What is the difference between high strength alloy steel 4140 and 4130?

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What is the difference between high strength alloy steel 4140 and 4130?

4140 is an alloy steel with high strength, hardenability, good toughness, small deformation during quenching, and high creep strength and enduring strength at high temperatures. Chemical composition: carbon C: 0.38~0.43 silicon Si: 0.15~0.35 manganese Mn: 0.75~1.00 sulfur S: ≤0.040 phosphorus P: ≤0.030 chromium Cr: 0.80~1.10 nickel Ni: ≤0.030 copper Cu: ≤0.030 molybdenum Mo: 0.15~0.25.


4130 steel is an American grade, which is equivalent to 30CrMo in my country. Due to proper hardenability, after proper metal heat treatment, the microstructure is uniform sorbite, bainite or very fine pearlite, so it has a higher tensile strength and yield ratio (generally in 0.85), higher toughness and fatigue strength, and lower toughness-brittle transition temperature, can be used to manufacture machine parts with larger cross-sectional dimensions.


4130 structural steel has high strength and toughness, high hardenability, and the critical hardening diameter in oil is 15~70mm; the thermal strength of steel is also good, with sufficient high temperature strength below 500℃, but at 550℃ Its strength is significantly reduced; when the alloying element is at the lower limit, the welding is quite good, but when the alloy element is close to the upper limit, the weldability is medium, and it needs to be preheated to 175℃ or more before welding; The range of 300~350℃ has the first type of temper brittleness; there is a tendency to form white spots.


AISI 4130 alloy steel (G41300), executive standard: Standard: ASTM A29/A29M-04.

AISI 4130 is mainly used in: In the medium-sized machinery manufacturing industry, it is mainly used to manufacture quenched and tempered parts with large cross-sections and working under high stress conditions, such as shafts, spindles, and high-load control wheels, bolts, studs, and gears.


AISI 4130 alloy steel contains chromium and molybdenum as reinforcing agents. It has low carbon content and is therefore easy to weld.

4140 (G41400) steel belongs to ultra-high-strength steel, and its implementation standard: ASTM A29M UNS-2012 (Standard Specification for General Requirements for Hot Forged Carbon Steel and Alloy Steel Bars).


4140 (G41400) has high strength and toughness, good hardenability, no obvious temper brittleness, high fatigue limit and multiple impact resistance after quenching and tempering, and good low-temperature impact toughness. The steel is suitable for manufacturing large and medium-sized plastic molds that require certain strength and toughness.