Underwater plasma cutting machine applications

At present, the most widely used underwater plasma cutting machine is underwater arc-oxygen cutting of steel pipe strips. The cutting method is easy to operate, flexible, simple equipment, low cost, used to cut steel plate thickness of no more than 40mm, operating technology is easy to grasp, is an underwater cutting method with the most widely used and deepest application depth. However, the cuts need to be replaced frequently, which affects the cutting efficiency and the incisions are also rough.

The faster cutting speed is the molten water jet cutting method and the underwater plasma arc cutting method. These two kinds of cutting methods have high cutting efficiency, and the quality of the incision is also relatively good. Underwater welding can be performed without trimming or slight trimming.

From the perspective of equipment types and application fields, the current global underwater plasma cutting machines are mainly divided into the following major categories:

1. Underwater arc-oxygen cutting

Underwater arc-oxygen cutting is the use of an arc generated between a hollow electrode (ie, a cutting line) and a workpiece to melt the workpiece, oxygen is blown from the electrode hole, and the hot workpiece metal is oxidized and burned, and the molten metal is blown off. Slag, thereby forming an incision method of cutting.

2. Underwater plasma arc cutting

Underwater plasma arc cutting is a cutting method that uses a high-temperature and high-speed plasma gas flow to melt a metal plate and remove the molten metal by means of a high-speed airflow or water flow to form an incision. Since the plasma arc is difficult to form between the electrode and the workpiece, the pilot arc must be first ignited between the tungsten electrode and the nozzle by means of high frequency or direct contact, and then transitioned between the tungsten electrode and the workpiece. The plasma arc cutting guns used today for the cutting of underwater metal materials are in the form of transfer arcs.

3. Molten polar water jet underwater cutting

Melting Polar Water Jet Underwater cutting uses the heat generated by the arc to melt the metal and blows away the molten metal and slag with a high pressure water jet to form a clean cut surface.

4. Underwater oxygen-flame cutting

Underwater oxygen-flame cutting is to use a gas flame to preheat the surface of the workpiece to be burned, and then to inject oxygen to burn the metal and blow off the molten metal and slag to form an incision.

5. Hot cutting spear cutting

The hot spear is a steel pipe filled with steel wire. When the steel pipe is preheated from the outside and brought to the ignition point, oxygen is blown from the steel wire inside the steel pipe. The heat released from combustion of the steel pipe and wire melts the workpiece and reaches The purpose of cutting. The heat released by the hot cutting spear and the oxygen blown by the hot cutting spear make the cut piece melt and burn to form an incision, which is a melting-oxidation process. However, the difference with underwater arc-oxygen cutting is that hot cutting spears play a leading role in the heat generated by their own oxidation, while underwater arc-oxygen cutting is dominated by oxidized metals.

6. Hot cut cable cutting

The hot cut cable is a hollow cable made of fine steel wire, and the cutting principle is basically the same as that of the hot cutting spear cutting: the hot cable is first preheated to the burning point, and then the oxygen is used to burn the hot cutting cable to melt the workpiece. To achieve the purpose of cutting.

7. Underwater forming explosive explosion

Molded packs are specially formulated explosives that are contained in a soft metal (such as copper, aluminum, lead) enclosure. The cross-section of the drug pack is usually inverted V-shaped. The principle of cutting is: the drug package is placed on the part to be cut of the workpiece to be cut. When the explosive detonates and the explosion wave breaks the metal shell, the formed high-temperature high-speed metal particle stream and the high-energy shock wave are directed and focused on the workpiece. , thereby breaking the workpiece into an incision. The underwater cutting can straight cut, perforate, and cross sections of standard geometries (such as cutting pipes, steel cables).

8. High-pressure water jet cutting

High-pressure water jet cutting uses high-speed, high-pressure water jets ejected from nozzles to break the workpiece to achieve the purpose of cutting. The cutting process has no thermal effect during the cutting process and will not cause metallographic structure change of the workpiece near the incision, nor will it produce thermal deformation. In addition, the incision is of good quality and can cut three-dimensional curved workpieces.

9. Underwater mechanical cutting

The principle of underwater mechanical cutting is the same as that of onshore mechanical cutting. Saw, grinding, planing and milling are also used to cut the components. The cutting speed is much slower than thermal cutting, but the quality and precision of the cutting are very high. The workpiece can be processed. Precision machining.