Latermec- Wearproof and hard chroming systems€ Very good wear resistance. ‐ Price. ‐ High coefficient of friction. ‐ presence of cracks when it starts to wear. ... Microsoft

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LATERMEC SRL Via L. Da Vinci, 6 ‐ 43056 Torrile (PR), Italy.

TEL. +39 0521.810108 ‐ FAX +39 0521.810170 C.C.I.A.A. PR n. 259019 ‐ P. IVA IT 02687680344 Mail: [email protected]; [email protected]

web: www.latermec.com

Latermec: Wearproof and hard chroming systems

Latermec has more than twenty‐five years of experience in the field of wearproof for the bricks, tiles and ceramics industry. Based on characteristics of the clay, on wear and model of the Extruder we can offer different anti‐wear solutions.

Solution “A” Welding wearproof

Traditional wearproof is done welding tungsten and chromium carbides on the metal surface.

Tungsten carbides

Chromium carbides

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Solution “A” – Wearproof with tungsten and chromium carbides

Advantages Disadvantages

‐ Possibility to use different types of tungsten carbide and chromium carbide. ‐ Very good wear resistance. ‐ Price.

‐ High coefficient of friction. ‐ presence of cracks when it starts to wear. ‐ The clay paste inside the cracks increasing the resistance to extrusion and decline the performance of the machine. ‐ High energy consumption. ‐ Risk of hub deformation during welding process (at high temperature the metal deforms and expands).

Example of wearing auger welded with tungsten and chromium carbides:

The wearproof of chromium and tungsten carbides has a high coefficient of friction. When wear starts, the welded surface with carbides tends to have cracks. During the extrusion process, the clay tends to stick inside these small cracks. As wear increases, this phenomenon is becoming more evident. These cracks increasing and becoming more pronounced, causing more energy consumption of the extruder. Although the extruder continues to produce, the effort is higher and higher. This phenomenon is accentuated when the regeneration was made several times repairing without changing the spiral of the auger.

Cracks

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Solution “B” Hard Chroming

It is a galvanic chrome plating that depose a layer of hard chroming on surface. The chrome protects the equipment against wear, maintains a smooth and slippery surface that allows a better slide of the clay and a more efficient push of the extruder.

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Solution “B” – Hard Chroming


‐ Low friction. ‐ Good wear resistance. ‐ Surface smooth and slippery. ‐ Better pushing of the extruder. ‐ Less energy consumption.

‐ Faster wear for clays with a high percentage of coarse sand. ‐ Faster wear exterior of the external part of the auger. ‐ Less fluidity for very fat clay.

Example of wearing augers with hard chroming:

Hard chroming system has much lower coefficient of friction compared to welded tungsten or chromium carbides. It allows to have a smoother surface, clay slides easier and the extruder uses less energy.

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Solution “C” Welded wearproof + Chroming (“A” + “B”)

The solution "C" is a combination (total or partial) of the "A" solution (welded wearproof) and solution "B" (chroming). Combining the benefits and features of both types of treatment against wear it's possible to increase the lifetime of the spares.

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Solution “C” Welded wearproof + Chroming


‐ Coefficient of friction lower than for welded augers. ‐ Excellent wear resistance (better than welded or chromed). ‐ Smooth surface and better slippery compared to welded augers. ‐ Better pushing for the extruder compared to welded augers. ‐ Less maintenance.

‐ Coefficient of friction higher than chromed augers. ‐ Less smooth and slippery surface that for chromed augers.

Example of wearing augers with welded wearproof + hard chroming:

Welded wearproof

Welded wearproof + hard chroming

The technology that allows chrome plating after welded wearproof offers advantages in terms of lifetime. After the chromium layer (first level of protection) is worn, it remains the welded wearproof (the second level of protection). That allows to have a longer lifetime, less maintenance while productivity increases.

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Analyzing the pictures we can see that the augers in the central part is still chromed and smooth, the external part (where the effect of centrifugal force is higher), the auger is much worn. Additionaly we can observe cracks. This means that the augers are not pushing uniformly any more and the friction is increased. So when the augers were protected by the chrome, the surface was smooth. When chrome is consumed (the first level of protection), there are still the welded wearproof (the second level of protection). This extends the lifetime. However compared to chrome plating, the welded wearproof, when is subject to wear, tends to have cracks.

The analysis of an example The customer was using augers with welded wearproof an all surface (tungsten carbides and

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chromium carbides). With these augers the producing capacity of the extruder was up to 3‐4 months. Latermec was called to improve the life and the pushing of the extruder.

Latermec decided to replace completely the spiral by saving only the hubs of the auger and use an other wearproof system.

Tungsten carbides

Chromium carbides

Analyzing the augers we note the following issue: Although the diameter of the auger was worn but still acceptable, was not possible to continue the production because of friction and too much effort for the extruder. This was due to the wear of welded wearproof and the presence of many cracks on the surface of the augers. Repair welded wearproof with another welded wearproof would not improve because if put carbides (hard material) on an already hard surface, it will accentuate the cracks when starts again the wear.

Cracks

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After 4‐5 months of production the augers have mostly maintained a smooth, gliding surface. The friction due to cracks significantly decreased and the performance of the extruder improved.

We made new spirals and used a combination of chroming and welded wearproof.

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Conclusions For many clays the combination of chroming and welded wearproof shown many advantages: ‐ Longer lifetime. ‐ A smoother surface, clay slips more easily. ‐ Less friction and less mechanical stress to the extruder (also for the engine and gearbox). ‐ Reduced maintenance while productivity increases. ‐ Lower energy consumption.

Latermec- Wearproof and hard chroming systems€ Very good wear resistance. ‐ Price. ‐ High coefficient of friction. ‐ presence of cracks when it starts to wear. ... Microsoft

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