Anyone else ever try this? If not give it a try. You do not have the required permissions to view the files attached to this post. Wed May 09, pm I guess if you found a procedure that gets you by then more power to you. If you take the cleaning cycle out the weld will be dirty to say the least and won't pass any inspections if needed. If your just sticking 2 pieces of aluminum together fine but I'll stick to AC.
Wed May 09, pm CoreyMac wrote: I guess if you found a procedure that gets you by then more power to you. When it is called out on the print it's handy to know how to do. Thu May 10, am You seemed to have proven your point to yourself. But I have to ask If so, why not stick to AC??? Thu May 10, pm rahtreelimbs wrote: You seemed to have proven your point to yourself.
Sat Oct 06, pm Sorry, I had to register to comment on this. Yes, aluminum can be welded with DC and pass whatever tests given all day long! The preferred method is AC because people do not know what they are doing when it comes to aluminum DC plain and simple. If you brush the material with a stainless brush, clean with acetone, machine settings, torch angle, etc the weld will be just as pretty as AC and have deep penetration as well.
The sooty layer will be present in the weld but very minimal, just lightly brush it off and you are good to go. Sat Oct 06, pm bryce39 wrote: Sorry, I had to register to comment on this. If everything is correct, people cannot tell the difference between DC and AC aluminum. I will take a picture of the weld before I brush it off so you know that I am not bullshitting you. Sat Oct 06, pm Bryce, Don't be "sorry" that you had to register.
All input is welcome here. I have no doubt on the DC Al. Though I've never had to do it myself, the logic is sound. The pre-clean is the key, as you don't have the electrode-positive phase to do that work for you. I look forward to seeing the pictures, and since I love to learn new things, I may have a question or two for you and RedIron. I have a great deal of autonomy at work, so I can experiment with this there.
There is an application that comes to mind where the penetration is more important than the appearance as I assume, like most things, I won't master it in the first go Steve S. However, there are special situations where a welder may want to consider experimenting with a TIG weld on DC power. Aluminum could warp if you are welding with AC power and need to get enough penetration for a strong weld. Aluminum is notoriously tricky, as a little pre-heating can help, but too much pre-heating can cause big problems when you start welding.
This is great if you need a lot of penetration, but things can get out of hand very quickly. Welders who have experimented with this have noted that they created sloppy welds that are OK if you need something done in a pinch. TIG welding machines and welding supplies will also deliver different results. This would mean that the current changes times each second. The number of cycles per second frequency in a standard machine is dictated by the mains frequency which in the UK is 50Hz.
It is worth noting that as frequency increases magnetic effects increase and items such as transformers become increasingly more efficient. Also increasing the frequency of the welding current stiffens the arc, improves arc stability and leads to a more controllable welding condition. However, this is theoretical as when welding in the TIG mode there are other influences on the arc. The AC sine wave can be affected by the oxide coating of some materials which acts as a rectifier restricting the electron flow.
This is known as arc rectification and its effect causes the positive half cycle to be clipped off or distorted. The effect for the weld zone is erratic arc conditions, lack of cleaning action and possible tungsten damage.
The sinusoidal wave consists of the positive element building up to its maximum from zero before falling back to zero often referred to as the hill. As it crosses zero and the current changes direction towards its maximum negative value before then rising to zero often referred to as the valley one cycle is completed. Many of the older style TIG welders were only sine wave type machines. With the development of modern welding inverters with increasingly more sophisticated electronics came development on control and shaping of the AC waveform used for welding.
Due to these electronic controls the cross over from positive to negative and vice versa can be made almost in an instant which leads to more effective current in each half cycle due to a longer period at maximum. The effective use of the magnetic field energy stored creates waveforms which are very near square. The system would allow control of the positive cleaning and negative penetration half cycles. The problems that can be encountered are that once cleaning has occurred in less than the positive half cycle time then some of the positive half cycle is not productive and can also increase potential damage to the electrode due to overheating.
However, this type of machine would also have a balance control which allowed the time of the positive half cycle to varied within the cycle time. This can be achieved by placing the control to a position which will enable more time to be spent in the negative half cycle with respect to the positive half cycle. This will allow for higher current to be used with smaller electrodes as more.
0コメント