MIL 4340 Structural and constructional steels

Material group: Ferrous Alloys / Structural and constructional steels
Country / Standard: United States / MIL
Indicative price:

Data updates

Latest Update: 2022-12
Total number of updates: 3
Update History
2014-10 2014-09

This material has 98 properties — only a subset is shown here.

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MIL 4340 Chemical Composition

CRITERIA
VALUE
UNIT
CAS NUMBER
CRITERIA
C
VALUE
0.3800 – 0.4300
UNIT
%
CAS NUMBER
7440-44-0
CRITERIA
Cr
VALUE
0.7000 – 0.9000
UNIT
%
CAS NUMBER
7440-47-3
CRITERIA
Cu
VALUE
≤ 0.3500
UNIT
%
CAS NUMBER
7440-50-8
CRITERIA
Mn
VALUE
val1
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UNIT
%
CAS NUMBER
7439-96-5
CRITERIA
Mo
VALUE
val1
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UNIT
%
CAS NUMBER
7439-98-7
CRITERIA
Ni
VALUE
val1
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UNIT
%
CAS NUMBER
7440-02-0
CRITERIA
P
VALUE
val1
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UNIT
%
CAS NUMBER
7723-14-0
CRITERIA
S
VALUE
val1
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UNIT
%
CAS NUMBER
7704-34-9
CRITERIA
Si
VALUE
val1
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UNIT
%
CAS NUMBER
7440-21-3

MIL-S-5000E: 1982 / Steel, chrome-nickel-molybdenum (4340) bars and forging stock

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MIL 4340 Physical Properties


Temperature

PROPERTY / VALUE
Modulus of Elasticity
190 — 210 GPa
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Density
7.67 — 7.86 kg/dm³
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Poisson Coefficient
0.27 — 0.3
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This material has 98 properties — only a subset is shown here.

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MIL 4340 Heat Treatments


  • (a) Normalize at 900°+/-14°C (1650°+/-25°F) for 1 hour. (b) Austenitized at 815°+/-14°C (1550°+/-25°F) for 1/2 hour. (c) Quenched in oil at 24-60°C (75-140°F). (d} Double tempered at 246°+/-8°C (475°+/-15°F) for 2-4 hours.
  • Normalizing temperature range 1600-1700°F, air quenched; Annealing temperature range 1525-1575°F; Furnace cool to 800°F or below; (Recommended subcritical anneal temperature is 1250°F); Austenitizing temperature range 1500-1550°F; Medium for quenching: oil.

MIL 4340 Mechanical Properties


Temperature

PROPERTY / VALUE
Tensile Strength
862 — 1930 MPa
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Brinell Hardness (HB)
≤ 265
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Elongation, A
≥ 4 %
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Reduction of Area
val1
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%
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Rockwell Hardness (HR)
val1
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Yield Strength, Rp0.2
val1
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MPa
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MIL 4340 International Equivalent Materials


Showing 15 of 40 results.

MATERIAL
STANDARD
COUNTRY / PRODUCER
EQUIVALENCE CATEGORY
MATERIAL
STANDARD
UNS
COUNTRY / PRODUCER
United States
EQUIVALENCE CATEGORY
Official
STANDARD
ASME
COUNTRY / PRODUCER
United States
EQUIVALENCE CATEGORY
Composition 100%
MATERIAL
STANDARD
SAE
COUNTRY / PRODUCER
United States
EQUIVALENCE CATEGORY
Composition 100%
MATERIAL
STANDARD
AISI
COUNTRY / PRODUCER
United States
EQUIVALENCE CATEGORY
Composition 100%
MATERIAL
STANDARD
AISI
COUNTRY / PRODUCER
United States
EQUIVALENCE CATEGORY
Composition 100%
MATERIAL
STANDARD
ASTM
COUNTRY / PRODUCER
United States
EQUIVALENCE CATEGORY
Composition 100%
STANDARD
ASTM
COUNTRY / PRODUCER
United States
EQUIVALENCE CATEGORY
Composition 100%
MATERIAL
STANDARD
ASTM
COUNTRY / PRODUCER
United States
EQUIVALENCE CATEGORY
Composition 100%
MATERIAL
STANDARD
ASTM
COUNTRY / PRODUCER
United States
EQUIVALENCE CATEGORY
Implicit
MATERIAL
STANDARD
ASTM
COUNTRY / PRODUCER
United States
EQUIVALENCE CATEGORY
Implicit
STANDARD
ASTM
COUNTRY / PRODUCER
United States
EQUIVALENCE CATEGORY
Implicit
MATERIAL
STANDARD
NBR
COUNTRY / PRODUCER
Brazil
EQUIVALENCE CATEGORY
Composition 100%
MATERIAL
STANDARD
NMX
COUNTRY / PRODUCER
Mexico
EQUIVALENCE CATEGORY
Composition 100%
MATERIAL
STANDARD
PROPRIETARY
COUNTRY / PRODUCER
EQUIVALENCE CATEGORY
Composition 100%
MATERIAL
STANDARD
SAE
COUNTRY / PRODUCER
United States
EQUIVALENCE CATEGORY
Composition 100%

Equivalence categories reflect chemical-composition and mechanical-property comparison — always verify suitability against the governing specification for your application.

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  • 40Cross References

  • 18Composition
  • 30Mechanical Properties
  • 3Physical Properties
  • 2Heat Treatment
  • -Metallography
  • -Machinability

  • -Stress-Strain
  • -Formability
  • -Fatigue
  • -Fracture
  • -Creep

  • -Joints
  • -Coatings
  • -Dimensions
  • -Tribology

  • -Corrosion
  • -Ageing
  • -Weatherability
  • -Irradiation

  • 5Total Suppliers