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Different grades of Maraging Steel

What is Maraging Steel?

High alloy structural steels classified as “maraging grades” have a chemical makeup that is mostly composed of nickel, cobalt, and molybdenum. They fall under the category of iron-nickel alloys, tool steels, and structural steels for heat treatment after the chemical composition itself. The amount of carbon included in alloy grades for improvement, carburizing, or nitriding is significantly more (typically 0.1%) than it is in Maraging steel (0.03%). The separation of intermetallic phases replaces the solid carbon solution and carbide phase as the second thing to take into account.

Maraging steels are one of the hardest iron-nickel alloys with a high degree of plasticity and are one of the few materials that can function in a wide range of temperatures, from -200 to 600 °C. Good machinability, weldability, and the capacity to operate continuously in both high and low temperatures are other benefits (depending on grades). The name Maraging is made up of two words related to heat treatment and the structure that resulted from them: Martensite and Aging.

Chemical composition and Characteristics:

Nickel, cobalt, titanium, and molybdenum are among the chemical elements found in steel. Aluminum, occasionally Chromium, Zirconium, Tungsten, Niobium, and Beryllium make up the remaining parts in trace amounts. Each of the primary alloying compounds mentioned above has a major impact on the material’s structure, mechanical and physical properties, and performance traits in specific situations. To decrease the occurrence of undesirable carbides, carbon restriction was implemented. One of the most beneficial alloying additions, nickel lowers the brittleness threshold, causes hardening, and helps the conversion of the structure into martensitic. Hardness and durability are strongly impacted by cobalt, particularly at high temperatures. The use of a substitute that will increase the strength and hardness is necessary since the composition lacks an adequate amount of carbon. The solubility of molybdenum and tungsten in alpha iron is further decreased by cobalt. The third most concentrated element is molybdenum, which works closely with cobalt. It increases the ductility of steel and aids in the development of intermetallic phases inside the grain.

Different grades of Maraging Steel:

There are 3 most popularly used grades of Maraging Steel

Maraging C250:

Low-carbon, vacuum induction melted and vacuum arc melted alloys are known as Maraging C250, and/or Vascomax 250. 

Maraging steels have a toughness that can be considered above average along with extremely high strength. Maraging steels are primarily composed of iron, with nickel, cobalt, and molybdenum serving as important alloying additives. The addition of titanium and aluminum, as well as the low carbon content, are equally significant. The mixture produces extremely high strength while still being easily weldable.

Maraging steels are offered in the annealed state, where fine martensite makes up the microstructure. Aging is a relatively low temperature process that produces the ultimate qualities of great strength and toughness. Since distortion is at a minimum after this low temperature treatment, close to final size machining is possible. Maraging steels can be nitrided, have corrosion resistance comparable to that of normal martensitic stainless steels, and maintain their strength up to 450°C (840°F).

The yield strength of this maraging steel can be increased to more than 240 KSI (1655 MPa) with a straightforward, low temperature heat treatment. Maraging steel grade C250 is easily weldable and has good ductility at high strength levels.

Features of Vascomax C250 (Maraging C250)

The nickel/cobalt steel alloy Vascomax C250 as a result of being carbon-free and having other alloying components in the mixture such as moly, aluminum, and titanium produces superb maraging steel with qualities like meeting the requirements of AMS 6512, it complies with ASTM A 538 requirements as well, in addition also complies with MIL-S-46850D requirements, and complies with UNS K 92890 requirements. It owns incredible toughness, it has a relative softness that doesn’t compromise strength or toughness, exceptional tensile strength, defends against corrosion and fracture growth, excellent polishability, and cleanliness, and it is easily welded.

Maraging steel has several industrial uses, some of which are in the nuclear and military industry in the form of rocket and missile motor cases, munitions, land-based, distinct equipment parts that require toughness, tools for aerospace extrusion, high performance fasteners, gears, and shafting

Several providers offer the nickel/cobalt alloy maraging C250 in the following forms welded and seamless pipe, welded and seamless tube, bars, Wire, sheet, Plate, Forgings, Pipe connections, and Flanges.

