- Grade / Alloy
- 1.4594
- EN / W.Nr.
- 1.4594X5CrNiMoCuNb14-5
- AISI / SAE
- —
- UNS
- —
- Family
- Precipitation hardening
Chemical composition
Chemical composition
Composition limitsComposition limits within the EN 10088-3 long-product scope.
| Element | Content (% by mass) |
|---|---|
| CCarbon | ≤ 0.07 |
| SiSilicon | ≤ 0.7 |
| MnManganese | ≤ 1 |
| PPhosphorus | ≤ 0.04 |
| SSulfur | ≤ 0.015 |
| CrChromium | 13–15 |
| MoMolybdenum | 1.2–2 |
| NiNickel | 5–6 |
| CuCopper | 1.2–2 |
| NbNiobium | 0.15–0.6 |
Values describe the grade, not the analysis of a specific batch. The applicable product specification and material certificate determine acceptance. A dash does not mean zero.
What is 1.4594 PH stainless steel?
1.4594 is a precipitation-hardening stainless steel containing chromium, nickel, molybdenum, copper and niobium. The PH family serves components that need high mechanical strength alongside stainless properties. An important characteristic of 1.4594 is its combination of load-bearing strength and toughness. Toughness describes the ability to resist fracture under impact or sudden loading.
1.4594 — heat-treatment conditions
For 1.4594, +AT identifies the solution-annealed state and +P designations identify strength classes after precipitation hardening. The number is not a temperature. The following cycles summarise the informative guidance in EN 10088-3:2005; acceptance of a current product follows its own specification.
Temperatures are nominal. Holding time starts after the material reaches the specified temperature. The table explains the conditions; furnace tolerances, section size and acceptance requirements follow the applicable product specification.
| Condition | Temperature (°C) | Time at temperature | Cooling |
|---|---|---|---|
| +AT | 1030–1050 | Per product specification | Oil or air |
| +P930 | 620 | 4 h | Air |
| +P1000 | 580 | 4 h | Air |
| +P1070 | 550 | 4 h | Air |
Where is it used?
Applications include structural aerospace components, heavily loaded shafts and fasteners. It also has a role in energy and industrial equipment where mechanical strength and corrosion resistance are needed together. A shaft, for example, may need more than the ability to carry a steady load: its surface must withstand the surrounding environment while the component experiences changing forces. Such combinations of requirements help explain the applications associated with 1.4594.
How it differs from other PH steels
Like 17-4 PH and 15-5 PH, 1.4594 belongs among high-strength stainless steels. A shared family does not make these materials the same grade. Their alloy balances and material definitions differ, so the PH designation alone does not establish interchangeability. The chemical designation of 1.4594 is X5CrNiMoCuNb14-5. It can share useful characteristics with other steels developed for similar applications while remaining a distinct material.
Bar and cut material forms
Round bar is a familiar starting form for shafts and other cylindrical components. Pieces cut from forged material are associated with components in other sections and sizes. In products made from 1.4594, geometry complements the mechanical properties of the steel. Bar and cut-to-size material therefore serve different component shapes within the same grade. Stainless behaviour does not mean unlimited resistance to every chemical or to seawater: the value of this material lies in its balance of mechanical properties and corrosion resistance.
Typical application areas
Aerospace components, shafts and fasteners.
Product and cutting options
Relevant product forms for this material are listed below. Availability varies with grade and dimensions.