4130 Vs 4130N

[KyBearhawk]

So after closer inspection I now realize that I screwed up and made my wing attach bars/fittings out of 4130 and the plans call out 4130N. I ordered the Wicks wing steel kit which came with 4130 not 4130N. What do I do? Should I order some 4130N and remake them? Anyone else order the wing steel kit from Wicks? Also I notice that the pulley mount that goes where the attach fittings are also should be 4130N and Wicks provided just plain 4130. Not stressed about those as I have not made them yet but that is what caused me to catch this mistake.

[Mark Goldberg]

There is 4130A (annealed) and 4130N (normalized). The N material is almost always what Bob wants. In a few places the A material is fine - like the tail ribs & the little tabs that are welded onto the tubes for the floor attach. The N material is MUCH stronger. Mark

[KyBearhawk]

After talking to Wicks on the phone they said that all they sale on sheet steal is 4130N, Normalized, despite that some item descriptions call it out specifically as normalized and some of the items do not. Disaster averted... if they are telling the truth. What "simple" process can a person do to tell if the metal is normalized or annealed?

[Battson]

A hardness tester is one way of determining what is what.
They aren't something you find lying around, you'd probably have to find a company which does materials testing.

[DesertBearhawk]

Customer service issues with Wicks? Go figure...

[Robert440]

So, I take it that they might not be a great source of materials? I just requested their prices for the material kits!

[alaskabearhawk]

Usually aircraft metals will be marked by the manufacturer with the alloy and temper (or condition) such as 2024T3 for aluminum or 4130N for steel and the material thickness. Whenever you buy materials, you can request a certificate of origin, certificate of conformance or mill test report. This company website explains it the best: http://www.onlinemetals.com/mtr.cfm. Other than that, you cannot tell the difference between mild steel and 4130N sheet or tubing just by looking at it.

FWIW, in my shop I always keep my materials segregated. I have a shelf that has only 4130N or 4130A sheet stock on it, including all the bits and pieces I have cut off. Even on the smallest piece usable piece I write on it the alloy and the thickness with a sharpie. That way I never have to guess, otherwise it ends up in the real scrap heap. My tubing is stored in the same way. I do a number of other projects in my shop and all my scraps of mild steel I write "MS" on it with a marker. I pay way too much for my aircraft grade stuff to have it just wind up in the real scrap heap because I can't be sure where it came from or if it's the proper material.

There is a good thread on the Tailwind forum about 4130N tubing from China.

[bestbearhawk1231]

I usually ask for the certificate when I order steel or aluminum, mainly so I can show the inspector at the end of the project if there are any questions. I guess it is a habit from working avionics. I always label my steel and aluminum when I get it and also as I use it. My mild steel gets labeled as "mild (thickness)" and 4130 is labled as "4130(A or N) x thickness"...aluminum is labeled in the same way with the exception of the aluminum I buy at the hardware store which gets labeled as "hardware store". I use either a silver sharpie for steel (or blue if silver doesn't show up) and a blue one for the aluminum. Keep it simple and stay consistent.

As for Wicks customer service...well, they have lost a few thousand dollars worth of business due to the way I was treated on one of my initial orders. I was also sent a bunch of very hard rivets (old) in an assortment I bought from them in one of my other initial orders. The rivets would simply crack when bucked which is a sign that they were old and needed to be re-tempered which I don't have the capabilities to do. Unfortunately, they are the only ones who carry the 14' capstrip material needed for the rear spar so I guess I will have to try my luck with them again.

[4trade]

Your welding heat will anneal your 4130N part close to welding seam, so it should not make any difference in a practical matter

[Mark Goldberg]

I strongly suggest that you use 4130N sheet as recommended by the design engineer where he calls for it to be used. Mark

[KyBearhawk]

Bob is pretty frugal and I would assume if he is calling for it then he really means it.

[alaskabearhawk]

I respectfully disagree 4trade. The designer (in this case Bob) chooses the metal based on the application. Welding one component does not alter the entire structure to an annealed state. Certainly after welding the parent metal strength is not at the original spec, but the welding process if followed correctly will have the joint strength closely match the parent metal. From a welding web site that says it best:

"Q. When I use ER70S-2 filler material, do I give up strength for elongation?
A. Yes. The filler material, when diluted with the parent material, will typically undermatch the 4130. However, with the proper joint design (such as cluster or gusset, for example), the cross-sectional area and linear inches of weld can compensate for the reduced weld deposit strength."

Proper cooling is critical as well after welding.

[MG1143]

I have just looked at my sheets that have been laying around and came from Wicks. Some have the writing on them that says AMS 6345B. Since I ordered smaller pieces not all have that visible. Looking here

http://www.aircraftmaterials.com/data/alstst/4130.html

AMS 6345b is normalized. I think I got that right anyway.

[4trade]

My point was that all 4130N material will lose their strength when welded. Welding will drop that tensile strength, because welding is heat treatment too. Designer choose anneal material usually pieces, that need to bend tight curves and these curves always rise risk of metal failure, if bend too tight. Use your designer material. It is design there.