41xx steel
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41xx steel is a family of high-strength low-alloy (HSLA) steels, as specified by the American Iron and Steel Institute (AISI). Alloying elements include chromium and molybdenum, and as a result these materials are often referred to as "chromoly" steels. They have an excellent strength to weight ratio, and are commonly used for structural tubing, for example in bicycle or race car frames. They are also used in aircraft, and 41xx grade structural tubing is sometimes referred to as "aircraft tubing".
While these grades of steel do contain chromium, it is not in great enough quantities to provide the corrosion resistance found in stainless steel.
Contents |
[edit] Chemistry Data
| AISI Grade | % Cr | % Mo | % C | % Mn | % P (max) | % S (max) | % Si |
|---|---|---|---|---|---|---|---|
| Typical | 0.70 - 1.10 | 0.8 - 0.35 | 0.xx* | 0.40 - 1.00 | 0.035 | 0.040 | 0.15 - 0.35 |
| 4130 | 0.80 - 1.10 | 0.15 - 0.25 | 0.28 - 0.33 | 0.40 - 0.60 | 0.035 | 0.040 | 0.15 - 0.35 |
| 4140 | 0.80 - 1.10 | 0.15 - 0.25 | 0.38 - 0.43 | 0.75 - 1.00 | 0.035 | 0.040 | 0.15 - 0.35 |
* - The carbon composition of the alloy is denoted by the last two digits of the AISI specification number, in hundreths of a percent (eg., 4130 is ~0.30% carbon)
[edit] Properties
Typical properties for the common 4130 grade steel.[2]
| Physical | |
|---|---|
| Density | 7.85 g/cc |
| Mechanical | |
| Hardness (Brinell) | 197 |
| Young Modulus | 205 GPa |
| Bulk Modulus | 140 GPa |
| Shear Modulus | 80 GPa |
| Poisson's Ratio | 0.29 |
| Tensile Strength (Yield) | 435 MPa |
| Tensile Strength (Ultimate) | 670 MPa |
[edit] Other Characteristics
One of the important characteristics of the 41xx class of steels is their ability to be hardened, by carburization of the surface. The core of the material retains its bulk properties, while the outside is significantly hardened to reduce wear and tear on the part. This makes this grade of steel an excellent material for such uses as gears, piston pins, crackshafts, etc.1
[edit] References
- ^ Erik Oberg, et. al., "Machinery's Handbook," 27th ed., Industrial Press Inc., 2004.
- ^ http://www.matweb.com/search/SpecificMaterial.asp?bassnum=M4130Y
