Many manufacturers use passivation processes to improve the chemical resistance of their stainless steel components. For these processes, it’s necessary to have an incredibly sturdy and chemically-resistant container to hold parts through the passivation process.
The issue is, what kind of baskets could possibly hold parts through a process that’s meant to strip the surface of stainless steel? Baskets for passivation would have to be very specialized to survive for multiple uses. Some factors that could impact the cost of a passivation basket include:
The Specific Chemicals Used in Your Passivation Process
Passivation is not a one-size-fits-all kind of process. There are different chemicals that could be used in a passivation process depending on the specific alloys used for the parts. Using the wrong kind of chemical on the wrong metals could actually cause damage to the parts being passivated rather than improving the oxide layer.
For example, a nitric passivation system is generally milder on parts than a hydrofluoric acid (i.e. pickling) passivation process. This would allow slightly less corrosion-resistant steel alloys to be used for the passivation basket. Citric passivation equipment would also require a specific level of corrosion resistance for prolonged use.
The harsher the passivation chemicals used, the more resistant the steel of the baskets will need to be—and some of the most resistant stainless steel alloys, such as 316L SS, cost more than less resistant alloys do.
The Dimensions of the Parts and Load Weight
The bigger and heavier the parts being passivated are, the larger and stronger the basket carrying them through the passivation process will have to be. Additionally, larger parts may need to be passivated for longer periods of time to achieve the desired effect.
To improve the basket’s performance when holding heavy loads for extended periods of time, larger, thicker wires will be needed. This directly translates into increased material costs.
Basket Longevity and Total Cost of Ownership
Passivation processes can be very tough on the baskets used in them. This can lead to a shorter useful life as the baskets are worn away by the chemicals used to strip the top layer of free iron molecules from your parts.
The amount of time that a basket can last in your passivation process can have a significant impact on your total cost of ownership.
For example, say you have a choice of two different baskets:
- Basket “A” is built to barely meet the minimum requirements of the job and has a useful life of 8 months on average. After that 8 months, the basket becomes too degraded to use safely with your passivation equipment.
- Basket “B” is built to far exceed the minimum requirements needed for your passivation process and has a useful life of 4+ years on average. However, basket B costs 2.5 times as much as basket A.
In this theoretical example, 10 units of basket A would cost $2,000, and 10 units of basket B would cost $5,000. In the short run, basket A might seem like the better purchase, but in the long run, basket A would actually end up costing far more than basket B.
Let’s say you use the same passivation process for the next 8 years. In that time, basket A will cost $24,000, because you’d have to buy the baskets 12 times at a cost of $2,000 each time. Over that same period of time, basket B would only have to purchased twice at a cost of $5,000, for a total of $10,000.
This makes the more expensive, but longer-lasting, basket much more affordable in the long run.
If you need a stainless steel basket for passivation keeping in mind the nature of your passivation process and the expected longevity of the baskets for passivation that you order are a must for managing costs.
Learn how Marlin Steel delivers quality, engineered quick for stainless steel passivation baskets and many other specialty applications by contacting a mechanical engineer.