At Green Packaging Inc., we’ve been been providing our anti-corrosion supplies for sale to foundries across the country for over a decade. We’re doing more than simply selling the products, however: We’re sharing our knowledge of rust-prevention with the masses. Needless to say, we don’t like oxidation on our metal pieces, and we’re doing everything we can to eliminate it from foundries and shipping processes across the country.
This month, we’re covering the 8th step in our twelve essential processes, working with the right PH.
PH controls a lot of things, from the taste of the food you eat to what kinds of trees can grow in soil. 1-6.9 on the PH scale is considered acidic, with 0 being the most acidic. 7.1-14 on the PH scale is considered alkaline, or basic with 14 being the most alkaline, . A 7.0 on the PH scale is considered neutral.
The PH of a metalworking fluid is one of the most important indicators of its effectiveness. Different fluids operate at different PHs, however, most are slightly alkaline, typically between 8.5 and 10.5 on the scale. There are a good number of metalworking fluids that work at peak performance between 7.0 and 8.0 and a handful that even operate at acidic; these are the exception, however, not the rule.
So why is PH so important?
Ferrous metals are protected against corrosion in higher PH fluids, whereas white and yellow metals tend to be amphoteric, meaning they are least likely to corrode at a PH of 7.0 but corrode as fluids get more acidic or alkaline.
Another consideration in metalworking fluids is the tools used. PH levels can affect machines and tools at certain extremes, resulting in costly replacements.
When raising a PH level of metalworking fluids, most foundries choose to use sodium hydroxide, often aiming for a 9.0 PH. 9.0 is typically considered the most functional as it protects ferrous metals against corrosion without irritating the skin or sinuses, as it does once it reaches 9.5. Triethanaolamine also raises the PH of working fluid, but provides it with more “staying power” because of the reserve alkalinity.
Metalworking fluids need to be consistently evaluated to ensure that they are properly protecting metals and maintaining their PH over time.