Как варить дуговой сваркой: Как правильно варить электросваркой красивые швы

Как правильно сваривать металл инвертором: инструкция для новичков

Для соединения заготовок и листов используется специализированное оборудование. Самыми популярными считаются аппараты инверторного типа. Чтобы сделать качественный шов, новичкам нужно знать, как правильно сваривать металл инвертором.

Сварка инвертором

Что такое сварочный инвертор и как он работает

Инвертор представляет собой современное оборудование, которое используется для соединения металлических деталей. Принцип сварки инвертором аналогичный другим сварочным аппаратам. Прибор вырабатывает ток максимальной силы, благодаря которому появляется электрическая дуга. В дальнейшем она поддерживается за счёт мощного напряжения и позволяет разогревать металл. В случае с инвертором дуга появляется между обрабатываемой поверхностью и электродом. Его отличие в том, что в стандартных моделях мощное напряжение вырабатывается с помощью трансформатора. В инверторе другая система.

Чтобы создать мощное напряжение, входной ток в 220В проходит через специальный выпрямитель. Там он преобразуется в постоянный. Далее постоянный ток преобразуется в переменный с частотой до 100 кГц. На последнем этапе происходит выпрямление потока и последующее его использование в сварочных работах. Важно знать, как сварить заготовки вместе и что для этого нужно, чтобы получить прочную конструкцию.

Конструкция и преимущества инверторных сварочных аппаратов

Перед тем как покупать сварочное оборудование инверторного типа, желательно ознакомиться с его устройством и сильными сторонами.

Конструкция инвертора представляет собой 4 ключевых детали:

1. Трансформатор. В моделях инверторного типа по размеру этот элемент не более пачки от сигарет. Он предназначен для снижения высокочастотного переменного напряжения.
2. Высокочастотный выпрямитель. Этот элемент выравнивает переменный ток, поступающий от общей сети. После него ток попадает в высокочастотный фильтр и выходит постоянным потоком.
3. Фильтр. Представляет собой конденсатор и дроссель. Предназначен для сглаживания выпрямленного тока.
4. Выпрямитель. Диод, в который поступает начальный поток тока из общей сети.

Все элементы помещаются в металлический или пластиковый корпус, на котором расположена система управления аппаратом.

Преимущества инвертора:

1. КПД у таких аппаратов может достигать 90%. Практически вся энергия, которую потребляет оборудование, уходит на создание и поддержку дуги.
2. Потребляемая мощность ниже, чем у моделей с большим трансформатором.
3. Небольшие габариты. Малая масса. Благодаря этому использовать сварочный аппарат можно в труднодоступных местах.
4. Минимальное количество брызг расплавленного металла в процессе работы.
5. Минимальный уровень нагрузки на общую электросистему.
6. Возможность подбирать электроды нужной характеристики.

Работать с инвертором просто. Человеку без опыта достаточно попробовать 2–3 раза сварить между собой детали, чтобы понимать, как правильно делать шов.

Инверторный сварочный аппарат

Подготовка к работе

Перед тем как производить сварку металла инвертором, требуется подготовить рабочее место, электроды, оборудование. Чтобы научиться варить электросваркой не нужно искать профессиональные приспособления и рабочие верстаки. Для начала подойдёт небольшой металлический стол. Главное, чтобы на нём свободно размещались все инструменты, сварочный аппарат и заготовки.

Важно подготовить качественное освещение и вентиляцию в помещении. При сварке металлов выделяются вредные испарения. Помимо освещения и вентиляции требуется убрать как можно дальше горючие материалы и жидкости. Сварщику нужно стоять на материале, не проводящем электричество.

Электроды выбираются в зависимости от того какие металлы нужно сваривать и какой они толщины. На упаковках с расходными материалами указывается для какого материала они предназначены.

После выбора электродов и подготовки рабочего места, требуется подключить оборудование. Из инвертора выходит два кабеля. Один представляет собой массу и имеет «металлический крокодил» на конце. Он прицепляется на обрабатываемую деталь или к металлическому столу. Второй кабель представляет зажим для электрода.

