TECHNICAL TOOL
Comparator: stainless, nickel alloy, titanium and copper grades
Two to four grades side by side: composition, PREN, relative cost, standards, applications and contraindications. Every value comes from one source, the same one that feeds the grade pages.
| Property | Inox 316L | Inox 904L |
|---|---|---|
| EN / ASTM designation | 1.4404 / 316L | 1.4539 / 904L |
| Composition (%) | ||
| C | ≤ 0,03 | ≤ 0,02 |
| Si | ≤ 1,00 | — |
| Mn | ≤ 2,00 | ≤ 2,00 |
| P | ≤ 0,04 | — |
| S | ≤ 0,01 | — |
| Cr | 16,50–18,50 | 19,00–21,00 |
| Ni | 10,00–13,00 | 24,00–26,00 |
| Mo | 2,00–2,50 | 4,00–5,00 |
| N | ≤ 0,11 | ≤ 0,15 |
| Cu | — | 1,20–2,00 |
| PREN | 24–26 | 34–36 |
| Cost index (base 100 = 304L) | 130 | 340 |
How to read this comparator
Comparing two grades across different suppliers' documents means comparing composition ranges set by different standards, with mechanical values taken on different product forms. This comparator removes that problem: all data comes from the same reference set, and every value carries its source and its status.
The comparator also shows what it cannot compare. PREN does not exist for titanium or copper-nickels, and the formula is meaningless on those families. It is calculable but misleading on heat-resistant grades and some nickel alloys. C-276 uses a different formula, PREW, whose value is not comparable to a PREN. These cases are flagged, never flattened into one common figure — the "gap" view never highlights a PREN row carrying a reservation.
Limits of this comparison
Frequently asked questions
- Why are some cells empty?
- Because we do not display a value we cannot tie to a source. An empty cell means the data is not documented in our reference set, not that the property does not exist. Ask us and we will look for it.
- Why can't the PREN of a titanium and a stainless be compared?
- Because PREN is a formula built on the chromium, molybdenum and nitrogen of stainless steels. Titanium contains none of these as alloying elements. Assigning it a value would be inventing a number.
- Is the cost index a price?
- No. It is an indicative ratio between grades, base 100 for 304L, useful for framing a trade-off. The real price depends on size, quantity, source, and on supply, demand and the market on the day.