Equivalent Grades of 630 / 1.4542 / S17400 / 17-4PH / X5CrNiCuNb16-4
The following table shows the difference between 630, 1.4542, S17400,
17-4PH, and X5CrNiCuNb16-4 in terms of naming system, standard origin, and common usage.
In most cases, these designations refer to the same precipitation hardening stainless steel grade, but they come from
different international standard systems.
Grade Comparison Table
| Grade / Designation | Standard System | Standard Origin | Type / Meaning | Description |
|---|---|---|---|---|
| 630 | AISI / ASTM Common Commercial Naming | Commonly used in ASTM material systems such as ASTM A564, ASTM A693, ASTM A705 | American grade name | Grade 630 is one of the most common U.S. designations for this precipitation hardening stainless steel and is usually associated with 17-4PH. |
| 17-4PH | AISI / Commercial Name | Derived from American naming practice | Commercial alloy name | 17-4PH stands for approximately 17% chromium and 4% nickel, with PH meaning precipitation hardening. It is the most widely recognized market name for this material. |
| S17400 | UNS | Unified Numbering System | Unified material number | S17400 is the UNS number used for international material identification. The letter “S” indicates stainless steel. |
| 1.4542 | EN / DIN | EN 10088 | European material number | 1.4542 is the European numeric steel designation corresponding to the same alloy family as 17-4PH / 630. |
| X5CrNiCuNb16-4 | EN / DIN | EN 10088 | European chemical designation | This is the chemical composition based designation in the European system. It reflects the main alloying elements: chromium, nickel, copper, and niobium. |
Main Difference Between These Designations
| Item | 630 / 17-4PH | S17400 | 1.4542 / X5CrNiCuNb16-4 |
|---|---|---|---|
| Nature | U.S. grade and commercial naming | Unified international numbering system | European grade system |
| Main Use | Sales, market communication, product specification | Material identification across standards | European drawings, specifications, and certificates |
| Material Equivalence | Usually equivalent | Usually equivalent | Usually equivalent |
| Main Difference | Naming under U.S. practice and ASTM product standards | Only a unified alloy number, not a full product delivery standard | Defined under EN standards with European naming format |
Simple Explanation
These names usually refer to the same precipitation hardening stainless steel grade, but they come from different systems:
- 17-4PH = the most common commercial name
- 630 = common U.S. grade designation
- S17400 = UNS number
- 1.4542 = European numeric designation
- X5CrNiCuNb16-4 = European chemical designation
Important Note for Buyers and Engineers
Although these designations are generally equivalent, they should not be considered fully interchangeable without checking the exact product standard,
delivery condition, and heat treatment state.
In actual projects, you should also confirm:
- The exact material standard, such as ASTM A564, ASTM A693, ASTM A705, or EN 10088
- The supply condition, such as solution treated, H900, H1025, or H1150
- The product form, such as bar, forging, plate, wire, or pipe
This is important because mechanical properties and acceptance requirements may differ depending on the relevant standard and condition.
Post time: Mar-24-2026