Jethete M152 is a nitrogen-bearing, 12% chromium martensitic stainless steel developed by Firth Vickers for jet-engine service and still widely specified today under AMS 5719 and UNS S64152. Unlike simple 410/420-type martensitic stainless, M152 carries meaningful nickel (2-3%) and molybdenum (1.5-2%) alongside vanadium and a controlled nitrogen addition, which together push its creep-rupture strength and temper resistance well above what a plain 12Cr grade can hold at elevated temperature. It is supplied and used in the hardened-and-tempered condition, retaining good toughness and dimensional stability in continuous service up to roughly 1040°F (560°C).

That combination of hot strength, creep resistance, and corrosion resistance is why M152 became a standard material for compressor discs and blades, turbine hardware, shafts, high-temperature bolting, and rings in gas turbine and jet-engine assemblies. In the DIN/EN system it corresponds to X12CrNiMoV12-3, Wnr. 1.4938 — note that the closely related X12CrNiMoV12-2 carries the similar-looking number 1.4939, and the two are sometimes confused in supplier literature.

M152 is normally machined in the hardened-and-tempered condition rather than annealed, which puts it firmly in the same challenging category as other PH/creep-resisting martensitic aerospace stainless grades: high cutting forces, accelerated flank wear from the alloyed carbide- and nitride-forming elements (Mo, V), and low thermal conductivity that concentrates heat right at the cutting edge. It does not work-harden as aggressively as an austenitic grade, but a dull edge or excessive dwell will still glaze the surface and shorten tool life on the next pass.

Rigid tooling and workholding matter more here than on lower-strength stainless — deflection under cutting load is a bigger threat to accuracy than on a soft annealed part. Sharp, positive-rake inserts with adequate feed to stay below any work-hardened layer, combined with steady coolant flow, are the standard approach. Because tempered hardness varies with the temper temperature selected by the heat treater, always confirm actual hardness before committing to aggressive speeds.

Turning

Parting / Grooving

Milling