Hi
Have a look at this site. It will guide you. <a href="http://www.corrprev.org.au/Galvanic.htm">http://www.corrprev.org.au/Galvanic.htm</a>
We use Titanium for our heat exchanger tubes, but all our pumps are 316 SS.
Stainless steels are susceptible to crevice or pitting attack in chloride bearing waters. Very tight crevices increase the likelihood of attack. Rough surfaces, sheared edges, scratches and similar imperfections also tend to increase the incidence of attack. Crevice or pitting attack also occurs under deposits and under biofouling growths attached to the metal surface.
The velocity of sea water flow has an effect on 316 Corrosion. Static sea water causes pitting corrosion. When the sea water flows, there is some protection by passivation due to oxygen transfer. At high velocities, shear stress comes into play and impingement driven corrosion takes place. (No velocity figures were obtainable from the literature but one of our pipes failed where the velocity was 3.8 m/s.)
Guidelines for relative resistance of stainless steels to crevice attack in
natural waters
Alloy Chloride concentration below which crevice corrosion is rare
400 series: crevice attack occurs in fresh waters
304SS: 100-200 ppm
316SS: 1000 ppm
The 4 1/2% Mo and duplex stainless steels are more resistant than type 316, but suffer varying degrees of crevice attack in brackish water and seawater. Also have a look at this site. <a href="http://www.hghouston.com/ss_sea.html">http://www.hghouston.com/ss_sea.html</a>
Ahmed Vawda
Process Engineer
Al Khaleej Sugar _ Dubai
-----Original Message-----
From: saud [mailto:saud@bushnak.com]
Sent: Wednesday, October 31, 2001 2:57 PM
To: <a href="/group/PipingDesign/post?postID=JTQ-XBiJBW91-l3Z41OBTbDXWXwVHCC1Bejg7JMKHSfOleKVy3AI0-cbUHepbEx4FdwAP_hXimNInC8kelRGJdIpaIg">PipingDesign@yahoogroups.com</a>
Subject: [PipingDesign] Sea water application material
Can any one suggest a good corrosion resistance material (metalic) for Seawater application.
Disclaimer :
Our server is equipped with a Virus protection system and scans most
recent viruses automatically prior to receiving / sending messages. We have
taken maximum possible care by installing state-of-the-art protection
programs to safeguard against viruses. However, since there can be no
absolute protection, we are not responsible for any damage, loss of data
and/or hardware damage caused by viruses to the recipients of mails sent or
received through our server.
Bushnak Water Group
www.bushnak.com
Your use of Yahoo! Groups is subject to <a href="http://docs.yahoo.com/info/terms/">http://docs.yahoo.com/info/terms/</a> Received on Wed Oct 31 23:39:00 2001
This archive was generated by hypermail 2.1.8 : Tue Mar 04 2008 - 11:40:17 EST