Работа инвертором

Перед включением аппарата желательно ознакомиться с тем, как варить инверторной сваркой. В комплекте с покупным оборудованием присутствует инструкция. Ниже будут описаны основные этапы работы.

Розжиг дуги

В первую очередь необходимо разжечь дугу. Для этого применяется два метода:

1. Чирканье — сварщик начинает вести электродом по обрабатываемой заготовки, а потом поднимается над ней до образования искры.
2. Постукивание — более популярный вариант розжига дуги. Сварщик постукивает концом электрода по месту будущего сваривания до появления искры.

Способ розжига дуги выбирается в зависимости от комфорта и удобства.

Передвижение электрода

Чтобы качественно приварить деталь к детали, необходимо знать, как двигать электродом. Новички думают, что достаточно зажечь дугу и медленно провести электродом по месту соприкосновения деталей, чтобы получился ровный шов. Важно правильно выбирать постоянный угол движения электрода, скорость перемещения рабочей части оборудования. Вести электрод прямо под прямым углом допустимо для тонколистового металла.

Сварка электродом

Контроль дугового промежутка

Ещё один важный момент при сварке инвертором — расстояние между концом электрода и металлической поверхностью. Если расстояние около 2-х мм, проварка будет неглубокой и шов получится не прочным. Когда дуга более 4 мм, она становится нестабильной. Разбрызгивание металла увеличивается, а точность шва снижается. Располагать рабочую часть инверторного аппарата желательно на расстоянии 3 мм от металлической поверхности.

Правила создания ровных швов

Чтобы правильно варить металл и делать ровные швы, требуется учитывать некоторые особенности:

1. Выбор угла сварки. Оптимальным считается диапазон углов от 30 до 40 градусов.
2. Класть шов требуется продольными и поперечными движениями. В интернете существуют различные схемы, по которым можно тренировать движения нанесения шва.

Скорость выбирается в зависимости от выбранного способа работы электродом. Если вести электрод медленно, можно перегреть поверхность. При быстром ведение шов получается не прочным.

Оборудование и техника безопасности

Можно осуществлять не только сварку, но и резку металла сварочным инвертором. При проведении работ сварочным оборудованием, требуется учитывать правила техники безопасности:

1. Оборудование требуется проверить на наличие дефектов и поломок.
2. Сварочный процесс является вредным для здоровья. Чтобы защитить глаза, требуется использовать специальную маску сварщика. Она комплектуется светофильтрами, которые защищают зрение.
3. Помимо маски сварщику нужны защитные перчатки, спецодежда, обувь.

Место, в котором работает сварщик, должно оборудоваться специальной шторкой, которая защищает зрение посторонних людей.

