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Full analysis of metal 3D printing materials and processes

3D printing will promote a new space race

According to relevant data analysis reports, the scale of 3D composite printing materials in the future market will continue to increase, and the application of metal materials will also increase year by year. It is expected that composite materials are expected to reach US$111 million in 2022, and the market size of 3D printing metal materials will reach US$800 million. , R&D and production of metal materials will have a broader market space.

Full analysis of 3D printing materials and processes

Metal 3D printing materials

Different from ordinary materials, 3D printing materials need to be prepared using unique technologies to meet the special requirements of 3D printing products and 3D printing equipment for materials. Depending on the 3D printing technology used and the purpose of the manufactured parts, the required materials are also different.

Full analysis of 3D printing materials and processes

Metal 3D printing materials mainly come in powder form and wire form. Powder materials are the most commonly used materials. The main materials include cobalt-based alloys, stainless steel, tool steel, die steel, nickel-based alloys, titanium and titanium alloys, and various aluminum alloys.

1. Tool steel and martensitic steel

Take tool steel and martensitic steel as examples. The applicability of tool steel comes from its excellent hardness, wear resistance and deformation resistance, and its ability to maintain cutting edges at high temperatures. Martensitic steel, taking martensite 300 as an example, is also known as “maraging” steel. Its high strength, toughness and dimensional stability during the aging process are well known.

Full analysis of 3D printing materials and processes

Due to its high hardness and wear resistance, Martensite 300 is suitable for many mold applications, such as injection molds, light metal alloy casting, stamping and extrusion, etc. At the same time, it is also widely used in aerospace, high-strength body parts And racing parts.

2. Stainless steel

At present, there are mainly three types of stainless steel used in metal 3D printing: austenitic stainless steel 316L, martensitic stainless steel 15-5PH, and martensitic stainless steel 17-4PH.

Austenitic stainless steel 316L, with high strength and corrosion resistance, can drop to low temperatures in a wide temperature range, and can be used in aerospace, petrochemical and other engineering applications, as well as in food processing and medical fields.

Full analysis of 3D printing materials and processes

Martensitic stainless steel 15-5PH, also known as maraging (precipitation hardening) stainless steel, has high strength, good toughness, corrosion resistance, and can be further hardened, and it is ferrite-free. At present, it is widely used in aerospace, petrochemical, chemical, food processing, papermaking and metal processing industries.

The martensitic stainless steel 17-4PH still has high strength and high toughness at 315°C, and has super corrosion resistance. With the laser processing state, it can bring excellent ductility.

3. Alloy

The most widely used metal powder alloys for metal 3D printing materials mainly include pure titanium and titanium alloys, aluminum alloys, nickel-based alloys, cobalt-chromium alloys, and copper-based alloys.

Full analysis of 3D printing materials and processes
(1) Pure titanium and titanium alloy

The pure titanium currently used in the market, also known as commercial pure titanium, is divided into grade 1 and grade 2, and grade 2 is stronger than grade 1. It is also corrosion-resistant for most applications. Because pure titanium grade 2 has good biocompatibility, it has broad application prospects in the medical industry.

Full analysis of 3D printing materials and processes

Titanium is the key to the titanium alloy industry. At present, the titanium alloys used in metal 3D printing are mainly titanium alloy grade 5 and titanium alloy grade 23. Because of their excellent strength and toughness, combined with corrosion resistance, low specific gravity and biocompatibility, they are used in aerospace and automobile manufacturing. It has a very ideal application, and because of its high strength and strong fatigue resistance, it is used in the production of biomedical implants.

(2) Aluminum alloy

At present, aluminum alloys used in metal 3D printing mainly include AlSi12 and AlSi10Mg. Al-Si 12 is a lightweight additive-manufactured metal powder with good thermal properties. It can be applied to thin-walled parts such as heat exchangers or other auto parts, and can also be used in aerospace and aviation industry-grade prototypes and production parts. Components: The combination of silicon/magnesium makes the aluminum alloy stronger and harder, making it suitable for thin-walled and complex geometrical parts, especially in applications with good thermal performance and low weight.

Full analysis of 3D printing materials and processes
(3) Nickel-based alloy

In general, nickel-based alloys have good tensile, fatigue and thermal fatigue resistance. At present, there are mainly Inconel 738, Hastelloy X, Inconel 625, Inconel 713, Inconel 718, etc.

Inconel 738 has good high temperature creep rupture strength, and its thermal corrosion resistance is a super alloy with low chromium content. It can be exposed to high temperature and corrosive environments up to 920-980℃ for a long time. It is suitable for aircraft engines and gas turbines.

Full analysis of 3D printing materials and processes

Hastelloy X has high strength and oxidation resistance at high temperatures, and also has good ductility in environments up to 1200°C. At present, it is mainly used in aerospace technology, such as gas turbine components and combustion zone components such as transition tubes and combustion It is also used in industrial furnaces, petrochemical and chemical process industries because of its resistance to stress corrosion cracking.

