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What many people new to welding refer to as “iron” can be one of two possibilities: wrought iron or cast iron. And one of the most commonly asked questions are ‘can you weld steel to iron?’ The answer is yes, both are readily weldable to steel. Firstly, wrought iron has an interesting characteristic of not rusting the way carbon steel does. After it forms surface rust, the rust tends not to penetrate deeper. For this reason, it is crucial to weld wrought iron with stainless electrodes (the default is 309L, but there are others you can use as well) or braze it with an oxygen-acetylene torch if you want to reduce the amount of residual stress. These methods work well in most situations, though they are not ideal for welding wrought iron to medium or high-carbon steel.

The reason is that the extra carbon content’s strength will be redundant because wrought iron gives out under higher loads than medium/high-carbon steels are designed for. That said, if the medium or high-carbon steel is to be used for loading common to low-carbon steels, then the weld will hold no problem.

There Are Four Main Parameter You’ll Want to Follow to Weld Cast Iron to Steel

One is that you need to preheat the cast iron before welding begins. A preheat of anywhere from 300-600 degrees Fahrenheit should be sufficient. Secondly, it is paramount that you thoroughly grind clean the area welded on the cast iron before even tacking the two pieces together. Any dirt, oil, or even scale coating of the cast iron that gets into the weld will drastically increase the weld puddle’s surface tension and make it prone to cracking. Thirdly, you’ll find the most success in using nickel-alloy electrodes. The nickel will reduce contamination of the weld puddle, which is a common threat to welding cast irons. The final tip for welding cast irons to steel involves starting with stitch-welds and then welding in the gaps after the initial pass has been completed all-around. By welding only about one inch at a time, you’ll help to avoid cold cracking.

To learn more about how to weld steel to iron or for professional welding services in the Greater Toronto Area, contact the Central Mobile Welding team today.