4130, what is it good for?
Absolutely nothing, huh! A lot! 4130 is a popular steel alloy with chromium and molybdenum added in. For this reason, odds are good you’ve heard it called “chromoly” or something similar. It offers some of the best weight-to-strength ratios available in steel. Also, it is stronger and harder than standard 1xxx series steels. It also remains easy to weld, though it is slightly more difficult than welding 1xxx series steels. 4130 can also be case hardened for special high-wear projects. Lastly, most people who know about 4130 know about the tubes, but 4130 round bar is a great material as well!
In the sky and on the road
4130’s high strength-to-weight ratio, ease of machining, and ease of welding make it extremely popular in the automotive and aviation industries. Though increased popularity of aluminum in these same industries has reduced 4130’s popularity, it still remains common. This is especially true for vintage and modern custom vehicles.
Aircraft and motorcycles tend to use 4130 tubes for weight reduction. As both planes and motorcycle frames have evolved, a greater emphasis has been put on having the lowest weight possible. However, planes and bikes still use 4130 round bar for smaller structural supports. Likewise, automobiles make more extensive use of the solid bars as weight is less of an issue.
Also, check out this blog post about a customer of ours who used our 4130 to build a 1931 Pietenpol Air Camper!
4130 round bar, normally normalized
When 4130 round bar is normalized, a whole new level of applications opens up. This is because the 4130 becomes significantly harder while still remaining ductile. Consequently, the bar has extra strength but also some flexibility so you don’t have to worry about it shattering under force like some other types of hard metal.
Due to these attributes, 4130 round bar is often machined down into gears, shafts, pins, and other engine components.
What should I use it for?
You should use 4130 round bar in applications where you need high strength, lower weight, ease of machining, and ease of welding. Whether that be building your own motorcycle or airplane, or machining parts to go into an engine. Specifically, 4130 is optimal when you need more strength than 1018 steel or aluminum, but more ductility than stainless steel, and you don’t need the weight reduction of aluminum or titanium.
I hope that is useful, and as always, we love to see what our customers are working on. Please send us pictures of all the cool and amazing things you make! We can be reached via email, Facebook, Twitter, and Instagram.