MARAGING (C) 350

MARAGING (C) 350 | UNS K93120 | Mil-S-46850D | AMS 6515 | Vascomax C350 | DIN 1.6356

General

Maraging is a 18% nickel, cobalt strengthened steel (C-type), with excellent mechanical properties, workability and heat treatment characteristics.

Introduction

Alloy steels are designated by AISI four-digit numbers. They comprise different kinds of steels having composition exceeding the limitations of B, C, Mn, Mo, Ni, Si, Cr, and Va set for carbon steels. They quickly respond to mechanical and heat treatments than the carbon steels.

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.

Composition

  • C : 0.03 max
  • Mn : 0.10 max
  • Si : 0.10 max
  • P : 0.10 max
  • S : 0.10 max
  • NI : 18.00-19.00
  • Co : 11.50-12.50
  • Mo : 4.60-5.20
  • Ti : 1.30 -1.60
  • Al : 0.05-0.15
  • Cr : 0.50 max
  • Cu :  0.50 max

Material Melt Method Maraging melt method is a VIM (Vacuum Induction Melt) + VAR (Vacuum Arc Remelt)

Physical Properties

The physical properties of maraging 350 alloy steel are listed in the following table.

Properties Metric Imperial
Density 8.08 g/cc 0.292 lb/in³


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.

Minimum Properties after Aging:

  • Hardness ……………… 56 Rc
  • Charpy V-notch ……… 6 ft/lbs. min
  • Reduction of Area ……. 25%
  • Elongation ……………. 2.8%
  • Yield Strength …………. 330 ksi
  • Fracture Toughness ….. 25

Mechanical Properties

The mechanical properties of annealed maraging 350 alloy steel are outlined in the following table.

Properties Metric Imperial
Tensile strength 1140 MPa 165000 psi
Yield strength (@ strain 0.200%) 827 MPa 120000 psi
Bulk modulus (typical for steel) 140 GPa 20300 ksi
Shear modulus (estimated from elastic modulus) 77 GPa 11200 ksi
Elastic modulus 200 GPa 29000 ksi
Poisson’s ratio 0.3 0.3
Elongation at break (in gage length 4.5 times the square root of the area) 18% 18%
Reduction of area 70% 70%


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

  • Mil-S-46850D
  • UNS K93120
  • AMS 6515
  • Vascomax C350
  • DIN 1.6356

 

FountainHead Alloys is ISO 9001:2015 approved. © FountainHead Alloys 1996