Do you know the most powerful knife in the world? Some would think: Damascus knives in India, made from ingots of Uzi steel, with cast patterns on the surface. After more than 2600 years of ingenious creation by masters of all dynasties, it formed the four characteristics of "hardness and sharpness, combination of hardness and softness, cold light and skillful decoration" and is recognized as the best of swords!
Others say: Absolutely not.
It must be the Tang Knife of our country! It wraps the soft iron inside with a thin sheet of high-carbon steel, and part of the cutting edge uses local hardening technology, that is, burning the blade with the ground. The blade is hard enough to cut through armor, and the blade itself is strong and durable.
Is that really true?
Nothing but water.
Yes, that's right. Water has not only a soft side, but also a hard one: in ancient China, there was a saying that dripping water wears away stones, and it was believed that water is the sharpest substance in the world. And seemingly weak water can cut diamonds, you won't believe it, so let's see how strong it is?
Water can cut everything, because water can be a knife, that is, a “water knife”.
How did the water knife come about?This technology originated in the United States and was used in the military space industry. In the 1930s, engineers in some developed countries such as the United States and the Soviet Union began using ultra-high speed waterjet cutting technology to cut rock and coal. This is also the earliest waterjet cutting technology we have discovered.
Actually, this was not given much attention in the beginning. It wasn't until 2011 that a water cannon expert from my country, Ji Xingan, invented a water cannon that broke the stereotype that a water cannon should not be used in hazardous areas. and has been widely developed and applied.
How powerful is the water jet?Currently, waterjet cutting is widely used in ceramics, stone, glass, metal, composite materials and many other industries. At present, in China, the maximum water jet pressure has reached 420 MPa. Some technologically advanced companies have improved 3-axis and 4-axis water jet, 5-axis water jet is also becoming mature.
The biggest feature of the water jet is that it can cut through any object along any curve in one go, and this is even known as "cutting iron like dirt". For example: cutting insulating materials with a water jet, cutting cement boards, stone materials, various metals, etc.
Of course, water doesn't cut iron like dirt does. Applying water power also requires special water cutting equipment.
This equipment consists of ultra high pressure pump, water jet cutting head, water jet moving x-y flat cutting table, controller, software package and other components.
First, an ultra-high pressure pump pumps water up to 400 MPa, high pressure water enters the accumulator, and then it is ejected through a very small nozzle. The nozzle diameter is approximately 0.1 to 0.4 mm. Although the nozzle diameter is small, its power is not ordinary.
The high-pressure water ejected from the nozzle is equivalent to a sharp arrow at a speed of almost a thousand meters per second, which we call a water jet. Of course, what a water jet can cut is primarily determined by the pressure of the water. Water pressure above 30MPa is a low pressure water jet, which can do some simple cutting work, but it will be different if it continues to increase.
Now, thanks to continuous improvement, its role is becoming larger and larger. If it is a traditional cutting technology, it will generate heat, static electricity, and even open flames. This risk factor is still very high and this cutting method is completely inapplicable for special materials.
In its absence, most people resort to incineration. This method will only pollute the environment and cause an impact on the atmosphere until the appearance of water jets disturbed this situation.
What is the difference between waterjet, laser and ion cutting?The investment in laser cutting equipment is high, and the cost of maintenance is also high. Most of them are used for cutting thin steel plates and some non-metal materials. The cutting speed is fast and the accuracy is high. However, during laser cutting, arc marks and thermal effects occur on the kerf. There are also cases where the incision is not very obvious or even impossible.
Waterjet cutting is characterized by low investment, low operating cost, wide range of cutting materials, high efficiency and easy operation and maintenance.
Ion cutting also has the same problems as laser cutting, namely: obvious thermal effect, poor accuracy, and the cutting surface is not recyclable.
Waterjet cutting basically does not require secondary processing, it belongs to cold cutting, no thermal deformation, and the quality of the cutting surface is good. Of course, sometimes this is not difficult if processing is required.
In fact, the water jet not only thrives in the cutting area, but also plays a huge role in the cleaning area.
Ultra high pressure water jet cleaning is a physical cleaning method. Compared with traditional manual, mechanical, chemical, biological and other cleaning methods, it has many advantages, such as:
Firstly, the pressure and flow rate of the water jet can be easily adjusted, so it will not damage the base of the object being cleaned;
Secondly, the ultra-high pressure water jet does not cause secondary pollution. If there are no special requirements after cleaning,no cleanup required;
Thirdly, wash objects of complex shape and design, and perform cleaning operations in places with narrow space or in harsh conditions;
Fourthly, unlike chemical cleaning and biological cleaning, ultra-high pressure water jet cleaning has no emission of harmful substances and environmental pollution;
Fifth, ultra-high pressure water jet cleaning is fast and thorough. For example, the degree of cleaning of the heat exchanger exceeds 95%, and the degree of cleaning of the boiler from scale exceeds 95%;
Sixth, the cleaning cost is low, only about 1/3 of chemical cleaning, that is, ultra-high pressure water jet cleaning belongs to fine jet and belongs to energy-saving equipment;
Seventh, ultra-high pressure water jet cleaning does not impose special requirements on the material of the equipment, characteristics, shape and types of contaminants, only that the water jet can reach it.
Why is the water cannon so popular?One reason: waterjet cutting is affordable.
Second reason: ease of operation, ease of use and a wide range of applications.
Example: Waterjet once solved a security problem.
In June 2010, an unexploded aerial bomb was discovered at a construction site in Zhengding City, Shijiazhuang Province. EOD experts and technicians of the Ruixun group worked together to outline the aerial bomb in the open field, successfully disassembled the aerial bomb using waterjet cutting technology, and completed the one-time dissection of the outer steel shell, TNT explosive layer, the inner detonating tube and the process of forming a fault-like section created the world's first record for dismantling an air bomb in the field.
Waterjet cutting is for safety only. The invention and practical application of portable waterjet cutting eliminates the hidden dangers of high temperature, static electricity and open flame operations, reduces the danger of manual operation, and performs partial cutting and cutting safely and efficiently. large equipment. The elimination of disassembly truly eliminates the shortcomings of traditional waterjet cutting equipment, and solves the problems of safety, speed, low carbon emission and environmental protection from the source.
In general, the value of waterjet cutting will become higher and higher, and its application area will also expand day by day with great development potential. We can turn soft water into a blade, which reflects our wisdom in everything. I tell us not to underestimate any object, when they come together they can resist all forces!
Water is one of the most important material resources necessary for human survival and development. Water performs many physiological functions for the human body, and currently it alsoplays an important role in various fields.