4130 steel tubing (chromolly) is one of the most widely used materials in aviation and racing industries because of its weldability and ease of fabrication. 4130 steel is ideal when strong light weight steel tubing is needed. The weldability of 4130 chromolly steel tubing is excellent. 4130 tube is resistant to scaling and oxidation and has a clean, smooth finish both on the outside and inside of the tubing. Fabricators and engineers use 4130 tubing because of its outstanding strength, forgoing mild steel, where a thicker wall must be used to have equivalent strength as the 4130 chromolly steel tubing.
Who uses 4130 Chrome-Moly tubing. Chassis and components of
NHRA and
IHRA drag racing.
NASCAR suspension components.
IndyCars,
Sprints and other open wheel cars. High end Bicycles,
Experimental Aircraft as well as
racing snowmobiles use 4130 tubing.
OK, so what is 4130. First let’s quickly understand steel. Merriam-Webster defines steel as commercial
iron that contains
carbon in any amount up to about 1.7 percent as an essential alloying constituent, is
malleable when under suitable conditions, and is distinguished from cast iron by its
malleability and lower carbon content. AISI4130 Chrome-Moly is a steel alloy or more simply a mixture of base metals.Chrome is short for Chromium. Moly is short for Molybdenum. “Chrome” and “Moly” are two of the added base metals that add to the alloys strength.
The number ‘4130’ is a code of the
American Iron & Steel Institute (AISI 4-digit code system) The American Iron and Steel Institute (AISI) naming system is one of the most widely accepted systems that defines the approximate chemical composition of the steel.
Designations usually consist of a four digit number, but sometimes this extends to five. The first two digits indicate what the major alloying element is, while the last 2 or three indicate the carbon content in hundredths of a percent.
The ‘41’ indicates a low alloy steel containing chromium and molybdenum and the ‘30’ indicates a carbon content of 0.30 percent.Below is a table showing the chemical composition of 4130 Chrome-Moly shown in percentages.
| Carbon | 0.28 - 0.33 |
| Chromium | 0.8 - 1.1 |
| Manganese | 0.7 - 0.9 |
| Molybdenum | 0.15 - 0.25 |
| Phosphorus | 0.035 max |
| Silicon | 0.15 - 0.35 |
| Sulphur | 0.04 max
|
Now you know what 4130 Chro-Mo is next time we'll talk about why it is used and how to weld it.
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