Hi Gonzo, Larry and Joe as well if you're still following this thread ;)
Yes! I do agree Larry, and that's why I suggested to run some trials as you put it to see what sort of consistency Gonzo ends up with... what I wasn't sure of until now since he's elaborated further, was the fact that his company is now actually changing the joint geometry in order to achieve CJP (Complete Joint Penetration) as opposed to just thinking of the possibility to do so, and there's nothing wrong with doing so as long as everyone in the chain of command is on board especially the customer and their representatives...
Now with that being said, I believe the questions I'm about to ask you are warranted, because after all it will determine whether or not you have the capability to customize your weld penetration profile to where you and the customer desire it to be based on the configuration of your stated joint geometry as well as the relative difference in thickness the 2 parts have with each other (i.e. the tube wall and the flange itself).
1.) What type of power source are you using to weld these parts together, and do you have the capability really customize the waveform, i.e. true square wave capability as well as a very wide margin of pulse capability, i.e. low to very high hertz range to dial in for controlling not only your penetration, but also the weld profile as well??? I ask this because an inverter type power source with true square wave capability as well as a very wide frequency range for pulsing would certainly be a better choice when it comes to controlling the weld penetration profile consistency as Larry (Lawrence) has already alluded to. ;)
I also think that the differences in the thickness of the two parts would make it real hard to achieve similar consistency with this type of joint such as a flange to a tube as opposed to welding it instead with the type of power source I just mentioned including the application of pulsing with even straight argon alone... At the thicknesses you're welding together Gonzo, there really is no need to use helium since it is relatively easy to achieve CJP within those thicknesses, and adding helium may just make matters worse with respect to controlling the consistency of the weld penetration profile which would be of primary concern with this type of joint...
2.) Correct me if I'm wrong but, if you're going to weld the flange to the tube, you're describing it as the tube having a wall thickness of 1/8th of an inch, or .125 of an inch thick to a flange which has an overall thickness of .101 of an inch thick right? So, you're talking about a difference of .024, or 24 thousandths of an inch which is probably why in the drawing you posted, one member has a "J" groove geometry and if I'm correct, that is machined on the flange right? Unless the "J" groove is machined to the tube wall itself where the tube is cut to length which either way looks very unclear according to the drawing you provided in your earlier post since it doesn't show the differences in thickness between the two parts (tube and flange) when they are shown together in one view shown... I say this because what I'm interpreting in the drawing is two members of the same thickness being joined together instead of what you typed which would be the thickness dimensions I wrote in my first sentence of this paragraph...
In any event, the purpose of the "J' groove may just be incorporated into the joint configuration so that residual stresses in the weld can be minimized somewhat, and enough so that when the component is Post Weld Heat Treated, certain behaviors may be controlled or minimized in order to avoid some forms of cracking either in the weld or adjacent to it as well. ;)
It also doesn't show the orientation of where the weld is to be deposited in relation to where the flange meets the tube wall... In other words, you wrote: "They're sputtering targets ,so I guess the sand blasting being so coarse created micro cracks on the welds now we're just going to make a bigger weld prep to get 100% penetration and make the weld as thick as the tube wall to take the friction of the sand blasting were going to remove the weld machine a weld prep (no coolant),flanges are tacked on the inside of tube weld prep will be 45 degrees x 100 depth. I'll try Dc with helium two passes." I hope that I re-wrote that paragraph in the way you expressed it! ;)
Okay, now where I'm confused in this paragraph you wrote, is when you write: "remove the weld, machine a weld prep using no coolant..." Then this is where I'm a bit confused because of the drawing... "flanges are tacked on the inside of tube." Then you finish with: " weld prep will be 45 degrees x .100" depth... I'll try DC with helium two passes." Now did I interpret that in the manner which you meant ot describe what you guys wetre going to do next along with adding another 10 degrees included angle into the "V' groove geometry???
Also, if the tacks are to be placed inside the tube, does this mean that you are going to orient the inside surface of the tube parallel, or perpendicular to the face of the flange, because it really isn't clear in the drawing and would not make sense to me if you were to orient the face of the flange parallel to the inside surface of the tube wall... Now if it is the surface which represents the thickness of the flange is to be oriented with the inside surface of the tube wall, then it would make perfect sense, so that is where the drawing is very unclear in showing htis important factor I'm emphasizing so far... I hope you understand what I'm getting at so far - CAPECHE??? :)
Oh and by the way, Gonzo, you do not have to call me "Mr. Henry" even though I know you mean it as a sign of respect and I do appreciate it - really but, it's not necessary and you will not be disrespecting me by calling me by my first name only either - CAPECHE??? ;) ;) ;0 In fact, you can even call me "Hank" if you want to, okay??? :) :) :) So I'll await your clarification on this discrepancy although, please do not interpret this by stopping what you all plan on doing with respect to fabricating and welding together some trial sputtering targets because that's what you need to get ready - first and foremost, and remember that we're all just throwing out suggestions to you without any warranties or guarantees that what we suggest will indeed work - Okay??? Btw, I almost forgot to "Weldcome you to the World's Greatest Welding Forum!!!" So once again, "WELDCOME!!!" :) :) :)
Respectfully,
Henry