Post Weld Heat Treatment of 4130
Post Weld Heat Treatment of 4130
(OP)
I currently have a welded structure made of various wall thickness 4130 square tubing. The tubing is all 1x1 inch with wall thicknesses ranging from .035 to .125 inches.
The tubes have varying lengths between 4 to 18 inches and are interconnected.
I do not know exactly how the welds were made, but I do know that the welder is very competent (Im sorry I cant give more information beyond that).
I have recently become concerned with potential issues with heat treatments for strength. We are planning on getting the structure heat treated by quenching and tempering to a temperature to achieve approximately 1000 MPa yield.
My main concern is that there could be problems during the quench process that could potentially damage the welds.
Do you guys have any advise to give as to the best course of action to take from this point?
I appreciate your input.
The tubes have varying lengths between 4 to 18 inches and are interconnected.
I do not know exactly how the welds were made, but I do know that the welder is very competent (Im sorry I cant give more information beyond that).
I have recently become concerned with potential issues with heat treatments for strength. We are planning on getting the structure heat treated by quenching and tempering to a temperature to achieve approximately 1000 MPa yield.
My main concern is that there could be problems during the quench process that could potentially damage the welds.
Do you guys have any advise to give as to the best course of action to take from this point?
I appreciate your input.





RE: Post Weld Heat Treatment of 4130
Have a look at this site:-
http://www.netwelding.com/Heat_Treated_4130.htm
it may help
desertfox
RE: Post Weld Heat Treatment of 4130
RE: Post Weld Heat Treatment of 4130
RE: Post Weld Heat Treatment of 4130
RE: Post Weld Heat Treatment of 4130
RE: Post Weld Heat Treatment of 4130
The tubes were all normalized prior to welding.
RE: Post Weld Heat Treatment of 4130
From the earlier link I posted there is another link:-
http://www.netwelding.com/Welding%204130.htm
From the above link I found this information regarding post heat treatment.:-
If the part will be heat-treated after welding to achieve very high strength, a matching chemistry filler metal to the 4130 should be employed. Because of the relatively high carbon, a minimum of 200 degrees C, (400 degrees F) preheat and very slow cooling after welding should be used to avoid cracking. After welding, the part can be heated to 870 degrees C (1600 degrees F), quenched in oil or water then tempered back to say 370 degrees C (700 degrees F). A complex cycle, but this will result in a tensile strength of approximately 1380 MPa (200,000 psi). Since the weld is the same chemistry as the base material, it and the heat-affected zone will have the similar properties as the base material when heat-treated. All critical welds of this type should be inspected for internal soundness to assure they are free from cracks.
RE: Post Weld Heat Treatment of 4130
Here is a picture of the frame. There are 2 separate pieces. One piece slides on the other.
This should give you a better idea of what we are working with.
Thanks
RE: Post Weld Heat Treatment of 4130
RE: Post Weld Heat Treatment of 4130
http://ww
Perhaps a well-controlled marquenching setup could produce acceptable results, but I not personally familiar with any heat treat vendors that would process such a large part in this manner. Vac Aero is one supplier that could do this type of work, as they process complicated aerospace landing gear components, but I have no idea about cost, etc. Here is a link to their website.
http://vacaero.com/Ontario-Plant-No.1.html
RE: Post Weld Heat Treatment of 4130
RE: Post Weld Heat Treatment of 4130
RE: Post Weld Heat Treatment of 4130
Are any of you familiar with the IntensiQuench process?
From what I have seen, there are a few types of quenching that minimize distortion:
Gas quenching from a vacuum furnace (8+ bar)
Salt Bath Heat treating followed by oil quench
Intensiquench?
There is also austempering. Any thoughts on that?