18Ni Maraging Steel Special Alloy
Chemical composition%of the ladle analysis of grade18Ni Maraging Steel
| C(％) | Si(％) | Mn(％) | P(％) | S(％) | Cr(％) | Ni(％) | Mo(％) | Cu(%) | Co(%) | Al(%) | Ti(%) | Other(%) |
|---|
| 0.03 | 0.10 | 0.10 | 0.010 | 0.010 | 0.50 | 18.00-19.00 | 4.60-5.20 | 0.50 | 8.50-9.50 | 0.05-0.15 | 0.50 -0.80 | Fe Bal |
General: Maraging is a 18% nickel, cobalt strengthened steel (C-type), with excellent mechanical properties, workability and heat
treatment characteristics.
Applications: Typical applications for maraging include missile and rocket motor cases, landing and takeoff gear, munitions,
aerospace, extrusion tooling, die casting, high performance shafting, gears and fasteners.
Material Melt Method: Maraging melt method is a VIM (Vacuum Induction Melt) + VAR (Vacuum Arc Remelt)
As Shipped Condition: Maraging is supplied in the annealed and descaled condition. The alloy is very tough, relatively soft (36
Rc Max.), therefore, readily machined and formed.
*Bar Tolerances: .250” - .499” .500” - .999” 1.000” – 3.625” 3.626” – 6.000” 6.001” – 8.000” 8.001” – 10.000”
-.000/+.005 -.000/+.010 -.000/+.031 -.000/+.047 -.000/+.063 -.000/+0.078
Minimum Properties after Aging:
Hardness ……………… 52 Rc Charpy V-notch ……… 12 ft/lbs. min Reduction of Area ……. 47%
Elongation ……………. 5.0% Yield Strength …………. 280 ksi Fracture Toughness ….. 60
Physical Properties:
Density………………………………… .289 lbs./cu. In
Average Coefficient of Thermal Expansion (70 – 900 F) ……………… 5.6 x 10 -6 in/in. F
Heat Treatment Aging Process: (Non Die Casting Applications)
Material is to be heat treated to 900 F +/- 10 holding at temperature for 6 hours then cooling at room air temperature. During the aging
treatment maraging shrinks uniformly and predictably on all dimensions .001 in/in
Heat Treatment Aging Process: (Die Casting Applications)
Following the rough machining of the die, anneal at 1500-1525 F for 1 hour per inch of thickness is recommended. After finish
machining , an aging heat treatment of 980-1000 F for 6 hours is recommended.
Machining:
Maraging steel in the annealed condition is comparable to 4340. However, when maraging is aged, the type of cutting tool and speeds
change. Rigid equipment, firm tool supports, sharp tools and abundant coolant are essential.
Welding:
Maraging is weld able without preheat, in both the annealed and aged condition. Only an aging heat treatment is needed to restore in the
weld.
Standards:
AMS 6514 ASTM A 538 *Mil-S-46850D UNS K93120
*DMI product is not supplied to the dimensional tolerances of MIL-S-46850D.
*The information, data and specifications presented here are representative only, and are not guaranteed values. Material or products
applications described are solely for illustrative purposes and should not be construed as express or implied warranties for fitness for these
or other applications
Mechanical properties of grade18Ni Maraging Steel
Proof strength
Rp0.2(MPa) |
Tensile strength
Rm(MPa) |
Impact energy
KV(J) |
Elongation at fracture
A(%) |
Reduction in cross section on fracture
Z(%) |
As-Heat-Treated Condition |
Brinell hardness(HBW) |
| 438(≥) |
431(≥) |
44 |
44 |
41 |
Solution and Aging,Annealing,Ausaging,Q+T,etc |
233 |
Physical properties of grade 18Ni Maraging Steel
| Property |
Density
kg/dm3 |
Temperature T
°C/F |
Specific heat
J/kgK |
Thermal conductivity
W/mK |
Electric resistance
µΩ·cm |
Modulus of elasticity
kN/mm2 |
Expansion rate |
| 723(≥) |
658(≥) |
24 |
12 |
13 |
Solution and Aging,Annealing,Ausaging,Q+T,etc |
341 |
Temp.
°C/°F |
Creep strain limit
(10000h)
(Rp1,0)N/mm2 |
Creep rupture strength
(10000h)
(Rp1,0)N/mm2 |
|
|
|
|
|
| 172 |
973 |
341 |
|
|
|
|
18Ni Maraging Steel Range of products
| Product type |
Products |
Dimension |
Processes |
Deliver Status |
| Plates/Sheets |
Plates/Sheets |
0.08-200mm(T)*W*L |
Forging,hot rolling and cold rolling |
Annealed,Solution and Aging,Q+T,ACID-WASHED,Shot Blasting |
| Steel Bar |
Round Bar,Flat Bar,Square Bar |
Φ8-1200mm*L |
Forging,hot rolling and cold rolling,Cast |
Black,Rough Turning,Shot Blasting, |
| Coil/Strip |
Steel Coil/Steel Strip |
0.03-16.0x1200mm |
Cold-Rolled&Hot-Rolled |
Annealed,Solution and Aging,Q+T,ACID-WASHED,Shot Blasting |
| Pipes/Tubes |
Seamless Pipes/Tubes,Welded Pipes/Tubes |
OD:6-219mm x WT:0.5-20.0mm |
Hot extrusion,Cold Drawn,Welded |
Annealed,Solution and Aging,Q+T,ACID-WASHED |
Product shapes we supply: