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Up Topic Welding Industry / General Welding Discussion / AR400 plate
- - By Jim Hughes (***) Date 02-08-2013 18:23
It has been a while since I asked a question on this forum. Can anyone help with qualifying a WPS to AWS D 1.1 for AR 400 to AR 400 ? Our client is asking us to use a FCAW process and a 90K series wire with 200 preheat and 300 max interpass temp. This material might be better known as Hardox 400. It is a ware plate material. My only experience with this material is on fillet welds using E7018 H4. Thanks for any advice anyone can give me.

Parent - - By ssbn727 (*****) Date 02-08-2013 22:32
Hi Jim!

This one is pretty straight forward:

Quenched and Tempered Steel

Steel such as the common T-1 or AR plate all fall into the family of quenched and tempered steel

After the steel is rolled it is quenched (water) to increase the hardness and strength...
In this state the material tends to be too brittle for practical use so it is then tempered (in a furnace) to regain the lost ductility and toughness...

First of all, "T-1 & AR" is like saying "Xerox Oreo or Kleenex," They are trade names...

T-1 Steels (trade names such as: "Algoma 100, N-A-Xtra 100, HY-80, etc.") - these steels are generally 100ksi yield strength... Although you can strength match these materials when welding (E11018 electrodes for example) it is actually often less problematic to "undermatch " with say a 80ksi YS consumable... You will find these materials used in trailer frames, truck parts, structural members, surface & submersible vessels, etc...

AR Plate (trade names such as:"Algoma 500 , AR500, Hardox, etc.) are all quenched and tempered but through a higher alloy content, the plate can achieve a much higher hardness and strength. These Q&T plates are generally used for abrasion & wear resistance...

Generally speaking, steel mills name their AR plate as follows:

AR400 = 400 brinell harness . A good rule to know is brinell hardness divided by 2 is the approximate tensile strength... For example, your AR400 is approximately 200ksi TS... Needless to say, you don't have any possibility to strength match this plate, nor does it matter since these AR type plates are used for their abrasion & wear resistant properties not strength...

Because of this, the best filler material to weld AR plate (since you can't strength match anyways) is any low hydrogen filler such as E7018 / E8018... Often in the heavy equipment industry they use a 80ksi filler that has 1% nickel (such as E8018-C1) for the low temperature impact properties if the plate will see lots of pounding...

Need for Low Hydrogen and Preheat

No need to get into specifics but, it is because of the higher alloy content that increases the need for preheat and a low hydrogen process... Generally speaking these high strength plates are more crack sensitive... This problem is increased by excessive hydrogen content (from the welding consumable) and excessive quench (lack of preheat)...

It has little to do with these plates having higher hydrogen content than their mild steel counterparts but rather they are just more susceptible to cracking if the hydrogen content is not controlled originating from the consumable filler metal... Just be careful with the preheat because it is real easy to get carried away...

Need to Avoid Excessive Preheat and Inter-pass Temperature

The steel makers will all give you a maximum inter-pass temp. and /or heat input... The reason that you must watch these two is that you can put too much heat into the steel therefore, softening it... In essence you will destroy the hardness and abrasion properties of the material if both are not controlled before, during even after welding as well...

Low Hydrogen Processes

Welding processes that are considered low hydrogen are all GMAW (MIG), all submerged arc, most gas shielded flux cores, some self shielded flux cores and obviously low hydrogen SMAW (stick) electrodes... Where it gets tricky is when using self shielded flux cores... A good rule is most self shielded flux cores that are qualified for seismic welding will be low hydrogen...

If you are ever in doubt, you can always look on the certificate of conformance (legal document that all welding consumable manufacturers must have on all their filler material) where it states the "diffusible hydrogen"suffix/number... The letter "H" and the corresponding number indicates milliliters of diffusible hydrogen per 100 grams of weld metal...
They are designated as H16, H8 and H4... For example, a designation of H4 indicates that there is 4mL of diffusible hydrogen per 100 grams of weld deposit... In other words, the lower the number, the lower the hydrogen content will result in the weld metal deposit.:eek::roll::lol::wink::cool:

Well, that's about it for now... Hope this helps.:lol:

Parent - By Cumminsguy71 (*****) Date 02-09-2013 15:01
As always, excellent information Henry!! Thanks for posting that!!!
Parent - By rcwelding (***) Date 02-10-2013 00:54
Henry it is always a pleasure reading your posts..!! Thank you for sharing some of your knowledge with us..!!
Parent - - By Jim Hughes (***) Date 02-11-2013 18:13
thanks for your posting. It is always very refreshing to know the forum has people of your caliber on it. Your post, along with others have helped me to nail down a procedure going foreward. Alot of what you posted was a good refresher for me. Thanks again.
Parent - By ssbn727 (*****) Date 02-12-2013 05:30
"Use Undermatching Weld Metal Where Advantageous" Duane K. Miller, P.E.

