also be supplied static or dynamically balanced, if required.
Typical alloys of construction are HF, HK, MO-RE® 1 and MO-RE® 2.
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Furnace Roll End Bells
These statically cast end bells,
or tunnions, are cast in heat resistant alloy then
inserted and welded into the body of a high temperature
furnace roll. A forged steel shaft is then inserted into
the small end of the trunnion to complete the roll
assembly. The inside can be fitted with blanket
refractory and heat shields to protect the steel shaft
and roll bearings from the heat of the inside of the
furnace.
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Roll Body
Large diameter, heavy-walled centrifugals, such as this, are no problem for Duraloy. They can be produced in a variety of alloys, however they are most typically produced in ASTM A351 Grade CF-3(304L), Grade CF-3M (316L), ASTM A743 Grade CA15 (410SS), or 52100.
This roll may be sent on to our fabrication department for assembly into a finished machined sink roll for a galvanizing line, or could be sent to the customer in a rough machined or as-cast condition for finishing by others.
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Reheat Furnace Skid Riders
These statically cast rider blocks are used to carry slabs through a reheat furnace. The slabs are heated up prior to being rolled into plate or sheet. These rider blocks are normally pinned to an underlying skid and are designed to keep the slab elevated off of the skid to avoid scratching the slab surface and provide for more even heating.
Skid riders are normally cast in very high alloys, such as Duraloy's proprietary alloys MO-RE® 1, MO-RE® 2, 22H® or Super 22H®.
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Reheat Furnace Dropout Skids
These statically cast dropout skids are also used in a reheat furnace. Like rider blocks, they are normally pinned to an underlying skid and are designed to keep the slab elevated off of the skid to avoid scratching the slab surface and provide for more even heating.
Dropout skids and skid riders are normally cast in very high alloys, such as Duraloy's proprietary alloys MO-RE® 1, MO-RE® 2, 22H® or Super 22H®.
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Large Radiant Tube Assemblies
These very large radiant tube assemblies are cast, machined and fully fabricated at Duraloy. The size of the assembly is dictated by the size of the furnace and the amount of heat that is required by the furnace design.
These radiant tube assemblies are cast in Duraloy's proprietary alloy Super 22H®. alloy.
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Furnace Roll Ends
These statically cast roll ends are welded into the ends of a centrifugally cast barrel. These ends are then machined to form the trunnion and shafting for a roll used in the steel industry.
These roll ends are cast in ASTM A297 Grade HT alloy.
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Heavy Wall Centrifugal Tube
Duraloy produces a wide variety of centrifugal sizes, shapes and alloys. While a typical centrifugal size is between 3.5"(89mm) to 24" (610mm) in outside diameter, Duraloy can produce tubes from 2" O.D. (51mm) up to 54" O.D. (1372mm) in our facility.
Castings are cast, then blasted to clean the surfaces, cut to length, straightened and then either sent for inclusion in other products or shipped to the customer.
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Plate Hardening Furnace Rolls
These rolls are used in a roller hearth, plate hardening furnace in the steel industry. The roll is fabricated from a centrifugally cast barrel, two statically cast roll ends and shafts made from forged bar. Depending on the customer requirements, rolls such as these can be statically balanced, dynamically balanced, coated, machined, etc., as designed and specified by the customer order.
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Radiant Tube Assemblies with Bellows
Duraloy also produces specialized radiant tube assemblies, like these "U"-Tubes with expansion bellows shown here.
These assemblies have a high alloy bellows welded into one leg, outside the bung plate, to allow for differential thermal expansion between the two centrifugal legs. This bellows expands and contracts to reduce the stress that occurs when the firing leg is hotter than the discharge leg.
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Lime Kiln Bar
These hollow, triangular shaped bars provide structural support in the feed end of a lime kiln. The lime is produced to support both the agricultural markets and the steel industry.
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Furnace Skids
These statically cast furnace skids are used in a heating furnace as a support member to keep the material being heated from laying on the floor of the furnace. This elevation allows the heat to circulate more evenly and promotes faster heating of the parts or slabs.
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Centrifugal Tubes
These centrifugal castings have been cast, blasted, cut to length and beveled prior to being welded into a radiant tube assembly for use in a continuous galvanizing furnace.
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Radiant Tube Assemblies
These radiant tube assemblies are complete and fully inspected, bundled and ready for shipment to the customer. You can easily see the tube support "foot" that has been welded to the apex of the return bend during the fabrication process.
Alloys that are typically used to produce radiant tubes are Duraloy's proprietary alloys 22H®, Super 22H®, or MO-RE-1®, depending on the temperature that the tubes will be exposed to in service.
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Radiant Tube Return Bends With Lugs
These return bends are statically cast, beveled then sent to our fabrication department to have the statically cast lugs or "support foot" welded on. After the lugs are installed, the returns are sent to the fabrication bay to be assembled and welded into radiant tube assemblies.
These returns can be cast in any alloy, but are typically done in Duraloy's proprietary alloy MO-RE-1®, Super 22H®, or HK-40 alloy as required.
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Sinter Plant Deck Plates
These statically cast deck plates are used in a steel mill sinter plant to handle and support iron ore pellets prior to being charged into a blast or BOF furnace. Some of the plates can be produced with cast in "slots" while others are manufactured with a solid top.
These rails can be cast in just about any heat resistant alloy, however, they are most commonly produced in HF alloy.
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Steckel Mill Entry Gate
This gate is used to divert a slab or plate up and into the coiler drum slot of a Steckel Mill during rolling. The gate can be raised and lowered by the mill operator as required during the rolling operation.
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Bearing Housing
These statically cast bearing housings are made in ASTM A351-Grade CF-8M. This picture shows both the upper and lower housings. These housings will be drilled to allow the two halves to be bolted together after having the bearings and shafts installed. The cast in holes in the base will be used to bolt the entire assembly to the housing mount.
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Large Diameter Hemispherical Pipe Caps
These hemispherical pipe caps are cast in Duraloy's proprietary alloy MO-RE-21® and are welded to the ends of pipes that are transferring fluids at high temperature and pressure.
They will have a weld-prep bevel placed on the open end prior to fabrication.
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