Abrasive Wear
Hard particles such as sand, silica, ash, slag or mineral fillers cut the surface like sandpaper and remove material. The right solution depends on particle hardness, impact load and the final dimensions the part needs.
Symptoms
- Parallel scratches and grooves in the flow direction, polished shiny surface
- Rounded flight, screw and blade edges; shortened tips
- Lower capacity: the screw conveys less, the mixer needs longer
- Increased clearance, leakage or vibration due to dimensional loss
Typical Parts
If the particle is harder than the part surface, every contact removes a micro-chip. Wear rate is driven by particle hardness, size and sharpness, contact pressure and speed. Hardening the base material is often not enough; the surface needs a carbide phase harder than the particle.
Not Every Screw Wears the Same Way
Different wear conditions of conveyor, feed and press screws; HVOF carbide coatings, bimetallic PTA and zonal protection options.
Turkish narration on screen, English subtitles.
Which Process for Which Case?
In abrasion the decision depends on whether impact is present and how many millimetres the part has lost.
| Solution | Material System | Typical Thickness | When Is It the Right Choice? |
|---|---|---|---|
| HVOF thermal spray | WC-CoCr, WC-Co | 100–400 µm | Shafts, rolls, sliding surfaces; when tight tolerances and low heat input are needed and impact is low |
| PTA hardfacing | NiCrBSi + 40–65% WC | 1.5–5 mm | Screw flights, mixers, crushers: thick, metallurgically bonded protection |
| Weld hardfacing | Chromium carbide / complex carbide | 3–10 mm and more | Large surfaces, scrapers and liner plates; economical thick protection |
| Restoration + coating | Weld build-up + HVOF/PTA | Depends on loss | Parts that have lost a lot of material: first rebuild the geometry, then protect |
Values are typical ranges; the final choice is made after the part, base material and operating conditions have been seen.
The hardest coating is not always the right one
If impact is present, a thin and very hard WC coating can crack and spall off in flakes; if the base material is soft, the coating can collapse under load like an eggshell. We first separate abrasion, impact or both, then choose thickness and bond type.
FAQ
Which coating gives the best resistance to abrasive wear?
Without impact, tungsten carbide based coatings (HVOF WC-CoCr or PTA NiCrBSi+WC) give the highest resistance. With impact, tougher hardfacing alloys are preferred. The final choice should not be made without seeing the part.
Can a worn screw be repaired instead of buying a new one?
In most cases, yes. The flight profile is rebuilt by welding, the working zone is hardfaced and machined if required. Cost is usually below a new part and lead time is shorter.
How much longer will the coated part last?
It depends on the environment; under the same conditions we aim for several times the life of an uncoated part. We give a realistic expectation once we know the operating conditions and current part life.
Let’s Talk About Your Part
Take a photo of the damaged area and send it by e-mail or WhatsApp, or call us directly. On the phone we identify the mechanism together and give a suitable process and a rough cost/lead-time indication in the same call.
- Close-up and overall photo of the damaged area
- Diameter / length or a technical drawing
- Operating conditions: temperature, medium, particles, speed