Heat Treatment of alloystellite (marketing department of Shanghai HY Industry Co., Ltd)
Typical grades of alloy stellite are: Stellite1, Stellite4, Stellite6, Stellite8, Stellite12, Stellite20, Stellite31, Stellite100 and so on. In China, aloy stellite high-temperature alloy is mainly studied more deeply and thoroughly. Unlike other high temperature alloys, stellite high temperature alloys are not strengthened by the ordered precipitation phase which is firmly bonded with the matrix, but by the austenite fcc matrix which has been solid solution strengthened and a small amount of carbide distributed in the matrix. Cast stellite high-temperature alloys, however, rely heavily on carbide strengthening. Pure cobalt crystals have a dense hexagonal (hcp) crystal structure below 417°C, which transforms to fcc at higher temperatures. to avoid this transformation of stellite high temperature alloys in service, virtually all aloy stellite is alloyed with nickel to stabilize the organization in the room temperature to melting point temperature range. aloy stellite has a flat fracture stress-temperature relationship, but show superior thermal corrosion resistance above 1000°C than at other high temperatures, probably because of the alloy’s high chromium content, a characteristic of this alloy.
Size and distribution of carbide particles and grain size in alloy stellite are sensitive to the casting process, and the casting process parameters are controlled in order to achieve the required lasting strength and thermal fatigue properties of cast stellite parts. aloy stellite requires heat treatment, mainly to control carbide precipitation. For casting stellite, the first high temperature solution treatment, usually about 1150 ℃, so that all the primary carbide, including part of the MC-type carbide solution into the solid solution; and then at 870-980 ℃ for aging treatment, so that the carbide (the most common M23C6) re-precipitation.
alloy stellite surfacing alloy contains 25-33% chromium, 3-21% tungsten and 0.7-3.0% carbon. As the carbon content increases, the metallographic organization changes from sub-eutectic austenite + M7C3 eutectic to per-eutectic M7C3 primary carbide + M7C3 eutectic. The more carbon content, the more incipient M7C3, the greater the macro hardness, and the improved abrasive wear resistance, but the impact resistance, weldability, and machinability are reduced. The aloy stellite alloyed with chromium and tungsten has good oxidation resistance, corrosion resistance and heat resistance. It can still maintain high hardness and strength at 650°C, which is an important feature that distinguishes this type of alloy from nickel-based and iron-based alloys. aloy stellite has low surface roughness after machining, high scuff resistance and low friction coefficient, and is also suitable for adhesive wear, especially on sliding and contact valve sealing surfaces. But in high stress abrasive wear, low carbon content cobalt-chromium-tungsten alloy wear resistance is not as good as low carbon steel, therefore, the choice of expensive allloy stellite, to have the guidance of professionals to bring out the potential of the material. Internationally there are also used chromium, molybdenum alloyed with Laves phase of alloy stellite overlay alloys, such as Co-28Mo-17Cr-3Si and Co-28Mo-8Cr-2Si. because Laves compared to the carbide hardness is low, in the metal friction sub with which the paired materials wear less.
Shanghai HY Industry Co., Ltd is qualified Nickelalloy & cobalt alloy materials professional manufacturer,
As a leading factory in China of superalloy production，HY has 20 years craftsman spirit, Superalloy solution expert, Qualified supplier for GE & Siemens .
In recent years, with the deepening of research on high-end materials, for the long-term development of the company, the company focuses on the development of cobalt-based materials casting and forging, and has achieved great development, stellite 6, stellite 6B, stellite 6K, stellite12 , stellite21 has become an important series of products of the company.The quality can reach the international standard of similar products
Shanghai HY Industry Co., Ltd has international first-class material production equipment such as high temperature alloy isothermal forging production line, CONSARC vacuum melting furnace, etc., with strong professional ability and highly responsible management team. If you have superalloy material inquiry, please contact us without hesitation. Shanghai HY Industry Co., Ltd will provide you with sincere and thoughtful service.
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