При использовании инвертора требуется учитывать конструкцию оборудования, знать способы ведения электрода, правильно выбирать угол и скорость ведения рабочей части. Нельзя забывать про технику безопасности и подготовку рабочего места.90000 Arc Welding Fundamentals 90001 Arc welding is one of several fusion processes for joining metals. By applying intense heat, metal at the joint between two parts is melted and caused to intermix – directly, or more commonly, with an intermediate molten filler metal. Upon cooling and solidification, a metallurgical bond is created. Since the joining is an intermixture of metals, the final weldment potentially has the same strength properties as the metal of the parts. This is in sharp contrast to non-fusion processes of joining (i.e. soldering, brazing etc.) in which the mechanical and physical properties of the base materials can not be duplicated at the joint. 90002 90003 90004 90005 90006 90007 90008 90009 90003 90011 90012 90006 90014 90015 Fig. 1 The basic arc-welding circuit 90016 90011 90012 90019 90020 90002 90003 90002 90003 90002 In arc welding, the intense heat needed to melt metal is produced by an electric arc. The arc is formed between the actual work and an electrode (stick or wire) that is manually or mechanically guided along the joint.The electrode can either be a rod with the purpose of simply carrying the current between the tip and the work. Or, it may be a specially prepared rod or wire that not only conducts the current but also melts and supplies filler metal to the joint. Most welding in the manufacture of steel products uses the second type of electrode. 90003 90002 90015 90029 Basic Welding Circuit 90029 90016 The basic arc-welding circuit is illustrated in Fig. 1. An AC or DC power source, fitted with whatever controls may be needed, is connected by a work cable to the workpiece and by a “hot” cable to an electrode holder of some type, which makes an electrical contact with the welding electrode .90003 90002 An arc is created across the gap when the energized circuit and the electrode tip touches the workpiece and is withdrawn, yet still with in close contact. 90003 90002 The arc produces a temperature of about 6500ºF at the tip. This heat melts both the base metal and the electrode, producing a pool of molten metal sometimes called a “crater.” The crater solidifies behind the electrode as it is moved along the joint. The result is a fusion bond. 90003 90002 90015 90029 Arc Shielding 90029 90016 However, joining metals requires more than moving an electrode along a joint.Metals at high temperatures tend to react chemically with elements in the air – oxygen and nitrogen. When metal in the molten pool comes into contact with air, oxides and nitrides form which destroy the strength and toughness of the weld joint. Therefore, many arc-welding processes provide some means of covering the arc and the molten pool with a protective shield of gas, vapor, or slag. This is called arc shielding. This shielding prevents or minimizes contact of the molten metal with air. Shielding also may improve the weld.An example is a granular flux, which actually adds deoxidizers to the weld. 90003 90002 90003 90004 90005 90006 90007 90008 90050 90003 90011 90012 90006 90014 90015 Fig. 2 This shows how the coating on a coated (stick) electrode provides a gaseous shield around the arc and a slag covering on the hot weld deposit. 90016 90011 90012 90019 90020 90002 90003 90002 Figure 2 illustrates the shielding of the welding arc and molten pool with a Stick electrode. The extruded covering on the filler metal rod, provides a shielding gas at the point of contact while the slag protects the fresh weld from the air.90003 90002 The arc itself is a very complex phenomenon. In-depth understanding of the physics of the arc is of little value to the welder, but some knowledge of its general characteristics can be useful. 90003 90002 90015 90029 Nature of the Arc 90016 90029 An arc is an electric current flowing between two electrodes through an ionized column of gas. A negatively charged cathode and a positively charged anode create the intense heat of the welding arc. Negative and positive ions are bounced off of each other in the plasma column at an accelerated rate.90003 90002 In welding, the arc not only provides the heat needed to melt the electrode and the base metal, but under certain conditions must also supply the means to transport the molten metal from the tip of the electrode to the work. Several mechanisms for metal transfer exist. Two (of many) examples include: 90003 90076 90077 Surface Tension Transfer® – a drop of molten metal touches the molten metal pool and is drawn into it by surface tension 90078 90077 Spray Arc – the drop is ejected from the molten metal at the electrode tip by an electric pinch propelling it to the molten pool (great for overhead welding) 90078 90081 90002 If an electrode is consumable, the tip melts under the heat of the arc and molten droplets are detached and transported to the work through the arc column.Any arc welding system in which the electrode is melted off to become part of the weld is described as metal-arc. In carbon or tungsten (TIG) welding there are no molten droplets to be forced across the gap and onto the work. Filler metal is melted into the joint from a separate rod or wire. 90003 90002 More of the heat developed by the arc is transferred to the weld pool with consumable electrodes. This produces higher thermal efficiencies and narrower heat-affected zones. 