The large forgings for heat treatment of copper pipes are mainly forged directly from ingots, so it is necessary to consider the effects of smelting, ingot casting and forging on the internal quality of the castings during heat treatment. Only the factors affecting the quality of the castings are the existence of uneven chemical composition in various smelting defects; coarse and uneven grain size; more gas and impurities; larger forging stress and heat treatment stress.
The purpose of heat treatment after forging of large forgings is to avoid white spot and hydrogen embrittlement, improve the internal structure of forgings, eliminate forging stress, reduce hardness and improve cutting performance, so as to obtain good mechanical properties or prepare for future heat treatment. The forging culture of 317L stainless steel pipe belongs to the casting of large forgings. Manganese can improve the strength of steel, weaken and eliminate the adverse effects of sulfur, and improve the hardenability of steel. High alloy steel (high manganese steel) with high manganese content has good wear resistance and other physical properties. Silicon can improve the hardness of steel, but the plasticity and toughness drop. The steel used in electrical engineering contains a certain amount of silicon, which can improve the soft magnetic properties. Tungsten can improve the red hardness and thermal strength of steel and the wear resistance of copper tubes. Chromium can improve the hardenability and wear resistance of steel, improve the corrosion resistance and oxidation resistance of steel.
Vanadium can refine the grain structure of steel and improve its strength, toughness and wear resistance. When it melts into austenite at high temperature, it can increase the hardenability of steel; on the contrary, when it exists in the form of carbide, it will reduce its hardenability. Molybdenum can obviously improve the hardenability and thermal strength of copper tubes, avoid tempering brittleness, improve remanence and coercivity. Titanium can refine the grain structure of copper tubes, thereby improving the strength and toughness of copper tubes. The convection technology of copper tube has the advantage of light weight. Under the same heat dissipation condition, the inner cavity of copper tube convection radiator is larger and lighter than that of other radiators. Assuming that the heat dissipation value of steel column is 1.0, the finned tube convector is 1.06, the plate type is 0.7, and the copper tube convective radiator is only 0.51; after the copper tube convective radiator is filled with water, the structural load of the building is lighter. After the copper tube convective radiator is filled with water, the structural load of the building is lighter. The adjustment is flexible. Because of the different mechanism and internal structure of the radiator, the water capacity of the copper tube convective radiator is the smallest. Therefore, the application of temperature control valves in this kind of products can adjust the indoor temperature sensitively and accurately, and the temperature rise is fast.
It can save energy of water and heating system by using centralized heating system. Users of household heating can use it. The heat dissipation of copper tube convective radiator is the highest in all kinds of radiators with the same length and height under the standard working conditions. Taking a 1-meter radiator as an example, the heat dissipation of copper tube convective radiator is 1.4 times as much as that of steel tube heating. Because of the installation of radiation protection board, it effectively reduces the invalid heat loss of radiator and external wall. The average temperature of copper tube convective radiator can be compared with the average room temperature without dead angle. It is especially suitable for heating civil residential buildings with small height and area, and the room is warm. The corrosion allowance of copper pipes is to consider the value of pipe wall thickness increased by the thinning of pipe wall thickness caused by the corrosion of medium to pipes. Its size directly affects the value of pipe wall thickness, or directly affects the determination of wall thickness grade. At present, there is not a set of data about the corrosion rate of various corrosive media under different conditions in China. Therefore, in most engineering cases, the corrosion margin is confirmed by experience.