NADCAP Heat Treating Accreditation

Karl Gillihan

🔥 NADCAP

NADCAP Accredited Heat Treating Suppliers

NADCAP Heat Treating is the accreditation that turns AMS 2750 from a document into a verified shop-floor reality, and it is the credential aerospace primes lean on hardest for thermal processing. Unlike a quality-system certificate, it audits the furnace itself, by temperature range and instrumentation class, against checklists written by people who understand pyrometry failure modes.

NADCAPAS9100ISO 9001

What the AC7102 Audit Actually Examines

NADCAP, administered by the Performance Review Institute (PRI) on behalf of a consortium of primes, accredits special processes against task-group-specific criteria. Heat treating is audited under the AC7102 baseline checklist plus job-audit and slash-sheet checklists (AC7102/1 through /8 and related) covering pyrometry, the specific processes performed, and the actual jobs run on the floor. A NADCAP heat treat audit is performed by a metallurgically qualified auditor, not a generalist, and it is far deeper than a quality-system surveillance. The audit walks live and historical jobs: the auditor selects real travelers, reconstructs the furnace cycle from recorder data, checks the thermocouples and instrumentation classes against AMS 2750, and confirms the achieved results match the spec. Findings (nonconformances) must be addressed with root-cause corrective action before accreditation issues or renews, and the merit-based cycle means strong performers earn longer intervals while weak ones get audited more frequently. This depth is why NADCAP carries the weight it does. A clean NADCAP Heat Treating accreditation is evidence that an outside metallurgical expert reconstructed the shop's actual furnace cycles and found them conforming, not merely that the shop has procedures on a shelf.

Pyrometry: SAT, TUS, and Why Furnace Class Matters

The technical core of NADCAP heat treating is AMS 2750 (Rev F in common use), which governs thermocouples, instrumentation, system accuracy tests, and temperature uniformity surveys. A System Accuracy Test (SAT) compares the controlling thermocouple and instrument against an independent calibrated probe to confirm the furnace reads true. A Temperature Uniformity Survey (TUS) maps the working zone with multiple thermocouples to prove the qualified work zone holds temperature within the required tolerance across its volume. Furnaces are classified by uniformity (Class 1 through 6, tightest first) and instrumentation type (A through E), and the qualified temperature range is established by TUS. This is the part buyers most often miss: a furnace qualified for a 1000 to 1300 F tempering range is not automatically valid for a 1950 F solution treat. SAT and TUS frequencies are defined by AMS 2750 and tighten for more critical classes, and lapsed SAT or TUS coverage immediately invalidates the qualification. When you source NADCAP heat treating, the meaningful question is whether your specific process and temperature land inside a currently surveyed, correctly classed furnace. A shop can be NADCAP-accredited overall and still lack current TUS coverage for the exact range your part needs.

Reading the Scope Before You Commit

NADCAP accreditation is scoped by process and by capability, and the scope is published in PRI's online database (eAuditNet) where buyers and primes can confirm it directly. The scope lists which heat treat processes the shop is accredited for, for example annealing, hardening and tempering, carburizing, solution treat and age, or vacuum heat treating, and the audit history. Confirm your process is named, not merely 'heat treating' in the abstract. Check accreditation status and expiry in eAuditNet, and watch for accreditations in a probation or suspended state, which signal unresolved findings. Because the cycle is merit-based, a shop with a recent string of clean audits will show longer intervals, which is itself a quality signal. A recently shortened interval or a reinstated accreditation warrants a closer conversation. The most common scope mismatch is alloy-driven: a shop accredited and TUS-current for steel hardening in the 1500 to 1600 F range may not be qualified for nickel-alloy solution treating near 1950 F or aluminum aging in the low hundreds. Match the eAuditNet scope and the surveyed furnace ranges to your engineering requirement before you release the PO.

