The valve body parts suitable for working temperature introduction
The valve body parts suitable for working temperature introduction
1 overview
One of the key considerations for valve design and selection is the temperature of the valve. In order to standardize the suitable working temperature of the valve body material, from various types of valve with steel and alloy material performance of China's petrochemical industry, chemical industry, fertilizer, power and metallurgy industries with the suitable working temperature of the valve body material and related requirements made clear rules, for valve product design, manufacturing and inspection. In addition, from the technical management and production management and material purchasing, etc into consideration, for each type of steel should choose good comprehensive performance, unfavorable choose too much steel grade and alloy nameplate, in case of chaos.
Low temperature condition
2.1 ultra-low temperature valve material
Cryogenic valves (liquid hydrogen) ~ (- 254-101 ℃ (ethylene); the subject material must choose face-centered cubic lattice of austenitic stainless steel, copper alloy, or aluminum alloy, its low temperature mechanical properties after heat treatment, especially the low temperature impact toughness must meet the standard requirements.
The following austenitic stainless steel can be used to make ultra-low temperature valves. ASTM A351 CF8M, CF3M, CF8 and CF3, ASTM A182 F316, F316L, F304 and F304L, ASTM A433 316, 316L, 304, 304L and CF8D (lanzhou high pressure valve factory design, factory standard code gfq81-93). Cryogenic valve body, valve cover, disc or disc before finishing, must be conducted in liquid nitrogen (196 ℃) cryogenic processing.
2.2 low temperature valve material
Suitable for cryogenic valves (100 ~ 30 ℃) the body of the austenitic stainless steel material with low temperature and low pressure with ferrite and martensite steel.
The low-temperature austenitic stainless steel has ASTM A351 CF8M, CF3M, CF8 and CF3, ASTM A182 F316, F316L, F304 and F304L, ASTM A433 316, 316L, 304, 304L and CF8D.
Low pressure with ferrite and martensite steel has ASTM A352 LCA (- 32 ℃), LCB, LCC (46 ℃), LC1 (59 ℃), LC2, LC211 (73 ℃) and LC3 (100 ℃).
The materials in the ASTM A352 standard are low in primary price, but the chemical components must be reliable and require strict internal control standards in smelting. The heat treatment process is complicated and needs to be made several times to meet the requirements of low temperature impact toughness. The production cycle is long. It is not allowed to use for low temperature steel when low temperature impact toughness fails to meet the standard requirements. Therefore, it is only used when the batch is large and can be smelted, and austenitic stainless steel is used in general.
3 non-corrosive conditions
When the valve working medium is water, steam, air and oil and other non-corrosive substances, generally carbon steel. The valve USES carbon steel to refer to WCB, WCC cast steel and ASTM A105 forged steel in ASTM A216 standard. Valve with carbon steel is suitable for working temperature for - 29 ~ 425 ℃. But for the sake of safety, considering the working medium temperature fluctuations likely, therefore, generally the use of carbon steel temperature should not exceed 400 ℃.
4 corrosive conditions
4.1 chrome-molybdenum heat steel
The Cr - Mo high temperature cast steel of the valve is mainly used in the ASTM A217 standard WC6, WC9 and C5 (ZG1Cr5Mo). The corresponding rolling materials are F11, F22 and F5 in ASTM A182 respectively.
The low chrome-molybdenum steel is used
Low chrome-molybdenum steel has WC6, WC9, F11 and F22, and its applicable working medium is water, steam and hydrogen. It is not suitable for sulfur oil. WC6, and F11 appropriate working temperature for - 29 ~ 540 ℃, WC9 and making appropriate working temperature is - 29 ~ 570 ℃.
The chrome 5 molybdenum high temperature steel
Chromium 5 molybdenum high temperature steel has C5 (ZG1Cr5Mo) and F5, and its applicable working medium is water, steam, hydrogen and sulfur oil.
C5 (ZG1Cr5Mo) when used for steam, the highest working temperature is 600 ℃. For the working medium such as oil, sulfur its highest working temperature is 550 ℃. Therefore, the rules C5 (ZG1Cr5Mo) working temperature is 550 ℃ or less.
4.2 stainless steel resistant steel
Stainless steel acid resistant steel is used in petrochemical and chemical industry, chemical fertilizer industry to resist corrosive acid, sulfuric acid, acetic acid and organic acid and other corrosion resistant chromium nickel or chromium nickel molybdenum stainless steel. Acid-proof stainless steel cast steel is mainly using ASTM A743 or ASTM standard A744 CF8, CF8M, CF3, CF3M, MCU and CN7M CF8C, CD - 4, its corresponding rolling respectively in the ASTM standard A182 F304, F316, F304L, F316L UNS N08020, F347, F53 and the United States.
