BMJ Engineering | Welding and farming
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Welding and farming

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Welding and farming

Welding and farming? They have more in common than you might think. In fact, one astute farmer recently noted, “you can’t run a farm without welding.” This farmer was absolutely correct — to keep equipment in working order for the critical seasons of planting and harvesting, welding and hardfacing during the off-season are musts. A good working knowledge of these processes also comes in handy when your equipment breaks down during off-hours and you need to quickly fix so you can continue your work.

In this article, we will introduce you to some of the key concepts in welding and hardfacing. When we refer to welding, we are talking about joining metal pieces together to build something. The weld is primarily for strength purposes. Hardfacing, on the other hand, is depositing (by welding with special hardfacing electrodes) wear- resistant surfaces on existing metal components which are under stress to extend their service life. Hardfacing is very commonly done to metal edges that scrape or crush other tough materials -like the blade on a road grader.

We will discuss different applications, ways to identify metallurgy, basic welding procedures and safety. So often, the beginning or novice welder will not get the desired results and assume his welding machine or electrodes are not working properly. In many of these instances, though, the farmer did not take the necessary preparations before welding or has chosen the wrong process, parameters or consumables. In this article, we hope to educate you so that you will know what to use in a few applications and can get the best results. Realize that although a little welding knowledge could help you a lot, there is a lot to becoming a true welding expert, which would cover many books!

Welding Applications

Farmers constantly need to repair and modify machinery and equipment to suit their specific needs. This instant ability to alter steel gates, chutes, animal pens, and machinery is such a tremendous benefit to the farmer. Repairing a broken plow or combine in the field by welding it where it broke in minutes can literally save an entire crop. The needs of beef cattle can usually be taken care of with mild steel. Dairy cattle, and virtually their entire milk-handling system require stainless steel. Two similar appearing animals with very different welding needs. But both needing welding to succeed.

Hardfacing Applications

There are many different items that could potentially benefit from hardfacing on the farm. They can basically be put into three “wear” categories – abrasion, impact, and metal-to-metal. Abrasion is one of the most common wears you will see on a farm, in this category falls all earth engaging implements such as tractor buckets, blades, teeth, grain handling products and feed mixers. Under the impact heading you will find equipment used to pound and smash such as crusher hammers. Metal-to-metal refers to wear from steel parts rolling or sliding against each other. Metal-to-metal wear occurs on such items as crane wheels, pulleys, idlers on track-drives, gear teeth and shafts.
Although farmers use welding and hardfacing techniques to rebuild old, worn-out components, Lincoln recommends hardfacing many new components as well. By hardfacing something that is new, it may increase the overall life expectancy of that product.

Basic Metallurgy

Before you can weld or hardface, you first need to identify the parent metal. A good rule of thumb on the farm is that nothing is mild steel. Almost all implements are high strength steels (either high or low alloy) and many are higher carbon steels. But how do you tell the difference? There are a couple of tests that can help.

The first is a magnetic test. If a magnet will stick to the implement then it is likely iron-based. A magnet that will not stick indicates probably a manganese or stainless product. Secondly, try the spark test. If you take a grinder to the item, do you get 30″ long, moderately large volume of yellow sparks with just a few sprigs and/or forks indicating mild steel, or do you achieve 25″ long, slight to moderate volume of yellow orange sparks, a few forks with intermittent breaks but few if any sprigs to indicate alloy steels or do you get 15″ long short, red sparks in large volume with numerous and repeating sprigs, which are telltale signs of a high carbon metal? Another test, the chisel test, will help indicate the type of metal as well. If the metal fractures in large chunks when you take a chisel to it, this means you have cast iron, which can be very difficult to weld unless using special high-nickel electrodes and heat-treating. On the other hand, if the chisel yields corkscrew-like shavings, you are looking at a weldable steel.

What Is the Goal?

Now that you have identified the base material, you need to assess your final goal. In a farm type setting, you need to ascertain whether you need to strengthen the item or prevent wear? If the item in question is a hitch bar on a tractor, the ultimate goal is strength and ductility so that it will not break. WELD IT! If you are talking about an earth-engaging tool, you don’t want it to wear out. HARDFACE IT!

Identify What Method to Use

There are three types of welding methods to consider. They differ by speed and cost. The methods are all available to all welding and hardfacing products. However, specific products often have properties that are somewhat unique and not exactly duplicated when utilized by a different process.

Stick Welding

Manual or stick welding requires the least amount of equipment and provides maximum flexibility for welding in remote locations and in all positions. Typically, each rod permits welding for about one minute. In seconds, one can change from mild steel to stainless to hardfacing. In seconds, the electrode can change from small to large diameter for small or large welds. Although simplest, this type of welding takes the greatest operator skill.

Semiautomatic

This type of welding uses wire feeders and continuously fed electrodes. The welding gun is hand-held by the operator. The gun keeps feeding wire as long as the trigger is depressed. This is also much easier to learn than stick welding. This type of setup is becoming more popular on farms, which do more than minimal repair work. Semiautomatic welding increases deposition rates over manual welding because there is no need to stop after burning each rod.

Automatic

Requiring the greatest amount of initial setup, automatic welding has the highest deposition rates for maximum productivity. The welding gun is carried by a mechanized carriage and the welding operator just pushes a start button. This would rarely be found on a farm, but is common at repair centers for heavy equipment that would rebuild your parts for you if the schedule was mutually acceptable.

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