Agricultural Knives:  Thermal Spray Case Study III.

The Background.

Since implementing our Thermal Spray Hard-face process, Kondex has been involved in numerous field test projects with its customers. The purpose of these tests is two-fold:

•Set benchmarks for comparing Kondex technology to existing material/coating technology

•Evaluate new material/coating technologies as a means of improving wear resistance and or improving the cost of agricultural knives.


Based on data collected from these tests, Kondex can prove its thermal spray technology is as good as any existing supplier - and in most cases better.

This case study was conducted to evaluate newer material/tungsten carbide thermal spray combinations not typically used in agricultural cutting blades. A major manufacturer of combine harvester attachments contacted Kondex with a request to produce a longer lasting agricultural chopping blade. These blades are mounted on the interior of a housing that makes them difficult to replace—especially out in the field.

The Comparison.

The existing blade is made with an austempered boron steel base material with a chrome carbide hard-face coating on the cutting edge. This material and coating are generally a cost effective combination due to low material costs, making it a tough challenge for that factor. Knowing that performance was just as critical, the Kondex team pursued a higher performance option instead of just competing on cost.

After deliberation and discussion, the team made the following recommendations for the test:

1.  Increase the wear resistance of the base steel blade by specifying a medium alloy, chrome-moly steel. Although more costly than boron steel, the austempered medium alloy steel has increased wear resistance because of the high chrome content.

2.  Maximize the effectiveness of the thermal spray hard-facing by specifying tungsten carbide at 30 percent. Tungsten carbide coatings have discrete, hard tungsten carbide particles in the coating that resist wear in highly abrasive applications. Chrome carbide, though very hard, does not contain discrete particles.
 

3.  For further experimentation we would also test tungsten carbide at 50 percent.

Samples of each blade type were produced for two separate field-tests versus the current Brand A blade.

Kondex 30 percent Tungsten Carbide vs. Brand A

Kondex 50 percent Tungsten Carbide vs. Brand A

All blades were marked and weighed and shipped to the customer for field evaluation

Results.

Kondex 30 percent Tungsten Carbide vs. Brand A – 30 percent Improvement.
Kondex 50 percent Tungsten Carbide vs. Brand A – 40 percent Improvement.

Conclusion.

These results validated the Kondex Engineering Team’s efforts to provide a better performing part while maintaining a high level of value for our customer. Once again, Kondex’s unique industry experience and expertise in metallurgy and hard coatings provided a significant market advantage to our customer.