What Accreditation Costs You in Time and Money

NADCAP rigor is not free, and the buyer feels it. Maintaining accreditation requires recurring SAT and TUS on every qualified furnace, calibrated test instrumentation, qualified personnel, and the audit fees and corrective-action labor that come with the cycle. Shops fold this into their rates, so NADCAP heat treating runs at a premium over commercial work for the same furnace cycle, often a substantial one on low-volume aerospace lots. Lead time reflects scheduling around currently surveyed furnaces and the documentation each job carries. A routine accredited temper or stress relief may still turn in about a week, while solution-treat-and-age cycles on PH stainless or nickel alloys, with full record packages, commonly run two to three weeks. First-article and new-process work takes longer because the job may itself become part of an audit sample. The honest framing for a buyer: you are paying for verified pyrometry and an audit trail an expert reconstructed, which is exactly what flight-critical and high-consequence parts require. For commercial parts that do not need it, NADCAP is overspend, and a properly scoped ISO 9001 heat treater is the better value.

Frequently Asked Questions

They verify different things and are complementary, not interchangeable. AS9100 is a company-wide aerospace quality-management certification, audited by an accredited certification body, that confirms the organization runs a controlled, traceable, risk-managed system. NADCAP Heat Treating is a special-process accreditation, administered by PRI and audited against the AC7102 checklists by a metallurgically qualified auditor, that confirms the specific thermal process on specific furnaces conforms to AMS 2750 pyrometry, including current SAT and TUS coverage. A shop can hold AS9100 without NADCAP, which is normal for integrators who outsource furnace work, but the supplier actually running aerospace heat treat cycles is typically required by primes to hold both. Think of AS9100 as proving the system is sound and NADCAP as proving the furnace is honest. When sourcing flight hardware, verify the AS9100 scope includes heat treating and that the NADCAP scope in eAuditNet covers your alloy's temperature range.

They are the two pyrometry checks that make NADCAP heat treating trustworthy, both defined by AMS 2750. A System Accuracy Test (SAT) compares the furnace's controlling thermocouple and instrument against an independent calibrated probe to confirm the furnace actually reads the temperature it displays. A Temperature Uniformity Survey (TUS) places multiple thermocouples throughout the working zone and demonstrates that the entire qualified volume holds temperature within tolerance, establishing the furnace's qualified temperature range and uniformity class. Buyers should care because a lapsed SAT or TUS immediately invalidates the qualification, and because a furnace surveyed for one temperature range is not valid for another. The practical risk is a part that looks fine but was processed in an out-of-tolerance or unsurveyed condition, which can fail in service. When you place NADCAP work, confirm the specific furnace your part will run in has current SAT and TUS coverage spanning your exact process temperature, not just that the shop is accredited in general.

Use PRI's eAuditNet database, which is the authoritative public record. Look up the supplier and confirm the Heat Treating accreditation is active, not in probation or suspended, and check the expiry and audit history. Then read the scope: it should name the specific processes you need, such as hardening and tempering, carburizing, solution treat and age, or vacuum heat treating, rather than a generic 'heat treating' label. The most common trap is alloy and temperature mismatch: a shop accredited and TUS-current for steel hardening near 1550 F may not be qualified for nickel-alloy solution treating near 1950 F or aluminum aging at low temperatures. Confirm the qualified temperature range of the actual furnace covers your process. Because NADCAP uses a merit-based cycle, a shop showing long clean intervals is a positive signal, while a recently shortened interval or a reinstated accreditation is worth a direct conversation about what findings prompted it.

It depends entirely on consequence of failure. For flight-critical aerospace, gas-turbine, and high-consequence energy hardware, NADCAP is typically required by the prime and is worth every dollar, because you are paying for verified pyrometry and an audit trail that a metallurgical expert reconstructed from your actual furnace cycles. The premium over commercial work can be substantial, especially on low-volume lots, and lead times stretch because work is scheduled around currently surveyed furnaces and carries heavy documentation; a routine accredited temper may turn in about a week while nickel or PH stainless solution-treat-and-age cycles with full records run two to three weeks. For commercial structural, agricultural, tooling, or general machinery parts that do not carry flight or life-safety risk, NADCAP is usually overspend, and a properly scoped, accredited ISO 9001 heat treater with measured-value certs delivers the right assurance at a far better price. Match the credential to the risk rather than buying the most impressive logo by default.

Last updated: July 2026

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