SAE4340 GB 40CrNiMoA EN 10028-3 Alloy Steel Round Bar OD 300mm DIN
1.6511 Alloy Forged Rod
1.Supply Form & Size & Tolerance
| Supply Form | Size(mm) | Process | Tolerance |
Round | Φ6-Φ100 | Cold Drawn | Bright/Black | Best H11 |
Φ16-Φ350 |
Hot Rolled | Black | -0/+1mm |
| Peeled/ground | Best H11 |
Φ90-Φ1000 |
Hot Forged | Black | -0/+5mm |
| Rough Turned | -0/+3mm |
Flat/Square/Block | Thickness :120-800 |
Hot Forged | Black | -0/+8mm |
| Width:120-1500 | Rough Machined | -0/+3mm |
Remark:Tolerance can be customized as per requests
2.Chemical Composition
| Standard | Grade | C | Si | Mn | P | S | Cr | Ni | Mo |
| ASTM A29 | 4340 | 0.38-0.43 | 0.15-0.35 | 0.6-0.8 | ≤ 0.035 | ≤ 0.04 | 0.7-0.9 | 1.65-2.0 | 0.2-0.3 |
EN10250 | 36CrNiMo4 |
0.32-0.4 |
≤ 0.4 |
0.5-0.8 |
≤ 0.035 |
≤ 0.035 |
0.9-1.2 |
0.90-1.2 |
0.15-0.3 |
| 1.6511 |
BS 970 | EN24 |
0.36-0.44 |
0.1-0.4 |
0.45-0.7 |
≤ 0.035 |
≤ 0.04 |
1.0-1.4 |
1.3-1.7 |
0.2-0.35 |
| 817M40 |
| JIS G4103 | SNCM439 | 0.36-0.43 | 0.15-0.35 | 0.6-0.9 | ≤ 0.03 | ≤ 0.03 | 0.6-1.0 | 1.6-2.0 | 0.15-0.3 |
| GB 3077 | 40CrNiMoA | 0.37-0.44 | 0.17-0.37 | 0.5-0.8 | ≤ 0.025 | ≤ 0.025 | 0.6-0.9 | 1.25-1.65 | 0.15-0.25 |
3.Physical Property
| Density g/cm3 | 7.85 |
| Melting point °C | 1427 |
| Poisson's ratio | 0.27-0.30 |
| Machinability (AISI 1212 as 100% machinability) | 50% |
| Thermal expansion co-efficient µm/m°C | 12.5 |
| Thermal conductivity W/(m.K) | 44.5 |
| Modulus of elasticity 10^3 N/mm^2 | 210 |
| Electric resistivity Ohm.mm2 /m | 0.19 |
| Specific heat capacity J/(kg.K) | 460 |
Modulus of elasticity 10^3 N/mm2 | 100 ℃ | 200 ℃ | 300 ℃ | 400 ℃ | 500 ℃ |
| 205 | 195 | 185 | 175 | 165 |
Thermal expansion 10^6 m/(m.K) | 100 ℃ | 200 ℃ | 300 ℃ | 400 ℃ | 500 ℃ |
| 11.1 | 12.1 | 12.9 | 13.5 | 13.9 |
4. Mechanical Property
| Mechanical Condition | T | U | V | W | X | Y | Z |
| Ruling Section (mm) | 150 | 100 | 63 | 30 | 30 | 30 | 30 |
| Tensile Strength Mpa | 850-1000 | 930-1080 | 1000-1150 | 1080-1230 | 1150-1300 | 1230-1380 | >1550 |
| Yield Strength,Mpa | ≥665 | ≥740 | ≥835 | ≥925 | ≥1005 | ≥1080 | ≥1125 |
| Elongation % | ≥13 | ≥12 | ≥12 | ≥11 | ≥10 | ≥10 | ≥5 |
| Izod Impact J | ≥54 | ≥47 | ≥47 | ≥41 | ≥34 | ≥24 | ≥10 |
| Charpy Impact J | ≥50 | ≥42 | ≥42 | ≥35 | ≥28 | ≥20 | ≥9 |
| Brinell Hardness HB | 248-302 | 269-331 | 293-352 | 311-375 | 341-401 | 363-429 | >444 |
5.High Temperature Strength
| For quenched and tempered heavy forgings |
Diameter mm | Yield strength MPa |
| 20 ℃ | 100 ℃ | 200 ℃ | 250 ℃ | 300 ℃ | 350℃ | 400℃ |
| ≤250 | 590 | 549 | 510 | 481 | 441 | 412 | 371 |
| 250-500 | 540 | 505 | 471 | 451 | 412 | 383 | 353 |
| 500-750 | 490 | 466 | 441 | 422 | 392 | 363 | 343 |
6.Forging
Forging temperature should be carried out between 1150℃-1200℃,The
lower the forging-ending temperature ,the finer the grain size
.hold suitable time for the steel to be thoroughly heated before
forge, but don’t forge below minimum forging temperature 850°C.
AISI 4340 has good forging characteristics,but crack is easily
occured when improper cooling way after forged,so it should be
cooled as slowly as possible in still air or in sand after forged.
7.Normalizing
Normalizing is used to refine the structure of forgings that might
have cooled non-uniformly after forged,and considered as a
conditioning treatment before final heat treatment.Normalizing
temperature for AISI 4340 steel should be carried out between
850℃-880℃. hold suitable time for the steel to be thoroughly heated
to complete the ferrite to austenite transformation.Cool in still
air.
8.Annealing
Full annealing is recommended for AISI 4340 before machining, AISI
4340 should be carried our at a nominal temperature of
830℃-850℃,hold suitable time for the steel to be thoroughly heated,
then furnace cooling to 610℃ at a rate of 11℃ per hour, finally air
cooling.
9.Hardening
This heat treatment will obtain martensite structure after
quenched.It will increase the surface hardness and strength.AISI
4340 should be carried out between 830℃-865℃, hold suitable time
for the steel to be thoroughly heated, soak for 10-15 minutes per
25 mm section, oil quench is recommended.Tempering should be
followed immediately after quenched.
10.Tempering
AISI 4340 alloy steel should be in the heat treated or normalized
and heat treated condition before tempering.Tempering is usually
carried out to relieve stresses from the hardening process, but
primarily to obtain the required hardness and mechanical
properties. The actual tempering temperature will be chosen to meet
the required properties.it is usually carried out at 450℃-
660℃,hold until temperature is uniform throughout the section, soak
for 1 hour per 25 mm of section, and cool in still air.Tempering
between 250℃-450℃ is not avoided as tempering within this range
will seriously reduce the impact value,result in temper
brittleness.
11.Application
AISI 4340 is often used in preference to AISI 4140 at the higher
strength levels because of its better hardenability and improved
CVN impact toughness.
Typical applications include:Heavy-duty axles, shafts, heavy-duty
gears,spindles, pins, studs, collets, bolts, couplings,sprockets,
pinions, torsion bars, connecting rods,crow bars, conveyor
parts,forged hydraulic,forged steel crankshafts etc.
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is a very professional a trade company for steel products.we can
also provide a wide range of steel products.
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A: The sample could can provide for customer with free,but the
courier freight will be covered by customer account.
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A: Yes absolutely we accept.
Q: How could you guarantee your products?
A: Each piece of products is manufactured by certified workshops,
inspected by worker piece by piece according to national QA/QC
standard. We also could issue the warranty to customer to guarantee
the quality.
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