High Pressure Pipe Flanges Class 150/300/600/900/1500 Forged Stainless Steel Flange Asme B16.5 904l

Super austenitic stainless steel (904L stainless steel plate) is a highly alloyed austenitic stainless steel with very low carbon content. It has good corrosion resistance in dilute sulfuric acid and is specially designed for environments with harsh corrosion conditions. It has high chromium content and sufficient nickel content. The addition of copper makes it have strong acid resistance, especially high resistance to chloride crevice corrosion and stress corrosion cracking, and is not easy to appear pitting and cracking. The corrosion ability is slightly better than other steel grades, and it has good machinability and weldability, and can be used for pressure vessels.

grade
Chinese grade: 00Cr20Ni25Mo4.5Cu

German sign number: 1.4539

AMERICAN NUMBER: N08904

European Standard: 904L

Chemical composition% of 904L stainless steel

C≤0.03, Si≤1.00, Mn≤2.00, P≤0.035, S≤0.03, Ni: 23.0-25.0, Cr: 18.0-20.0,

Mo: 3.0-4.0, Cu: 4.0-5.0.

performance
Alloy and Condition: 926 ,

Tensile strength (Rm N/mm2): 490,

Yield strength (RP0.2N/mm2): 216,

Elongation A5 %: 35.

Density: 8.24g/cm3

use
Petroleum, petrochemical equipment, such as reactors in petrochemical equipment, etc.

* Storage and transportation equipment for sulfuric acid, such as heat exchangers, etc.

* The flue gas desulfurization device of the power plant is mainly used in the tower body, flue, door plate, internal parts, spray system, etc. of the absorption tower. * Scrubbers and fans in organic acid treatment systems.

*Seawater treatment devices, seawater heat exchangers, paper industry equipment, sulfuric acid, nitric acid equipment, acid production, pharmaceutical industry and other chemical equipment, pressure vessels, food equipment.

*Pharmaceutical plants: centrifuges, reactors, etc.

*Plant food: soy sauce jars, cooking wine, salt jars, equipment and dressings.

Matching welding material model: electrode (E385-16/17), welding wire (ER385).

904L stainless steel plate is widely used and has good corrosion resistance, heat resistance, low temperature strength and mechanical properties; good hot workability such as stamping and bending, no heat treatment hardening phenomenon. Widely used in household items (1 and 2 tableware), cabinets, indoor pipelines, water heaters, boilers, bathtubs, auto parts, medical appliances, building materials, chemicals, food industry, agriculture, ship parts.

Precautions
1 Welding performance

Like general stainless steel, 90 4 L can be welded by a variety of welding methods. The most commonly used welding methods are manual arc welding or inert gas shielded welding. The electrode or wire metal is based on the composition of the base metal and has a higher purity. The content of molybdenum is higher than that of the base metal. Preheating is generally not required before welding, but in cold outdoor operations, in order to avoid condensation of water vapor, the joints or adjacent areas can be heated evenly. Note that the local temperature should not exceed 100 ℃, so as not to cause carbon agglomeration and cause intergranular corrosion. When welding, it is advisable to use small line energy, continuous and fast welding speed. Generally, no heat treatment is required after welding. If heat treatment is required, it must be heated to 1100~1150℃ and then cooled rapidly.

2 Machinability

The machining characteristics of 904L are similar to those of other austenitic stainless steels, and there is a tendency for tool sticking and work hardening during machining. Positive rake angle cemented carbide tools must be used, and vulcanized and chlorinated oil is used as cutting coolant. The equipment and process should be based on the premise of reducing work hardening. During the cutting process, slow cutting speed and feed amount should be avoided.

3. Production process

As a general-purpose corrosion-resistant material, 904L stainless steel sheet can be cold-rolled to obtain high-performance products, which can be used in many fields including food industry equipment, kitchen utensils and electronic industries. The use of each field is different, and the performance requirements of cold-rolled stainless steel 904L stainless steel are also different. Especially when the thickness of the stainless steel strip is small, it is extremely important to seek its comprehensive cold working performance. By analyzing the influence of rolling and annealing processes on its properties and microstructure, and studying the influence of production process parameters on its microstructure and properties, experimental data can be provided for on-site production optimization and performance improvement.