90003 90002 Since there must be an ionized path to conduct electricity across a gap, the mere switching on of the welding current with an electrically cold electrode posed over it will not start the arc.The arc must be ignited. This is caused by either supplying an initial voltage high enough to cause a discharge or by touching the electrode to the work and then withdrawing it as the contact area becomes heated. 90003 90002 Arc welding may be done with direct current (DC) with the electrode either positive or negative or alternating current (AC). The choice of current and polarity depends on the process, the type of electrode, the arc atmosphere, and the metal being welded. 90003 90002 90029 90015 View more Arc Welding Process and Theory articles 90016 90003 90002 90015 View Arc Welding How-To articles 90016 90003 90002 90015 View Arc Welding Solutions articles 90016 90003 .90000 Arc Welding Tutorial 90001 90002 This tutorial is intended to offer practical advice to beginner arc welders. It was produced with a great deal of help and guidance from professional welders whose time was funded by forum members and supporters. Take the tutorial slowly and practice the work covered on each page before moving onto the next. 90003 90002 Arc welding (short for Manual Metal Arc (MMA) welding and also known as Stick and SMAW) is a very involved subject and we only cover enough to get you up to speed.There are many books on the subject, and more detailed information can be found elsewhere on the internet. Also we have a very friendly forum that can help. 90003 90002 As with any other electric welding process, skin and eyes need to be properly protected from UV light. Electric shock, fumes, burns, and fire are other risks. 90003 90002 The safety page discusses how to minimise these risks. 90003 90010 90002 The arc is started by touching the electrode momentarily against the work to complete the electrical circuit before raising the electrode to establish the arc.90003 90002 ‘Tap starting’ and ‘scratch starting’ are the two common methods of starting the arc. Which one to use is a personal preference, and can be influenced by rod and welder type. Both techniques are illustrated with videos on this page. 90003 90015 90002 The basics of arc welding are covered on this page with practice laying beads in the flat position. 90003 90002 Rod angle, arc length, travel speed and welding motion are illustrated with photos and videos, and a video shows the effect of varying the arc length.90003 90020 90002 When learning any new process you’ll likely start off doing things wrong. Profiles and sections of welds with various faults are compared with good welds on this page. 90003 90002 The faults covered are incorrect travel speed, incorrect arc length, and incorrect amps. 90003 90025 90002 Arc welding is especially suitable for joining thick material as cold joins are easy to avoid.That makes it possible to tackle thicker material using multiple passes of weld. 90003 90002 This page covers joint preparation and techniques used in multiple pass arc welding. 90003 90030 90002 Having spent time getting the root weld right on the previous page you’ll find fillet welding a breeze. 90003 90002 Multiple passes are also commonly used in fillet joints. This page covers rod angle, weld sequence, and a little joint design.90003 90035 90002 For most people a DC inverter is the best type of arc welder to go for. They have many advantages over the older types, but can fall down on repair costs and longevity. 90003 90002 The page covers what to look for in inverter welders and other types of arc welder. 90003 90040 90002 Arc welding has been around for a while, and there are big differences between the technologies used in older secondhand welders and new ones.90003 90002 This page discusses the pros and cons of different types of arc welder. 90003 90002 How to weld just about anything from a nuclear power station to a bicycle frame! 90003 90002 This section summarises the welding procedures and consumables that might be used to weld the more widely used types of steel including Mild Steel, Corten, Weldox, Hardox, Stainless Steel, Chrome Moly, EN19, EN24 / EN24T, EN8, Cast Iron, Cast and Manganese Steels, Wrought Iron, and Hardfacing.There is also a page explaining hydrogen embrittlement. 