18Ni300 Alloy Powder Stainless Steel Nickel

Introduction

Today, I would like to introduce 18Ni300 alloy powder to you, but first of all, I would like to emphasize that don’t be confused by the word “nickel” in its name. It is not the a kind of stainless steel, but one kind of maraging steel with excellent performance in the field of precision manufacturing. Next, I will take you to understand all the mysteries of 18Ni300 alloy powder from the perspective of a material scientist.

Composition and microstructure of 18Ni300 alloy powder

In my opinion, to understand the material, we must first start with its “gene”-chemical composition and microstructure. This is like dissecting a complex machine. Only by figuring out each part and how they are assembled can we truly understand how it works.

Chemical composition

The reason why 18Ni300 can achieve such high strength and toughness is due to its precise and complex chemical composition. It is the 1 typical iron-based alloy in which:

• Nickel (Ni): The content is up to about 18%, which is the core element for the formation of low-carbon martensite phase and an important part of the precipitation phase in the late aging strengthening process.
• Cobalt (Co): About 9% Cobalt helps to reduce the residual amount of austenite after quenching and promotes the formation of martensite. At the same time, it can also improve the strength and toughness of the material, and also has a positive effect on improving the aging hardening effect.
• Molybdenum (Mo): About 5% molybdenum is an important solid solution strengthening element, which can form a substitutional solid solution with iron and hinder dislocation movement. More importantly, molybdenum is also a key element in the precipitation of strengthening phases (such as Ni3Mo) during the aging process.
• Titanium (Ti): About 0.6% Titanium, although not high in content, is a decisive small particle precipitation strengthening element. It forms Ni3Ti precipitated phase with nickel, which is one of the main factors contributing to the ultra-high strength of 18Ni300.
• Aluminum (Al): usually contains a small amount of aluminum (about 0.1%), as a deoxidizer and grain refiner, to improve the cast tissue and subsequent heat treatment effect.
• Carbon (C): The carbon content is very low, usually less than 0.03%. Low carbon is a major feature of 18Ni300 maraging steel, which makes the formed martensite have higher toughness and avoids the brittleness of traditional high-carbon martensite.

Austenite-martensite transformation

After solution treatment, the material will form an austenitic structure. However, in the subsequent quenching process, the austenite is almost completely transformed into low-carbon martensite. This martensite is different from the traditional hardened steel martensite, it has a very low carbon content, so it has a higher toughness. In my opinion, it is this unique martensite matrix that lays a solid foundation for subsequent aging strengthening.

Extraction enhancement mechanism

We know that the charm of 18Ni300 maraging steel is largely reflected in the key link of its aging treatment. Usually, we will hold for several hours in the temperature window of 480-520°C.

Under this well-set condition, those tiny intermetallic compounds, mainly Nielevated Ti and Nielevated Mo, will be uniformly precipitated from the low carbon martensite matrix.

The formation of these precipitates is not simply piled up, they are cleverly combined with the matrix in a common or semi-common manner, which greatly improves the yield strength and tensile strength of the material.

Let me talk specifically about these two main reinforcement phases:

Ni₃Ti phase: Usually, we will observe that they are precipitated in a small spherical or ellipsoidal shape, and the size is often controlled between 5-20 nanometers. Their pinning effect on dislocation motion is very strong and is the core factor that contributes to the amazing strength of the material.

Ni₃Mo phase: They will also precipitate in a similar way, but may be more plat-like or spindle-like in morphology, and may be slightly larger in size. Niincreased Mo not only can provide significant strengthening effect, but also, from the point of view of tissue stability, it also plays an important role in stabilizing the matrix tissue, preventing the occurrence of undesirable phase transformation.

The type of these nanoscale precipitates, their specific size, morphology and their distribution uniformity in the matrix, all of these details directly determine the final mechanical performance of 18Ni300.

Powder morphology and properties

For additive manufacturing, the quality of the powder itself is crucial. 18Ni300 alloy powder is typically prepared using gas atomization or plasma atomization techniques, which ensures that the powder particles have good sphericity, low void ratio, and high flowability. Ideal powder morphology and particle size distribution directly affect the uniformity and density of powder spreading during the printing process, thus determining the performance of the final part.

