Shielded Metal-arc Welding (SMAW) is the simplest and used for many joining processes. More than 50% of industrial and maintenance welding currently is performed by this welding process. The research results indicated that the treatment process of 150°C, 250°C and 300°C produced the changes of mechanic charateristics with the tensile strength of 42 kgf/mm2 when the temperature had reached 300°C, but at the temperature 300°C, the its toughness would decrease to Hi = 0.836 j/m2 and its hardness would increase to 40.83 at the temperature of 300°C. A third class mechanic must demonstrate an intermediate understanding of various structural welds and how to operate and maintain the machines that fabricate and repair metal structures, equipment and machinery. Must be proficient in obtained welding certification: SMAW plate, SMAW Pipe, GTAW Pipe, and any other certification. Mechanics is the branch of Physics dealing with the study of motion when subjected to forces or displacements, and the subsequent effects of the bodies on their environment. Various branches include Classical, Quantum and Statistical mechanics,Find out more fun ways to learn about Mechanics and its branches @Byju's. The target is a mechanic for another agency named Burke (Jeff Chase), who frequents the same coffee shop Steve has been going to. Furthermore, Steve is told that Burke's only weaknesses are that he is interested in young men and small dogs (such as the chihuahua they adopted).
Stick welding also called Shielded Metal Arc Welding, is among one of the most demanding processes to learn. Especially for those who do not weld every day or are new to welding. Experienced welders make this process look easy. They take a stinger, insert an electrode in and give us some tremendous looking welds one after other, which leave others in awe.
Your skill in basic stick welding can be easily learned if you know what to do theoretically and can apply what you know. Primarily, you should consider where and which type of welding materials you will be welding. Knowing where you will weld and the materials you are going to weld will help you figure out the exact processes that you are going to follow and which machine setup you should employ.
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What is Stick Welding?
Stick welding is short for SMAW. SMAW means Shielded Metal Arc Welding. This type of welding gets its name because of the electrode from which welds the metal. The electrodes come in the shape of a “Stick.” Stick welding is the general term to identify this type of weld throughout the welding industry.
Using the simplest explanation, Arch Welding uses electricity to melt a stick/electrode/metal filler rod. This cause both electrode and the metal joints to melt and join together two pieces of metal, all at one time. Then, simultaneously, fill the joint with filler metal. Electrode is the term used by industry.
Welding Environment & Conditions Suitable For Using Stick Welding
Smaw Notes The Mechanic
The welding method that you should employ depends on several factors, but one factor must figure out prominently in your choice, and that factor is the location in which you are going to weld. If you are going to weld indoors, you could have a variety of welding methods to choose from. But if you are welding outdoor, you only have limited option, and your best option is that of stick welding.
The reason for this is that you would surely have some difficulties with TIG, MIG, and other welding methods when welding outdoor for these methods are not ideal for outdoor welding wherein strong wind can play a critical role. Stick welding, however, is surely perfect for outdoor welding for it is convenient to use even if it is windy. Moreover, it can weld almost all types of metals, including those metals that are already corroding.
The selection of stick welding electrode entails an understanding of the strength of weld that an electrode can provide. An electrode called “6011,” for example, can handle tensile strength of 60,000 pounds per square inch, while 7018 has a tensile strength of 70,000 pounds per square inch. Hence, you should take note of the electrode’s first two digits to figure out the tensile strength of the weld per square inch.
Similarly, if you want to figure out the tensile strength of a graded steel, you must simply look at the number associated with the steel. A36 steel, for example, has a tensile strength of 36,000 pounds per square inch. Hence, if you know the tensile strength of the steel, you will also know the type of electrode you are going to use. Always bear in mind that the weld should be at least twice the tensile strength of the steel to be welded. The last two digits, however, of the electrode rod refers to the shielding gas of the rod or the flux. Hence, if a rod has higher last two digits, it means that it has higher amount of shielding flux.
How Much Amperage or Power is Needed for Stick Welding?
