Pump sleeves have proven to be an effective application of the boriding technology by dramatically increasing the wear resistance of the sleeve exterior. Typically, pumps see very high wear on pump sleeves and this necessitates using expensive processes such as hard chrome, thermal spray etc to combat the wear action.
The preparation required for these processes are expensive, and after coating, the sleeve has to be ground again – which again adds cost.
Coatings can also suffer from adhesion failure where delamination or chipping can occur. Sub-layer corrosion from porosity or cracks in the coating can also cause delamination leading to a sharp and deep scar that quickly slices the packing seal and requires immediate replacement. .
In contrast, Borided pump sleeves can be made from conventional hollow bar material such as ST52, machined to the final size and given a basic and inexpensive preparation process before treatment. Very light finishing off is only required after the Boriding treatment. Boriding converts the surface to ceramic iron boride which diffuses more than 0.2 – 0.4 mm into the surface of the sleeve with a hardness of over 75 HRc. Due to the saw-tooth like diffusion pattern, chipping and delamination is basically eliminated. Boriding is a simple, high performance, cost effective process.
We have also embarked on an extensive research programme to optimise the Boriding process and we are now able to deep-case boride the sleeves for extended life.
An overall better economy is achieved with Boriding with regards to wear performance and reduced cost.
The advantages of Boriding for pump sleeves are the following:
- no complicated preparation or finishing off of parts
- smooth, even wear with no delamination or release of hard particles
- boriding is a smooth, pore free coating and hence no corrosion initiation points.
- no under-coating corrosion at the coating/steel interface
- boriding is highly resistant to thermal shock
- Stainless steels, nickel based alloys and cobalt based alloys can also be treated with little or no corrosion resistance but with dramatic improvement in wear resistance.
For more information concerning your particular application, please contact us.