Kontakt oss
Change language:  

Maraging

 

HIGH STRENGTH MARAGING STEEL

 

CHEMISTRY

Nominal Analysis C Si Mn Ni Co Mo Ti Al Fe
C250 ,03 max ,10 max ,10 max 18,50 7,50 4,80 ,40 ,10 Bal.
C300 ,03 max ,10 max ,10 max 18,50 9,0 4,80 ,60 ,10 Bal.
C350 ,03 max ,10 max ,10 max 18,50 12,0 4,80 1,40 ,10 Bal.


GENERAL CHARACTERISTICS
Maraging is a 18% nickel, cobalt strengthened steel (C-type) with excellent properties, workability and heat treatment characteristics. Maraging is double vaccum melted by VIM (Vaccum Induction Melt) followed by VAR (Vaccum Arc Remelt) Maraging material is supplied in the annealed and descaled condition. The alloy is very tough, relatively soft (RC 30/35), readily machined or formed. Maraging provides a high value for critical parts in aerospace, structural, components and tooling applications.

MARAGING
*MARtensitic – a very hard form of steel crystalline structure
*Subsequent AGING (precipitation hardening –approx 3-6 hours @ 900°F yields optimum material characteristics)

* SPECIFICATIONS:

AMS 6512 = C250 maraging
AMS 6514 = C300 maraging
AMS 6515 = C350 maraging
Mil-S-46850 (applies to all grades) – FRACTURE TOUGHNESS APPLIES

MACHINING
Machinability of annealed maraging steels is comparable to steels such as 4340 at the same hardness level (Rc30/35). However, when the material is aged (heat treated), the choice of cutting tools and machining conditions become very important. Rigid equipment, very charp tools and an abundance of coolant are essential.

PHYSICAL PROPERTIES

C250 C300 C350
Density .289 lbs./cu. in. .289 lbs./cu. in. .292 lbs./cu. in.
Average Coefficient of Thermal Expansion 5.6×10-6 in./in./ °F 5.6×10-6 in./in./ °F 6.3×10-6 in./in./ °F
Modulus of Elasticity 27.0×10-6 psi 27.5×10-6 psi 29.0×10-6 psi

 

HEAT TREATMENT


Maraging alloys are essentially carbon-free, a protective atmosphere is not required during annealing or aging. Material is supplied in the solution annealed condition with a hardness of 30/35 RC. Typical heat treat time/temperature are listed below. Large cross sections should be aged for longer periods.

 AGING (heat treatment)

  *AGING TEMP *AGING TIME *RESULTING HARDNESS
Maraging 250 900/925 °F 6 hrs 48/52 Rc
Maraging 300 900/925 °F 6 hrs 50/55 Rc
Maraging 350 900/925 °F 6 hrs 55/60 Rc
Or 950 °F 3 hrs 55/60 Rc

 

TYPICAL – ROUND BAR
MINIMUM PROPERTIES
AFTER AGING Rc TENSILE STRENGTH ,02% YIELD ELONGATION REDUCTION
(LONGITUDAL DIRECTION)     KSI STRENGTH IN 4,5 a% OF AREA
250 50 254 248 11,0 53
300 54 293 286 10,0 46
350 57 342 336 6,2 28

NOTE: A modified aging cycle is suggested for die casting applications for increased die life. The following thermal treatments have been used to obtain desirable characteristics for die casters. Following the rough machining of the die, anneal at 1500-1525 °F for 1 hour per inch of thickness is typical. After finish machining, an aging heat treatment of 980-1000 °F for 6 hours is typical.

AVAILABILITY
Maraging is available as billet, bar, rod, plate, sheet and customized forgings.

 

ADVANTAGES OF MARAGING


EXCELLENT MECHANICAL PROPERTIES
*high yield and ultimate tensile strengths
*high toughness, ductility and impact strengths
*high fatigue strength
*high compressive strength
*hardness and wear resistance sufficient for many tooling applications

EXCELLENT WORKABILITY
*high resistance to crack propagation
*readily formed – cold, warm, hot (w/o in process anneals)
*good weldability w/o quenching
*excellent polishability

EXCELLENT HEAT TREATMENT CHARACTERISTICS
*low furnace temps required
*precipitation hardening, aging heat treatment
*uniform, predictable shrinkage during heat treatment
*freedom for carburization or decarburization
*through hardening w/o quenching
*minimal distortion during heat treatment (.0009 in/in C250 //.001 in/in C300)

ADVANTAGES DURING APPLICATION
*low coefficient of expansion minimizes heat checking
*pitting and corrosion resistance superior to common tool steel
*good repair weldability
*excellent mechanical properties have led to longer tool life
*easily reworked and retreated for secondary tool life

 

The technical information, presented in this department are representative only, and are not guaranteed values.