Is it safe to fire in the processing of magnesium alloy?www.easoar-soon.com
Is it safe to fire in the processing of magnesium alloy?
Traditionally, magnesium alloys are considered to be dangerous and unsafe materials.
How the truth is, let's follow MagMagnesium Industry to understand a little knowledge about magnesium alloy combustion and safe processing.
Do magnesium blocks burn and explode?
In recent years, through a large number of production practice, people have been gradually out of the traditional misunderstanding. In fact, the theoretical risks can not be summarized in practice, and in fact, the solid mass of magnesium is quite safe and does not burn or explode. The magnesium will not burn even if heated and burned directly in front of a flame. Even if the magnesium block is ignited, as long as the flame is evacuated, the magnesium block will be rapidly lost because of heat, the temperature drops to below the ignition point, the flame will automatically extinguish.
Magnesium block has the characteristics of large heat capacity, fast heat loss and high ignition point. Magnesium block combustion must be the first solid magnesium block heated to 650℃ (melting point), solid magnesium block after melting and then the liquid magnesium continues to heat to 100℃ (boiling point), then there will be magnesium vapor escape, gas magnesium has a strong combustion and explosion hazards.
Does Magnesium Alloy Powder Explode?
However, the dust, debris and light material of magnesium do have certain combustion and explosion hazards. It is generally believed that: when the concentration of magnesium dust in the air reaches 20 mg/L. it may cause an explosion; Direct heating of magnesium dust to 340-560 ° C may also cause combustion of magnesium dust.
Combustion and explosion accidents in the die casting industry of magnesium alloy production are often caused by magnesium dust, debris and thin material. Due to the good thermal conductivity of magnesium dust, debris, light and thin materials, heat accumulation fast, and can not fully heat each other, as well as their large surface area, full contact with oxygen (conducive to the reaction of magnesium and oxygen), once the magnesium dust meets Mars, sparks, flames will lead to rapid combustion and explosion.
What is the key to safe production of magnesium alloy?
Therefore, the key to ensure the production safety of magnesium alloy is to effectively manage and control the dust, debris and light material of magnesium alloy. Machining magnesium alloy
The reason why magnesium alloy processing is easy to catch fire?
Magnesium is a fine powder and will not burn below the melting point. But cutting powder or dust through the local heat and fire risk is very great.
The ignition of chip is caused by the excessive friction heat between the tool and the material, which makes the temperature of fine dust reach above the ignition point.
The problem of chip ignition must be considered when machining magnesium alloys. Chips will ignite when heated to near the melting point. Rough or medium finish machining chip produced by large, machining is not easy to ignite, but the spark can ignite the chip produced by finish machining.
Machining magnesium alloy
What should be paid attention to when machining magnesium alloy?
(1) keep the tool sharp, the front and back corners are appropriate, avoid using blunt, curling or notched tools;
(2) the use of strong cutting with large feed to form thick chips to avoid small feed;
(3) When the feed amount is small, mineral oil cooling is used to reduce heat generation
(4) at the end of cutting should be immediately back, otherwise the workpiece continues to rotate to form small chips easy to catch fire;
(5) try not to use cutting fluid, especially not use water-soluble cutting fluid;
(6) in the production of fine chip high-speed cutting occasions, can blow compressed air or carbon dioxide gas;
(7) The machine tools near the processing machinery should be kept dry;
(8) regularly clean the chips and store them in a steel drum with a cover;
(9) Sand or other hard objects adhered to the casting should be removed before machining;
(10) to avoid sparks caused by tool impact on steel inserts;
(11) Smoke and fire are not allowed near the processing area;
(12) It is not allowed to accumulate chips on the machine tools or working clothes. Dust and chips should be removed regularly and stored in a labeled flame retardant container with a lid;
(13) In the place where the operator can reach, ensure that there are sufficient fire extinguishing facilities.
Factory building is on fire
How to do magnesium alloy fire?
After the chippings are ignited, they will not burn unless stirred. Once the chips burn, it is strictly prohibited to use water, foam, carbon dioxide, dust should be avoided, with asbestos cloth lightly covered, and aluminum spade to dry magnesia press on the asbestos cloth, so that the magnesium chips isolated air, suffocate the flame.
Fire control propaganda
Magnesium alloy fire safety tips
(1) Content of fire safety measures. Safety first, eliminate safety risks; Combination of prevention and elimination, effectively extinguish the initial fire. Three and four: know how to report to the police; Understand the fire protection knowledge of magnesium and magnesium alloy and the hazard of magnesium alloy combustion and explosion; Know how to find safety hazards; Ability to set up and maintain fire fighting equipment; Will report to the police; Be able to use fire equipment correctly; It will put out early fires.
(2) magnesium fire protection "three use", "three prevention" and "four harm". "Three uses", that is, "D out "(D-grade fire extinguisher), dry sand, covering agent:" three prevention ", that is, fire prevention, waterproof, high temperature prevention; "four hazards", that is, strong light, high heat, rapid combustion, water explosion.
(3) Eight measures of magnesium fire protection:
Use Class D fire extinguishers, dry sand, and mulching agent as early as possible to extinguish initial fires;
1 Call the police;
2 Power cuts.
4 Ban water:
5 Isolation of air:
6 Escape from danger;
7 Prevent fire expansion.