316l pipe to 304 L O-Let

By js55

Date 02-11-2009 13:27

316L will work fine, but you don't generally need 316. 308L is often cheaper.

By JeremyW83 (***)

Date 02-12-2009 02:02

Why do you say that you do not need to use 316? I have always gone by the general rule of equal or greater SS number usage.

I got it resolved today because there will be a valve seperating the two types on the line I could go ahead and use the one made out of 304 instead.

By Weldconsultant (*)

Date 02-12-2009 18:00

308 would be preferred since it has more ferrite content than 316 and hence will reduce the likelihood of weld cracking due to impurity elements that are soluble in the ferrite phase. Some 316 compositions are purely austenitic and can be prone to cracking.

Girish

http://www.welding-consultant.com

By Metarinka (****)

Date 02-12-2009 20:24

Per AWS D1.6 308L is the reccommended filler material between 304L and 316L. In generall 308L or 309L are the two preferred filler metals for 304L to most any other austenitic stainless steel.

308L was designed specifically for the purposes of joining austenitic stainless steel and as welding-consultant mentioned has a higher ferrite content compared to 304 or 316L

316 could be used but it's more expensive with no advantage, so it's not worth it in my opinion

By JeremyW83 (***)

Date 02-13-2009 02:50

We have both types on the jobsite.

By 522029

Date 02-13-2009 01:45

JeremyW83,

" I have always gone by the general rule of equal or greater SS number usage. "

That is generally accepted but is wrong.

Griff

By medicinehawk01 (**)

Date 02-16-2009 16:08

I have always used 316L filler wire for the GTAW process and have never had an issue join 304L to 304L or 316L to 304L or 316L to 316L. My company is generally responsible for this and I trust my employer's QA/QC Manager. I woud think the mechanical properties of the higher grade (316L) to join the 304L should be sufficeint. IMO.
Be well,
Hawk

By 522029

Date 02-17-2009 00:29

See JS55's reply.

Griff

By js55

Date 02-16-2009 16:59 Edited 02-16-2009 17:28

The greater SS number myth is not only wrong, it could be dangerous.
You wouldn't use 312 for a 310 application.
You wouldn't use 310 for a 309 application.
You wouldn't use 347 for a 320 application.
You wouldn't use 321 for a 316 application.

By 522029

Date 02-17-2009 00:30

Thank you for a better, more detailed reply than the one I submitted.

Griff

By mightymoe (**)

Date 02-21-2009 03:14

On our job joining 304 to 316 we've been using 308. I was told always use a grade up from the lowest grade base metal. Does that sound right to you guys? I would guess each job will have it's own requirements and specs.

By 803056

Date 02-22-2009 02:36

Some people are under the misconception that as the AISI number increases, so does the alloy content, i.e., Cr and Ni increases as the AISI number increases. That is incorrect. There is no direct correlation between the AISI alloy number and the alloy content.

Compare the alloy contents of several common Austenitic stainless alloys; 304, 308, 309, 310, and 316.
AISI   304    308    309    310 316
Cr 19    20    23    25 17
Ni    9 11    13    21 12

In the case of the lower alloy numbers, the alloy content does increase, but the alloy content of 316 drops back to something between 304 and 308, but with the addition of Molybdenum. The percentages I've listed are about the mid-range values for Chrome and Nickel.

One way to determine which filler metal is appropriate is to use the WRC diagram to approximate the Ferrite Number and shoot for something between 3 and 10 and make sure you are in the Ferrite to Austenite transformation range for the solidification mechanism.

Best regards - Al

By mightymoe (**)

Date 02-22-2009 13:18

Great reply. Right now I'm " just a welder". Your post will help me be a more complete welder. thanks

By ctacker (****)

Date 02-25-2009 19:19

here is a link to help give a general guideline on which fillers to use!
http://www.unibraze.com/TechTalk/TECHTALKVol1Is5.pdf