To weld or not to weld?
R.G. LeTourneau was the first man to make electric arc welding an accepted mass manufacturing and permanent repair process, especially for heavy equipment. He was an engineering genius and recognized the value and capability of welding and put it at the forefront of his manufacturing processes in his factories.
Previously, manufacturing relied heavily on casting, riveting and bolting and machining individual components to create a greater one. And in some cases, oxy acetylene welding was accepted. LeTourneau typically found a way to make a weld work in many areas no one could have thought of previously. To us today, the science of welding is relatively simple. We can weld, cut and reweld seemingly anything we’d like. But back then welding was not a practice that could be trusted fully and was typically held suspect. Even now, there are times when it may not be the best repair process and you might require special welding techniques.
Special alloys of steel and aluminum now produced are not designed to withstand the stress of welding. You need to really be sure of the type of metal you are using before welding it up. Not knowing basics about its metallurgical properties can be dangerous and cause serious failures.
Aluminum that is hard to weld can crack just in the cooling process without the proper preheating and post-heating treatment. If you don’t know what mystery metal you are working with, you may want to try to braze it, depending upon the application or use silicone bronze to “weld” it up with. Of course machining an item out of a solid billet may be the best solution, if you have access to a CNC milling machine. But it still requires the knowledge of basic metallurgical properties of the metal you are working with.
The problem still exists with using mystery metals. A test and see approach can be used, but unless radiological analysis is used, you probably won’t be able to see much visible defect. A visible problem won’t always show up until it is too late. If you are leaning toward welding an item, it’s a good idea to consult a professional if you are not sure of the metal makeup.
Even the most ordinary scrap piece of metal you pick up at the junk yard or welding shop as a “drop” may have metallurgical properties that require special welding techniques. If you can determine the origin of the metal, consult with texts to determine if there is any special requirement to weld it. You may be surprised by the recommendation for even many common metals.