1 Hydrogen
Hydrogen (H2) molar mass 2.016g / mol, a density 0.0899kg / m3, a melting point of -259 ¡æ, boiling point -252.8 ¡æ, ignition temperature 572 ¡æ; and air mixture explosion limit of limit ¦× (H2) = 4.0%, the upper limit of ¦× (H2) = 75%; high calorific value value 2800kJ, low 10790kJ. It dissolves very little in various liquids. H2 is a strong reducing gas, at room temperature inactive, but in the presence of heat or a catalyst is very lively, with many non-metal and metal compounds directly. All bottled water contain trace amounts of hydrogen and oxygen, there may be traces of methane, nitrogen, carbon monoxide and carbon dioxide and other impurities, and its content varies with the preparation method.

Hydrogen gas is often used as heat treatment protection for low-carbon steel, stainless steel, electrical steel and bright annealing and tungsten carbide, titanium carbide sintering non-ferrous metals.

2 Nitrogen
Nitrogen (N2) of the molar mass 28.0134g / mol, a density 1.2507kg / m3, a melting point of -209.86 ¡æ, boiling point -195.8 ¡æ. Its chemical properties and lively, but at a high temperature, nitrogen molecules gain enough energy to promote its covalent bond cleavage, with some metal or non-metal compounds, and can directly with hydrogen and oxygen. Nitrogen gas as a heat treatment at 1000 ¡æ is stable, a neutral gas; above 1000 ¡æ, was active, able to play a nitriding steel.
Nitrogen gas as the main nitrogen-based atmosphere, mainly for steel bright annealing, quenching and carbonitriding like.

3 Ammonia
Ammonia (NH3) in the molar mass 17.03g / mol, a density 0.7710kg / m3. Under normal pressure can be liquefied into a colorless liquid (temperature monitoring boundary 132.4 ¡æ, prison community pressure 11.22Mpa), the boiling point of -33.5 ¡æ. Ammonia easily cured to a solid form of snow, m.p. -77.7 ¡æ. Ammonia dissolved in water, ethanol and ether, will break down into nitrogen and hydrogen at high temperatures. When the presence of a catalyst, the ammonia can be oxidized to an oxidation of ammonia.
Ammonia is a gas nitriding and ion nitriding of nitriding agent. Ammonia decomposition of ammonia atmosphere and burn atmosphere, can be used as steel, sintered powder metallurgy beryllium protection of the atmosphere and heating parts.

4 propane (Propane)
Propane (C3H8) molar mass of 44.9g / mol, a density 0.5005kg / m3, boiling point -42.17 ¡æ, m.p. -189.9 ¡æ. The heating value of propane 90730kJ / m3, ignition temperature 505 ¡æ, ignition temperature limit of the volume fraction of 2.4%, the upper limit of the volume fraction of 9.5%, the theoretical combustion temperature of 1977 ¡æ.
Propane can be used as Endothermic and exothermic atmosphere of feed gas, mainly used for workpiece carburizing, carbonitriding, nitrocarburizing, and annealing, normalizing, quenching and tempering. Oxide at normal temperature and pressure of the gas can be pressurized liquefied.

5 butane (Butane)
Butane (C4H10) molar mass 58.12g / mol, a density 0.5783kg / m3, boiling point of -0.5 ¡æ, m.p. -138.3 ¡æ. Butane heating value 118490kJ / m3, ignition temperature 431 ¡æ, ignition temperature limit of the volume fraction of 1.8%, the upper limit of the volume fraction of 8.4%, the theoretical combustion temperature of 1982 ¡æ.

6 methanol (Methanol)
Formula CH3OH
Molecular weight of 32 specific gravity 0.792
Boiling point 64.7 ¡æ
The relative weight of methanol vapor (air = 1) 1.11
Vapor Pressure (20 ¡æ) 96mmHg
Gas combustion limit 6 Vol%
Feeling limit 200PPM
Environment allows maximum concentration 200PPM
Flash Point 9.5 ¡æ (Closed) 16 ¡æ (opening)
Ignition point 470 ¡æ
Methanol cracking reaction CH3OH CO + 2H2

7, CO (Carbon Monoxide)
Formula CO
Molecular weight 28
Heat 12620Q / kJ.m-3
Theoretical combustion air amount 2.38
The gas concentration mixed gas (volume fraction) (%) Upper: 74.2
Lower: 12.5
Burning speed 0.43m.s-1
Ignition temperature of 609 ¡æ
Theoretical combustion temperature of 2102 ¡æ
8, propylene propylene
Formula C3H6; CH3CHCH2 molecular weight 42.08
Appearance: colorless hydrocarbon odor of gas
Vapor Pressure: 602.88kPa / 0 ¡æ Flash point: -108 ¡æ
Melting point: -191.2 ¡æ Boiling point: -47.7 ¡æ
Solubility: soluble in water, ethanol
Density: Relative density (water = 1) 0.5; relative density (air = 1) 1.48

Category: Technology Seminar