# Tag Info

10

is it possible to increase the heat output of the burner by connecting two low-pressure supplies in parallel via a T-piece like this one? The primary factor is gas pressure at the tee. If the gas pressure drop from the low pressure regulator to the tee is negligible and the first tank & low pressure regulator is able to supply enough gas to ...

9

No, connecting two tanks together will not double the flow. The regulators fitted to tanks limit the pressure and flow rate so all you do is double the amount of gas the burner has available ie doubles the time of use. Do NOT interfere with the regulators. There are automatic change over systems that have both tanks connected and it switches over when one ...

7

The short answer: it's not optimal, but may work. Hopefully if these welds are critical, they're being performed to some code (In the US, for most structural work they'd be AWS D1.1 and D1.2 respectively.) Aluminum is considered among the hardest metals to weld well, so quality control is especially important there. Overall, the wire feeder itself doesn't ...

7

No, this is not classed as a "short-circuit". This is a circuit with a designed current flow - ie a 60 to 150A range is common... A "short-circuit" is a circuit where the current flow is not following the designed current path ie it is taking a "shorter" route to ground.

6

You are not exactly right. The purpose of Cr and Ni in stainless steel, besides the stainless part, is to tailor the microstructure. Cr promotes ferrite, Ni promotes austenite. Other elements have similar effects and must be taken into consideration. Beware of carbide formation changing properties and reducing weldability. The three different graphs plot ...

6

This assumes US codes are used. The question of whether or not a quality weld can be produced needs to be proven through testing. Per AWS (American Welding Society) codes (D1.1, D1.5, etc) the welder (person) must be certified for the weld type (FCAW, SMAW, etc), the materials to be joined, and the position to be welded (flat, vertical, overhead, etc). In ...

5

According to TWI-Global TIG welding electrodes usually contain small quantities of other metallic oxides which can offer the following benefits:- facilitate arc starting increase arc stability improve current-carrying capacity of the rod. reduce the risk of weld contamination increase electrode life Oxides used are primarily ...

5

To give at least some context to this. Titanium is generally considered 'exotic' for welding purposes as it is quite sensitive to both temperature change and contamination by atmospheric gasses, even at temperatures significantly below its melting point. Like aluminium, titanium is quite reactive but protects itself from corrosion by formation of a stable ...

4

There are a couple of issues here. To get a proper fusion weld both surfaces need to melt and whether or not this happens depends on the details of the heat transfer for the whole system. It is certainly possible that heat could be conducted way from the interface too quickly for the surface to melt well enough to get good fusion. In this situation the ...

4

According to this slideshow it looks like a weld between stainless and carbon or low-alloy steels would be within the scope of D1.6 entirely. It would not be prequalified so it would have to be qualified by testing. Table 4.2 (reproduced in the slide show) covers the test types if you want to qualify with a CJP, but you would need a full copy of D1.6 to see ...

4

The welder you are using forms a very large inductive loop when the contacts are welding. Any conductive materials you bring within that loop will form one half of a transformer, and they will "steal" some of the energy meant to go into the weld. In order to break this effect you need to eliminate conductive paths within the magnetic field developed by the ...

4

Other than inspection/NDE , the only treatment would be for appearance. For stick , you need to knock off the slag to examine it for quality. In some situations the hardness would be a concern and minor grinding for hardness tests would be needed. Stainless is the same; clean for inspection/NDE, anything else like glas bead blasting and pickling is for ...

4

First of all, one small but important note: The relationship between shear yield stress $S_{sy}$ and the (tensile) yield stress $S_y$ is dependent on the failure theory. Von Mises: $S_{sy} = 0.577 S_y\approx 0.6 S_y$ Tresca: $S_{sy} = 0.5 S_y$ I.e. the Tresca is a more conservative criterion.. That is probably the reason that it is preferred for materials ...

4

Probably not. The friction welding process presupposes a certain level of ductility so the mating surfaces can deform together and completely bond. Ceramics lack the deformation mechanisms that metals have and so one would not expect bonding to easily occur. In addition, getting the workpieces hot enough to melt by friction requires tremendous pressures ...

3

I think brazing would be correct for your application. Unless, the entire tray system needs to be stainless steel for hygienic and/or anti-corrosive reasons. Brazing is like soldering, you likely may be able to find a smaller handheld torch and the correct brazing rod for less than the cost of a TIG welding service. Also, it will require some skill and ...

