Spring steel is medium-carbon steel or high-carbon steel with a high yield strength and malleability. Thanks to its unique and beneficial features, spring steel has a variety of applications such as knives, piano wire, antennas, springs. If you’re a blacksmith and struggling to figure out how to make spring steel, don’t worry. This article will explain thoroughly from the simplest to the most complicated steps.
The Manufacturing Process
What to know?
A key thing you need to know is to use suitable steel, which contains a certain amount of carbon. Virtually mild steel has zero carbon, so it can’t resist the heating process. That means you’ll need a material that contains at least 0.6% of carbon.
How Is Spring Steel Made?
Use a pair of tongs to transfer the metal to a forge, or you can use a blowtorch to heat it. The most crucial thing in this stage is reaching the critical temperature. The steel will lose its magnetism at the critical temperature, so you can try a quick test by applying a magnet.
If the magnet doesn’t stick to the steel, it has achieved the required temperature. In terms of color, you can check whether it’s warmer red (cherry red) or not. If this trick doesn’t work for you, just stick to the first one. Then put it straightaway into a suitable liquid that is often water, brine, 50/50 antifreeze, or oil. According to some experienced blacksmiths, it’d be better to warm up your oil first. You can put a hot piece of metal in the liquid container before heating the metal.
After taking the hot steel out and letting it cool, it is very hard, like a file but not pliable enough for you to turn into springs. Therefore, it asks for another heat treatment, which typically involves heating it to about 570 F or 293 C. Mentioning the color, what you’re looking for is a blue color (like clock-spring blue). However, don’t be fooled by the first blue you see; it’s still brittle at that stage, so go a bit further when you get a darker blue. The bright white surface on the hardened piece can act as a tempering indicator. When you see those spots, gently and carefully reheat them until achieving the right temperature.
Color recognition requires specific experiences and operator skills. Thus, If you are a beginner, it is best to use the temperature-controlled oven for tempering rather than the color recognition technique above to ensure quality.
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Frequently Asked Questions
What Metal Used To Make Springs?
Each metal has different properties, weaknesses, and strengths. Depending on the end-use purpose, you can decide which metal to produce springs. Here is the introduction of some materials that manufacturers widely use.
Steel
One of the best metal uses for manufacturing springs is steel. Steel is iron alloyed with elements like carbon, and that’s why it maintains both toughness and pliability. Here are some types of steel.
Low-alloy Steel
The addition of nickel or molybdenum helps the spring withstands hot compressive strength, which means it can last longer under axial stress. Combined with chromium, low-alloy steel is believed to improve creep strength.
Cool-Form Steel
What’s unique about cold-formed steel is the high tolerance to stress and temperature and the incredible ability of tensility. It perfectly works for creating wire form and springs like tension springs and die springs. The quality and shape will change based on each respective application.
Stainless Spring Steel
Unlike other materials, stainless spring steel contains a high amount of chromium, which varies from 10% to 17%. This high concentration makes stainless spring steel possess excellent strength tolerance and avoids oxidization and some organic acids. That’s why it’s widely used daily like lock picks, washers, antennae, springs. However, this spring steel requires a pretty hot working environment which cannot be below 1700F to get optimized quality.
Copper And Titanium Springs
Unlike steel, copper is softer, so it can barely withstand heavy loads. Meanwhile, titanium is expensive and more brittle for day-to-day use. However, both still apply in many specific parts of the production industry. The anti-corrosion and conductive properties make copper strings widely used in the electrical field. Meanwhile, titanium springs involve in various medical equipment.
How Do You Harden Spring Steel?
You can use a gas blowtorch or specialized equipment like a forge to harden steel. You need to heat the metal directly over the heat. Then you can check the right temperature by noticing the red cherry color or using a magnet to test whether the metal loses its attraction to magnetism. After that, quickly quench the steel into a liquid container to cool it down. Submerge the hot metal in the liquid for a few minutes and take it out to let it naturally cool down.
Final Thoughts
Now that you know how to make spring steel, you can get to work using any of the methods mentioned in the article. Always keep in mind the type of metal to use, the required temperatures, and you will be good to go.