Techniques for joining metal components under conditions of extreme heat have existed for centuries. Early welding equipment would have consisted of a forge, such as a blacksmith would use, and a metalworking hammer. A forge is a large fireplace which is designed to hold a fire hot enough to soften metal to the point where it can be worked and shaped. A blacksmith would use bellows to blow air into the fire. Increasing oxygen would cause the fuel to burn more quickly, making for a hotter and more efficient fire. Once the fire was hot enough to melt the metal to be worked, the blacksmith would use tongs to move the piece to an anvil, which is like a specially shaped metal workbench. To join two pieces of metal together, they would be placed together on the anvil and pounded together with a hammer until the two molten surfaces formed a bond. When the newly formed piece of work was dipped in cold water or brine, the metal would harden and the shape be made permanent. This primitive welding equipment could also be used to work metal in many other ways, such as shaping and cutting. It’s no wonder a skilled blacksmith was considered an important and influential figure in the community.
Around the time of the industrial revolution, great leaps forward were made in harnessing and utilizing the power of electricity. Polish and Russian scientists passed electricity through carbon electrodes to create carbon arc welding. This was the first time equipment had been developed which could accomplish electric arc welding. Over the subsequent decades, materials technology continued to advance and better and better electrical welding equipment was produced. This was a time of great innovation in the fields of science and engineering, and techniques like resistance and thermite welding followed hot on each other’s heels. The development of a new kind of torch around the year 1900 meant acetylene gas, discovered over fifty years earlier, could be used in welding equipment.
As was the case with so many other fields of endeavour, the great wars of the twentieth century, though tragic, drove technological progress an unprecedented rate. Ships and aeroplanes started to incorporate welded structural elements, and the mass production of armour, weapons, ammunition and other equipment made full use of the process. Civil engineering practice was affected too; in 1927, the first welded road bridge in the world was completed in Poland.
The biggest advancement in welding techniques and equipment between the wars came as a result of problems inherent to existing methods. Due to the extreme localized heating of the components welds became contaminated by gases in the air such as oxygen and nitrogen. This led to brittleness of the joint, and in some cases welds would become porous, absorb moisture are succumb to corrosion. The solution was to flood the atmosphere with inert, or unreactive, gas at the moment of bonding. This prevented any reactions in the surface of the metal, making for a stronger bond.