Complaint
2. AISI 4340 Steel Specification and Relevant Standards
| Country | USA | Britain | Britain | Japan |
| Standard | ASTM A29 | EN 10250 | BS 970 | JIS G4103 |
| Grades | 4340 | 36CrNiMo4/ 1.6511 | EN24/817M40 | SNCM 439/SNCM8 |
3. ASTM 4340 Steels And Equilvalents Chemical Composition
| Standard | Grade | C | Mn | P | S | Si | Ni | Cr | Mo |
| ASTM A29 | 4340 | 0.38-0.43 | 0.60-0.80 | 0.035 | 0.040 | 0.15-0.35 | 1.65-2.00 | 0.70-0.90 | 0.20-0.30 |
| EN 10250 | 36CrNiMo4/ 1.6511 | 0.32-0.40 | 0.50-0.80 | 0.035 | 0.035 | <=0.40 | 0.90-1.20 | 0.90-1.2 | 0.15-0.30 |
| BS 970 | EN24/817M40 | 0.36-0.44 | 0.45-0.70 | 0.035 | 0.040 | 0.1-0.40 | 1.3-1.7 | 1.00-1.40 | 0.20-0.35 |
| JIS G4103 | SNCM 439/SNCM8 | 0.36-0.43 | 0.60-0.90 | 0.030 | 0.030 | 0.15-0.35 | 1.60-2.00 | 0.60-1.00 | 0.15-0.30 |
4. AISI Alloy 4340 Steel Mechanical Properties
| Mechannical Properties
(Heat Treated Condition ) | Condition | Ruling section mm | Tensile Strength MPa | Yield Strength MPa | Elong. % | Izod Impact J | Brinell Hardness |
| T | 250 | 850-1000 | 635 | 13 | 40 | 248-302 | |
| T | 150 | 850-1000 | 665 | 13 | 54 | 248-302 | |
| U | 100 | 930-1080 | 740 | 12 | 47 | 269-331 | |
| V | 63 | 1000-1150 | 835 | 12 | 47 | 293-352 | |
| W | 30 | 1080-1230 | 925 | 11 | 41 | 311-375 | |
| X | 30 | 1150-1300 | 1005 | 10 | 34 | 341-401 | |
| Y | 30 | 1230-1380 | 1080 | 10 | 24 | 363-429 | |
| Z | 30 | 1555- | 1125 | 5 | 10 | 444- | |
Thermal Properties
| Properties | Metric | Imperial |
| Thermal expansion co-efficient (20°C/68°F, specimen oil hardened, 600°C (1110°F) temper | 12.3 µm/m°C | 6.83 µin/in°F |
| Thermal conductivity (typical steel) | 44.5 W/mK | 309 BTU in/hr.ft².°F |
5.Forged Steel Size we can supply:
| Forged Steel Round Bar | Φ85mm~1200mm |
| Forged Square steel Bar: | 150×150-800×800mm |
| Forged Flat Blocks: | (150mm-800mm)*(200mm-800mm) |
| Forged Shaft and Forged Ring | According to Customer's drawing |
| Steel series | Representative steel type |
| Carbon Steel series | AISI 1020,1045,A36,S355JR,S355JO |
| Petroleum machinery series | AISI4150,AISI4140,AISI4130, |
| 30CrMo,4145H | |
| Tool mold series | 1.2714,5CrMnMo,5CrNiMoV, |
| 1.2738,1.2311,1.2312 1.2714 H13 | |
| Bearing series | 52100,GCr15,SUJ2 |
| Marine series | 4140,42CrMo,SCM440, |
| 709M40 | |
| Car series | SAE8620,20CrNiMo, |
| SNCM220 | |
| Heavy-duty transmission series | 40CrNiMo,SNCM439, |
| SAE4340,EN24 | |
| Mining machinery series | 655M13,826M40, |
| 25CrMo | |
| Wind power gear series | 18CrNiMo7-6, 17CrNiMo6, 1.6582,1.6587,SAE8620 |
| Wind power spindle series | 34CrNiMo6,817M40 |
| Nitriding series | 20MnCr5,38CrMoAl, |
| 31CrMoV9 | |
| Pressure vessel series | 15CrMo,13CrMo4-4 |
| Metallurgical roll series | 21CrMoV511,W1.7225, |
| EN19,709M40 |
