I do not thing that the issue is martensite here. The issue is the delta phase which is formed when metal is still hot and therefore the problem of those dissimilar welds is the hot cracking
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"mohit sharma" <mohit104@rediffmail.com>
Sent by: materials-welding@googlegroups.com 08/09/2010 13:17
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for joining the dissimilar metals end microscopic structure is not only the issue but number of factors which play the role,some important are metallurgical stability of dissimilar metal composition and thermal expansion etc.
On Fri, 09 Jul 2010 13:04:46 +0530 wrote
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Welding of stainless steel with carbon steel electrodes results in formation of martensite structure which is prone to cracking under stress or it may crack immediately during welding depending upon the welding conditions, thickness of the part being welded, deposition of consumable etc. But in actual practice, cracks do not come up always. Many a times, welders weld the stainless steel piping with carbon steel in order to avoid the need of purging and they successfully make the weld without any defects that can be picked up in radiography. They weld the root pass with carbon steel consumables and the rest of the welding is made in SS consumable.
However, welding of stainless steel with low alloy steel electrodes would definitely come up with cracking as it is more susceptible to cracking than carbon steel consumables. Same martensite structure formation would occur and LAS consumable being used without any preheating protocol would crack itself during welding mainly due to uncontrolled cooling.
Both of the situations can be seen visually during inspection and one can say that carbon steel or LAS consumable has been used but if gone un-inspected then one may not get it picked with radiography especially in the case of carbon steel consumable, however, LAS consumable has pretty higher chances of getting cracked and picked up.
On Thu, Jul 8, 2010 at 10:09 PM, Ankur Mande wrote:
Hello friends,
I have just joined this wonderful & group with "active members". I
have one query. Please let me know as to why we observe cracking when
carbon / low alloy steel is accidently welded on stainless steel. If
any body has any backup or paper related to this, request you to post
it.
Regards,
Ankur Mande.
09925027848
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Thanks & regards,
MOHIT SHARMA
ENGINEER (PRODUCTION)
ISGEC │ YAMUNANAGAR│HARYANA
+91 9034868324
Email: mohit104@gmail.com
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