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AISI 4340 1.6511 36CrNiMo4 SNCM439 Round Steel Bar Round Bar Round Bar Rod
AISI 4340 steel (UNS G43400) is an ultra-high strength medium carbon low alloy steel, which combines deep hardenability, high ductility, toughness and strength, and has high fatigue resistance and creep resistance. 4340 steel & equivalents: 36CrNiMo4, 1.6511, EN24, SNCM439 etc.
Standard | JIS ASTM GB EN AISI | |
Size | Diameter:16-250mm | Length:4000-15000mm |
Technique | Hot Rolled / Cold Rolled / Forged | |
Package | Export Standard Package,bundled or be required | |
Service | Cutting Service , Customized Fabrication Service | |
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
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 | |
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 |
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 |