To create value for customers, to be proud
of customers' continuous satisfaction
- Nickel Based Alloy
- Experiment Ways
- Fasteners Industry
- Auto Parts Industry
- Bearing Industry
- Boiler Industry
- Oil and Gas
- Drill Tool Industry
- High Speed Steel
- Tool Steel
- Cutting Tool Industry
- Springs Industry
- Alloy Steel
- Stainless Steel
- Carbon Steel
- Another Downstream Industry Technology
- Company Policy
- Surface Treatment
- Metal Cutting
- Heat Treatment
- Metal Forming
- Steelmaking
What Is Pitting Resistance Equivalency Number (PREn)?
What Is Pitting Resistance Equivalency Number (PREn)?
The Pitting Resistance Equivalency Number (PREn) is an objective way to do an initial comparison of the relative resistance to corrosion of various metals. It is based on a calculation that considers the weight percentage of alloying elements.
PREn = % Cr + (3.3 x % Mo) + (30 x % N)
A simple examination of the components of the PREn calculation indicates those alloys that contribute to corrosion resistance. Chromium, Molybdenum and Nitrogen are all included because their presence in the alloy grade, in combination, contributes to corrosion resistance. Sometimes Tungsten is also included in the calculation because of its contribution to pitting resistance.
As there are ranges of alloy percentages that define the alloy grade (MetalTek 304, for example contains 18-21% chromium), the PREn calculation also is a range. PREn ranges of >40 typically describe the Super Duplex or Super Austenitic families, describing a higher concentration of the key elements and, in the right conditions, more corrosion resistance.
A few common alloys and their PREn values:
Grade | Typical PREn |
304 | 17 – 21 |
316 | 23 – 29 |
2205 | 31 – 38 |
254 SMO | 42 – 48 |
- Name:
- Florence Tang
- Tel:
86-731-89903933
- Email:
- info@fushunsteeltube.com
- Address:
- ADD: No. 812-813, Floor 8, Building C2, Yongsheng Commercial Plaza, 222 Labor East Road, Yuhua District, Changsha City, Hunan, China.
sign up for the latest catalogue, new design and promotion