AISI 4620 Alloy Steel (UNS G46200)

Topics Covered

Introduction
Chemical Composition
Physical Properties
Mechanical Properties
Other Designations
Fabrication and Heat Treatment
     Machinability
     Forming
     Welding
     Heat Treatment
     Forging
     Hot Working
     Cold Working
     Tempering
     Hardening

Introduction

Alloy steels are designated by AISI four-digit numbers and are more susceptible to heat and mechanical treatments than carbon steels. They comprise different kinds of steels having compositions which exceed the limitations of Va, Cr, Si, Ni, Mo, C and B in the carbon steels.

The following datasheet provides an overview of AISI 4620 alloy steel, which has good strength and toughness. AISI 4620 alloy steel can be heat treated to obtain high strength.

Chemical Composition

The chemical composition of AISI 4620 alloy steel is listed in the following table.

Element Content (%)
Iron, Fe 96.405 - 97.38
Nickel, Ni 1.65 - 2
Manganese, Mn 0.450 - 0.650
Molybdenum, Mo 0.2 - 0.3
Carbon, C 0.170 - 0.220
Silicon, Si 0.150 - 0.350
Sulfur, S  0.04
Phosphorous, P  0.0350

Physical Properties

The following table shows the physical properties of AISI 4620 alloy steel.

Properties Metric Imperial
Density 7.85 g/cm3 0.284 lb/in3
Melting point 1421°C 2590°F

Mechanical Properties

The mechanical properties of annealed AISI 4620 alloy steel are outlined in the following table.

Properties Metric Imperial
Tensile strength, ultimate 510 MPa 74000 psi
Tensile strength, yield 370 MPa 53700 psi
Modulus of elasticity 190-210 GPa 27557-30458 ksi
Bulk modulus (typical for steel) 140 GPa 20300 ksi
Shear modulus (typical for steel)) 80 GPa 11600 ksi
Poissons ratio 0.27-0.30 0.27-0.30
Elongation at break (in 50 mm) 31.30% 31.30%
Reduction of area 60.30% 60.30%
Hardness, Brinell 149 149
Hardness, Knoop (converted from Brinell hardness) 169 169
Hardness, Rockwell B 80 80
Hardness, Vickers (converted from Brinell hardness) 155 155
Machinability (hot rolled and cold drawn. Based on 100 machinability for AISI 1212 steel) 65 65

Other Designations

Other designations that are equivalent to AISI 4620 alloy steel include the following:

  • AMS 6294
  • AMS 6294C
  • ASTM A29 (4620)
  • ASTM A322 (4620)
  • ASTM A331 (4620)
  • ASTM A505
  • ASTM A519 (4620)
  • ASTM A535 (4620)
  • ASTM A646 (4620-3)
  • ASTM A752 (4620)
  • ASTM A829
  • SAE J1397 (4620)
  • SAE J404 (4620)
  • SAE J412 (4620)
  • MIL SPEC MIL-S-7493 (A4620)

Fabrication and Heat Treatment

Machinability

AISI 4620 steel can be easily machined in annealed or normalized conditions.

Forming

Forming of AISI 4620 steel can be performed in annealed or normalized conditions.

Welding

AISI 4620 steel can be welded using conventional methods.

Heat Treatment

AISI 4620 steel can be heat treated at 843ºC (1550ºF) and oil quenched. This steel can be normalized at 927ºC (1700ºF) and then air cooled prior to heat treatment.

Forging

AISI 4620 steel can be forged at temperature ranging from 982 to 1232ºC (1800 to 2250ºF).

Hot Working

Hot working of AISI 4620 steel can be performed at 816 to 1038ºC (1500 to 1900ºF).

Cold Working

AISI 4815 steel can be cold worked in the annealed conditions using conventional methods.

Tempering

Tempering of AISI 4620 steel can be done at 204 to 704ºC (400 to 1300ºF) based on the desired strength levels.

Hardening

AISI 4620 steel can be hardened by heat treatment or cold working.

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