In the process of machining magnesium alloy, the powder produced has the risk of explosion. The generation of cutting heat increases in the same proportion with the cutting speed. The higher the relative temperature, the greater the possibility of ignition. Or some other factors will cause the chip to reach the ignition point. Therefore, we should pay attention to reasonable operation in the machining of magnesium alloy.

Safe operation rules for machining

a. Cutting tools should be kept sharp, and large back angle and clearance angle should be grinded; blunt, chip sticking or broken cutting tools are not allowed.

b. In general, large feed rate should be used as far as possible to avoid using small feed rate to produce larger thickness chips.

c. Do not let the tool stop on the workpiece.

d. When using small cutting amount, use mineral oil coolant to reduce cooling.

e. If there is steel core lining in magnesium alloy parts, it is necessary to avoid sparks generated by collision with cutting tools.

f. Keep the environment neat and clean.

g. It is strictly prohibited to smoke, light fire, electric welding and other operations with fire source in the processing area.

Safety problems in grinding

a. There must be a special grinder for magnesium alloy parts processing. The vacuum cleaner should be thoroughly cleaned before dressing the grinding wheel.

b. When the surface of magnesium alloy parts washed by chromate is reworked and ground, sparks may be caused. Therefore, special care should be taken to avoid dust accumulation nearby.

c. Grinding equipment operators should use smooth hats, smooth gloves and smooth flame retardant clothing without pockets and cuffs. The apron or protective clothing used should be clean and dust-free and easy to take off.

d. The storage of magnesium scraps should be cleaned up in time and the longest storage time limit should be set.

e. Sufficient amount of yellow sand should be stored in the working area to prevent fire fighting.

Treatment of magnesium chips and fine powder

The waste must be stored separately and should not be drenched with rain

The magnesium scraps produced in the process are packed in barrels and soaked with special cutting fluid for magnesium processing. It should be placed in a well ventilated place that can not be exposed to rain and water, and the cover should not be covered, so that the hydrogen that may be produced will volatilize naturally (hydrogen can not be fully volatilized, which may cause explosion).

Smoking, welding and other behaviors with fire source are strictly prohibited.

Extinguishment of magnesium dust burning

a. Class D fire extinguisher.

Its material usually uses sodium chloride based powder or a kind of graphite based powder after passivation. Its principle is to extinguish the fire by eliminating oxygen.

b. Covering agent or dry sand.

Small area fire can be covered by it, and its principle is to extinguish the fire by eliminating oxygen.

c. Cast iron chips.

It can also be used in the absence of other good fire extinguishing materials. Its main function is to lower the temperature below the ignition point of magnesium, rather than smother the fire.

Therefore, once the magnesium alloy is on fire in the machining process, do not use water and standard fire extinguisher to extinguish the fire. More importantly, the standard operation can avoid injury.