When selecting stainless steel in corrosive environment, in addition to having a detailed understanding of the specific service conditions of stainless steel, the main factors to be considered include: corrosion resistance, strength, toughness and physical properties, processing, formability, resources, price and difficulty of obtaining.



Corrosion resistance includes rust resistance and resistance to acid, alkali, salt and other corrosive media, as well as oxidation resistance, vulcanization, chlorination and fluorination at high temperature. Since different stainless steels are mainly selected to solve various corrosion problems encountered in practical engineering, how to improve the corrosion resistance of stainless steel in corrosive environment is the first thing to be considered by material selection personnel. Corrosion is the damage caused by chemical or electrochemical action between metal and medium, and corrosion resistance refers to the ability of stainless steel to resist the corrosion damage of medium. Therefore, when corrosion resistance is involved in material selection, the following points should be paid attention to.



The standard of corrosion resistance is artificially determined. It should be recognized and used, but it can not be bound by it. The specific standard of corrosion resistance should be determined according to the specific application requirements. At present, grade 10 standard is mostly used for the corrosion resistance of stainless steel. Which grade is selected as the corrosion resistance requirement should consider the characteristics of equipment and parts (thickness and size). Requirements for service life and product quality (such as impurities, color and purity). Generally speaking, level 1 ~ 3 standards can be selected for equipment, instruments and components requiring smooth mirror or precise size during use;

"In recent years, China's steel industry has made significant progress in terms of energy consumption per ton of steel and emissions per ton of steel, but due to the sharp increase in the total output of crude steel since the new century, the total energy consumption and emissions of the steel industry have not decreased, but significantly increased!" Yin Ruiyu, academician of the Chinese Academy of Engineering and former vice minister of the Ministry of Metallurgy, said at a recent exchange conference on energy-saving technology and high-efficiency energy-saving motors in the steel industry.



As a big carbon polluter, how to remove the cap of high carbon steel industry has become the focus of the industry. Academician Yin Ruiyu's remarks just pointed out the great difficulty and serious problem of carbon emission reduction in the steel industry, especially in the context of China's efforts to achieve carbon peak by 2030 and strive for carbon neutrality by 2060, the significance of energy conservation and emission reduction in the steel industry has been raised to a new height.

Is carbon steel better than low carbon steel? Low carbon steel is a kind of carbon steel. Carbon is present in all steels. As long as this carbon is the main alloying element, the alloy is considered to be carbon steel. "Low carbon" steel is another name for low carbon steel. There are other carbon steels with different carbon content. Which is better depends on the use of steel.

More than 1.5 billion tons of steel are produced each year for various products, such as sewing needles and structural beams of skyscrapers. Carbon steel is the most commonly used alloy steel, accounting for about 85% of all American production. The carbon content of the product is within the range of 0-2%. This carbon will affect the microstructure of steel, making it have legendary strength and toughness. These alloys also contain small amounts of manganese, silicon and copper. Low carbon steel is a commercial term for low carbon steel, in which the carbon content is in the range of 0.04-0.3%.

Carbon steel category

Carbon steel can be classified according to the chemical composition and characteristics of the product. Low carbon steel also belongs to the category of low carbon steel, because its carbon content is similar. Ordinary carbon steel does not contain alloy and can be divided into four categories:

1. Mild steel

The carbon content of low carbon steel is 0.04-0.3%, which is the most common carbon steel grade. Low carbon steel is also considered as low carbon steel because it is defined as having a low carbon content of 0.05-0.25%. Low carbon steel has ductility and high plasticity, which can be used for automobile body parts, plates and wire products. At the high end of the low carbon content range, plus up to 1.5% manganese, mechanical properties are suitable for stamping parts, forgings, seamless tubes and boiler plates.

2. Medium carbon steel

The carbon content range of medium carbon steel is 0.31-0.6%, and the manganese content range is 0.6-1.65%. This steel can be heat