3

In general when we talk about welding metals the process involves melting and re-fusing two separate pieces in order to join them. This has the potential to create a joint at least as strong as the parent metal and so it is most relevant to high strength materials like steel and aluminium. In the context of lower strength, soft materials like pure tin ...

3

In your situation (as long as you don't actually intend to use the thing!) 6061-T6 will be just fine. The main reason to pick it is that many more product forms are available in it than most other alloys, and it is relatively inexpensive. It is one of the strongest among the weldable aluminum alloys and very easy to machine (as most aluminum is.) The one ...

3

The only test method I've seen is in the RWMA Resistance Welding Manual. They recommend the use of a pusher block and support to test the pull strength of cross wire welds. It is shown on page 6-5 of the revised 4th edition manual. There is also a reference table with weld strengths based on setdown and various weld parameters on the same page.

3

It's hard to give a definitive answer for welding questions like this because there are so many variables, but here are some possible things to try: Technique From the photos it looks like you aren't able to maintain an arc on the inside corner. Likely you need to decrease your arc length (if using stick/SMAW) or wire feed speed (if using MIG/GMAW) and/or ...

3

Don't worry about the frequency of the applied power. Worry about the fact that a spark gap is a fairly efficient way (and can be a really efficient way) of generating radio frequency radiation. It's the way Heinrich Hertz made the first man-made radio waves. I would test. I would start by getting a spectrum analyzer in the same room as your arc welder ...

3

You basically can't. The same way carbon fiber is made: Epoxy. Fiber-filled if need be...but won't be as strong as a weld though. The only other potential method I know of is to get carbon fiber composite that uses a thermoplastic matrix like nylon and try ultrasonic or friction welding it. But not only is nylon thermoplastic difficult to find raw, you need ...

3

The fastest method to attach hex nuts to sheet metal would be to modify a stud welder. A commercial stud welder is grounded to the metal plate and the threaded stud is held in the opposite electrode. Applying pressure to the stud against the plate closes a switch, dumping a rather large current through the stud, effectively spot welding it to the plate. A ...

2

A prime example of welders that would perform such welds would be a Lincoln PowerMig 210, Hobart Handler 210 MVP. This is just to name a few. Miller and Everlast also have the "MVP=Multi Variable Process" units. Keep in mind most Multiprocessing welders have a lower production time or more clearly defined as "Duty Cycle time" due to the Multi-variable ...

2

A little late to the game. A method recommended in B&W's Steam, Its Generation and Use, is to drill small, closely set holes in the metal substrate, insert the individual wires into the holes, and peen them in place. This avoids the issues others have raised of welding affecting the properties. It provides intimate contact with the measured surface. ...

2

For an easily removable option you can use Kapton tape. It is heat resistant and works well for holding a thermocouple temporarily in place. I also wrap the wires in Kapton for electrical isolation.

2

I ended up finding a solution that works (haven't tried the cements suggested by others yet). The trick was to use a spot welder rather than a tig welder. With the correct power settings, that stuck the TC to the surface without damaging either component. It's not exceptionally strong (I used very fine TC wires), but it should result in conditions that ...

2

Quick answer, you are both right and wrong. Arc Welding has many types and for Shielded Metal Arc Welding (SMAW), Gas Metal Arc Welding (GMAW), Flux Cored Arc Welding (FCAW) and SAW processes electrode positive polarity increases depth but for Gas Tungsten Arc Welding (GTAW) electrode negative polarity increases penetration depth. I'm not at the office so ...

2

Assuming you're talking about plates: it would depend on you code, but usually it's the angle between the two joints that matters. If you mean a 90 degree joint with two 45 degree miter angles, I would still treat it as a corner joint. If there is a 10 degree miter angle on each piece so the dihedral angle in the joint is 160 degrees, it would be considered ...

2

Yes, you can plug a higher rated load into a lower rated breaker if the load is monitored to minimize trips. If you are using a different plug, make sure that the other plug is removed entirely there are no exposed wires or contacts. I assume you are in europe and the standard wall voltage is indeed 220V (If someone in the US is reading this in the future, a ...

2

That does look a lot like aluminium. All grades of aluminium are non-magnetic as are some stainless steels. The best test is weight as aluminium is significantly less dense than steel but has lower tensile strength so judging by the bulk aluminium seems likely. a final test is that if you grind aluminium with an abrasive wheel it will produce virtually no ...

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