Stainless Steel Cracking When Welding

276 is a group of iron based alloys that contain a minimum of approximately 11 chromium.

Stainless steel cracking when welding. 4 stainless steel welding characteristics by definition stainless steels are iron base alloys containing 10 or more chromium which imparts to the metal the. An excessively concave bead profile is a common problem with fillet welds especially those on stainless steel inconel alloys and aluminum but plain carbon steel isn t immune. A convenient and commonly used shorthand identifying the individual alloy within the austenitic stainless steel group is the astm system. Steels with over 0 20 c often require a post weld heat treatment to soften and toughen the weld.

A fully austenitic stainless steel weld is more prone to cracking than one containing between 5 10 of ferrite. Current commercial grades of duplex stainless steels contain between 22 and 26 weight percent chromium 4 to 7 weight percent nickel up to 4 5 weight percent molybdenum as well as some. The development of nonrusting stainless steels with distinct attributes that include varying degrees of corrosion resistance strength and workability has been a tremendous benefit to steel users. This type of cracking is also known as underbead cracking toe cracking or delayed crack ing because this cracking occurs after the steel has cooled below approximately 400 f it can be called cold.

The balance between the cr and ni. Although it is related to the welding process the crack occurs in the base material not in the weld material. I am trying to weld a stainless steel fitting to 5 8 stainless barstock that has been gundrilled 3 8 inside everything looks great after grinding and polishing the weld smooth but after pressure testing to 3500 psi with water in the tube i keep getting hairline cracks allowing water seepage i am using a tig at 55 amps on a 115 circut with 17 cfh of argon too much not. A certain amount of concavity may be acceptable depending on the welding requirements.

They are the most easily weldable of the stainless steel family and can be welded by all welding processes the main problems being avoidance of hot cracking and the preservation of corrosion resistance. 3 3 austenitic stainless steel the austenitic stainless steels contain 16 26 cr 8 24 ni mn up to 0 40 c and small amounts of a few other elements such as mo ti nb cb and ta. When these forces exceed the strength of the weld cracking ensues. Solidification cracking and hydrogen cracking are concerns when welding duplex stainless steels but not as significant for some other stainless steel alloys.

3 a composition that prevents the iron from rusting as well as providing heat resistant properties.