03.25.25
| 5 min read
Case Study
For manufacturers, switching heat treaters isn’t just about finding a new supplier—it’s about trust. A successful transition depends on more than just moving a process from one facility to another. It requires confidence that the specifications will be met exactly as intended, ensuring product performance, compliance, and supply chain continuity.
But what happens when a process that worked for years suddenly doesn’t deliver the right results?
That’s the challenge one power generation fastener manufacturer faced when they brought a critical fastening component to Paulo for heat treatment as part of their reshoring initiative. Despite following the documented heat treatment recipe precisely, the parts failed to meet the required hardness range. The problem wasn’t with the spec itself—it was with the process used to achieve it.
Through advanced testing, metallurgical expertise, and process optimization, Paulo uncovered a critical disconnect: the previous supplier had been using a completely different process than what was documented. By reverse-engineering the actual process, Paulo helped the manufacturer correct their heat treatment recipe, ensuring full compliance, process transparency, and a scalable production process moving forward.
A Long-Term Partner Facing a New Challenge
The manufacturer is a leader in power generation fastening systems, supplying critical components used to secure large-scale power generation installations. Their products must meet precise hardness and mechanical property requirements to function reliably in the field.
Having worked with Paulo for years on other fastener components, they trusted Paulo’s expertise in heat treatment. When quality and delivery issues arose with their previous supplier on this particular component, they decided to move its processing to Paulo—expecting a smooth transition.
What they didn’t anticipate was that the process recipe they had been using was fundamentally incorrect.
The Component: A Precision Fastening System
The part in question consisted of two critical components:
- A mandrel, requiring high hardness for strength.
- A collar, which needed to be softer and more ductile for proper fastening.
Maintaining the correct balance of hardness between these two parts is essential for the fastener’s performance. But as soon as Paulo began processing the parts, it became clear that the existing heat treatment recipe could not produce the expected results.
The Challenge: When the Recipe Doesn’t Match Reality
Why Switching Heat Treaters Can Reveal Hidden Issues
It’s common for manufacturers to assume that their documented processes accurately produce the specified results. However, when transitioning to a new heat treater, discrepancies often emerge—especially if the previous supplier made unofficial adjustments that were never documented.
That’s exactly what happened in this case.
The Manufacturer’s Dilemma
The manufacturer provided a well-defined specification outlining minimum and maximum hardness values. They also supplied a heat treatment recipe—a step-by-step outline of the process required to achieve the spec. When Paulo followed the provided recipe exactly, the parts did not meet the required hardness range. With strict compliance requirements, the manufacturer couldn’t accept deviations—but something wasn’t adding up.
What Paulo Discovered
Paulo’s team conducted comprehensive testing on:
- Parts processed at Paulo using the prescribed recipe.
- Parts heat-treated by the previous supplier.
Metallurgical analysis showed that the previous supplier had not actually been following the documented recipe. Instead of using annealing, they had been using neutral hardening and tempering—a completely different process that was never reflected in the manufacturer’s official documentation. This misalignment meant the recipe for achieving the spec wasn’t actually correct—until now.
The Paulo Solution: Reverse Engineering & Process Optimization
Step 1: Metallurgical Analysis & Testing
Our metallurgical engineers performed a deep-dive analysis to identify the true process previously used.
Microscopic examination of the parts confirmed that the previous supplier’s method was different from what was documented. By comparing microstructures, our team identified the actual heat treatment cycle that had been producing in-spec parts all along.
Step 2: Aligning the Process Recipe with Reality
Once the real process was uncovered, Paulo worked with the manufacturer’s engineering and quality teams to rewrite the heat treatment recipe to match what was actually required.
Instead of annealing, the updated process specified neutral hardening and tempering, which delivered the correct hardness range. The specification remained unchanged—it was the process used to achieve it that was corrected. We provided comprehensive data and documentation to justify the process update.
Step 3: Process Validation & Scaling Up Production
We ran test batches to confirm the revised process consistently met all quality requirements.
Once validated, production was scaled up at our Murfreesboro facility, utilizing a belt furnace for high-efficiency processing.
Step 4: Ensuring Long-Term Compliance & Repeatability
With the new process recipe documented and validated, the manufacturer could now ensure repeatability—no matter who was running production. Our datagineering approach provides a fully traceable dataset, verifying that every batch met the required spec.
A Cautionary Tale for All Manufacturers
This truth is, this wasn’t an isolated incident—it’s something we see all the time when manufacturers switch heat treaters. A process or recipe that appears to be working can often be masking undocumented adjustments, and those inconsistencies only surface once production moves to a new facility.
With decades of metallurgical expertise and unparalleled heat treating data, we’re able to quickly help manufacturers get the results they expect—every time.
If you have concerns about your process or parts, get in touch with one of our heat treating experts today.
