What is a graphite crucible made of?
The crucible is made from high quality graphite which makes the graphite crucible to have a good thermal conductivity, resistant to acidity and alkalinity and a high temperature resistance, therefore, ensuring quality of products. As the graphite has a great heat performance, the time spent on melting is short, therefore saving energy.
What metals can be melted in a crucible?
Metals such as nickel and zirconium are also used as melting crucibles. Graphite crucible can withstand the high temperature of metals and has a good resistance to chemical erosions and thermal shock. Graphite crucibles are most especially ideal for melting precious metals, aluminium, copper, etc.
What is the best furnace crucible material?
Of all furnace crucible types and materials, the best and most suitable furnace crucible material is graphite. Graphite crucibles are made from raw graphite. Graphite material is typically grayish-black in colour, opaque, and has a radiant blaack sheen. Graphite is a distinct material that displays the properties of both metal and nonmetal.
What are the physical and chemical properties of crucible?
The body of the crucible is made of natural graphite and keeps its chemical and physical properties. When melting at a high temperature, the thermal coefficient is small but has strain resistance to rapid heating or cooling. Brass has a low melting point and must be heated rapidly before the component metals oxidize.
How do you make a crucible out of graphite?
0:0314:54Making a Graphite Crucible - YouTubeYouTubeStart of suggested clipEnd of suggested clipVery similar to this one with a flange we're going to use that flange to give a lip on the crucibleMoreVery similar to this one with a flange we're going to use that flange to give a lip on the crucible which is better for grip. And every sitting on cinder blocks. And we'll be compressing plenty in it.
Are graphite crucibles conductive?
Crucibles with high graphite content in the carbon binder offer high thermal conductivity for fast melting in gas-fired furnaces.
What material is a crucible made of?
Ceramic crucible Ceramic crucibles are made from kiln-fired clay and are stable at high temperatures. They have been used in metalworking for over 7000 years. Modern ceramic crucibles are often manufactured with clay and graphite to ensure durability.
Can a graphite crucible melt steel?
My understanding is that even the best made (e.g. Morganite) clay graphite crucibles are rated for about 2900 F. Thus they can be used to melt cast iron, limited number of times. I would not recommend these crucibles for melting steel.
What is the melting point of a graphite crucible?
Graphite Crucibles Properties (Theoretical)Molecular Weight12.01AppearanceBlack solidMelting Point3652 - 3697 °C (sublimes)Boiling Point4200 °CDensity1.8 g/cm39 more rows
How many uses does graphite crucible have?
Graphite Crucibles Grade 2020 offer high performance with good technical and economic effect. They are used in metallurgy, casting, chemical and (scientific) industry in general; they are also used to produce alloy tool steel melting and non-ferrous metal and alloy melting.
What is the best material to use for a crucible?
0:435:38Which CRUCIBLE should you use for melting Metal? - YouTubeYouTubeStart of suggested clipEnd of suggested clipAnd taking the crucible out of a furnace that is almost 1,400 degrees Celsius hot which means weMoreAnd taking the crucible out of a furnace that is almost 1,400 degrees Celsius hot which means we have a temperature difference of over 1,000 degrees Celsius which the crucible needs to withstand.
Can you melt glass in a graphite crucible?
Glass remains a piece and does not adhere to graphite. Theoretically, you can glasses in graphite crucible melt under protective atmosphere and then slowly to cool with the furnace, but it does not work with all glasses.
What is the best crucible made with?
Tungsten Crucible Tungsten is a rare and hard chemical element that has the highest melting point, high tensile strength, high density and low vapor pressure. Tungsten crucibles are vessels made of tungsten or tungsten alloys and are used for melting and calcining materials at high temperatures.
Can you melt copper in a graphite crucible?
It is recommended that clay graphite crucibles be used for the induction melting of pure copper for rotor applications. These ceramic bonded crucibles are ideal for use with medium frequency induction melting, providing clean melting, good thermal conductivity and excellent resistance to chemical corrosion.
What crucible is best for melting gold?
When using a hydraulic tilting melting furnace or vacuum induction melting furnace to melt large quantity of gold, its best you opt for a quartz crucible—it can withstand the high temperature required.
Can you melt copper in a graphite crucible?
