FURNACE ROLLERS GX48NiCrWSi48-28-5
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KANTHAL Part of Sandvik Group FURNACE ROLLERS GX48NiCrWSi48-28-5 MATERIAL DATA SHEET FEATURES GX48NiCrWSi48-28-5 is a cast austenitic alloy with 48% nickel, 28% chromium and tungsten. A balanced composition provides excellent structural stability, high stress rupture strength and solid resistance to oxidation and carburization. PRODUCT FORMS GX48NiCrWSi48-28-5 was designed as centrispun tube material to match specific design criteria in terms of carburization and oxidation resistance, creep rupture strength and weldability. It is available as centrispun tubes, statically cast and investment cast product forms. The presence of carbon leads to the formation of a series of carbides: a) lntergranularly occurring primary carbides, nitrides or carbonitrides of the general form M6(C,N) where M is tungsten. These greatly affect the generation of good high temperature properties. The phase is visible in unetched micro-specimen, its colour varying from the orange/yellow of the nitride to the gray/mauve of the carbide. b) Chromium-rich intergranular carbides of the M7C3 and M23C6 types. These carbides have a profound influence on the properties due to decomposition and re-precipitation reactions in service, producing secondary carbides in a uniform dispersion. By this mechanism, dislocation movement is impeded which results in significant strengthening at elevated temperatures. Other forms may be supplied on request. Additional information including maximum and minimum sizes is provided by our sales representatives in your region. Nickel Balance This is a typical composition which may be slightly modified according to the application.

APPLICATIONS The alloy is typically used for tubular systems that require resistance to carburization and oxidation, combined with high creep-rupture strength and creep-resistance. No heat treatment is required in most applications. Main high-temperature applications for the material are: MECHANICAL PROPERTIES (only for wall thickness less than 25 mm, in the as-cast condition). TENSILE PROPERTIES MINIMUM TENSILE PROPERTIES AT 20°C: PROCESS Steam cracking Furnace support component Direct reduction of iron ore Ultimate tensile strength: MAX. OPERATING TEMPERATURE, °C TYPICAL TENSILE STRENGTH...

CARBURIZATION RESISTANCE OXIDATION RESISTANCE INCREASE IN CARBON CONTENT VS. TEMPERATURE AFTER PACKED CARBURIZATION FOR 260 HOURS AT INDICATED TEST TEMPERATURE OXIDATION WEIGHT LOSS VS. TEMPERATURE FOR 10 THERMAL CYCLES IN AIR BETWEEN INDICATED TEMPERATURE AND ROOM TEMPERATURE Carbon Increase, % 7 hours hold time per cycle at test temperature PARAMETRIC STRESS RUPTURE STRENGTH PARAMETRIC STRESS RUPTURE Average Lower Scatter Band LMP = Larson Miller Parameter. LMP = T (21.5 + log tr )/1000. Where T: temperature [K] and tr: rupture time [h]. Lower Scatter Band represents 95% confidence level

MANUFACTURING CHARACTERISTICS MACHINING In general terms the machinability of GX48NiCrW-Si48-28-5 is similar to that of other heat-resistant alloys. WELDING For critical, highly-stressed and corrosion-resistant joints and coated electrodes, flux-cored wire and bare filler materials are commercially available. These welding consumables have high-strength properties at elevated temperatures with well-retained ductilities. In addition to fillerless PAW, TIG and MAW have been used satisfactorily for component fabrication or repair welding. Preheating and postweld heat treatment of joint is not...