Why the Frame Rings of FX800 and Larger Butt Fusion Machines Are Finished in Black
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- publisher
- RUBR
- Issue Time
- Dec 31,2025
Summary
FX800 and larger butt fusion machines use black-finished frame rings instead of standard blue due to material and manufacturing considerations. After high-temperature forging, the frame rings exhibit surface imperfections that would be more visible under a blue coating. A black finish helps achieve a more uniform and visually stable appearance suitable for large-scale welding equipment.

Within the FX series of butt fusion machines, models from FX800 upward feature black-finished upper and lower frame rings, rather than the standard blue used on smaller sizes. This change is not a matter of visual styling, but a decision driven by material properties and manufacturing processes.
For FX800 and larger models, the frame rings are manufactured using a material formulation that incorporates additional components. Following high-temperature forging, the resulting surface naturally exhibits certain imperfections. This surface condition is an inherent outcome of the material selection and forging process.
If a blue coating were applied, these surface imperfections would become more apparent, affecting the overall visual consistency and perceived quality of the machine. To mitigate this effect and maintain a more uniform appearance, a black finish is applied to the frame rings.
As such, the use of a black finish on FX800 and larger models is not intended to alter the product’s visual identity. Instead, it is a practical solution that aligns the surface treatment with the actual forged condition of the material, ensuring a more stable and balanced appearance suited to large-scale welding equipment.