41xx steel

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Template:Short description 41xx steel is a family of SAE steel grades, as specified by the Society of Automotive Engineers (SAE). Alloying elements include chromium and molybdenum, and as a result these materials are often informally referred to as chromoly steel (common variant stylings include chrome-moly, cro-moly, CrMo, CRMO, CR-MOLY, and similar). They have an excellent strength to weight ratio and are considerably stronger and harder than standard 1020 steel, but are not easily welded, requiring thermal treatment both before and after welding to avoid cold cracking.[1]

While these grades of steel do contain chromium, it is not in great enough quantities to provide the corrosion resistance found in stainless steel.

Examples of applications for 4130, 4140, and 4145 include structural tubing, bicycle frames, gas bottles for transportation of pressurized gases, firearm parts, clutch and flywheel components, and roll cages. 4150 stands out as being one of the steels accepted for use in M16 rifle and M4 carbine barrels by the United States military. These steels are also used in aircraft parts and therefore 41xx grade structural tubing is sometimes referred to as "aircraft tubing".

Properties

Alloy composition by weight (%)[2]
SAE grade Cr Mo CTemplate:Efn Mn P, max. S, max. Si
4118 0.40–0.60 0.08–0.15 0.18–0.23 0.70–0.90 0.035 0.040 0.15–0.35
4120 0.40–0.60 0.13–0.20 0.18–0.23 0.90–1.20 0.035 0.040 0.15–0.35
4121 0.45–0.65 0.20–0.30 0.18–0.23 0.75–1.00 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
4135 0.80–1.10 0.15–0.25 0.33–0.38 0.70–0.90 0.035 0.040 0.15–0.35
4137 0.80–1.10 0.15–0.25 0.35–0.40 0.70–0.90 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
4142 0.80–1.10 0.15–0.25 0.40–0.45 0.75–1.00 0.035 0.040 0.15–0.35
4145 0.80–1.10 0.15–0.25 0.43–0.48 0.75–1.00 0.035 0.040 0.15–0.35
4147 0.80–1.10 0.15–0.25 0.45–0.50 0.75–1.00 0.035 0.040 0.15–0.35
4150 0.80–1.10 0.15–0.25 0.48–0.53 0.75–1.00 0.035 0.040 0.15–0.35
4161 0.70–0.90 0.25–0.35 0.56–0.64 0.75–1.00 0.035 0.040 0.15–0.35
Template:Noteslist
Mechanical properties
Material Condition Tensile strength Yield strength Elongation at fracture,
2-inch gauge [%]
Hardness,
Rockwell
4130 Cold drawn, normalized[3] Script error: No such module "convert". Script error: No such module "convert". 20–30 B 90–96
4142 Hot rolled, annealed[3] Script error: No such module "convert". Script error: No such module "convert". 20–30 B 90–95
Cold drawn, annealed[3] Script error: No such module "convert". Script error: No such module "convert". 15–25 B 96–100
4150 Hot rolled, annealed[3] Script error: No such module "convert". Script error: No such module "convert". 20–30 B 90–96

Other characteristics

One of the characteristics of this class of steel is the ability to be case hardened by carburization of the surface. The core of the material retains its bulk properties, while the outer surface is significantly hardened to reduce wear and tear. This makes this grade of steel an excellent material for uses such as gears, piston pins, and crankshafts.[2]

4140 Steel

4140 Steel[4] (Quenched and Tempered) Mechanical Properties

Diameter d ≤ 16 16 < d ≤ 40 40 < d ≤ 100 100 < d ≤ 160 160 < d ≤ 250
Thickness t ≤ 8 8 < t ≤ 20 20 < t ≤ 60 60 < t ≤ 100 100 < t ≤ 160
Tensile Strength Template:Cvt Template:Cvt Template:Cvt Template:Cvt Template:Cvt
Yield Strength (Min) Template:Cvt Template:Cvt Template:Cvt Template:Cvt Template:Cvt
Elongation (% Min) 10 11 12 13 14
Reduction (% Min) 40 45 50 50 55
Impact Strength (J) ≥ - Template:Cvt Template:Cvt Template:Cvt Template:Cvt


See also

References

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