chromium % of ER 309MoL

By RonG

Date 09-10-2001 12:19

ASME SFA5.9 (EC309MoL) AWS A5.9 UNS W30953

C- 0.03max
Cr-23-25
Cu-0.75 max
Mn-1.0-2.5
Mo-2.0-3.0
Ni-12.0-14.0
etc

By RonG

Date 09-10-2001 17:15

I guess I don't understand the question also.

316L with the exception of the Cr content is the same as the 309MoL.

Are you saying you tested the filler wire or the weld metal and it was 21% Cr.?

By pdweldor (*)

Date 09-10-2001 16:18

This does not meet the DIN Standard 8556 for type SG X8 CrNiMo 23 13, which is the DIN equivalent of 309LMo. The DIN spec requires 22 to 25% Cr. It might meet BS 2901 Pt. 2, but I don't have a copy of it. According to my Metrode Catalogue (a British Manufacturer), the Cr range is 21 to 25%.

What are they using this for, a buffer layer between the carbon steel and 316 cladding? If so, why does the Cr matter so much unless there are special metallurgical considerations like ferrite content? If you are looking for 316 chemistry in the final deposit, it would only require 18 - 20 Cr. I would worry more about Mo dilution than Cr dilution, since Mo is what makes 316 superior in pitting resistance.

Regards.

By rajaramc Date 09-11-2001 09:14

Thank you for your detailed reply.

By - Date 09-10-2001 19:28

I suspect that the situation you have is that you are trying to join (e.g. a butt joint) C/Steel plate that has been clad with 316 plate. (Explosion bonded?)

In such a situation, you will typically weld the C/Steel portion of the joint with a C/Steel filler such as ER 70S-6. Then a "buffer layer" of ER 309MoL is used as the last layer when joining the C/Steel and a portion of the 316 cladding. Either the complete joint of the cladding portion could be finished with the 309, or the final layers could be deposited using an ER 316L filler. The situation would depend on your particular requirements on the job.

The bottom line as far as I am concerned, is whether the welding procedure and filler metal meets code requirements. Have they got a qualified procedure? If so, with what filler was it qualified? ER309MoL? (ASME IX, F6, A8) If so, then you have to ask yourself whether the filler they have purchased meet the code requirements. If it does, and it meets the chemical composition requirements of the procedure, then it would be OK.

If you want to perform some calculations to check if the final compositions will be OK, there is a paper dealing with claddings on the following wedsite:

www.proknownet.com

Follow the papers link from the LHS frame and place the search term "cladding" in the keyword entry block and search.

In addition, there is an excel spreadsheet, also on the PROKNOWNET site, that helps you to perform the calculations for dissimilar metal welds and claddings. To download this, follow the software link in the LHS frame and search as you did for the paper.

Hope this helps.

Niekie

By rajaramc Date 09-11-2001 09:05

THe welding is to be done for clad piping of dia 8" to 14". Since back gouging is not possible , the entire joint is to be welded with ER 309MoL+E-309MoL. The welding procedure was earlier qualified with welding consumables above. Due to non-availability of earlier used filler wire, new lot was procured from different supplier. I got the filler wire tested to confirm the chemistry. Basically the filler wire is not meeting the chemical composition requirement as per ASME sec IIC . However, from a practical point of view, I wanted an expert opinion.

Rajaram