Here's a real gem for you Jim:

Parent - By hojopens3 (**) Date 02-13-2013 21:57
WOW, it does seem that 11018 rods and some per heat will work on T1 and AR afterall :twisted:
Parent - - By Abranques Date 08-24-2017 19:50

I have over here an AR 400 welding using 200C Preheat, 110A, and E7018-H4. I need a hardness on the weld metal around 320HB, I already tried 3 different cooling rates, covered with a blanket overnight, 2hs using a compressor blow and 15min splash water, but all this cooling rate gave me the same final hardness on the weld metal.

I think the  E7018-H4 must be changed to a filler metal with more Cr percent.

Do you have some opinion about? thank you.
Parent - By Northweldor (***) Date 08-25-2017 12:39
You should post this as a new thread.
Parent - - By pipewelder_1999 (****) Date 02-09-2013 00:38 Edited 02-09-2013 03:11
One other thing to keep under consideration is cracking due to joint restraint. Tightly fitting tee or corner joints may be prone to craxking due to the higher yield if the matetial. If you experience that problem, consider fitting joints in a manner/sequence that facilitates the joint to move while welding. Crush wires at tees/corners, butt joints that allow movement into correct angular alignment as opposed to holding them in place, and as mentioned above, preheat.

Gerald Austin
Parent - By Tommyjoking (****) Date 02-09-2013 01:48 Edited 02-09-2013 01:55
In other words it is the same scenario with any Tempered material.....READ YOUR SPEC SHEetS...PROCEED ACORDINGLY.

My advice would be to follow Henry..I.E. ssbn727    Hardox plates will weld out correctly when warmed up to joining preheat =bad welds.  There are a few other folks working in defense who lay down lbs upon lbs of this daily who may comment.
Parent - - By swsweld (****) Date 02-09-2013 11:52 Edited 02-11-2013 06:00
As a contractor, we did a large car crushing structural steel job a few years ago that had lots of AR plate in it and the owner had us use E309 and E309T1 but offered little in technical details as to why...

As an inspector, repairing MRAP's battle damage (Mine Resistant Ambush Protected) combat vehicles in Afghanistan, SS 309 was the filler material of choice for company 'A' due to it's toughness, ductility and elongation properties. Armox, Weldox, ASTM A-517 and HSLA (High Strength Low Alloy) are common materials in our application.

Obvious differences between Abrasion Resistant and Ballistic Armor but there are similarities as well.

I have seen Company 'A' use 70K wire and company 'D' use 110K wire and company 'B' & 'C' use everything in between, all with acceptable PQR's. SS filler materials have all but been banned but not due to poor performance.
Scratching head.

Just some general suggestions if you want a good starting place for the 90K FCAW WPS/PQR;
75/25 Ar/CO2 @ 30cfh
E91T1 H4M Dual Shield
Preheat 150F
Interpass 400F
***** The 200F-300F range mentioned in the OP is a tight range that might be a problem in the field IMO*****
.045 Diameter
170-190 Amps
25-30 Volts
7-8 Travel Speed
Vertical Progression-Uphill

Hope this helps.
Parent - - By Jim Hughes (***) Date 02-09-2013 13:15
thanks for your help. Your input has helped alot. I have been doing welding engineering work for a number of years and typically I will get enough information to put a procedure together, but this time I have no specs or technical details to go off, just "here is the material please weld it, so it's back to basics. Your post has helped alot. It gives me a good starting point for WPS/PQR parameters.

Parent - By swsweld (****) Date 02-11-2013 06:23
You're welcome.
Glad to help.
Parent - - By fschweighardt (***) Date 02-09-2013 22:32
Pretty sure D1.1 only goes up to 100 KSI yield steels.
Parent - By swsweld (****) Date 02-11-2013 06:26
You are correct.

Butcept for the EOR specifying the 110ksi wire, we would be out of compliance.
Parent - By Tyrone (***) Date 02-12-2013 12:24
Hey Jim,
If the client is directing you to use a specific process, get it in writing. :wink:

The key is preheat and interpass temp.  I would consider 300F preheat and 500F max interpass.  It all depends on your plate thickness and level of restraint. 
Different fillers can be used.  Europeans and South Africans (MRAP), use 309 because of its affinity to hydrogen.  They've been doing that for years, so they stick with what they know.  70, 80, 90K wires are all good, but I personally prefer the lower end because of ductility.

Hope this helped.

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