Physical Properties of 18Ni300 Alloy Powder

In addition to microstructure, macroscopic physical properties are also factors that our engineers must consider when selecting materials.

Density

The density of 18Ni300 alloy typically ranges from 8.0 g/cm³ to 8.2 g/cm³. This density is moderate for high-strength steel, and compared to some ultra-high-strength alloys (such as tungsten alloys), it does not impose an excessive weight burden on the structure. In the aerospace field, every gram of weight is crucial; therefore, this moderate density, combined with its excellent strength, makes it a preferred material for lightweight designs.

Melting point range

It has a melting point in the range of approximately 1410°C to 1425°C. This relatively high melting point ensures that the material maintains good structural integrity and mechanical properties in high temperature environments, such as engine components. At the same time, for additive manufacturing processes, knowing the precise melting point range helps engineers set the best process parameters such as laser power and scanning speed to ensure that the powder is fully melted and forms a dense printed layer.

Thermal conductivity

The thermal conductivity of 18Ni300 alloy is relatively low, about 20-25W/(m · K). This value is lower than high thermal conductivity materials such as pure copper or pure aluminum, but is similar to many high-strength steels. In some applications, lower thermal conductivity may mean that effective heat dissipation design needs to be considered to avoid local overheating. However, in other applications, such as components that require local insulation, or when operating under high temperature gradients, this lower thermal conductivity may instead be an advantage.

Extensive Application of 18Ni300 Alloy Powder

Its unique combination of properties-ultra-high strength, excellent toughness, good fatigue performance and dimensional stability-makes it an irreplaceable role in many key areas.

Aerospace

In the field of aerospace, every performance improvement means great progress. Weight is the eternal enemy of aircraft design, while strength is the lifeline to ensure flight safety. With its extremely high strength-to-weight ratio and excellent toughness, 18Ni300 has become an ideal material for manufacturing key components such as aircraft structural parts, landing gear parts, satellite precision parts, rocket engine nozzles and turbine blades.

Through additive manufacturing technology, we can use 18Ni300 powder to produce lightweight parts with complex internal structure and topology optimization design, which can not only significantly reduce weight, but also realize the functional integration and performance of the parts without sacrificing performance.

Precision mold manufacturing

For precision molds, especially demanding die-casting molds, injection molds or hot work molds, the material must not only have high hardness, high strength to resist wear and deformation, but also have good toughness to avoid early cracking, and excellent polishing To meet the surface quality requirements. After proper aging heat treatment, 18Ni300 alloy can reach the ultra-high hardness above HRC 50, and its martensite matrix gives it excellent comprehensive toughness.

Therefore, the 18Ni300 alloy powder excels in the manufacture of long-life, high-precision molds that can withstand harsh working environments. Its excellent performance can significantly extend the service life of the mold, reduce production costs, and improve product quality.

Medical Devices

In the field of medical devices, especially surgical tools, certain orthopedic fixation devices and customized medical components, there are extremely high requirements for the strength, toughness, corrosion resistance and sterilization of materials. Although 18Ni300 alloy is not an implant-grade biomaterial in the traditional sense, its ultra-high strength and good fatigue performance make it show great potential in the manufacture of non-implantable medical devices that withstand high stress and require high reliability.

For example, in some complex custom surgical guides, instrument handles, or robotic-assisted surgical tool components, 18Ni300 can provide performance that is unmatched by traditional materials. I believe that with the development of biocompatible coating technology, its application in the broader medical field is promising.

Conclusion, reaffirming the key role of 18Ni300 alloy powder in high-performance manufacturing

18Ni300 is more than just a 1 material, it is more like a key, unlocking countless possibilities in the field of high-performance manufacturing. Its perfect combination with additive manufacturing technology is leading us to a new era of lighter, stronger and more complex parts. I believe that in the future, 18Ni300 alloy powder will continue to shine in the high-tech field, and promote the engineering design and manufacturing level to a new height.