Steel 3D prints stainless and is more resistant to ordinary steel

Despite being booming in the world, 3D printing technology is currently effective on materials such as plastic or porous steel - meaning that many materials still do not meet the requirements of core bearing structure. hard. Recently, a team of researchers has developed 3D printing technology that produces stainless steel products, both hard and flexible - a step that can bring a faster and cheaper production method with everything from engines. missiles to components in nuclear reactors or oil rigs.

Stainless steel technology was first invented about 150 years ago, until now it is still popular. Made from traditional molten steel - a combination of iron and carbon (can add metal like Nickel) - adding chromium and molybdenum, stainless steel is resistant to rust and corrosion. This is followed by a complex process consisting of several steps: cooling, heating, rolling, which helps the steel achieve micro structure with compacted metal particles, and the thin separation layer between the particles. Form a structure quite similar to cells. When steel foil is bent or stretched, the crystal surfaces (including atoms) are slipped, cut into each other, leading to a deficiency when these layers are combined - causing a fracture. However, the creation of thick separators can "stop" this situation, making the steel much harder but still flexible enough to bend into the desired shape.

Under certain conditions, stainless steel from 3D printing can be three times as hard as conventional steel.

Researchers have long tried to find a way to replicate such a structure. They began experimenting by pouring a layer of powder - consisting of mixed metal molecules - onto a flat surface. A high-powered, computer-controlled laser beam is projected back and forth on the surface. Metal molecules that come into contact with the laser will become molten. After that, a new layer of powder was added, further processed with a laser to melt the molecules and bind to the underlying layer. Repeatedly, engineers can create complex structures like in rocket engines.

A long-standing problem with stainless steel from printing technology is that the hollow rate is still high, making steel weak and easy to break. So, "this result is amazing," Yinmin Morris Wang, materials scientist at Lawrence Livermore National Laboratory in California, said. A few years ago, Wang and colleagues went on to use lasers and rapid cooling techniques to melt mixed metal molecules in the same density area, to create a compact structure.

To date, this steel has been greatly expanded when Wang's team designed a computer-controlled process, not only to make thick stainless steel layers but also to control chopping material structure at nanoscale to micro meters. This achievement allows 3D printers to build tiny cell-like structures that function like walls to prevent fractures and common common problems in steel. Experimental results also show that, in certain conditions, stainless steel from 3D printing can be three times as hard as steel produced by conventional methods, and still "malleable" - public report published in Nature Materials.

"What they do is really impressive , " said Rahul Panat, a mechanical engineer at Carnegie University in Pittsburgh (Pennsylvania). Furthermore, Panat believes that because Wang and his colleagues use new commercial 3D printing technology and lasers, many other groups can learn to make a wide range of stainless steel products such as fuel tanks. whether on the plane to the bearing pipes in nuclear power plants.

1. Learn about 3D printing technology