Beginning in World War II, “superalloys” were first used to describe a group of alloys developed in turbochargers and aircraft turbine engines that required high performance at high temperatures. The application range of superalloys has expanded to many other fields, including aircraft and land-based gas turbines, rocket engines, chemical and petroleum plants. They are especially suitable for these demanding applications. Superalloys are based on Group VIIIB elements and generally consist of various combinations of Fe, Ni, Co, and Cr with small amounts of W, Mo, Ta, Nb, Ti, and Al. The three main superalloys are nickel, iron, and cobalt-based alloys. Like iron and copper, nickel has been used in alloys since it entered civil society. But compared to steel, brass and bronze, nickel alloys are latecomers to the chemical industry. The development of nickel alloys has been promoted by the continuous advancement of metallurgical technology and manufacturing technology, which has promoted its wide application in the chemical industry. Nickel alloys have excellent corrosion resistance, strength, toughness, metallurgical stability, processability and weldability. Many nickel alloys also have excellent heat resistance, making them ideal for applications requiring high-temperature strength and high-temperature chemical resistance. The first commercially important nickel alloy was Alloy 400,...
In the past 10 years, with the continuous rise of iron ore prices, the cost of iron ore has accounted for about 40%-50% of the cost of steel production. The rise and fall of iron ore prices are directly related to the rise and fall of steel prices. Here, let us analyze why the price of iron ore is rising year by year? What will the price trend of iron ore be like in the future? As we all know, China is an iron-poor country with low domestic iron ore reserves and low grades. This has resulted in a high degree of dependence of Chinese iron and steel enterprises on foreign iron ore, and this situation is difficult to change. According to customs data, my country will import a total of 1.17 billion tons of iron ore in 2020, and its dependence on foreign countries will reach 82.3%. In 2021, my country will import 1.12 billion tons of iron ore, a year-on-year decrease of 3.9%. However, my country’s iron ore imports reached US$184.67 billion, a substantial increase of 49.3% year-on-year. The import volume hit the highest record since the import of iron ore in my country. The average price of...
What is the cause of cracking of duplex steel stainless steel pipe? There are experts in this area to crack the seamless steel pipe inspection, and the seamless steel pipe water quality analysis. Conclusion: The fracture is intergranular corrosion fracture. Under the condition of 60 ~ 120℃, the water chloride ion and the total hardness of seamless steel pipe are more than the standard, which is an important reason for the intergranular corrosion rupture of duplex stainless steel pipe in the ground stress. Metal cracking should be caused by environmental erosion. There must be two existence criteria to produce a split. The presence of ground stresses and corrosive substances. Intergranular corrosion is one of the key ineffective ways of stainless steel plate, and typical intergranular corrosion cracks show a network structure. Research on intergranular corrosion behavior of stainless steel under different corrosive substances is one of the core contents of stainless steel corrosion exploration. This paper shows a process of stress corrosion cracking of stainless steel plate and its harm to the system, expounds the reasons of its formation, and finds effective ways to prevent the occurrence of stress corrosion cracking. Stainless steel water supply pipe interface The key interface...
The ability of metallic materials to resist indentation of hard objects is called hardness. According to different test methods and application range, the hardness standards of sanitary stainless steel precision pipes can be divided into Brinell hardness, Rockwell hardness, Vickers hardness, Shaw hardness and microhardness. 1. What are the characteristics of high hardness pipe of sanitary stainless steel precision pipe? Quenching, tempering and annealing can be used for high hardness pipes. When hardness increases, tensile strength and yield strength increase, while elongation, section shrinkage and impact energy decrease. In addition, the corrosion resistance of high hardness pipe mainly depends on the chromium content. The carbon in steel indirectly affects the corrosion resistance of steel by forming stable chromium carbide with chromium. Therefore, the lower the carbon content, the higher the corrosion resistance, and the order of corrosion resistance and strength is reversed. Therefore, when processing high hardness products, in order to improve the strength and hardness of sanitary grade stainless steel precision tube, the carbon content will increase, leading to the reduction of product plasticity and corrosion resistance. Therefore, the corrosion resistance of products processed by sanitary grade stainless steel precision tubes is poor. 2. What is high hardness stainless...
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