SAE AISI 4130 Chromoly Steel, Alloy Material Properties, Chemical Composition

SAE AISI 4130 Chromoly Steel 4130 alloy

Introduction

AISI 4130 steel (UNS G41300), also known as 4130 Chromoly steel, is a chrome-molybdenum series low alloy steel with high strength, toughness and hardenability, usually used in quenched and tempered condition.

Uses

AISI SAE 4130 alloy steel can be made into steel plate, steel sheet, round and flat steel bar, steel pipe and tube, etc. and has many uses in pressure vessels, pumps and valves, pinions, shaft gears, ball studs, screws, general purpose profile steel, automotive parts, oil and gas industry, aerospace, and bike frame, etc.

Datasheet & Specification

Below is material AISI 4130 Chromoly steel datasheet including chemical composition, density, thermal expansion coefficient, thermal conductivity, yield strength, hardness, etc.

AISI SAE 4130 Chemical Composition

The table below lists AISI 4130 chemical composition.

AISI 4130 Chemical Composition (%)
Steel Grade (UNS)CSiMnP (≤)S (≤)CrMo
4130 (G41300)0.28-0.330.15-0.350.40-0.600.0350.0400.80-1.100.15-0.25

AISI 4130 Material Properties

Material AISI 4130 steel mechanical properties are given in the table below.

Steel (UNS)Tensile strength (Mpa)Yield strength (Mpa)Elongation in 50 mm, %Reduction in area, %Hardness (HB)Sample diameterConditions
AISI 4130 (G41300)67043525.559.519725mm (1 inch)Normalized at 870 °C (1600 °F)
56046021.559.5217Annealed at 865 °C (1585 °F)
104097918.163.9302Water quenched from 855 °C (1575 °F) & tempered at 540 °C (1000 °F)

AISI SAE 4130 Physical Properties

Notes: 10-6/K = 10-6.K-1 = (µm/m)/°C

AISI SAE 4130 coefficients of linear thermal expansion
Value (10-6/K)Temperature (°C)
12.220-100
13.720-400
14.620-600
Material 4130 chromoly thermal conductivity
Value (W/m·K)Temperature (°C)Treatment or condition
42.7100Hardened and
tempered
40.6300
37.3500
31.0700
Specific Heat of AISI 4130 Alloy Steel
Value (J/Kg·K)Temperature (°C)Treatment or condition
47750-100Hardened and
tempered
515150-200
544250-300
595350-400
657450-500
737550-600
825650-700
833750-800
Electrical Resistivity of AISI SAE 4130 Alloy Steel
Value (μΩ·m)Temperature (°C)Treatment or condition
0.2220Hardened and
tempered
0.27100
0.34200
0.53400
0.79600
1.10700
1.17900
1.221000

SAE 4130 Steel Heat Treatment

The following table shows alloy 4130 chromoly steel heat treatment and rockwell hardness.

Chromoly 4130 Steel Heat Treatment
4130 Heat TreatTemperature (℃)HardnessCooling/Agent
Normalizing885197 HBAir
Annealing865156 HBFurnace cooling
Quenching800-855Water
Tempering (2 hour)20447 HRCWater hardening
26045 HRC
31543 HRC
37042 HRC
42538 HRC
48034 HRC
54032 HRC
59526 HRC
64922 HRC

Normalizing

4130 alloy steel is typically normalized at 900 °C (1650℉), and should be cooled at a specified temperature in still air.

Spheroidizing Annealing

For spheroidizing annealing of 4130 alloy steel, it needs heat treated to 749 °C (1380 °F), followed by slowly cooling to 666 °C (1230 °F) at a rate of 6 °C (10 °F)/hour, or rapid cooling to 675 °C for 8 hours isothermal annealing.

Full Annealing

Heat treatment to 855 °C (1570 °F), slow cooling from 760 °C (1400 °F) at a rate of 18 °C (35 °F)/hour to 666 °C (1230 °F), or rapid cooling to 674 °C (1245 °F) for 4 hours isothermal annealing.

Tempering

Tempering temperature of 4130 alloy steel can be from 204-649 °C (400-1200°F) after normalizing and water quenching, and the corresponding Rockwell hardness can be obtained.

Forging

Material 4130 alloy steel forging temperature is about 1204 °C (2200 °F)

Welding 4130 Steel

All common arc welding processes, such as (SAW, SMAW, FCAW, GMAW, GTAW) can be used to weld 4130 alloy steel, but in order to prevent cracking, it must be preheated to 150-290 °C before welding, preheating interpass temperature depends on the section thickness of the steel.

Equivalent Grade

AISI 4130 equivalent to European EN (Germany DIN EN, British BSI, French NF…), Chinese GB and Japanese JIS standard.

AISI 4130 equivalent
USAEuropean UnionChinaJapanISO
StandardGrade (UNS)StandardGradeStandardGrade (Steel Number)StandardGradeStandardGradeStandardGrade
AISI;
SAE;
ASTM A29/A29M
4130 (G41300)AMSAMS 6350; AMS 6345EN 10083-325CrMo4
(1.7218)
GB/T 307730CrMoJISG 4105SCM430

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