AISI 4145 Alloy Steel (UNS G41450)

Topics Covered

Introduction
Chemical Composition
Physical Properties
Mechanical Properties
Thermal Properties
Other Designations

Introduction

Alloy steels are steels containing elements such as chromium, cobalt, nickel, etc. Alloy steels comprise a wide range of steels having compositions that exceed the limitations of Si, Va, Cr, Ni, Mo, Mn, B and C allocated for carbon steels.

In comparison with carbon steels, alloy steels are a lot more responsive to mechanical and heat treatments. Alloy steels can be subjected to unique melting and deoxidization processes for specific kind of applications.

The following datasheet provides an overview of AISI 4145 alloy steel.

Chemical Composition

The chemical composition of AISI 4145 alloy steel is outlined in the following table.

Element Content (%)
Iron, Fe 96.795-97.72
Chromium, Cr 0.800-1.10
Manganese, Mn 0.750-1.00
Carbon, C 0.430-0.480
Molybdenum, Mo 0.150-0.250
Silicon, Si 0.150-0.300
Sulfur, S ≤ 0.0400
Phosphorous, P ≤ 0.0350

Physical Properties

The following table shows the physical properties of AISI 4145 alloy steel.

Properties Metric Imperial
Density 7.85 g/cm3 0.284 lb/in³

Mechanical Properties

The mechanical properties of AISI 4145 alloy steel are displayed in the following table.

Properties Metric Imperial
Bulk modulus (typical for steels) 140 GPa 20300 ksi
Shear modulus (typical for steels) 80.0 GPa 11600 ksi
Elastic modulus 190-210 Gpa 27557-30458 ksi
Poisson's ratio 0.27-0.30 0.27-0.30
Hardness, Brinell 208 208
Hardness, Knoop (converted from Brinell hardness) 230 230
Hardness, Rockwell B (converted from Brinell hardness) 94 94
Hardness, Rockwell C (converted from Brinell hardness, value below normal HRC range, for comparison purposes only) 15 15
Hardness, Vickers (converted from Brinell hardness) 218 218
Machinability (annealed and cold drawn, based on 100 machinability for AISI 1212 steel) 60 60

Thermal Properties

The thermal properties of AISI 4145 alloy steel are given in the following table.

Properties Metric Imperial
Thermal conductivity 42.6 W/mK 296 BTU in/hr.ft².°F

Other Designations

Equivalent materials to AISI 4145 alloy steel are given in the following table.

ASTM A29 ASTM A322 ASTM A331 ASTM A519 ASTMA711
ASTM A752 ASTM A829 SAE J1397 SAE J404 SAE J412
ASTM A505 SAE J770 MIL SPEC MIL-S-16974

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