Laser Cladding and HV Spraying Bring Together New Opportunities for hardening small and Delicate Items of Highload Equipment.
We've just created together with our client a new success story in the field where it was too questionable. Pin mixers are known to be good equipment to provide well-mixed gypsum raw material that further leads to optimized drying time.
These mixers may process through itself up to 40 tons per hour that inevitably leads to wear issues.
Heterogeneous stream of gypsum, water, chemical additives describes the abrasive environment for mixer par ts. Typical degradations are presented further on the Pic 2. Parts Degradation.
Housing and items are produced from Stainless Steels (AISI 304, AISI 316 and others) which show high anti-corrosion properties but lack of strength and wear resistance.
Original suppliers use galvanized chrome for hardening mixing items while housing is left unprotected due to the lifetime of several months.
The losses are summarized from spare parts cost and multiple downtimes costs. Downtime costs are quite expensive.
Initially client had provided us data on common lifetime of descried items (presented in table 1). Also he had to stop the line for one day per week for service and parts substitution, so downtime ration was 1/14 (14 shifts per week).
To provide sustainability and decrease spare parts cost client started to use cheap 1045 hardened parts instead of Stainless Steel galvanized original ones. Cutting expenses on spare parts the downtime losses left at the same level so our task was:
• Increase parts lifetime;
• Decrease downtime losses.
We've started with using HVAF for Housing Ring, Detonation Spraying for Nozzle and Laser Cladding for both Pins.
Detonation Spray and HVAF (HighVelocity Air Fuel) may be called similar processes in terms of coatings properties, spraying material, speed and Temperature characteristics but they differ by the principles of heating and accelerating powder particles. They create a uniform dense layer of hard materials among which the tungsten carbide is most applicable. These coatings are commonly characterized by thickness 70–200 microns, 0,3–1% porosity, high bond strength.