What are the characteristics and practical applications of 601 alloy that is resistant to high temperature oxidation?
Today, "GNEE Steel" will talk about 601 high temperature resistant alloy.
Alloy 601, UNS grade N06601, German standard 2.4851, is a nickel-chromium alloy with good oxidation resistance at temperatures up to 1180°C. Even under very severe conditions, such as during heating and cooling cycles, 601 alloy can still form a dense oxide film and achieve high spalling resistance. Good carbonation resistance. Due to its high chromium and aluminum content, it is also often used to resist high-temperature oxidation in sulfur-containing atmospheres. At room temperature and high temperature, 601 alloy has good mechanical properties and good resistance to stress corrosion cracking.
601 alloy processing and heat treatment
Alloy 601 alloy is easy to process in common industrial processes. However, due to its high strength, high-power machines are required for cold and hot processing.
601 alloy preheating
The surface of the workpiece must be cleaned before and during the heating process to keep the surface clean. If the heating environment contains sulfur, phosphorus, lead or other low melting point metals, the 601 alloy will become brittle. Impurities come from marking paint, chalk, lubricating oil, water, fuel, etc. The sulfur content of the fuel should be low. For example, the impurity content of liquefied petroleum gas and natural gas should be less than 0.1%, the sulfur content of city gas should be less than 0.25g/m3, and the sulfur content of petroleum gas should be less than 0.5%.
The electric furnace for heating should preferably have more precise temperature control capabilities and purer furnace gas composition.
If the impurity content of the gas is low, you can also consider using a gas heating furnace. However, the furnace gas must be neutral or weakly alkaline, and fluctuations in oxidizing and reducing properties of the furnace gas composition should be avoided. The combustion flame cannot burn directly to the workpiece.
601 alloy hot processing
The suitable hot processing temperature for 601 alloy alloy is 1200-900℃. The cooling method can be water quenching or other rapid cooling methods. After hot processing, it should be annealed in time to ensure the best performance. During thermal processing, the material should be heated to the upper limit of the processing temperature.
After the furnace reaches temperature, the material is kept warm for 60 minutes per 100mm of thickness. After being kept warm for the specified time, it is immediately released and processed within the specified temperature range. If the temperature of the metal drops below the minimum processing temperature, it should be heated again.
601 alloy cold processing
Cold working should be carried out after solid solution treatment. The work hardening rate of 601 alloy is greater than that of austenitic stainless steel, so the processing equipment should be adjusted accordingly, and there should be an intermediate annealing process during the cold working process. When the cold deformation is greater than 10%, final solution treatment is required.
601 alloy heat treatment
The heat treatment temperature range of 601 alloy is 920-980℃, and the most suitable is 950℃.
In order to obtain high-temperature and durable performance, the high-temperature solution treatment temperature range of 601 alloy is 1100-1180°C. Water quenching provides maximum creep resistance and minimum carbon precipitation between 500-800°C. Materials with a thickness of less than 3mm can also be quickly air cooled.
601 alloy grinding
High temperature alloys will form a protective oxide film during operation. Therefore, check carefully whether polishing is required.
The oxides near the welds of 601 alloy workpieces are more difficult to remove than those of stainless steel. They need to be polished with a fine sanding belt or grinding wheel. Before pickling in a mixed acid of nitric acid and hydrofluoric acid, the oxides must also be removed with sandpaper or Salt bath pretreatment.
601 alloy machining
The machining of 601 alloy needs to be carried out after solution treatment, and the work hardening of the material must be taken into consideration. Unlike austenitic stainless steel, 601 alloy is suitable for low surface cutting speed and heavy feed.
601 alloy welding
Before welding, the material must be in an annealed or solution treated state, the surface must be clean, free of oil stains, chalk marks, etc., and the 25mm area around the weld must be polished to expose bright metal. The interpass temperature does not exceed 120°C, and no pre- or post-weld heat treatment is required.
Recommended welding materials:
Welding rod AWS A 5.11 ENiCrFe-3
Welding wire AWS A 5.11 ENiCrCoMo-1
601 alloy applications
Alloy 601 is widely used in various industrial fields, such as various thermal and chemical processes, pollution control and power generation, etc.
The typical applications summarized in "Special Steel 100 Seconds" are mainly in the following directions:
Pallets, baskets and fixtures for heat treatment plants
Wire split annealing and radiant tubes, high velocity gas burners, wire mesh belts in industrial furnaces
Isolation tanks in ammonia reforming and catalytic support grids in nitric acid manufacturing
Exhaust system components
Combustion chamber of solid waste incinerator
Duct supports and soot handling components
Exhaust gas detoxification system components
oxygen reheater
