Custom Carbon & Graphite Machining

04 Jan

Diffusion Barrier Coatings for Graphite Fixtures

Vacuum heat treating shops commonly use graphite fixtures on which to set parts to be treated. Graphite fixtures have excellent thermal stability, allowing them to be used again and again through multiple heat treat cycles. In addition to that, graphitedoes offer significant cost advantages, when compared to other materials used to make fixtures (high nickel/chromium or moly alloy type fixtures)Graphite Fixtures and Ferrous MaterialsIf you are using graphite fixtures, it is important to remember that graphite is carbon, and pure carbon likes to react chemically with metals containing iron, especially stainless steel, to form low melting eutectic compositions at temperatures...

07 Dec

Graphite Fixtures and Eutectic Bonding

Eutectic melting is the process where an alloy of two or more metals, when heated, will completely change from solid to liquid at the same temperature. There are processes in which the eutectic melting is a desired result, such as brazing. There are thousands of eutectic compositions used in brazing applications. They can play a major role when heating a brazing filler metal up to the brazing temperature, as well as when cooling after brazing. During heat-up and melting, the eutectic composition will/should be the first to melt, and because of its narrow melting range (solids and liquids are the...

30 Nov

Aerospace and Graphite

At first you would not really think to put the two together as working partners. Yes…. They are. Graphite is used in the aerospace industry for a wide variety of applications. Heat Treating Synthetic graphite is used as engineered material to create precision machined plates, posts, nuts and bolts along with heating elements and fixtures used in the heat treatment of aerospace metals such as (titanium, stainless steel, and other alloys). The heat treatment process is used to give these metals improved strength, flexibility, or hardness. Graphite PlatesGenerally the graphite plates are preferred as fixtures because they are inert and...

27 Oct

Graphite Compressive Strength vs. Graphite Flexural Strength

Flexural Strength with most graphite material is on average only 50% to 60% of its Compressive Strength. By definition, Compressive Strength is the capacity of a material to withstand loads tending to reduce its size. Measured, it is the value obtained by plotting applied force against deformation. At compressive strength limit, the material will fracture, or deform irreversibly. Flexural Strength is defined as the ability to resist deformation under load. It is measured with the help of The Transverse Bending Test. In this test, a sample is bent until it fractures, using a 3 point flex test technique. Flexural Strength...

17 Mar

Explaining The Coefficient of Thermal Expansion in Graphite Materials

At Semco Carbon, we are constantly thinking of new, relevant and useful topics to incorporate into our periodic blogs.Let's Discuss The Coefficient of Thermal ExpansionIn a recent meeting our application engineers were working on a specific issue to assist one of our customers. A customer of ours had been experiencing premature component breakage in a new high temperature process they were testing. Looking at the specifics of their application, we determined that this experience would provide a good example of the importance of the Coefficient of Thermal Expansion.We thought this specific case study and other relevant experiences could be used...