Maraging C300:

It is also referred to as Vascomax 300. Low-carbon, high-temperature nickel-cobalt-molybdenum alloy Maraging 300 alloy sheets and plates of steel (also known as Maraging C300 and Vascomax C300) are vacuum induction melted and vacuum arc re-melted. Through straightforward, low-temperature heat treatment at 900°F (482°C), this material can reach yield strengths greater than 270 KSI (1862 MPa). Maraging steel 300 also shows excellent notch ductility, flexibility at high strength levels, and outstanding weldability.

The qualities of the materials used in the making of this grade of Maraging Steel are that the nickel or cobalt steel alloy Vascomax 300, which is readily available in the market, is essentially carbon-free; other alloying components include moly, aluminum, and titanium. This mixture produces excellent maraging steel that preserves many advantageous qualities, such as displays incredibly toughness, relative softness that doesn’t compromise strength or toughness, exceptional tensile strength, can easily defend against corrosion and fracture growth, possesses excellent polishability and cleanliness, it can be easily welded.

Maraging steel 300 has good machinability and may be cold-rolled up to 90% without breaking due to its low carbon content. When aged after being treated for the heat-affected zone, this material also offers outstanding weldability. Maraging 300 Alloy Steels also conform to the following requirements: UNS K 93120 AMS 6514 ASTM A 538 MIL-S-46850D. 

When it comes to application, due to its strength and malleability at the pre-aged stage, maraging steel can be formed more readily than other steels, resulting in a reduction in weight for a given strength. Additionally, Maraging 300 maintains remarkably stable characteristics and will only slightly soften when overaged as a result of high temperature reception. This material can be used for a variety of defense and military applications since it has a great strength-to-weight ratio. The Maraging C300 is typically used for applications such as rocket and missile motor cases, munitions, land-based equipment parts, in the aerospace industry, extrusion equipment, casting by dying, and in the making of high performance fasteners, gears, and shafting. 

Maraging 300 is one of the grades of a group of maraging nickel steels, which also includes Maraging 250 and Maraging 350. These steels are martensitic but ductile in their solution-treated state, and they may be aged at low temperatures to reach ultra-high strengths. A variety of versions of the nickel/cobalt alloy maraging C300, just like its other grades (Grade C250 and C350) are available in the market, including Bar, Wire, Sheet, Plate, and Forgings.

Maraging C350:

It is also called Vascomax 350. Despite being rather soft, the nickel-maraging alloy Maraging C350TM is incredibly durable. Additionally, Vascomax C350 is easily shaped and machined to the consumer’s specifications. Maraging steel’s hardness is also increased during the aging process to a degree suitable for many tooling applications.

A variety of features of Vascomax C350 (Maraging C350) include that vascomax 350 is a nickel/cobalt steel alloy that is nearly carbon-free. Moly, aluminum, and titanium are also used as alloying materials. This mixture produces superior maraging steel with many characteristics, such as it meets the requirements of AMS 6512, complies with AMS 6514 requirements too, and complies with MIL-S-46850 requirements as well. It is observed to be incredibly tough, allows for little distortion while cutting close, it has a uniform and dependable shrinking after heat treatment

simple to nitride, it can easily defend against corrosion and fracture growth, it has excellent polishability and cleanliness, and can be easily welded.

Maraging steel has several industrial uses, some of which are as follows:

In the nuclear industry as rocket and missile motor cases

Models of wind tunnels

Land-based equipment parts

In developing high performance fasteners, gears, and shafting

Like the other grades of Maraging Steel, the nickel/cobalt alloy maraging C350 is available in the general market in several forms, including welded and seamless pipe, welded and seamless tube, several bars, different forms of wire, sheet, plate, forgings, and flanges for pipe fittings. 

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