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Old 07-23-2013, 03:34 PM is offline
Join Date: Jun 2012
Location: Pittsburgh, PA
Posts: 7
Default 4130 Chrome Moly: FAQ Answered

We frequently get questions regarding TIG Welding 4130 Chrome Moly on our welding videos and when we are at events. So much, as a matter of fact, that we created this “Top 10” list of questions about 4130 with answers. Hope this helps for those of you venturing into 4130!

These procedures are intended for sporting applications, such as; experimental airplanes, racing car frames, roll cages, go-carts, bicycles, and motorcycle frames.

1. Can I weld 4130 using the TIG process?
Yes, 4130 Chrome-Moly has been TIG welded in the aerospace and aircraft industries for years.

2. Do I need to pre-heat?
Tubing applications do not require the normal 300ºF to 400ºF pre-heat to obtain acceptable strength. However, it is recommended that pre-heat of 100ºF to 125ºF be used to remove parent material moisture.

3. What filler material do I use?
Although there are several good filler materials, my recommendation would be ER80S-D2. This filler material will meet the strength and elongation requirements for experimental planes, racing car frames, roll cages, motorcycles and bicycle frames. Typically, you would obtain 20% elongation from this filler material after welding.

4. Why do I not use 4130 filler?
4130 filler typically is used for high strength and rigid applications. Due to its hardness or lack of elongation (flexibility), it is not recommended for sporting applications such as experimental airplanes, race car frames, roll cages, etc.

5. When I use ER80S-D2 filler material, do I give up strength for elongation?
Yes, the parent material will provide a tensile strength of approximately 95 Ksi. The filler material, when diluted with the parent material, will provide approximately 70 Ksi. However, with the proper joint design (such as cluster or gusset), the cross-sectional area and linear inches of weld will more than compensate for the strength.

6. Do I heat treat 4130 after welding?
NO! The term “heat treat” has been generically misused in the welding field, as has normalizing. Heat treat and normalizing operations are extremely sensitive to heat control (preferably oven-controlled) and do metallurgically change the strength value of the parent material. Stress-relieving is the recommended practice and 1,100ºF is the optimum temperature for tubing applications. Use temperature crayon 900ºF and mark approximately 1” away from weld areas. Use Oxy/Acetylene torch with neutral flame and oscillate to avoid hot spots.

NOTE: Excessive stresses are induced by too much heat input, poor fit-up, or both, therefore stress relieving can be avoided if all fit-ups are precision (using tools like the “’Ol Joint Jigger”) and applying minimum heat input, i.e. smaller welds. TIG welding should not require a weaving pattern in the welding technique.

7. Do I have to pre-clean 4130 material?
Yes, remove surface scale and oils with mild abrasives and acetone. Wipe to remove all oils and lubricants. All burrs need to be removed with a hand scraper or burring tool.

8. Do I need to back-purge 4130 material?
Whenever possible, it is recommended to back-purge all 4130 welds using Argon gas. However, many welds are closure welds and back purging is impractical.

9. Do I need 4130 plate for support gussets?
No, mild steel will provide adequate stress and strain distribution. Most gussets are designed with more than adequate linear inches of weld.

10. Should I cool the metal after I finish welding?
ABSOLUTELY NOT! Rapid quenching of the metal will create problems such as cracking and lamellar tearing. Always allow the weld to slow cool.
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Old 07-23-2013, 03:37 PM
Shawn C Shawn C is offline
Join Date: Mar 2013
Location: jackson, Mi
Posts: 110

i feel like they are using this as free advertisement........ and its working
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Old 07-23-2013, 03:40 PM
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LW Hiway LW Hiway is offline
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Join Date: Jun 2005
Location: Fuck Lake Charles
Posts: 21,434

Very informative. I've used this material on/with aircraft frame builds as well as repairs.


i feel like they are using this as free advertisement....
Heck, we give HF 100 times the mention. Sometimes weekly within a few threads/posts. lol
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Old 07-23-2013, 05:49 PM
FabberMcGee FabberMcGee is offline
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Join Date: Mar 2011
Location: Fairbanks, Alaska
Posts: 809

Doesn't look much like an ad to me. Couldn't see any sales pitch and it answered several questions I hadn't even thought to ask.

Pleased to know about filler material and gusset material. I've always used 4130 filler.... just because it seemed like the right thing to do.

If the guy that posted this has a first name or a handle, it would be nice to know. I feel uncomfortable hollering across the shop... "Hey Weld, how much post flow time do I need?" For now, I'm just assuming that .com is his last name. Anyway, thanks for all the good information Weld.
"The trouble with having an open mind, of course, is that people will insist on coming along and trying to put things in it."

“The thing about quotes on the internet is you cannot confirm their validity” Abraham Lincoln
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Old 07-23-2013, 06:21 PM
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brucew brucew is offline
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Join Date: Jan 2009
Location: Haskell, Texas
Posts: 1,319

Originally Posted by FabberMcGee View Post
Doesn't look much like an ad to me. Couldn't see any sales pitch and it answered several questions I hadn't even thought to ask.
I'm glad he chose to post. It doesn't look like an ad to me either. I watched several videos with "Mr.Tig" when I first got my tig machine and I found it very helpful, easy to understand, and well worth watching.

Keep posting, I'll keep reading.
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4130, chrome moly, tig welding

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