90003 90049 90050 More Soon: 90051 90002 Vertical up is the next positional weld we’ll cover, and a page on rod selection and welding different types of steel is on it’s way. In the meantime there’s a lot more information about arc welding in the forum library. 90003 90050 Credits 90051 90002 Many thanks to everyone who helped fund and prepare this tutorial.In particular, Snowcat for doing most of the welds and providing excellent advice over several welding and writing sessions, TechnicAl for the page about selecting rods for different types of steel, Matt from Lorch who lent me a h280 when my Syncrowave packed up, and Weldequip who donated a lot of gear and consumables to support the tutorial. 90003 90002 90003 .90000 Arc Welding Tips 90001 90002 90003 Here are some simple arc welding tips and techniques you can use to improve your stick welding skills. Let’s begin. 90004 90003 90006 By the way, when you weld be certain you wear some quality gloves, a helmet, clean quality lenses in your helmet, and safety glasses. 90007 90004 90003 90006 When you light your rod make sure you are comfortable. There’s nothing worse then getting tendonitis or carpel tunnel. 90011 90007 90004 90003 I know because I have it and wish I had followed some ergonomic positions a little better.90011 90004 90017 Scratching Method For Starting The Arc (Also Known As Brushing): 90011 90019 90003 Scratch the rod on your metal, and the bring the rod back to begin your molten weld puddle to start welding. 90004 90022 90017 The Tapping Technique For Starting The Arc! 90011 90019 90003 You can also use the tapping method to start the arc. Here’s how this works. You need to hold the welding rod in a 90 degree angle to the base metal. 90004 90003 You begin the arc by tapping it on the metal surface.After you tap it you will lift it to about the distance of the diameter of the welding rod. So if you have a 1/8 inch rod, you hold it about 1/8 of an inch from the surface. 90004 90003 You can also ‘bounce’ the welding rod rather than tapping it. 90011 90004 90003 You’ll know you have an arc when you hear the distinct stick welding sound which is a crackling sound. 90011 90004 90036 90017 Is Your Welding Rod Sticking? 90011 90019 90003 Whether you are using the tapping or scratching technique to start the arc you may find that the welding rod will stick as you pull it away to begin your weld.To free up the welding rod you can use a flick of your wrist in a sideways motion. 90004 90003 If this does not work then you’ll have to turn your arc welder off, or you can take the welding rod off the stick holder. Then, use your chipping hammer to get the rod off the material. 90011 90004 90045 In Arc Welding It’s All About The Puddle! 90011 90047 90003 When you begin your weld puddle make sure the arc gap is steady, and set your amperage settings at the right level in order to allow for your weld puddle to spread out.90011 90004 90003 The weld puddle, which is molten metal, will follow the heat generated by your arc. So avoid undercutting by filling in and along the edges of your material. 90011 90004 90003 90055 A simple but good arc welding tip is to add some filler metal to your weld puddle prior to taking it out and back over the weld. 90056 90004 90003 Always be observing your weld puddle because a good weld is always accomplished by focusing on what is occurring it it. As you are welding you will need to control how much filler material you’ll use and control how much heat is being generated, which totally effects the weld puddle.90011 90004 90003 What you do not want to do is look directly at the rod or the light. But what you do want to do is focus your attention on the molten metal or the weld puddle (others call it the weld pool). 90004 90063 90003 90055 Observe how much weld your are building up. 90056 Watch the edges of your weld, and see how fluid the weld is, and adjust slightly as you do all of this. 90004 90003 The main control of the heat is provided by the amp settings. The amp settings on your machine are what regulates how much current you are sending through your welding rod.90004 90003 If your settings are too low you will find that the weld puddle will just form under the end of your welding rod as seen here: 90011 90004 90073 90003 But if you increase the amps you will generate more heat and then you will create a molten pool (weld puddle). This is about where you want your puddle to be: 90011 90004 90077 90003 This is the point where you will be able to control the weld build up, and the edges of your puddle, and begin to get penetration of your base metal (you always want good penetration).90004 90003 A good arc welding puddle will flow nicely out from the edges of your welding rod like this, but not too much becauase you will lose control of your puddle: 90011 90004 90083 90003 The amount of heat you want to generate will change when the following occurs: 90011 90004 90087 90088 Metal thickness changes. 