(1) Cr - Ni stainless steel
The cr-ni class stainless acid resistant steel has CF8, CF3, F304, F304L, CF8C and F347, which apply to the working medium for nitric acid, such as nitric acid. The highest working temperature is 200 ℃ or less.
2 Cr - Ni - Mo stainless steel
The cr-ni - Mo class, which has CF8M, CF3M, F316 and F316L, is suitable for reducing acid, such as acetic acid, in the working medium.
CF8M, CF3M, etc. can replace CF8 and CF3, but CF8 and CF3 can't replace CF8M and CF3M. So, the United States and other countries mainly use CF8M, CF3M acid-proof stainless steel valve, the highest working temperature is 200 ℃ or less.
(3) CN7M alloy
CN7M alloy has good corrosion resistance, it is widely used in corrosion of harsh conditions, including sulfuric acid, nitric acid, hydrofluoric acid and dilute hydrochloric acid, caustic and sea water and thermal of chloride salt solution, etc., especially can be used for a variety of concentration and temperature of 70 ℃ or less range of sulfuric acid. CN7M and UNS N08020 alloy using temperature for - 29 ~ 450 ℃.
Double phase stainless steel
Duplex stainless corrosion resistant steel (table 1) for precipitation hardening stainless steel, they are in the ferritic matrix containing 35% ~ 40% of austenite, the yield strength of about 19 cr - ni austenitic stainless steel 2 times, and with high hardness and good plasticity and impact toughness. Particularly suited to work in both abrasion and erosion corrosion under the conditions of use, and widely used in the oxidation and reduction in the acid condition, in chloride environment have special performance of the resistance to stress corrosion cracking. MCU, CD3MN, CD - 4 CE3MN and F53 duplex stainless steel temperature - 29 ~ 316 ℃.
Table 1 double phase stainless steel material number control
brand
Casting material
Metal rolling
plank
bar
0 cr25 - Ni5 - Mo - Cu
A8901A
(CD4MCu)
00 cr22 - Ni5 - Mo3 - N
A8904A
(CD3MN)
A182
F51
A240
S31803
A479
S31803
00 cr25 - Ni7 - Mo4 - N
A8905A
(CE3MN)
A182
F53
A240
S32750
A479
S32750
4.3 corrosion-resistant nickel-base alloy
Corrosion resistance of nickel base alloy valve mainly use casting of ASTM standard A494 monel alloy casting (M35-1), nickel alloy (CZ - 100), British Cornell alloy (CY - 40), hartz alloy B (N, N - 7-12 mv m) and hartz alloy C (the CW - 12 mw, the CW - 7 m, the CW - 6 MC, the CW - 2 m).
Monel alloys for corrosion resistant Monel valves are mainly UNS N04400 (Monel 400) and UNS N05500 (Monel K500). Inconel 600 and Inconel 625 are the Inconel 600 and Inconel 625.
Monel metal
Monel has high strength and toughness, especially with excellent anti-reductive acid and strong alkali medium and seawater. So, usually used in the manufacture of hydrofluoric acid, salt water, neutral medium and reducing acid, alkali, salt and other media equipment and valves, and can also be applied to dry chlorine, hydrogen chloride, 425 ℃ and 450 ℃ high temperature and high temperature chlorine gas such as hydrogen chloride medium, but not the sulphur medium and oxidation resistance medium (such as nitric acid medium and high oxygen) corrosion. Overall is monel alloy valve material code for MM, inside is monel alloy valve, shell for carbon steel valves material code for the C/M and shell for CF8 valve material code for P/M and shell for CF8M, code-named R/M valve material. Monel alloy, Monel 400 and M35-1 Monel K500 alloy suitable working temperature for - 29 ~ 480 ℃.
Dic-cast nickel alloy
The chemical composition of nickel alloy (CZ - 100) is 95% Ni and 1.00% C, which has no corresponding rolling material. When cz-100 is used in high temperature high concentration or non-aqueous alkali solution, it has excellent corrosion resistance. Cz-100 is commonly used in the production of chlorine-based production of high corrosion concentration (including melting and unhydrated caustic soda) as well as in places where there can be no such products as copper and iron. The material of the CZ 100 valve is named Ni. CZ - 100 alloy suitable working temperature for - 29 ~ 316 ℃.
