This page covers the nickel-chromium case-hardening steel identified as Wnr. 1.5752 / DIN 14NiCr14, cross-referenced to SAE/AISI 3310 and 3415. It's a distinct alloy from the material also sold under the "3415" name on our other Steel 3415 page — if you're not sure which one matches your mill certificate, check the Wnr. and DIN designations above against your paperwork before ordering tooling. This grade carries roughly 3.25% nickel against a comparatively modest 0.75% chromium, a notably higher nickel content than close relatives like 3115 (which runs closer to 1.5% Cr and 1.5% Ni). That extra nickel is what defines the grade: it pushes core toughness and impact resistance well above what a leaner Cr-Ni case-hardening steel can deliver, at some cost to hardenability depth compared with higher-chromium grades.

Like other case-hardening grades, 14NiCr14 is low in carbon (around 0.17%) and is carburized, quenched, and lightly tempered after the bulk of the machining is finished. The alloy's strength lies in components that see both large cross-sections and heavy shock loading — gears, gear shafts, connecting rods, and crankshafts in aircraft and heavy equipment applications, where a tough, crack-resistant core matters as much as a hard wearing surface. It's a step up from lighter case-hardening grades when the part needs to survive impact loading, not just cyclic wear.

14NiCr14's high nickel content sets it apart from run-of-the-mill case-hardening steels at the machine tool. Nickel toughens the matrix and resists the kind of clean shearing that low-carbon steels normally give up easily, so chips tend to be tougher and more continuous than on a leaner grade like 3115, and cutting forces run a bit higher for a given depth of cut despite the low carbon content. Built-up edge is still a real risk at low speed, as it is on most soft case-hardening steels, but the nickel content also means the material work-hardens somewhat more readily under a dull or light-contact edge.

In the annealed or normalized state this steel is supplied and machined in, hardness stays moderate, so tool wear itself isn't the primary concern — chip control and surface finish are. A sharp, positive geometry with good chip-breaking action keeps the tougher chips from stringing and tangling in the working area, and helps maintain consistent finish across a run.

As with other case-hardening grades, the carburizing and hardening cycle happens after rough and most finish machining is complete, so shops encounter 14NiCr14 almost exclusively at annealed hardness. A coated carbide grade suited to low-carbon nickel-alloy steel, run at a steady moderate speed with consistent feed engagement, gets the best combination of tool life and part finish.