Chromoly Steel AISI 4130 (UNS G41300)
AISI 4130 steel (UNS G41300), also known as Cromoly 4130 steel, is a chromium-molybdenum series low-alloy steel with high strength, toughness and hardenability, generally used in quenched and tempered conditions.
Uses
AISI SAE 4130 alloy steel can be made into steel plate, steel plate, round and flat steel bar, steel pipe and tube, etc. and has many uses in pressure vessels, pumps and valves, pinions, shaft gears, ball pins, screws, general purpose profile steel, automotive parts, oil and gas industry, aerospace and bicycle frame, etc.
Datasheet and specifications
Below is the data sheet of AISI 4130 Chromoly material, including chemical composition, density, coefficient of thermal expansion, thermal conductivity, yield strength, hardness, etc.
AISI SAE 4130 Chemical Composition
The table below lists the chemical composition of AISI 4130.
| AISI 4130 Chemical Composition (%) | |||||||
| Steel Grade (UNS) | W | Yes | Mn | P (≤) | S (≤) | Cr | Mo |
| 4130 (G41300) | 0.28-0.33 | 0.15-0.35 | 0.40-0.60 | 0.035 | 0.040 | 0.80-1.10 | 0.15-0.25 |
Properties of AISI 4130 materials
The mechanical properties of AISI 4130 material are given in the table below.
| Steel (UNS) | Tensile strength (Mpa) | Yield strength (Mpa) | Elongation by 50 mm, % | Area reduction, % | Hardness (HB) | Sample diameter | Conditions |
| AISI4130 (G41300) | 670 | 435 | 25.5 | 59.5 | 197 | 25 mm (1 inch) | Normalized to 870°C (1600°F) |
| 560 | 460 | 21.5 | 59.5 | 217 | Annealed at 865°C (1585°F) | ||
| 1040 | 979 | 18.1 | 63.9 | 302 | Water tempered to 855°C (1575°F) and tempered to 540°C (1000°F) |
AISI SAE 4130 Physical Properties
Notes: 10 -6 /K = 10 -6 .K -1 = (µm/m)/°C
| AISI SAE 4130 linear thermal expansion coefficients | |
| Value (10 -6 /K) | Temperature (°C) |
| 12.2 | 20-100 |
| 13.7 | 20-400 |
| 14.6 | 20-600 |
| Material 4130 chromolytic thermal conductivity | ||
| Value (W/m·K) | Temperature (°C) | Treatment or condition |
| 42.7 | 100 | Hardened and temperate |
| 40.6 | 300 | |
| 37.3 | 500 | |
| 31.0 | 700 | |
| Specific heat of AISI 4130 alloy steel | ||
| Value (J/Kg·K) | Temperature (°C) | Treatment or condition |
| 477 | 50-100 | hardened and temperate |
| 515 | 150-200 | |
| 544 | 250-300 | |
| 595 | 350-400 | |
| 657 | 450-500 | |
| 737 | 550-600 | |
| 825 | 650-700 | |
| 833 | 750-800 | |
| Electrical resistivity of AISI SAE 4130 steel alloy | ||
| Value (μΩ·m) | Temperature (°C) | Treatment or condition |
| 0.22 | 20 | hardened and temperate |
| 0.27 | 100 | |
| 0.34 | 200 | |
| 0.53 | 400 | |
| 0.79 | 600 | |
| 1.10 | 700 | |
| 1.17 | 900 | |
| 1.22 | 1000 | |
SAE 4130 Steel Heat Treatment
The following table shows the heat treatment of 4130 alloy chromoly steel and rockwell hardness.
| Chromoly Steel 4130 Heat Treatment | |||
| 4130 Heat Treatment | Temperature (℃) | Toughness | Cooling/Agent |
| Normalizing | 885 | 197 HB | Air |
| girdling | 865 | 156 HB | Oven cooling |
| Tempera | 800-855 | Water | |
| Tempering (2 hours) | 204 | 47 HRC | Water hardening |
| 260 | 45 HRC | ||
| 315 | 43 HRC | ||
| 370 | 42 HRC | ||
| 425 | 38 HRC | ||
| 480 | 34 HRC | ||
| 540 | 32 HRC | ||
| 595 | 26 HRC | ||
| 649 | 22 HRC | ||
Normalizing
4130 alloy steel is normally standardized to 900°C (1650℉) and must be cooled to a specified temperature in still air.
Spheroidizing Annealing
For spheroidizing annealing of 4130 alloy steel, it needs heat treatment at 749°C (1380°F) followed by slow cooling to 666°C (1230°F) at a rate of 6°C (10°F) /hour, or rapid cooling to 675 °C for 8 hours of isothermal annealing.
Complete Annealing
Heat treating at 855°C (1570°F), slow cooling at 760°C (1400°F) at a rate of 18°C (35°F)/hour to 666°C (1230°F), or rapid cooling at 674°C (1245°F) for 4 hours of isothermal annealing.
Temperament
The tempering temperature of 4130 alloy steel can be 204-649°C (400-1200°F) after normalizing and water quenching, and the corresponding Rockwell hardness can be obtained.
Forging
The forging temperature of 4130 alloy steel material is about 1204°C (2200°F)
4130 Steel Welding
All common arc welding processes such as (SAW, SMAW, FCAW, GMAW, GTAW) can be used to weld 4130 alloy steel, but to avoid cracking, it must be preheated to 150-290°C before of welding, preheating the interpass the temperature depends on the thickness of the steel section.
Equivalence
AISI 4130 equivalent to the European EN standard (Germany DIN EN, British BSI, French NF…), Chinese GB and Japanese JIS.
| Equivalent to AISI 4130 | |||||||||||
| USA | European Union | China | Japan | ISO | |||||||
| Standard | Note (UNS) | Standard | Note | Standard | Class (Steel Number) | Standard | Note | Standard | Note | Standard | Note |
| AISI; SAE; ASTM A29/A29M |
4130 (G41300) | AMS | AMS 6350; AMS 6345 | EN 10083-3 | 25CrMo4 (1.7218) |
GB/T 3077 | 30CrMo | JISG 4105 | SCM430 | ||