It's a great caralloy
Inconel (Inconel) CY - 40 and Inconel 600 (ASTM)
B564 N06600) is mainly used in the anti-stress corrosion, especially in high concentrations of chloride, and when the Ni content is greater than 45%, the stress corrosion of chloride is "immune" effect. In addition, it can also be used to resist the corrosion of hot gases and burners of nitric acid, fuming nitric acid, sulfur and vanadium.
Inconel alloy has been widely used in the manufacture of boiler feedwater systems for nuclear power plants because it is more secure than stainless steel. At the same time, it is also suitable for high tensile strength, high pressure sealing and high tensile resistance, as well as industrial production of mechanical wear and antioxidant capacity in high temperature. High pressure (600 ~ 1500) is manufactured using Inconel 600 or Inconel 625 alloy (for HCW - 6MC)
LB) high concentration oxygen valve, etc. The materials of the cy-40 and Inconel 600 alloy valves are codenamed In. Appropriate working temperature for - 29 ~ 650 ℃.
kwot
Hastelloy is a commercial name, which includes a series of alloy plates. The main purpose of the corrosion resistant valve is HHS B
Hastelloy B and Hastelloy C.
The foundry alloy plate of Hastelloy B is n-12mv (n-12m-1) and n-7m in ASTM A494 standard, which is known as n-12m-2, also known as the Chlorimet2 alloy, and its rolling material is the UNS N10665 of the ASTM B335 standard. It is resistant to various concentrations of hydrochloric acid and is also resistant to non-oxidized salts and acids. The corrosion resistance valve of HHS B is considered suitable for the use of low carbon grade B (n-7m) from corrosion resistance and intergranular corrosion. There is no provision for the material code of haji alloy, the material code of the alloy B valve, which can be directly used in casting alloy plate number. Hartz alloy suitable working temperature for B - 29 ℃ ~ 425 ℃.
Hartz alloy C (Hastelloy C) casting alloy grades for the CW - 12 mw (some call it the CW - 12 m - 1) and the CW - 7 m (2, 12 m in the CW - also called it Chlorimet3 alloy) and Hastelloy C - 276 alloy, the alloy casting brand for the CW - 6 MC and Hastelloy C - 4 alloy, the alloy casting brand for the CW - 2 m. The corresponding rolling materials for the casting of the CW, CW, CW, 12MW, CW - 6MC and the CW - 2M are UNS N10001, UNS N10003, UNS N10276 and UNS N06455 respectively. The hydrochloric acid and nitric acid corrosion resistant to oxidizing solvent, low concentration and normal temperature.
The first generation of Hastelloy C (0 cr16ni60mo16w4) is characterized by oxidizing and reducing acid with strong corrosion medium, it has excellent corrosion resistance, but due to high nickel corrosion resistant alloy for austenitic organization, because Ni down C in solid solubility of austenite. Therefore, the Hastelloy C alloy of the Ni - Mo department Hastelloy B and Ni - mo-cr system has serious intergranular corrosion tendency or sensitivity, which can lead to stress corrosion and crevice corrosion at high temperature. In order to overcome the intergranular corrosion, and introduced the second generation of hartz alloy, Hastelloy C - 276 - reduced to 0.02% from 0.03% (C) 3 (superscript rd) generation hartz alloy C - Hastelloy C - 4, its characteristic is low Si (Si 0.08% or less) and superfine C (C 0.015% or less), and reduce the content of Fe and W, joined the stabilization of the Ti alloy elements, etc.
The corrosion resistance valves of HHS C are considered in terms of corrosion resistance and intergranular corrosion. The HCW c-276 (CW - 6MC) and the HCW c-4 (CW - 2M) are recommended. Hartz alloy material of the valve C code, and the performance and working temperature difference is big, so the CW - 12 mw, the CW - 7 m, 2 m the CW - 6 MC and the CW - with HC - 12 and HC, HC - 7, HC - 276-4, said or directly by the casting alloy.
The CW - 7 m and hartz alloy UNS N10001 alloy suitable working temperature for - 29 ~ 425 ℃, the CW - 12 mw and hartz alloy UNS N10003 alloy suitable working temperature for - 29 ~ 700 ℃, the CW - 6 MC and hartz alloy UNS N10276 alloy suitable working temperature for - 29 ~ 676 ℃, the CW - 2 m and hartz alloy UNS N06455 alloy suitable working temperature for - 29 ~ 425 ℃.