Inconel 625 still has good load performance at a high temperature of about 815℃, and has strong corrosion resistance. It is widely used in aerospace, chemical and power industries.

Inconel 713 has excellent thermal fatigue resistance and special breaking strength at 927°C. It is suitable for jet engine gas turbine blades.

Full analysis of 3D printing materials and processes

Inconel 718 is a superalloy based on iron and nickel hardening. It has good corrosion resistance and heat resistance, tensile, fatigue, and creep properties. It is suitable for various high-end applications, such as aircraft turbine engines and turbines.

(4) Cobalt-chromium alloy

Cobalt-chromium alloy has high strength, strong corrosion resistance, good biocompatibility and non-magnetic properties. It is mainly used in surgical implants including alloy artificial joints, knee joints and hip joints. It can also be used in engine parts and Fashion, jewelry industry, etc.

Full analysis of 3D printing materials and processes
(5) Copper-based alloy

The copper-based alloy used in the market, commonly known as bronze, has good thermal conductivity and electrical conductivity. It can combine design freedom to produce complex internal structures and cooling channels. It is suitable for cooling more effective tools to insert molds, such as semiconductor devices, and can also be used For the micro heat exchanger, it has the characteristics of thin wall and complex shape.

Full analysis of 3D printing materials and processes

Metal 3D printing technology

The current mainstream metal 3D printing technologies include: selective laser melting (SLM), laser near net shaping (LENS) and electron beam selective melting (EBSM) technology, direct energy deposition (DED) technology, etc.

1. SLM (Selective Laser Melting Technology)

SLM is currently the most common technology in metal 3D printing. Its working principle is: the computer converts the three-dimensional data of the object into layered cross-sectional 2D data and transmits it to the printer. During the printing process, the setting is laid on the substrate with a squeegee. Layer-thick metal powder, the focused laser scans under the control of the scanning galvanometer according to the pre-planned path and process parameters. The metal powder melts under the irradiation of the high-energy laser and solidifies rapidly to form a metallurgical bonding layer. When the printing task of one layer is finished, the substrate is lowered by one slice layer thickness, the squeegee continues to perform powder leveling, laser scanning processing, and this process is repeated until the entire part is printed.

Full analysis of 3D printing materials and processes

The advantage of this technology is that it can be widely used in the mass production of metal parts with complex shapes, and most metal powders are suitable for this technology, including titanium alloys, aluminum alloys, high-temperature alloys, copper alloys, cobalt-chromium alloys, stainless steel, high-strength Steel, die steel, etc., the obtained parts are nearly 100% dense.

2. LENS (laser cladding deposition technology)

LENS is based on coaxial powder feeding. The laser beam moves according to a preset path under control; at the same time, the powder nozzle directly conveys the metal powder under the laser spot, making it from point to line and from line to line. The sequence to the surface is solidified to complete the printing of a layered cross-section, so that layer by layer is superimposed, and the part entity is manufactured. Printers using this technology are usually mixed with corresponding CNC milling units.

Full analysis of 3D printing materials and processes

The biggest difference from SLM is that the powder is gathered on the work surface through the nozzle and converged with the laser at one point. After the powder is melted and cooled, a deposited cladding entity is obtained.

3. EBSM/EBM (electron beam selective melting technology)

EBM is a process of manufacturing 3D metal parts by layer-by-layer deposition using electron beam scanning and melting powder materials in a vacuum environment. The electron beam output energy of EBM is usually an order of magnitude larger than the laser output power of SLM, and the scanning speed is much higher than that of SLM. Therefore, during the construction of EBM, it is necessary to preheat the entire molding table to prevent excessive temperature during the molding process. To a larger residual stress. Compared with SLM technology, the processing efficiency is higher and the cost is lower, but the technical difficulty is relatively higher.

Full analysis of 3D printing materials and processes

4. DED (Direct Energy Deposition Technology)

A laser or other energy source generates a molten pool in the deposition area and moves at a high speed. The material is directly fed into the high-temperature melting area in the form of powder or filament, and then deposited layer by layer after melting, which is called laser direct energy deposition additive manufacturing technology. Since the printout is not done in a flat powder bed, another advantage of the direct energy deposition technology is that it can make a new object while repairing an existing object. Although objects produced by this technology require a certain degree of surface treatment (such as polishing with a machine), they can also be used directly as dense metal parts.

the application of metal 3D printing materials

Metal 3D printing materials have a wide range of applications, such as petrochemical engineering applications, aerospace, automobile manufacturing, injection molds, light metal alloy casting, food processing, medical treatment, papermaking, power industry, jewelry, fashion, etc. However, because of the material properties of metal 3D printing materials, they have specific application areas. Therefore, the process of selecting metal 3D printing materials is a process of weighing multiple factors. Moreover, 3D printing metal cannot be weighed solely by the parameters of the metal 3D printer. Each metal material has its own limit points, including application, function, stability, durability, aesthetics, and economy. Factors to consider.

Recommended reading《The metal 3D printing process consists of 3 steps in total

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