If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below. |
|
|
Thread Tools | Display Modes |
#10
|
|||
|
|||
Welding question -
On Sun, 21 May 2006 10:39:03 -0400, Chuck Harris wrote:
Mike Anderson wrote: The desire to use TIG with a higher end rod and post heat treat is the best but the question is answered correctly for a repair in structural aircraft members where heat treatment is not possible would be with an ER70 rod and OA welding. It was only a few years ago that the FAA even addressed TIG in the AC43.13. Mike Here is what Linde says in the "The Oxy-Acetylene Handbook", p233: Talking of 4130 "chrome moly steel: "One of the more familiar applications of this material is in structural tubing for aircraft. In such structures the light gage base material is welded using a slightly excess acetylene flame and the normal steel welding technique. Although the strength of the weld metal in such a weld is lower per unit area than that of the base metal, the weld is made to develop the desired strength by increasing the normal reinforcement considerably. By following such a procedure, this "Chrome-Moly" base metal can be successfully welded. On the other hand, if a S.A.E. X-4130 rod were used in welding such structures or if an attempt were made to follow a similar procedure in X-4130 plate material 1/2 or 3/4 in. thick, the weld would not be at all successful." They then direct us on to Chapter 22 to discuss the correct welding technique for 4130. There, they spell out in depth the problems with welding an air hardening steel, such as 4130. They mention that most of these problems can be handled by preheating welding areas to relieve hidden stresses, and using a low carbon steel rod, similar to Norway iron. They specify Oxweld No. 7 as being the desired rod for tubing of less than 0.1" thickness. They then go on to say that for tubing greater than 0.1" thickness, you will need a stronger steel in your rod, and suggest Oxweld No. 1 with a recommendation of heat treatment. For more rigorous applications, they then recommend Oxweld No. 32 with a requirement of heat treatment. Going into Linde's appendixes, finds that the Oxweld No. 7 rod isn't even a steel rod, but rather a pure iron rod with a 45KPSI tensile strength. The No. 1 rod is a High Test Steel (low carbon steel), and the No. 32 is Chrome Moly Steel (eg. 4130). The ER70 mig wire is a 70KPSI tensile strength mild steel. It is the same filler steel as any of the E70xx rods. Linde's book would be a very good place to go if one wanted to learn how to properly OA weld 4130. -Chuck O.K., you are correct. I agree that learning the proper method of joining any material you work with is important and I haven't any idea what FSDO he will try to use or who will be signing the log book or the 337 if it turns into that big a job. It was foolish to answer without enough information.... Who is going to sign the work off? There is where the answer should be sought. Mike |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Aluminum welding | Ernest Christley | Home Built | 5 | April 24th 06 11:47 AM |
Lyc. O-360 cylinder question | JB | Owning | 13 | November 27th 04 09:32 PM |
A question on Airworthiness Inspection | Dave S | Home Built | 1 | August 10th 04 05:07 AM |
TIG welding video? | Russell Duffy | Home Built | 3 | October 6th 03 05:55 AM |
Partnership Question | Harry Gordon | Owning | 4 | August 16th 03 11:23 PM |