What are the operation principles to be followed in the steel plate cutting process

With the increase of the thickness and hardness of steel plate, the difficulty of steel plate cutting is increasing, and the tendency of cracks on the cutting edge will also increase. In this case, in order to prevent the occurrence of steel plate cutting cracks, relevant operation principles shall be followed during cutting.

The steel plate cutting crack is similar to the hydrogen induced crack produced during welding. If the steel plate cutting edge produces crack, it will appear within 48 hours to several weeks of cutting thickness. Therefore, the cutting crack belongs to the delayed crack. The greater the thickness and hardness of the steel plate, the larger the cutting crack.

In order to prevent this kind of crack, the effective method is to preheat before steel plate cutting. Before flame cutting, the steel plate is usually preheated. The preheating temperature mainly depends on the quality grade and thickness of the steel plate. In order to determine the preheating effect of the steel plate, the required temperature should be tested on the hot quilt surface. It should be noted that preheating should make the whole steel plate interface evenly heated to avoid local overheating in the area contacting the heat source. If the whole plate cannot be preheated, the local preheating method can be used instead.

On this basis, the principle of low-speed cutting should be followed. Only the combination of preheating and low-speed flame cutting can further reduce the probability of cutting cracks. Whether the steel plate is preheated or not, the slow cooling after cutting will effectively reduce the risk of steel plate cutting cracks.

Especially for thick steel plate cutting, heating immediately after cutting is also an effective method and measure to prevent cutting cracks. Through low temperature tempering treatment, cutting stress can be effectively eliminated. Therefore, when cutting thick steel plates, mild carbonization flame should be used to avoid melting collapse of the upper edge of the incision, and at the same time, the outer flame can be longer.