Corrosion resistance
In the case of general heat treatment and welding, there will be no carbide precipitation, eliminating the risk of intergranular corrosion after general heat treatment and welding. Due to the high chromium-nickel-molybdenum content and the addition of copper, 904L can be passivated even in reducing environments such as sulfuric and formic acids. The high nickel content also results in a lower corrosion rate in the active state. In pure sulfuric acid in the concentration range of 0~98%, the operating temperature of 904L can be as high as 40 degrees Celsius. In pure phosphoric acid in the concentration range of 0~85%, its corrosion resistance is very good. In industrial phosphoric acid produced by the wet process, impurities have a strong effect on the corrosion resistance. Of all the various phosphoric acids, 904L is more corrosion resistant than ordinary stainless steel. In strong oxidizing nitric acid, 904L has lower corrosion resistance than highly alloyed steel grades that do not contain molybdenum. In hydrochloric acid, the use of 904L is limited to lower concentrations of 1-2%. in this concentration range. The corrosion resistance of 904L is better than that of conventional stainless steel. 904L steel has high resistance to pitting corrosion. Its resistance to crevice corrosion in chloride solutions is also very good. The high nickel content of 904L reduces the rate of corrosion in pits and crevices. Ordinary austenitic stainless steels may be susceptible to stress corrosion in a chloride-rich environment at temperatures above 60°C, and this sensitization can be reduced by increasing the nickel content of the stainless steel. Due to the high nickel content, 904L is highly resistant to stress corrosion cracking in chloride solutions, concentrated hydroxide solutions and hydrogen sulfide rich environments.

Flange is the parts which connects two pipe ends, flange connection is defined by the flange, gasket and bolt three are connected as a group of combined sealing structure of the detachable connection. The gasket is added between the two flanges and then fastened by bolts. Different pressure flange, thickness is different, and the bolts they use are different, when pump and valve connect with pipe, the parts of the equipment are also made of the corresponding flange shape, also known as flange connection, usually closured bolted connection parts are also known as flanges, such as the connection of ventilation pipe, this kind of parts can be called "flange type part", but this connection is only part of a device, such as the connection between flange and water pump, it's not inapposite to call water pump as flange type parts,but relative small valve,it can be called as flange type parts .

1. According to the material, it can be divided into carbon steel, cast steel, alloy steel, stainless steel, copper, and aluminum alloy. 2. According to the production method, it can be divided into forged flanges, cast flanges, welded flanges, etc. 3. According to the manufacturing standard, it can be divided into National Standard (GB) (Ministry of Chemical Industry Standard, Petroleum Standard, Electric Power Standard), American Standard (ASTM), German Standard (DIN), Japanese Standard (JB), etc. my country's national standard system for steel pipe flanges GB 1 nominal pressure of flanges: 0.25Mpa-42.0Mpa Series 1: PN1.0, PN1.6, PN2.0, PN5.0, PN10.0, PN15.0, PN25 .0, PN42 (main series) Series 2: PN0.25, PN0.6, PN2.5, PN4.0 2. Flange structure: a, flat welding flange PL; b, flat welding belt neck SO; c, butt welding flange WN; d, socket welding flange SW; e, loose flange PJ/SE f, integral pipe IF; g, threaded flange Th; h, flange cover BL, lining flange cover BL(S). 3. Flange sealing surface type: flat surface FF, raised surface RF, concave surface FM, convex surface MF, tongue and groove surface TG, ring connection surface RJ Carbon steel pipe connections over 2.5Mpa. The sealing surface of the flat welding flange can be made into three types: smooth type, concave-convex type and tongue-and-groove type. The application of smooth flat welding flange is the largest, and it is mostly used in the case of moderate medium conditions, such as low-pressure unpurified compressed air and low-pressure circulating water. Its advantage is that the price is relatively cheap. Butt welding steel flange: It is used for butt welding of flange and pipe. It has reasonable structure, high strength and rigidity, can withstand high temperature and high pressure, repeated bending and temperature fluctuation, and has reliable sealing performance. The butt welding flange with a nominal pressure of 0.25-2.5Mpa adopts a concave-convex sealing surface. Socket welding flange: commonly used in pipelines with PN≤10.0Mpa, DN≤40; Butt welding looper flange. It is often used in the case where the medium temperature and pressure are not high and the medium is more corrosive. When the medium is more corrosive, the part of the flange contacting the medium (flanging short joint) is made of high-grade corrosion-resistant materials such as stainless steel, and the outside is clamped by flange rings of low-grade materials such as carbon steel. In order to achieve sealing; Integral flange: the flange is often integrated with equipment, pipes, valves, etc. This type is commonly used in equipment and valves.

Flanges are usually used in constructions,petroleum, chemical industry, power, ship building, paper making, metallurgy, water supply and sewage work, light and heavy industry, plumbing and electric etc.