204Cu is the American Standard, also called S20430, is the United States developed successfully this year, the nickel type stainless steel, compared with 304, nickel content reduced by 5~6 percentage points, adding a small number of Cu elements, but its performance is similar to 304, still has rust and corrosion resistance, can meet the needs of the general use of stainless steel. O. Considering that China is a country with relatively lack of nickel resources, and the price of international nickel is too high, and most of the domestic use requirements are not very high. With the increasing familiarity of the market, the application scope of 204Cu will be more and more wide, and the future may be replaced by 304 in some areas.
2, CHEMICAL COMPOSITION
3. MECHANICL PROPERTIES (compared with 304)
Compared with 304, 204Cu has high tensile strength and yield strength, low cold work hardening rate, good cold forming performance, and 200 Series Steel's inherent wear resistance.
Grade. Yield strength (MPa), Tensile strength (MPa), Elongation (%) Hardness (HV).
304 ≥205 ≥515 ≥40 ≤200
204Cu ≥300 ≥700 ≥55 ≤210
4. CORROSION RESISTANCE
204Cu has unique corrosion resistance to H2SO4, and the corrosion resistance of HC1 and HNO3 is better than 304, but the high temperature oxidation resistance is worse than that of 304. It is not suitable to be used in the oxidizing environment of high temperature (≥400ºC).
(1). One kind of tableware: knives and forks.
(2). Kitchen utensils: washing tank, fridge, gas cooker and so on.
(3). Electrical appliances: washing machine, dryer and so on.
(4). Building materials: anti-theft doors and windows, staircase rails and so on.
(5). Steel pipe: decoration pipe, construction pipe, exhaust pipe.
(6). Transportation equipment: containers and railway vehicles.
The 304 general grade of steel, can replace 304 204Cu also has a wide range of potential industrial application prospect. In computer, communication, safety protection, food production, energy and tobacco processing industry, it has a large number of possibilities. For example, the computer needs high strength, non magnetic, cold forming, and abrasion resistant transmission shaft. The 300 series of 302HQ can not meet the requirements of anti wear, and the high strength must be pulled through the high reduction rate to achieve the required high strength. 200 series steel, such as modification 201, is used to make the transmission shaft without cracks, so it is difficult to form. 204Cu fills the gap, and combines high strength with good molding performance. It is the best choice material.
In the telephone communication industry, the overhead telephone lines need to be fixed with the overhead lines. For many years, rust prevention, moisture resistance and salt spray corrosion have been considered. 304 steel wires have been selected. 204Cu should be the best alternative material, and the test of using 204Cu to produce overhead lines is also successful. The production workers believe that the reduction rate of 204Cu is relatively small, and it is easier to straighten more than 304. Besides, 204Cu has low production cost and salt spray corrosion test. It is proved that overhead lines are not easy to rust.
The fasteners commonly used in industry are trapezoid buckles. These fasteners are mostly used to fix house panels and underground sewage pipes. Bolt forming and thread rolling have been hard to produce fasteners, but it is not difficult to make use of 204Cu.
In the safety protection industry, the most common product is spiny steel wire. The product consists of spiny components and reinforced steel wire. The reinforced steel wire has high tensile strength (greater than 200ksi). It must maintain good molding performance, resist atmospheric corrosion, use 204Cu to pull out large surface rate, and have successfully produced the diameter 2.5mm coil steel. Silk, whose production cost is less than 304204Cu, has been included in the ASTM 313 stainless steel spring wire standard.
A large number of 304 steel wires are used to make various transmission lines. Various transmission lines have different manufacturing processes, but the basic requirement is that steel wires must have good bending properties, can be rolled flat, and have good welding performance. Because steel wire is often used as reinforcement, it must have high tensile strength. Stainless steel conveyor belts are widely used in food production, such as grinder conveyor belt, biscuits and other foods into the oven conveyor belt. The chemical composition of the food conveyor belt made of 204cu steel wire has been approved by FDA (US Department of education and welfare, food and Drug Administration).
Screen steel wire is usually used on coal sorting equipment, sifting pulverized coal from mud. The mud will be corrosive, and coal powder wear on the screen is very powerful, the dual role of corrosion and wear make environment become very harsh, such as carbon steel and 410 stainless steel simply can not afford such corrosion, have to use the longer life of 304 204Cu steel, the price advantage is very attractive to screen industry, 204Cu is now widely use In this industry.