Guide to buy suitable welding machine
Developed in the general trend of the world, cutting technology in Vietnam in recent years has made great strides. Many new types of welding machines are born with different capacity, different functions, serving different needs of work. Depending on the needs of the work, the condition that the welder needs to know thoroughly before choosing to buy a suitable welding machine.
The selection of a welding machine should be based on the following:
1. Select the welding machine suitable for the power source and the maneuverability of the machine.
This is a factor related to the condition of the workshop or work where the welder works.
Power sources that the welders usually use can be either a one-way source (for home or small-scale work) or a three-phase source (for works or industrial zones).
There are several types of welding machines that can be used in single phase and three phase power supply without the need for switch power supplies.
In cases where there is no electricity grid available, welding equipment should be available.
The maneuverability of the welding machine is also an important factor affecting productivity. If you have to work in non-fixed terrain, it is possible to use lightweight, compact size welding machines, which must ensure the performance. Some current inverter welding machines have a compact design but still ensure a strong working power.
Small welding machines weighing less than 7kg can give welding currents up to 200A, and larger machines weighing less than 40kg can provide welding currents up to 500A. If the small machines can be portable, for large machines are equipped with additional wheels to facilitate the pulling push.
2. Select the welding machine by wire diameter, electrodes and load cycle of the machine.
How to choose the wire diameter, electrodes
The tables below let you know how much of the electrodes you are using can give you how much current you have
Welding current with welding rod electrode | |||||
Rod diameter and type | 2.4mm | 3.2mm | 4mm | 4.8mm | 6.4mm |
6010, 6011 | 40-85 | 75-125 | 110-165 | 140-210 | 210-315 |
6013 | 40-90 | 80-130 | 105-180 | 150-230 | 250-350 |
7018 | 60-100 | 110-165 | 150-220 | 200-275 | 320-400 |
Voltage and welding current for wire ( Part 1) | |||||
Wire diameter and types of wire | 0.8mm | 0.9mm | 1.2mm | 1.32mm | 1.6mm |
Core welding wire | N/A | N/A |
15-36V
105-340A
|
15-36V
105-430A
|
15-40V
140-480A
|
Mig welding wire |
17-23V
50-200A
|
18-25V
50-225A
|
18-34V
85-355A
|
21-39V
150-500A
|
26-40V
250-610A
|
Welding current and welding nozzle | |||||
Types of tungsten electrode and its diameter | 1.6mm | 2.4mm | 3.2mm | 4.8mm | 6.4mm |
Alloy 2% | 50-140 | 125-200 | 150-325 | 300-340 | - |
Purity | 60-90 | 125-160 | 190-240 | 260-320 | 330-450 |
Load factor of the machine
The welding current and welding cycle of the welding machine are closely related. The load cycle, also known as the machine's working efficiency, is the time that the welding machine can work for a period of 10 minutes. For example, a 200A welding machine with a 60% load cycle means that the machine with a 200A welding current can work continuously for 6 minutes and must have a 4 minute break to avoid overheating. . Some improved welding machines have up to 85% efficiency, such as the HK MIG 500I series with up to 500A welding currents.
For welding rods, welding rods usually only weld for a continuous period of 2 minutes. The most common welding rod is the 3.2mm rod. This type of welding only lasts for about 1 minute.
It is possible to select the load cycle of the welding machine according to the work demand as follows:
- If used in light industry, it usually requires the performance of the machine reaches about 20% with a current of about 200A.
- If the welding industry requires the machine capacity of about 40 - 60% with a current of about 300A.
- In heavy industry, 80-100% efficiency is required for welding currents greater than 300A.
3. Select the welding machine according to the ability to work with metal and weld material thickness.
Not all welding machines can weld with all metals. Each welding method is suitable for effective operation with different metals, namely:
Welding processes | |||||
Type of Metal | Mig | Flux core arc welding | Stick welding | DC Tig welding | AC Tig welding |
Steel | X | X | X | X | |
Stainless Steel | X | X | X | X | |
Aluminum & Magnesium Alloy | X | X | |||
Cast iron | X | ||||
Titanium | X | ||||
Copper & Brass | X | X |
Selection by material thickness
You have to calculate by the different material thickness that will require different welding currents. The simple formula for calculating the welding current that corresponds to 0.025mm material thickness is that conventional steel will need 1A output. If the welding material is about 3mm thick, then the formula requires a current of about 120A. For stainless steel, welding currents require less than 10% and 25% higher for aluminum. When welding a thin object that requires equipment that can work stably with small currents, thick-walled welds need a high-capacity welding machine and higher productivity.
4. Selection by welding method
You can not expect a welding machine that can weld everything for the best quality. It is important to determine what type of welding machine you need to make the right choice. More posts select the welding machine to meet the needs to choose the most suitable welding machine.
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» Plasma arc welding (06/05)
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» TIG welding A-Z (06/05)
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» Basic arc welding technique (06/05)