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Quality, verification and references
A hardened case you cannot measure is a claim, not a result. Every batch we run is verified against process coupons, and every technical figure on this site traces back to published literature you can read yourself.
Verification
What we measure, and what you get back.
Coupons of the same alloy and surface condition run with your parts, in the same load, through the same cycle. They are the record of what the batch actually received.
Micro-hardness traverse
Vickers indentation at low load on a mounted cross-section, stepping in from the surface to establish the hardness profile and the effective case depth rather than a single surface number.
Cross-section metallography
Mounted, polished and etched sections confirm a continuous case of even thickness, and confirm the absence of chromium carbide or nitride precipitation at grain boundaries.
Dimensional and finish check
Before-and-after measurement on trial parts, plus surface roughness comparison, so you can confirm tolerance and finish are intact before production release.
Corrosion verification
Where the application justifies it, comparative corrosion testing of treated against untreated material from the same lot, to demonstrate that passivity is retained.
Process records
Time, temperature and atmosphere data retained against the batch, so a result can be traced and a cycle can be reproduced.
Written process specification
Once a route is proven on your part, parameters are fixed to a documented specification, and that specification is what subsequent production runs to.
ISO 9001. Our work is carried out under an ISO 9001 quality management system, covering contract review, process control, calibration, traceability and records for every batch we treat.
References
Where the numbers on this site come from.
Expanded austenite has been studied for four decades and the property ranges we quote are drawn from peer-reviewed review articles and technical literature, not from marketing material. We think you should be able to check them.
| Source | Supports |
|---|---|
| Borgioli, F. — “From Austenitic Stainless Steel to Expanded Austenite—S Phase: Formation, Characteristics and Properties of an Elusive Metastable Phase”, Metals | Surface hardness up to 1450 HV nitrided and up to 1000 HV carburized; nitrogen content near 28.5 at.%; case depths of a few to tens of microns, to about 40 µm carburized; process windows of 300–450 °C for nitrogen-rich and 300–550 °C for carbon-rich S-phase; conventional nitriding at 500–580 °C and carburizing at 850–950 °C; thermal-stability incubation times. |
| Borgioli, F. — “Advances in Low-Temperature Nitriding and Carburizing of Stainless Steels and Metallic Materials”, Metals | Formation and properties of expanded phases; corrosion behaviour of low-temperature treated stainless steels. |
| Dong, H. — “S-phase surface engineering of Fe-Cr, Co-Cr and Ni-Cr alloys”, International Materials Reviews 55(2), 65–98 (2010) | Comprehensive review of S-phase structure, formation conditions, supersaturation, hardening mechanisms and metastability across stainless steels, cobalt-chromium and nickel-chromium alloys. |
| Bell, T. — “Surface engineering of austenitic stainless steel”, Surface Engineering 18(6), 415–422 (2002) | Historical development of low-temperature surface alloying of austenitic stainless steel and its application in the food, chemical, nuclear and medical sectors. |
| ASM International — Low-Temperature Carburization of Austenitic Stainless Steels | Industrial context and property outcomes for low-temperature carburizing of austenitic grades. |
Third-party trademarks and publications are referenced for technical comparison and attribution only, and imply no affiliation with or endorsement by their owners.