kaufmj42
Materials
- Sep 14, 2009
- 4
thread330-12001
Hello all! I'm currently experiencing issues with soft spots on carburized producted due to surface masking (confirmed by metallographic examination, hardness testing, carbon analysis, etc.) - similar to that described in the referenced thread above.
Some background - the product is machined with a water-based coolant, and is run through a pre-heat before carburization, and is not stacked. The process is well monitored at all stages, and records show that temperatures, gas concentrations, etc. were all spot-on when product in question was run. According to the company producing the coolant, our preheat temperature is sufficient to burn off coolant.
I've been able to replicate the phenomenon by intentionally applying machining coolant to the surface of product prior to carburization. While I'm not ruling out other potential causes of these soft spots, I feel pretty confident that this is something that needs further examination. Which brings me to my question: In the time since the ban of solvent-based coolants, what has your experience been with water-based coolants masking carburized product, and what have you found to be successful in mitigating the phenomenon?
For what it's worth, I've been considering the following:
-Increased pre-heat temperatures/time to burn off any reaction product that may form if coolant sits on the surface for a while
-Chemically cleaning/rinsing product prior to carburizing
-Adding in-line machining coolant monitoring systems to better control the coolant itself
Any and all feedback is appreciated. Thanks!
Hello all! I'm currently experiencing issues with soft spots on carburized producted due to surface masking (confirmed by metallographic examination, hardness testing, carbon analysis, etc.) - similar to that described in the referenced thread above.
Some background - the product is machined with a water-based coolant, and is run through a pre-heat before carburization, and is not stacked. The process is well monitored at all stages, and records show that temperatures, gas concentrations, etc. were all spot-on when product in question was run. According to the company producing the coolant, our preheat temperature is sufficient to burn off coolant.
I've been able to replicate the phenomenon by intentionally applying machining coolant to the surface of product prior to carburization. While I'm not ruling out other potential causes of these soft spots, I feel pretty confident that this is something that needs further examination. Which brings me to my question: In the time since the ban of solvent-based coolants, what has your experience been with water-based coolants masking carburized product, and what have you found to be successful in mitigating the phenomenon?
For what it's worth, I've been considering the following:
-Increased pre-heat temperatures/time to burn off any reaction product that may form if coolant sits on the surface for a while
-Chemically cleaning/rinsing product prior to carburizing
-Adding in-line machining coolant monitoring systems to better control the coolant itself
Any and all feedback is appreciated. Thanks!