90089 90088 Welding position changes 90089 90092 90003 As I mentioned above you must watch the puddle. And what you want to observe is how the weld puddle is flowing to either side of your welding rod.90004 90003 When you increase the amps your weld will spread out more and penetrate deeper. 90011 90004 90003 If you increase the heat too much you will not be able to control the your puddle. So what you want to do is play around with your amperage settings to the point where you find that you are getting smooth welds while also getting good penetration. 90004 90003 In other words you want to keep the amps as high as possible but not to the point where the puddle is to difficult to control.90004 90102 90017 Arc Welding Rod Tips, Types, and Their Weld Puddles: 90011 90019 90003 Welding rods have a coating of flux on them and these rods come in different diameters and they have different characteristics which effects how your weld puddle appears. 90004 90003 90055 6010 and 6011 Rods – The weld puddle is visible: 90056 90004 90112 90003 90055 6013 Rods – Slag covers the rim of your puddle. But the weld puddle is visible on both sides of the rod and the puddle moves fairly easy: 90056 90004 90117 90003 90055 7018 Rods – Slag will cover the whole weld puddle.90056 90004 90003 However, with 7018 welding rods you want to be able to see the puddle flowing on the sides of your rod as well as the slag solidifying behind it. 90004 90003 Also, as you weld the filler material is hardening beneath the slag covering. But the slag is still molten. So what happens is that the slag can drip if you are welding in the vertical or horizontal position. 90004 90003 Newbie welders will believe that the weld is way to hot as they see the slag drip, but that is not necessarily the case.90004 data-ad-format = “horizontal”> 90003 7018 is not the easiest welding rod to work with but it just takes a little practice and you’ll need to play around with the amperage settings as well. However, you’ll get a better overall weld if you can run it a little hot. 90011 90004 90131 90017 What Determines How Fast The Metal Heats Up In Arc Welding? 90019 90003 The amperage settings only give you the heat you need. It’s your rods angle that determines how fast the metal will heat up.90004 90003 If your welding rod is at a perpendicular angle, you’ll find that the molten weld will spread quicker which will allow you to weld at a faster speed. This also puts a limit on how much you penetrate your material. And this is good if you are welding on thinner materials. 90004 90003 You’ll also be depositing less filler metal thereby creating a smaller weld or you’ll have a flatter weld bead if there are beveled edges when you use a perpendicular angle. 90011 90004 90141 90003 When you take an angle with your welding rod you’ll put less heat on the material (base metal).This will create an opportunity to travel at a slower speed and this way you can create more weld build up (a crowned bead). 90004 90003 However, if you take too much of an angle you will not get enough heat to your base metal and you will have a thinner molten pool (in appearance). The bead will stack and then you’ll lose control of your weld puddle. 90004 90003 90055 This is a good angle: 90056 90011 90004 90151 90003 Most of the time you will keep the same rod angle for most joints, assuming they were prepared well with good fit up.However there are times when you will need to vary the angle of your rod. 90004 90003 For example you may need to fill a gap. So you’ll make more of an angle which will slow down your speed of travel and therefore you’ll deposit more metal into the gap. And then, you will go back to your original angle to complete your weld. 90004 90003 Changing and controlling your rod angle requires a little bit of practice. However, you’ll get better, faster, if you can stay relaxed. 90004 90003 90055 The main goal here is to keep the molten weld puddle in a uniform size throughout your welding.90056 And it does not matter if you are angling your rod to build up the weld deposit, or if you are need to flatten a bead by taking a more perpendicular angle. You should always maintain the size of the puddle with the travel speed. 90004 90045 More About Arc Gap! 90011 90047 90165 90003 The distance between the metal and the tip of your welding rod once the arc is struck is called the arc gap. And stick welding machines (arc welding machines) use a constant current power source.So when the amperage is set the voltage varies as it is maintaining the arc. 90004 90168 90003 You do not want your arc gap too short or too long. But you can use small adjustments in the arc length to help control the weld puddle. 90004 90003 90055 Generally speaking, a medium arc gap is good for building up weld. 90056 90011 90004 90176 90003 Conversely, a short arc gap length will limit the heat to the molten metal which in turn cools it down. 90004 90003 90055 7018 Rod Arc Welding Tip: 90056 When using 7018 rod, a shorter arc gap might work well if building up the weld is desired.90004 90183 90003 If you lengthen the arc a bit you’ll increase the heat and spread the weld puddle out. 90004 90003 If you combine a longer arc gap with a more perpendicular angle you’ll make a smaller bead or you’ll flatten your weld on thicker metal. 