Alloy 4340 in Plate
SPECIFICATIONS: AISI4340, ASTM A 829 / A6 SAE J404, AMS 2252/ 2301/6359 SAE J404
Castle Metals stocks Alloy 4340 plate through our global distribution network. Our service centers are located throughout the U.S., Canada, Mexico, U.K, France, Singapore, and Shanghai. Customers calling us for 4340 plate a lot of times are frustrated with on-time delivery issues. Castle Metals understands the pressures you face, and between material, processing, and technology solutions, we typically are able to take a lot of the hassle out of your supply chain.
Alloy 4340 plate is another general purpose grade of steel used for industrial and machining applications. The inclusion of Nickel in Alloy 4340 helps simplify heat treatment. In addition, the Nickel in Alloy 4340 increases hardenability of the steel.
An additional grade of Alloy 4340 is Alloy E-4340. E-4340 is critical for parts in aerospace and other industries where great strength is needed. The annealing of Alloy E-4340 characterizes the grade as containing excellent impact and strength properties with good ductility.
Bar Properties
Grade 4340 Bars: Annealed / Normalized & Tempered Properties
GRADE |
Shape |
size range |
Condition of Steel |
SPECIFICATION |
RELATIVE MACHINABILITY BASED ON AISI 1212 100% |
4340 | Rounds | 1/2"- 11" |
Hot Rolled M.S. & Annealed 235 HBW MAX |
ASTM A29/A322 |
57% |
10" - 30" |
Forged & Rough Turned & Annealed 240 HBW MAX |
ASTM A29/A322 |
57% | ||
1/2" - 3 1/2" |
Cold Finished & Annealed 241 HBW MAX |
ASTM A29/A108 |
57% | ||
E4340 AQ |
Rounds |
1/4" - 11/2" |
Cold Finished, Annealed 255 HBW MAX |
AMS 6415/2301 |
57% |
1" - 10 1/2" |
Hot Rolled M.S., Annealed 235 HBW MAX |
57% |
|||
Hexagons |
5/8" - 2" |
Cold Finished & Annealed 255 HBW MAX |
57% |
||
Squares |
1/2" - 2" |
Cold Finished & Annealed 255 HBW MAX |
57% |
||
Flats |
1/4"x1" Min. 1 1/2"x6" Max |
Cold Finished & Annealed 255 HBW MAX |
57% |
||
1 3/4"x 2" Min 4" x 6" Max |
Hot Rolled M.S., Annealed 235 HBW MAX |
57% |
|||
E4340 PREMIUM AQ (VAR) |
Rounds |
1 3/8" - 7 1/2" |
Hot Rolled M.S., Annealed 235 HBW MAX |
AMS 6414/2300 |
57% |
1" - 8 1/2" |
Normalized & Tempered 269 HBW MAX |
57% |
|||
E4340 300 M PREMIUM AQ (VAR) |
Rounds |
1" - 7" |
Hot Rolled M.S., Normalized, & Tempered - 311 HBW MAX |
AMS 6417/2300 |
57% |
Castle 4340 annealed hot roll bars are 80% minimum lamellar pearlite for improved machinability.
Grade 4340 Quenched and Tempered "Stress Free" Bar: Minimum Properties
SPEC |
SIZE RANGE |
TENSILE-KSI |
YIELD-KSI |
ELONGATION-% |
RED. OF AREA-% |
285/341 HBW ASTM A434- CLASS BD HR Rounds & Cold Finished (1-6") |
To 1.5" |
155 |
130 |
14 |
35 |
>1.5" to 2.5" |
150 |
120 |
14 |
35 |
|
>2.5" to 4" |
140 |
110 |
14 |
35 |
|
>4" to 7" |
135 |
105 |
14 |
35 |
|
>7" to 9.5" |
130 |
100 |
14 |
35 |
|
285/341 HBW Rounds |
>9.5" to 12" |
Reported |
Reported |
Reported |
Reported |
Grade 4340 Quenched and Tempered, Forged, Rough Turned Bar Properties
spec |
size range |
tensile- ksi |
yield- ksi |
elongation- % |
red. of area-% |
300/340 HBW Forged& RT |
10-1/2" to 30" |
NA |
NA |
NA |
NA |
For more information, see Alloy Steel Quick Guide
Chemistry(range or Maximum in %)
Chemistry (range or Maximum in %)
Grade | Thickness | C |
Mn | P |
S |
Si |
Ni |
Cr |
Mo |
AISI 4340 |
3/8" thru 8-1/8" | .36/.44 | .55/.80 | 0.035 | 0.04 | .15/.40 | 1.65/2.00 | .60/.90 | .20/.30 |