It is recommended that clay graphite crucibles be used for the induction melting of pure copper for rotor applications. These ceramic bonded crucibles are ideal for use with medium frequency induction melting, providing clean melting, good thermal conductivity and excellent resistance to chemical corrosion.
Can you use the same crucible for different metals?
It is better to use different crucibles for different types of metals to avoid contamination. Also make sure to completely empty the crucible after each use as the metal left to solidify may expand on re-heating, which may destroy the crucible. The crucibles should be "tempered" before usage.
Can you melt glass in a graphite crucible?
Glass remains a piece and does not adhere to graphite. Theoretically, you can glasses in graphite crucible melt under protective atmosphere and then slowly to cool with the furnace, but it does not work with all glasses.
What can I use as a crucible for gold?
If you don't have a crucible, a homemade method uses a potato to melt gold instead of a crucible. To use this method, cut a hole into the potato, and place the gold in it.
Why are crucibles used in the laboratory?
Crucibles are used in the laboratory to contain chemical compounds when heated to extremely high temperatures. Crucibles are available in many sizes and usually come with a corresponding size lid. When heated over a flame, the crucible is often held inside a pipeclay triangle which itself is held at the top of a tripod.
What are crucibles made of?
The crucibles and their lids are made of high temperature resistant materials, usually porcelain, alumina or an inert metal. One of the first uses of platinum was to make crucibles. Ceramics such as alumina, zirconia and especially magnesia will tolerate the highest temperatures. More recently, metals such as nickel and zirconium have been used. The lids are generally ill-fitting to allow gases to escape while heating a sample inside. The crucibles and their lids may have high shapes and low shapes and varied sizes, but small 10-15 ml porcelain crucibles are generally used for gravimetric chemical analysis. These small crucibles and their porcelain lids are quite cheap when sold in bulk to laboratories, and the crucibles are sometimes discarded after use in a precise quantitative chemical analysis. There is usually a big markup when they are sold individually in hobby stores.
Why is graphite used to make crucible?
Graphite is used to make crucibles because it is a good conductor of heat and electricity. The fact that graphite is able to resist chemicals and has a high melting point, also graphite is a good conductor of heat makes it adopted in the making of crucibles.
What is a graphite crucible?
A graphite crucible is a container made of graphite and it is used to melt and hold metals . They can be used at temperatures of up to 1600 degrees celsius and are suitable for refining and melting precious metals and base metals and other products. The graphite crucible is the crucible of choice for many users due to its outstanding properties, which include:
What is the best material for a crucible?
The best material for crucible is graphite. Graphite is an allotrope of carbon, which is a good electrical conductor. Being the most stable form of carbon under standard conditions, it is mined naturally to produce graphite crucibles.
What needs to be checked before using a crucible?
Then work the graphite crucible till red hot. Turn off the heat and leave the crucible to cool slowly. This process takes off any moisture in the crucible. Furnace crucibles should be properly checked for cracks prior to each application.
What is a melting crucible made of?
Melting crucible can be made of graphite, clay and graphite or silicon and graphite.
Why do you preheat a crucible?
A new crucible should be preheated slowly and evenly to 600 degree celsius on low power. Subsequently, the full heat input rate should be utilized to achieve a uniform bright red condition over the whole crucible at which point the crucible should be charged immediately taking care to avoid packing metal tightly or bridging ingots across the crucible. Preventing a crucible is done for the following reasons:
Why do we not allow the crucible to become red hot?
Run the furnace for 1/2 hour at 20% of maximum power and then increase to 50% until the crucible shows signs of red heat. Loosely charge the crucible with metal. Keep the power at 50% of maximum until approximately half the crucible contains molten metal. Then increase to maximum power. In 1 kHz furnaces the crucible does not absorb power; therefore the crucible should be preheated with a charge loosely in place. Run the furnace at 20% of maximum power until the crucible shows signs of red heat. If after 1/2 hour the crucible shows no evidence of red heat, increase the power input to 50% of maximum. Hold at 50% until half the crucible contains molten metal, then increase to maximum power. crucibles are prone to thermal shock if the rate of temperature charge is too rapid. To preheat the crucible use whichever power level is smaller, 100KW or 50% maximum power input. Heat until the crucible is bright red, this should take 20–40 minutes. The crucible can be preheated with or without charge material, depending on the specific furnace conditions
