In duplex stainless steel, the ferrite phase and austenite phase account for half in its hardened structure, and the minimum phase content may reach 30%. In the case of low C content, the Cr content is 18%~28%, and the Ni content is 3%~10%. Some steels also contain alloying elements such as Mo, Cu, Nb, Ti, and N.
This type of steel has both the characteristics of austenitic and ferritic stainless steel. Compared with ferrite, it has higher plasticity and toughness, no room temperature brittleness, significantly improved intergranular corrosion resistance and welding performance, while maintaining iron The 475 ℃ brittleness and high thermal conductivity of element stainless steel have the characteristics of superplasticity. Compared with austenitic stainless steel, it has high strength and significantly improved resistance to intergranular corrosion and chloride stress corrosion. Duplex stainless steel has excellent pitting corrosion resistance and is also a nickel-saving stainless steel.
Product Advantages

Compared with austenitic stainless steel, the disadvantages of duplex stainless steel are as follows:

(1) The universality and versatility of application are not as good as that of austenitic stainless steel. For example, its use temperature must be controlled below 250 °C.

(2) Its plasticity and toughness are lower than that of austenitic stainless steel, and its cold and hot working processes and forming properties are not as good as that of austenitic stainless steel.

(3) There is a medium temperature brittle zone, and it is necessary to strictly control the process system of heat treatment and welding to avoid the appearance of harmful phases and damage the performance.

Compared with ferritic stainless steel, the disadvantages of duplex stainless steel are as follows:

The content of alloying elements is high, the price is relatively high, and generally ferrite does not contain nickel.

Electroplating is the process of applying electrolysis principle to coat a thin layer of other metals or alloys on some metal surfaces. It is the process of using electrolysis to attach a layer of metal film to the surface of metal or other materials to prevent metal oxidation (such as corrosion), improve wear resistance, conductivity, reflectivity, corrosion resistance (copper sulfate, etc.), and improve aesthetics.

Basic Principles of Electroplating

During electroplating, the coated metal or other insoluble materials are used as anodes, the workpiece to be plated is used as cathode, and the cations of the coated metal are reduced on the surface of the workpiece to be plated to form a coating. In order to eliminate the interference of other cations and make the coating even and firm, it is necessary to use the solution containing the coating metal cations as the electroplating solution to keep the concentration of the coating metal cations unchanged.

The purpose of electroplating is to coat the substrate with a metal coating to change the surface properties or dimensions of the substrate. Electroplating can enhance the corrosion resistance of metals (most of the coated metals are corrosion-resistant metals), increase hardness, prevent abrasion, improve conductivity, smoothness, heat resistance and beautiful surface.

Due to different environments, the coating requirements are different. For example, ferrous metal parts are usually protected with zinc coating under general atmospheric conditions, and cadmium coating under marine climatic conditions. When the coating is required to be thin and has strong corrosion resistance, tin cadmium alloy can be used to replace cadmium coating; Marine instruments made of copper alloy can be protected by silver cadmium alloy; Ferrous metal parts in contact with organic acids, such as food containers, are protected by tin plating, which is not only strong in corrosion resistance, but also harmless to human health.

Titanium alloy has high strength and low density, good mechanical properties, good toughness and corrosion resistance.In addition, titanium alloy process performance is poor, difficult cutting, in hot processing, very easy to absorb hydrogen, oxygen, nitrogen, carbon and other impurities.And wear resistance is poor, the production process is complex.Industrial production of titanium began in 1948.The need of aviation industry development makes the titanium industry develop at an average annual growth rate of about 8%.The world's annual production of titanium alloy processing materials has reached more than 40,000 tons, titanium alloy brand nearly 30 kinds.The most widely used titanium alloys are Ti-6al-4V (TC4), Ti-5al-2.5SN (TA7) and industrial pure titanium (TA1, TA2 and TA3).



Titanium alloy is mainly used in the production of aircraft engine compressor parts, followed by rockets, missiles and high-speed aircraft structures.By the mid-1960s, titanium and its alloys had been used in the general industry, making electrodes for electrolysis, condensers for power stations, heaters for petroleum refining and seawater desalination, and environmental pollution control devices.Titanium and its alloys have become corrosion-resistant structural materials.In addition, it is also used to produce hydrogen storage materials and shape memory alloys.



China began to study titanium and titanium alloys in 1956.In the mid-1960s, the industrial production of titanium began and TB2 alloy was developed.



Titanium alloy is a new important structural material used in aerospace industry. Its specific gravity, strength and service temperature are between aluminum and steel, but it has higher strength than aluminum and steel and excellent seawater corrosion resistance and ultra-low temperature performance.In 1950, the U.S. first used f-84 fighter-bombers as rear fuselage heat shield, wind shield, tail cover and other non-bearing components.Since the 1960s, the use of titanium alloy

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.

"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

In the production of stainless steel pipe, because of the influence of the production process, there may be excess burrs on it, which should be removed in time to prevent the normal use of it.Then what methods can we follow to remove the burr in time?

1, scraper method: the device is equipped with a blade, the pipe into the device to form a rotation, can be cut and scraped on the burr, scraped out of the burr from the hole.

2. Roller method: through repeated gravity rolling, the burr properties on the stainless steel tube become fine and soft to achieve the removal effect.

3. Oxidation method: gas flow is passed into the welding, and the waste heat in the pipe is burr oxidation falling off by itself.

4, hand pull: for some small burrs, directly pull out by hand without the help of a tool, but pay attention to the sharpness of the product to avoid cutting the stainless steel pipe.

When removing burrs, we must pay attention not to scratch the stainless steel tube, and when using it, it should be used correctly.In order to avoid burr, we can choose the appropriate method.And timely polish work.