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How to effectively reduce the cost of flame cutting of steel plates in actual production?

Dec 04, 2018

The three basic factors affecting the flame cutting quality of the steel plate are gas, cutting speed and cutting nozzle height. Below we will analyze these three elements one by one to help you solve the problem of how to effectively reduce the cost of flame cutting of steel plates in actual production.


  1. Gas


  

When using flame cutting, one of the gases is essential, that is, oxygen. It is required for the combustion of combustible gases, and is also required for the combustion of steel after it has reached the ignition point. Therefore, the oxygen used is required to have a higher purity, generally more than 99.5%.


Industrial standards in some advanced countries require oxygen purity above 99.7%. For every 0.5% reduction in oxygen purity, the cutting speed of the steel plate is reduced by about 10%. If the oxygen purity is reduced by 0.8%-1%, not only the cutting speed is reduced by 15%-20%, but also the slit is widened. The lower end of the slit has more slag and is difficult to clean, and the quality of the cut section is also obviously deteriorated. Also with the increase. Obviously, this reduces production efficiency and cutting quality, and also significantly increases production costs.


In fact, in addition to oxygen, we can also use liquid oxygen, although its one-time investment is relatively large, but from an economic point of view, it is much better. The stability of the gas pressure is also critical to the cutting quality of the workpiece as it affects the cutting quality of the workpiece. If the oxygen pressure fluctuates, it will seriously affect the cutting section. The pressure, which is related to the type of cutting nozzle used, the thickness of the cut steel plate and other factors.


In the flame cutting of steel plates, commonly used flammable gases are acetylene, gas, natural gas and propane. Some foreign manufacturers also use MAPP, namely: methane + ethane + propane. Gas with high burning speed and high combustion value is more suitable for thin plate cutting, and vice versa for thick plate cutting, especially for steel plates with a thickness of 200mm or more.


2. Cutting speed

In terms of cutting speed, the cutting speed of the steel sheet corresponds to the burning speed of the steel in oxygen. In actual production, the cutting speed should be adjusted according to the performance parameters of the cutting nozzle used, the type and purity of the gas, the material and thickness of the steel plate. The cutting speed directly affects the stability of the cutting process and the quality of the cutting section.


If you want to artificially increase the cutting speed to improve production efficiency and slow down the cutting speed to optimize the quality of the cutting section, it can't be done, and the quality of the cutting section can only be deteriorated.


Too fast cutting speed will cause quality defects such as dents and slag on the cutting section, which may cause cutting interruption. The slow cutting speed will cause the upper edge of the slit to melt and sag, the lower edge to be rounded, and the lower half of the cutting section. Some of the deep groove pits with water jets appear and so on.


3. The height of the cutting nozzle.

In addition, the distance from the cutting tip to the surface of the workpiece being cut also determines the cutting speed and even the quality of the cut. The thickness of the steel plate is different, then the corresponding distance is also different, and the parameters of the cutting nozzle are also different. If you want a good cut quality, the distance should be consistent throughout the cutting process.