A514 Gr. A - Fan repair 1

[JIPMKWA]

We are doing base metal restoration of the primary Air fan blades and then doing a hard surfacing once we have the blade back to it's original thickness. It is made out of A514 Gr. A material (P 11B )

The only qualified welding procedure my company has for welding P11B to P11B utilizes 11018. The fan company says that they normally use 8018 to fix the blades. Once they use the 8018 and have the blade to flush - they do a layer of E309 and then use a hardsurfacing rod ( such as Hardalloy 155) on top of the 309.

My question is , if we did use the 11018 and THEN did the 309 / hardalloy 155 , would this be a more acceptable repair ? I am not a metallurgist but I was under the assumption that you would want your wire to match the base metals tensile strength ?

I do not know how well E309 welds to 11018.



Thank you in advance

 

[metengr]

The fan manufacturer recommended an under matching filler metal because there is less tendancy to develop cracks (depending on the repair groove length and depth). I have seen fan blade repair recommendations and have performed weld repairs on large boiler fans using either filler metal, under matching (80XX), and slight over matching (110XX) and (100XX). No issues were found with any of the filler metals.

Several words of advice for the blade repairs; first make sure that for the higher strength weld metal (110xx) and even for the 80XX weld metal you are using designated low hydrogen consumables (HR4). Second, I would make sure before any butter layer and hardfacing is applied, you wait 48 hours to perform a wet fluorescent MT for the blade material to ensure no delayed cracking. The rest of the advice provided in your post for buttering and hard facing is sound.

 

[JIPMKWA]

Thank you for the help as usual Metengr. I know D1.1 recognizes the need for waiting 48 hours to VT A514 material , but I think this falls under D14.6 ? Which I have never used before. I will purchase a copy tomorrow and do some reading.

Checking our WPS's today and I can't find one for welding P11B with 309 for our buttering layer. Or could I write that up as welding P1 ( the 11018 ) with 309 and then welding P8 (the 309) with hardfacing.

 

[metengr]

JIPMKWA;
You can also butter the fan blade with Inco A or 82/182, your choice. Most likely, you would need to qualify a WPS.

 

[Guest102023]

It is very easy to match filler metal to base metal on paper but then overmatch in reality. This is because the higher carbon content from base metal dilution is often not considered.

8018, as-welded, could come reasonably close to matching the base metal. My preference would be a nickel or nickel-moly grade from A5.5, for good ducility and toughness as well as strength.

"If you don't have time to do the job right the first time, when are you going to find time to repair it?"

 

[JIPMKWA]

Again the reasoning behind the 11018 is because of my companies WPS for P11B to P11B.

I tried going by the book on WPS's and found out I don't have one for the 309 to 11018 anyways...