L43 - 4340
Steel generally used in large size bolts up to 4” that require high performance of resilience at low temperatures , it has the same mechanical characteristics as the ASTM A320 L7 quality
References and Comparable Standards
Standard Reference: ASTM A320/A320M
| EUROPE |
ITALY |
GERMANY |
FRANCE |
UK |
USA |
| - |
(UNI 7847 - 78) |
(DIN) |
(NF A 35-552-86) |
(BS 970 pt. 1 - 96) |
ASTM A 29 |
| Grade |
N° |
|
Werkstoff |
N° |
|
|
|
| (40NiCrMo7) |
(1.6565) |
(40NiCrMo7) |
(40NiCrMo8-4) |
(1.6562) |
- |
(817M40) |
4340 |
Chemical Composition (Cast Analysis) (%)
| C |
Si |
Mn |
P/max |
S/max |
Cr |
Mo |
Ni |
Al |
| 0,38 ÷ 0,43 |
0,15 ÷ 0,35 |
0,60÷0,85 |
0,035 |
0,040 |
0,70 ÷ 0,90 |
0,20 ÷ 0,30 |
1,65 ÷ 2,00 |
0,020 ÷ 0,050 |
Mechanical Properties
Size
(mm) |
Quenched and tempered (+QT) |
| Rp0,2 (MPa) min |
Rm (MPa) min |
A5 (%) min |
Z (%) min |
HB/max |
KV-101°C/min |
| d≤100 |
725 |
860 |
16 |
50 |
321 |
27J |
Minimum tempering temperature 593°C
Working Temperatures Recommended
| Operation |
°C |
| Hot forgings deformation |
900÷1100 |
| Isothermal annealing |
800÷900-->640 |
| Normalizing |
860÷880 |
| Quenching in water or oil |
830÷860 |
| Tempering |
550÷650 |
Hardness Limits (Jominy Test)*
| Limits of range |
Hardness HRC at a distance from quenched end of test pieces (mm) |
| 1,5 |
3 |
5 |
7 |
9 |
11 |
13 |
15 |
20 |
25 |
30 |
35 |
40 |
45 |
50 |
| +H |
Max |
60 |
60 |
60 |
60 |
60 |
60 |
60 |
60 |
59 |
58 |
58 |
58 |
57 |
56 |
56 |
| Min |
52 |
52 |
52 |
52 |
52 |
52 |
52 |
52 |
51 |
50 |
49 |
48 |
47 |
45 |
44 |
*For reference only
