GGG 60 Cast Iron Welding

[siavash1111]

Hi

anyone in this forum can advice me min preheat and post weld heat treatment temperature which is required for welding of GGG 60 nodular cast Iron(DIN 1693). the welding electrode which i want to use for this cast iron is AWS SFA‐5.15 E NiFe-Cl

the damage part is piston of a air hammer with 31 cm diameter. a segment of this piston around 11*5*5 cm should be repaired .can anyone advice a guide line

Thank You in advance

 

[metengr]

Use this document as a guide. Look under welding;

http://www.nickelinstitute.org/~/Me...Ni_ResistandDuctileNi_ResistAlloys_11018_.pdf

 

[Tmoose]

What do you know about why and how the piston broke?

"When Welding-ductile-iron one should remember that the fusion zone will not resolidify as ductile iron because the graphite will precipitate as vermicular or quasi-nodular. That is why ductility and impact resistance will be drastically reduced, and some carbides are likely to form, particularly in the pearlitic grade.

Furthermore the Heat Affected Zone will produce martensite, hard and brittle, especially in the pearlitic grade, that must be heat treated as explained down this page to restore some ductility.

Ductile iron is more susceptible to welding stresses, and more likely to crack while welding or during cooling.

Therefore, highly stressed ductile iron castings or portions thereof should never be welded."

http://www.welding-advisers.com/Welding-ductile-iron.html

ASTM standards for the various iron castings probably are thinking similar to above when they say things like weld repairs are permissible if pr-arranged between customer and supplier.

=============

http://www.lincolnelectric.com/en-us/support/welding-how-to/pages/welding-cast-iron-detail.aspx

 

[siavash1111]

metengr :TWI suggested a preheat temperature for cast iron at below link . my i know what do think about that

http://www.twi-global.com/technical-knowledge/job-knowledge/weldability-of-materials-cast-irons-025/

Tmoose: i inspected the broken segment and piston surface - inside the work piece(piston) there is a large imperfection(procity) simillar size of an egg- that seems it is manufacturing defect and occurred in casting process

Thank You

 

[metengr]

siavash1111;
The TWI reference material is excellent information for use.