As is the case with machining most high temperature alloys, machining nickel 718 (also known by its tradename Inconel® 718) is tough business. Nickel 718 is a nickel-chromium superalloy widely used in aerospace for its high strength and heat resistance. Studies on tool wear in Inconel® 718 machining have shown that this alloy is notorious for destroying tooling, slowing cycle times, and driving up costs.
Too often, engineers focus solely on tooling geometry, carbide grade, or cutting parameters—while overlooking the often-forgotten variable: the machining fluid.
A recent independent study by Kratos SRE compared Halocarbon MWF32 to a leading competitor’s fluid in a full range of machining operations on Nickel 718. The study was designed to assess the effects of the cutting fluid on the productivity of machining nickel alloys. The findings were clear: tool life improved, cycle times dropped, and part quality increased.
Milling: Tool Life and Downtime Reduction
In slotting, face milling, and boring operations, the difference in end-mill life was dramatic:
- Halocarbon MWF32: A single ⅜” carbide end-mill machined two complete test articles without requiring replacement.
- Competitive Control Fluid (CCF): Required two end-mills to complete the same work.
- Downtime Impact: Each end-mill change added ~10 minutes of lost machine time.
Study photos showed that MWF32 end-mills retained sharp edges with minor wear, while CCF’s end-mills chipped at the corners and suffered significant edge fractures.
Halocarbon MWF: 3/8” Carbide end-mill after machining test articles using Halocarbon MWF 32.
Competitive Fluid: Two separate 3/8” Carbide end-mills after machining test articles using Competitive Control Fluid (CCF), showing significant and catastrophic tool wear.
Outside Diameter Threading: Reliable Machining and Insert Survival
Threading is a known failure point for Inconel® cutting fluids and tool life. In the study’s outside diameter (O.D.) threading operation:
- Halocarbon MWF32: Inserts completed both test articles and still had useful life left.
- Competitive Control Fluid (CCF): One threading insert fractured mid-cut, leaving a gouge in the workpiece.
The result? Fewer scrapped parts, lower tooling costs, and more reliable threading cycles.
Competitive Fluid: Carbide threading insert failure left significant gouging in the workpiece when using Competitive Control Fluid (CCF).
Tapping: The Critical Test
Tapping (creating a threaded hole) proved to be the most extreme differentiator between Halocarbon MWF and the Competitive Fluid. Using a ¼”-20 UNC tap:
- Halocarbon MWF32: Completed 17 threaded holes before breaking on the 18th.
- Competitive Control Fluid (CCF): Could not complete even one hole.
| Machining Fluid | Successful Holes Tapped | Result |
| Halocarbon MWF 32 | 17 out of 24 | Completed 17 holes before breakage on 18th hole |
| Competitive Control Fluid | 0 out of 24 | Tap broke immediately |
Every failed tap means wasted parts and machine downtime. By enabling reliable tapping in nickel 718, Halocarbon MWF32 turned a high-risk step into a predictable operation. In addition, the successful use of a tap equates to elimination of machining steps. For nickel 718, machinists typically rely on single-point end-mills to perform internal threading, requiring additional CNC machining programming, additional steps, and slower overall process.
Halocarbon MWF: 17 holes out of 24 successfully tapped using Halocarbon MWF 32
Competitive Fluid: Could not tap even one hole when using Competitive Control Fluid (CCF), resulting in 0 out of 24 holes tapped.
Drilling: Tool-Wear Patterns That Tell the Story
In drilling operations, both fluids completed the required holes, but the condition of the tooling told a different story:
- Halocarbon MWF32: Drill inserts showed moderate wear and could continue cutting additional parts.
- Competitive Control Fluid (CCF): Drill edges displayed heavy wear and chipping, requiring replacement after two test articles. In addition, the interior surfaces of the drilled holes were out-of-round and had poor interior surface finish.
This is where engineers know the truth—surface wear patterns are the most honest evidence of cutting fluid performance.
Halocarbon MWF: Machining insert using Halocarbon MWF 32 shows low wear after completing 24 holes. This tool can continue to machine additional parts.
Competitive Fluid: Machining insert using Competitive Control Fluid (CCF) shows significant wear after completing 24 holes. This tool requires replacement before machining additional parts.
Grooving and Cut-Off: Extending Insert Life
In grooving and parting operations, the story repeated itself:
- Halocarbon MWF32: inserts showed significantly less edge wear, meaning they could keep running.
- Competitive Control Fluid (CCF): inserts chipped away at the cutting edge, limiting useful life.
Halocarbon MWF: Machining insert using Halocarbon MWF 32 shows low edge wear. This tool can continue to machine additional parts.
Competitive Fluid: Machining insert using Competitive Control Fluid (CCF) shows significant edge wear and majority of tool coating has been removed. This tool has limited useful life.
Cycle Time and Efficiency
Beyond tool life, cycle time per part told the productivity story:
- Halocarbon MWF32: ~59 minutes per part
- Competitive Control Fluid (CCF): ~70 minutes per part
That’s a ~15% time savings without altering feeds, speeds, or depth of cut—just from the fluid!
Halocarbon MWF: Finished machined test articles that utilized Halocarbon MWF 32.
Competitive Fluid: Finished machined test articles that utilized Competitive Control Fluid (CCF).
Why It Matters
For engineers working with nickel 718 (Inconel® 718) in aerospace, defense, and energy, these differences add up:
✔ Longer tool life means lower consumable costs
✔ Fewer replacements mean less downtime
✔ Smoother threading and tapping means fewer scrapped parts
✔ Faster cycle times mean higher throughput
All from what many shops consider the “forgotten variable” – the Right Metalworking Fluid!
See the Results for Yourself
The study results are clear: Halocarbon MWFs deliver more than cooling and lubrication—they delivers measurable gains in tool life, quality, and cost savings when machining Inconel 718 (Nickel 718) and other difficult to machine alloys.