With a 140 amp Stick Welder, you can weld anything. Many a time, people are trapped up in the producer’s tactics of ‘maximum metal thickness’ and end up purchasing a larger welder. It is just a way of increasing sales! Even in power plants, fabrication shops and shipyards, there is no need for Stick welders of more than 130 amps. With 130 amps one can weld indefinite thickness metal. A ship hull of one-inch thickness can weld using just 120 amps.
Before welding, you should prepare the joints to be welded. The joints should be thoroughly cleansed of rust, water, or oil. Moreover, the joints should have no paint. If you don’t engage in joint preparation process, you may eventually fail with your weld. Furthermore, if you are using aluminum or aluminum alloys, you should not use sodium hydroxide or any cleaner that has higher pH level than 10.
Your choice of electrode usually determines the type of current setting you should use. It can determine whether you need to setup or use DC negative, DC positive, or Alternating Current. As a seasoned welder, you can easily measure the diameter of the contact tip of the electrode. You can also easily determine the electrode force based on the specification of the machine. Moreover, you can determine the welding time.
However, you will surely find the setting of the required welding current a bit difficult, considering that the resistance of the welding parts is more often unknown. You can simplify the process of setting the current for you if you are going to use Digital Storage Oscilloscope. You can also use a clamp ammeter or a voltmeter to find out the necessary current setting when welding.
Whether your appliance should be in AC or DC negative, DC positive, all depends upon the electrode that one selects. DC is a straight polarity which gives out a negative electrode, which in turn welds thinner, metal better. Positive electrodes give about 10% more infiltration at specified amperage than AC. So set it correctly and according to the requirements of the application of the weld. The correct setting depends upon the type of the electrode and diameter that one selects. Most manufacturers of electrodes will indicate the electrode’s operating range on the enclosed materials or the box. Based on the requirements of the electrode, welding position, and visual inspection of the finishing weld select the proper amperage. As a general rule of thumb for each .001 –inch of electrode diameter be prepared to have 1 amp. For overhead work, make sure to have as a welding position to use 15% lesser the amount of heat when compared to that of a flat weld. One at a time, adjust the welder by five to ten amps, till reaching the desired setting.
The correct length of arc usually varies according to electrode and application. A good tip would be to ensure that the arc length is not greater than the diameter of the electrode’s metal portion. Moreover, if you hold the electrode very near the joint, you would tend to decrease the welding voltage and eventually cause an erratic arc that usually extinguishes itself or causes a faster freezing of the electrode. The end-result of this is the creation of a bead with the obviously high crown.
Although there are patented ways to manipulate the electrode, every welder, however, has his/her own way of manipulating the electrode. Likewise, each welder has varied welding style, and usually, this style is developed by constantly practicing, by observing others, or by trial and error. It would be good to note that a side-to-side movement of the electrode would be appropriate for creating a wider bead on a wider or thicker material. Moreover, multiple passes would be great for covering wider area. In some instances, however, your weld will appear like fish scales. This happens when your forward movement is too quick, and you did not tarry long on the sides.
The angle of travel when stick welding is usually dependent on the position you sport when welding. If you are welding using a horizontal, flat, or overhead position, you should use backhand or drag welding technique. You can do this by holding the electrode at a perpendicular position to the joint. While in this position, you can tilt the top of the electrode approximately five to fifteen degrees from the direction towards which the electrode is traveling. However, if you would attempt a vertical welding, you must employ the use of forehand or push technique. You can do this by tilting the electrode top up to 15 degrees away from the travel direction.
Smaw Notes The Mechanical
It is necessary that you first create a weld puddle according to your desired diameter. Afterward, you can move at a speed that allows you to stay one-third in the leading of the puddle. If your movement is too slow, the heat will move towards the puddle and not towards the weld. This may cause cold lapping due to shallow penetration. On the other hand, if the travel speed is too fast, it would cause decrease penetration, produce a highly crowed bead, and create underfill. With this quick travel speed, the bead would obviously appear inconsistent.
In every method of welding, it is necessary to always put your safety first before anything else. Similarly, it is essential when engaging in stick welding to protect yourself from injuries like flash, burns, and other injuries concomitant with the welding process. Lastly, you should take safety precautions and wear the necessary protective gears before engaging in the welding process to prevent you from incurring any injury.