Maraging 350
Maraging 350: An Excellent Balance of High Strength and Good Ductility
Maraging steels are special high-alloy steels that stand out for their high strength, excellent ductility and excellent weldability. Within this group, Maraging 350 is widely used in aerospace, defence, automotive and high-performance industrial applications thanks to its superior mechanical properties and heat treatment capability. This article covers the chemical composition of Maraging 350, its mechanical properties, its AMS and ASTM standards, its production processes and its industrial fields of application in detail.
Maraging 350 Chemical Composition and Microstructure
It is generally a maraging steel type with low carbon and high nickel and cobalt contents. The typical chemical composition is as follows:
- Nickel (Ni): 18.0–19.0%
- Cobalt (Co): 11.5–12.5%
- Molybdenum (Mo): 4.6–5.2%
- Titanium (Ti): 1.30–1.60%
- Aluminium (Al): 0.05–0.15%
- Carbon (C): max. 0.03%
- Iron (Fe): balance
This composition provides high strength and hardness while also offering a good balance of toughness and ductility. Maraging 350 has a martensitic microstructure; its strength is increased by precipitation hardening through heat treatment.
Maraging 350 Mechanical Properties and Heat Treatment
The mechanical properties of the alloy are optimised by heat treatment. The heat treatment is generally in two stages:
- Solution annealing: carried out at roughly 820–860 °C to homogenise the alloy.
- Ageing (tempering): carried out between 480 and 510 °C to achieve precipitation hardening.
The mechanical properties obtained as a result of these operations are:
- Tensile strength: 2000 MPa and above
- Yield strength: around 1900 MPa
- Hardness: 50–55 HRC (Rockwell C)
- Elongation: between 5 and 8%, satisfactory ductility despite the high strength
- Impact toughness: adequate for high-performance applications
These properties make Maraging 350 suitable particularly for critical applications requiring high strength.
Maraging 350 AMS and ASTM Standards
Because of its widespread use in the aerospace and defence industries, it is controlled by various standards:
- AMS 6510: the basic standard for the chemical composition, heat treatment conditions and mechanical tests of Maraging 350 steels.
- AMS 6511: sets out the post-heat-treatment performance criteria for Maraging 350.
- ASTM A687: Maraging 350 may also be covered under the general production and quality control standards for stainless and alloy steels.
These standards ensure the performance of the material and guarantee its quality.
Maraging 350 Technical Properties and Specifications
It stands out for its high durability, excellent fatigue resistance and superior weldability. Thanks to its low carbon content in particular, the risk of crack formation in welding operations is minimised.
- A high strength-to-weight ratio
- A low coefficient of thermal expansion
- Good toughness and impact strength
- High hardness and wear resistance
Technical properties such as these make it the preferred material particularly in the defence industry and in high-performance engine components.
Maraging 350 Industrial Applications
- Aerospace industry: jet engine parts, landing gear, rocket and spacecraft components
- Defence industry: high-strength armour and missile components
- Automotive: suspension and chassis parts in performance vehicles
- Sports equipment: golf clubs and bicycle parts requiring high strength
- Industrial tooling: high-strength tool and die components
Maraging 350 is an indispensable material for sectors seeking durability and long service life in high-performance applications.
Maraging 350 Production and Machinability
The production process covers a wide range, from casting to machining. The low carbon content and high alloy composition of the material can make machining operations difficult. Special cutting tools and cooling methods are therefore used.
Since hardness and strength are quite high after heat treatment, care must be taken during machining. Welding operations are limited and require special techniques; preheating and post-weld ageing are generally applied for welded parts.
Advantages
- Very high tensile and yield strength
- Excellent fatigue and impact resistance
- A good balance of toughness and ductility
- High hardness and wear resistance
- A weldability advantage thanks to the low carbon content
- Long-lasting performance and durability
Disadvantages
- Its machinability is difficult and requires special equipment and knowledge
- The heat treatment process is complex and time-consuming
- Its cost is high because of the high alloy content
- Welding operations demand care and special procedures
- It is relatively less common than standard alloys and lead times can be long
Conclusion
It is an ideal superalloy for critical industrial applications requiring high strength, durability and toughness. Products certified under the AMS and ASTM standards are used with confidence in the aerospace, defence and high-performance automotive sectors. Although it requires special production and heat treatment processes, the superior mechanical performance it provides is the most important factor justifying its cost.
MARAGING350
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We supply this material
We supply Maraging 350 — to AMS 6510 and AMS 6511, in the size and form required. Contact us for stock and pricing.
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