One of the great benefits of a community of heat treaters is 
the opportunity to challenge old habits and look at new ways of doing things. Heat Treat Today’s 101 Heat Treat Tips is another opportunity to learn the tips, tricks, and hacks shared by some of the industry’s foremost experts.
For Heat Treat Today’s latest round of 101 Heat Treat Tips, click here for the digital edition of the 2019 Heat Treat Today fall issue (also featuring the popular 40 Under 40).
Today’s tips come to us from Quaker Houghton and Contour Hardening, covering Aqueous Quenching. This includes advice about effective filtration in removing particulates in aqueous quench systems and tips for aqueous quenchant selection.
If you have a heat treat-related tip that would benefit your industry colleagues, you can submit your tip(s) to [email protected] or [email protected].
Heat Treat Tip #5
Remove Particulates
Adding a strong magnetic filter in line after the main filtration system is an effective way to remove fine, metallic particulates in an aqueous quench system.
Submitted by: Contour Hardening
Heat Treat Tip #9
Aqueous Quenchant Selection Tips
1. Determine your quench: Induction or Immersion? Different aqueous quenchants will provide either faster or slower cooling depending upon induction or immersion quenching applications. It is important to select the proper quenchant to meet required metallurgical properties for the application.
2. Part material: Chemistry and hardenability are important for the critical cooling rate for the application.
3. Part material: Minimum and maximum section thickness is required to select the proper aqueous quenchant and concentration.
4. Select the correct aqueous quenchant for the application as there are different chemistries. Choosing the correct aqueous quenchant will provide the required metallurgical properties.
5. Review selected aqueous quenchant for physical characteristics and cooling curve data at respective concentrations.
6. Filtration is important for aqueous quenchants to keep the solution as clean as possible.
7. Check concentration of aqueous quenchant via kinematic viscosity, refractometer, or Greenlight Unit. Concentration should be monitored on a regular basis to ensure the quenchant’s heat extraction capabilities.
8. Check for contamination (hydraulic oil, etc) which can have an adverse effect on the products cooling curves and possibly affect metallurgical properties.
9. Check pH to ensure proper corrosion protection on parts and equipment.
10. Check microbiologicals which can foul the aqueous quenchant causing unpleasant odors in the quench tank and working environment. If necessary utilize a biostable aqueous quenchant.
11. Implement a proactive maintenance program from your supplier.
Submitted by: Quaker Houghton
