Fabricated Radiant Heat Tubes vs. Cast

Maintenance managers and maintenance personnel are always striving for better efficiencies and maximum furnace uptime. Achieving efficiencies in production involves evaluating each component of your equipment and understanding how you can improve it.

Radiant heat tubes are a prime candidate for evaluation. Early failure can cause a host of production delay issues that you want to avoid. As you’re preparing for a new furnace or the replacement of your current radiant tubes, it’s smart to consider all your options, which will likely start with a comparison of cast versus fabricated tubes.

Cast Radiant Tubes

Cast radiant tubes are made with a heavier wall which results in less heat transfer during your manufacturing process. Because of their weight, you need to be more aware of the support methods you use within the furnace.

Castings are inherently more brittle than fabricated tubes, so they are prone to breakages. When a break occurs, you’ll experience products of combustion entering your furnace which then contaminates your product.

However, some maintenance managers still prefer cast tubes over fabricated for three reasons:

• Their creep strength
• Strip impact
• Familiarity with cast from OEM

Fabricated Radiant Tubes

When compared to cast radiant tubes, the fabricated versions have several advantages. They are lighter and have thinner walls which results in better heat transfer. They are also more ductile, so they are less likely to fracture. Because they are lighter, fabricated radiant tubes are much easier to install and place less strain on the supports.

Also, fabricated tubes return bends, flanges, bungs, and straight components can be repaired or replaced on site. This can be a great time saver.

What about lifespan?

There’s no clear-cut answer as to which type of tube lasts longer. A lot depends on the furnace and how it’s used. Thermal cycling and proper burner alignment and calibration are two factors that can affect lifespan. We have a full article on why radiant tubes fail prematurely that’s worth your time if you’re continually experiencing failures.

What about cost?

In terms of up-front cost, they are very comparable. Cast tubes might have a slight advantage, but the higher weight coupled with longer lead times makes cast tubes less appropriate in most applications. It’s also helpful to know:

• Your historic replacement costs
• The typical lifespan of your radiant tubes
• The costs associated with furnace downtime

When you take all of these factors into consideration along with design, you might find that investing in fabricated radiant tubes is your best option.

Alloy Engineering fabricates tubes in any configuration and wall thickness and supports all furnace OEM tube designs. To learn more, contact us here or call us at 440.243.6800.