90004 90188 90045 Developing Your Own Arc Welding Technique! 90011 90047 90003 90055 The most crucial factor when you weld is to maintain consistency as you weld. 90056 When you change the arc gap as you weld you change the amount of heat to the weld puddle and creating a uniform weld is hard.90004 90003 As you learn all these different techniques and technicalities in welding you soon discover that there are many ways to run a weld bead. And that is the reason that most welders do things a little bit different than each other. 90004 90003 What all good welders have done or continue to do is practice and fiddle around with their welds so that they can find ways to manipulate the weld puddle. Watch it, and control it, and as you practice you will create a welding style for yourself.90004 90045 The Weld Bead and The Affects On Metal! 90011 90047 90003 The heat that is generated effects the metal you are welding. See, metal is made up of atoms that have been bonded, forming a grain. And when the metal you are welding is heated and cooled you create smaller grains which makes the metal even harder. 90004 90003 90055 Cooling the metal at a slow rate provides the opportunity for atoms to bond and form larger grains which in turn makes the metal softer. 90056 90011 90004 90003 When you are welding the metal, the metal which is just next to the bead you are forming gets very hot which changes the structure of the metal grains.90004 90003 And since there is a small area that is heating up from the weld bead the metal will cool down fast, and if you followed what I was saying above, grains are formed right along the side of the weld bead. The grains are smaller in size and they become hard. 90004 90214 90003 In addition, a weld bead causes the joint you are welding to ‘draw’. In other words, it expands as you are welding. And when it cools down it contracts. 90004 90003 90055 The metal will draw toward your weld.90056 So in other words the metal moves, no matter what and this causes stress in the metal if the metal has nowhere to go. 90004 90221 90003 So what you want to do is weld on both sides of the joint whenever you have the opportunity. You can also try tacking and us intermittent welding (staggering) your weld to reduce this from happening as severely, especially on square tubing or pipe. 90004 90003 When welding on metal and there are significant temperature issues there are greater effects on the material.For example, if the metal is really cold, you should pre-heat the material prior to welding with a torch. When you pre-heat freezing metal you’ll see moisture build up. Stop heating the metal until the moisture disappears (dries). 90004 90003 90055 In addition, when you are arc welding harder metal (high carbon steel) you’ll probably want to pre-heat it because high carbon steel does not like expansion and contraction. It may crack when it cools. 90056 90011 90004 90003 In welding, there’s a lot to consider.But do not overthink it too much. Simply do your best to finish a weld once it’s started. 90004 90087 90088 Do not create more weld buildup than is needed. 90089 90088 Let the metal cool down slowly when you are done welding. 90089 90092 90003 If your material cracks or breaks next to your weld then take a second look at the design you are working on as well as if the metal thickness is appropriate for the design. 90004 90003 90055 Recommended Arc Welding Tips Article: 90056 90004 90245 data-ad-format = “horizontal”> .90000 Arc Tutorial – Rod Position, Motion, and Technique 90001 90002 Arc welding takes some effort to learn, and it is 90003 90004 very 90005 90006 sensitive to the position of the work. It’s a good idea to keep things easy to begin with by laying beads on the flat. We’ll cover joints later. 90007 90002 The following setup is a good starting point for this tutorial: 90007 90010 90011 90004 Work: 90005 6mm mild steel. Arc welding is more tolerant to slightly rusty metal and mill scale than other electric welding processes, but it is good practice to clean the worst off with a grinder before welding.90014 90011 90004 Rods: 90005 3.2mm 6013 rods. USE GOOD QUALITY RODS! A forum member trying to learn with DIY store rods had terrible trouble until someone sent him a few brand name rods to prove a point. Also 3.2mm rods are easier to learn with than 2.5mm rods. 90014 90011 90004 Amps: 90005 110 amps. (If you want to use 2.5mm rods reduce the current to about 80 amps – the current is determined more by the rod size than the thickness of sheet).90014 90011 90004 Polarity: 90005 DCEP (rod positive, earth negative – this is the opposite of the polarity used in TIG). Use AC if that’s all you have. 90014 90027 90002 That’s what we’ve used over the next couple of pages. You can compare your practice with our efforts, in particular with the fault finding guide on the next page. Not all welders have perfectly calibrated amps, so you may need to adjust yours to avoid faults. 