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28 Feb 2014
Gas Diffusers |
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Benefits of gas diffusers:
1. Reduction in scrap rate
2. Improve quality of castings
3. Reduction in pin-holing
4. Removal of inclusions
5. Reduction in gas content
6. Temperature homogenization
7. Distribution of alloying agents and de-oxidants
How to Gas Diffuser work
1. Use argon gas connect to Gas Diffuser plug in the lining Base
2. Flow Gas about 10litres per minute, with pressure about 5-6 bar in order to flow gas through lining base porosity to the furnace
3. The argon gas which lower density than molten metal , collecting any gas in molten metal to top level 4. Molten metal will be cleaned and de-oxidation
| Specimen |
Diameter(mm) |
D2(mm2) |
Area(mm2) |
Yield point(N) |
Max. Load.(N) |
Yield Stress(Mpa) |
Max. Stress(Mpa) |
Elongation(%) |
Reduction(%) |
| With Gas Diffuser |
12.8 |
9.6 |
128.68 |
36872.81 |
68766.96 |
286.55 |
534.4 |
22 |
25 |
| Without |
12.4 |
9 |
120.76 |
30654.06 |
63143.33 |
253.84 |
522.87 |
19.16 |
21.12 |
From above structure the casting which used gas diffuser less impurity than without gas diffuser and the grains of structure is finer also mechanical properties such as tensile elongation better than without use gas diffuserThe above microstructure is carbon steel, also known as mild steel. It contains about 0.1% C by weight, alloyed with iron. The steel has two major constituents, which are ferrite and pearlite. The light coloured region of the microstructure is the ferrite. The grain boundaries between the ferrite grains can be seen quite clearly. The dark regions are the pearlite. It is made up from a fine mixture of ferrite and iron carbide, which can be seen as a "wormy" texture. You can also see small spots within the ferrite grains. These are inclusions or impurities such as oxides and sulphides. The properties of the steel depends upon the microstructure. Decreasing the size of the grains and decreasing the amount of pearlite improves the strength, ductility and the toughness of the steel. The inclusions can also affect the toughness. For example, they can encourage ductile fracture.
Installation and Equipment as well as cost
1 Argon gas tank (normal grade) price about 900 baht per tank(for 7 cubic)
2 Gas Diffuser plug price depend on size about 15,000 baht
3 Flow meter about 1500
4 Pressure gauge 700 baht
5 Gas hose about 100 baht per meter
6 Regulator about 2000 baht
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