Basic elements and concepts of steel:
The five basic elements of steel: C (carbon), Mn (manganese), Si (silicon), P (phosphorus), S (sulfur); steel is an alloy of iron and these five elements and a small amount of other elements.
The concept of stainless steel and the main components:
Stainless Steel broad concept refers to the resistance to air, steam, water and other weak corrosive media and acid, alkali, salt and other chemical leaching media corrosion of steel, also known as stainless acid-resistant steel.
In practice, the steel will often be weakly corrosive media called stainless steel, and will be resistant to chemical media corrosion of steel called acid-resistant steel.
From the chemical composition, stainless steel is the chromium Cr content of 13% (the chromium content necessary to produce passivity) or more iron-based alloys.
Only when the Cr content reaches a certain value, the steel has corrosion resistance, so Cr is one of the main elements that distinguish stainless steel from other steels.
The influence of each major element on the performance of stainless steel:
Cr chromium: chromium is the most basic element that determines the corrosion resistance of stainless steel, chromium can form a layer of corrosion media can not penetrate and dissolve the chromium-rich oxide film, and the steel Benjamin to my very dense and very solid, to protect the steel from external media oxygen leaching corrosion. Chromium can improve the strength, hardness and wear resistance of steel, but at the same time reduce plasticity and toughness.
NI (nickel): nickel has a strong corrosion resistance to acids and bases, but alone can not become stainless steel, only with chromium, to show strong corrosion resistance; rust and heat resistant function, that can mention the strength of steel, but also to maintain good plasticity and toughness.
C (carbon): for the mechanical properties of stainless steel plays a major role, carbon content increases, the yield point and tensile strength of stainless steel will rise. However, the increase in carbon content will reduce the plasticity and impact of stainless steel; high carbon content will reduce the welding performance and corrosion resistance of steel, increasing cold brittleness.
Mn (manganese): manganese and nickel have many similarities in the role of manganese in some stainless steel can replace nickel (2% manganese can replace 1% of nickel), that is, can maintain sufficient toughness, and has a high strength and hardness, improve the hardenability of steel, improve the hot workability of steel, reduce magnetic properties. Manganese is too high, weakening the steel corrosion resistance and welding performance.
Si (silicon): in the steelmaking process plus silicon as a reducing agent and deoxidizer, silicon can significantly improve the elastic limit of steel, yield point and tensile strength, silicon and molybdenum, tungsten, chromium and other combinations, have improved corrosion resistance and antioxidant effect.
Cu (copper): improve the ductility and plasticity of steel, while improving strength and toughness, easy processing.
Mo (molybdenum); make the steel grain refinement, corrosion resistance, acid and alkali resistance, improve hardenability and thermal strength properties, high temperature resistance, maintain sufficient strength and get creep capacity at high temperatures.
P (phosphorus), S (sulfur): in steel is an impurity, is a harmful element, phosphorus enhances the cold brittleness of steel, so that the welding performance is bad, reducing plasticity; sulfur makes steel thermally brittle, reducing ductility and toughness, in forging and system is caused by cracking. Sulfur is also detrimental to welding performance, reducing corrosion.
Stainless steel grade classification standards and representation:
In practice, at present we commonly use steel grades (grades) such as “304L”, is the reference to the AISI – American Iron and Steel Institute standard classification. The first number “3” indicates the series, and the last two numbers “04” indicate the steel grade, and additional letters indicate the steel grade modification (such as L indicates low carbon, H indicates high carbon, HC indicates high copper, etc.).
“SUS” (steel use stainless), SUS is the code for stainless steel in the Japanese JIS standard, the Japanese steel number if the grade is introduced from the United States, the three digits in front of the prefix “SUS”, if Japan’s own development of the steel number, the suffix “J said Japan, such as “SUS 316J”.
The national standard stainless steel grades, such as 0Cr18NI9, “0” indicates the percentage of carbon content (low carbon with “00”, high carbon with “1”, normal with “0”), “Cr” indicates the corresponding element, “18” indicates the percentage of Cr, and so on.
Simple method of distinguishing between common steel grades:
In practical applications, we usually distinguish different steel grades by the difference in nickel content. Because nickel is a rare resource, one of the main components of stainless steel, the price is higher, accounting for a larger proportion of the cost of stainless steel, nickel price fluctuations have the greatest impact on the price of stainless steel, so the difference in nickel content to simply distinguish between different steel grades, to facilitate production and operation. The following table distinguishes the method:
|Steel type||D665/D667||200CU||201CU||304ES/301||304||316/316L||316(National Standard)|
Classification of stainless steel:
Stainless steel is often divided into: martensitic steel, ferritic steel, austenitic steel, duplex stainless steel, precipitation hardening stainless negative by tissue state. In addition, according to the composition can be divided into: chromium stainless steel, chromium-nickel stainless steel and chromium-manganese-nitrogen stainless steel, etc..
Stainless steel products can be divided by form: plate, pipe, bar, wire.
The production process of stainless steel wire:
Stainless steel stretching line production process:
According to the process and quality requirements of the order, and the end use of the product, our stainless steel products have the following processes:
One pull and one anneal, two pull and two anneal, two pull and one anneal, two pull and one anneal + invert, two pull and one anneal + invert + anneal, one pull and one anneal + invert, one pull and one anneal + invert + anneal, etc.
Application industries and fields of stainless steel wire:
Stainless steel is used in a wide range of industries, such as aviation, aerospace, transportation, petroleum, chemical, marine engineering, electric power, environmental protection, construction, paper making, medicine, food, machinery, communications and other industries and home, etc. For our stainless steel products, the application areas are: re-stretching wire, weaving mesh, mesh belt, rope, bicycle spokes, standard parts, nail making, strap, bra wire, kitchenware, braided tube, brush making and so on.
Stainless steel wire drawing, process hardening fundamentals
Busbar strength is an assumed value