90007 90030 Rod Angle (lead angle) 90031 90002 For welding on the flat (as in the photo) the rod should be angled 10 to 20 degrees from vertical and pulled in the direction of the arrow.The angle of the rod prevents the slag overtaking the rod (welding over slag would cause inclusions in the weld). 90007 90002 In the photograph the rod has been bent at the electrode holder to position the holder at a more comfortable angle. 90007 90002 It’s OK to support the top of the electrode with your spare hand and this improves control of the electrode. Electric shocks are not a problem, but be careful to reposition your hand away from the heat before the electrode gets too short.90007 90038 90030 Arc Length 90031 90002 The arc length is the distance between the electrode and the weld pool. It should be roughly the same as the diameter of the rod. 90007 90002 90004 This is nowhere near as straightforward as it sounds! 90005 90007 90002 The photo shows how the electrode becomes recessed inside the flux covering on the rod. The weld pool will also be hidden by molten slag.90007 90002 To achieve the correct arc length using 3.2mm rods the distance between the flux coating on the rod and the flux on top of the weld might be less than 1mm. 90007 90051 90002 The arc length is normally judged by the sound and visible light from the arc. 90007 90002 In the video the arc length is varied between correct, too long, and too short. Both the intensity of light and the sound of the weld alter dramatically with the length of the arc.90007 90002 The arc should be kept short and hide the majority of the light from the weld without pushing the rod into the slag pool. A good short arc length will result in a consistent sharp crackling sound. 90007 90002 The appearance of the completed weld will provide further clues – see photos of welds with incorrect arc length on the faults page. 90007 90030 Maintaining Lead Angle and Arc Length 90031 90002 The rod becomes shorter as the weld progresses, and it takes a conscious effort to reduce the length of the arc as the rod gets shorter.Excess arc length can lead to an unstable arc, excess heat and undercutting and is probably the most common beginner fault. 90007 90002 The angle of the rod should also be maintained over the length of the weld. A little practice is required to avoid decreasing the lead angle as the weld progresses, as this can result in slag inclusions and even cause the arc to stall. The easy way to maintain rod angle is to focus attention on moving the rod holder rather than the rod as the weld progresses.90007 90002 The video shows a 2.5mm rod being consumed while running a bead around 200mm long. 90007 90030 Welding Motion 90031 90002 For most arc welding the rod is moved in a straight line to form a “Stringer”. A tiny amount of weave can be used to help control speed and direction. 90007 90002 In the video the arc is started with a tap start. The rod quickly becomes shorter as the weld progresses and the motion that can be seen is constant correction to maintain a short arc length.90007 90002 Note the rod angle is also maintained. It takes practice to maintain arc length and rod angle, especially if you are moving to arc welding from another welding process. 90007 90002 90007 90030 Slag 90031 90002 Do not look closely at a hot weld – bits of slag continuously ping off the weld as it cools and it is very painful to have them removed after they’ve burned themselves into your eye.Eye protection is also a good idea when chipping slag as it’s brittle and can fly a fair distance. 90007 90002 The slag covering the weld should be reasonably easy to remove, though it does depend on the type and quality of rods (we were using some good quality 6013 rods here so it was easy). 90007 90084 90030 Practice makes pads 90031 90002 Other positions will go disappointingly badly before you have perfected laying beads.A good way to practice is to weld a pad on 6mm plate. 90007 90002 Clean the plate thoroughly, then lay the first weld in a straight line near the edge of the plate. Remove the slag and lay a second weld immediately to the side of the first, close enough so the two welds merge together with no gap. Repeating several times should result in a pad of welds with a flat top. If you struggle maintaining a straight line then drawing a line in chalk might help.90007 90002 Turn the pad 90 degrees and weld the next layer of the pad. 90007 90002 In college training the pad would be sectioned to check for inclusions in the weld. The practice helps develop consistency, keeping the weld in a straight line, and is good preparation for thicker metal where the joint is often formed from multiple strings of weld. The technique is also used for hard facing and building up worn material.90007 90002 90007 .