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Valve material and valve standards-(7)- Monel alloy

Monel alloy for corrosion resistant valve
1. Introduction/overview of Monel alloy:
Monel alloy, cast nickel alloy, Hastelloy alloy, etc. are all materials for making special purpose valves. Monel alloy is a Ni-Cu alloy in nickel-based corrosion-resistant alloys. It was first developed by the US Nickel Company. Its typical composition is 70% Ni and 30% Cu. It is the most widely used nickel-based corrosion-resistant alloy.

Monel alloy not only has high strength and toughness, but also has excellent resistance to corrosion by reducing acid and strong alkali media and sea water, so it is usually used to manufacture and transport hydrofluoric acid (HF), salt water, neutral media, and alkali salts. And reducing acid medium equipment. Monel alloy is also suitable for dry chlorine, hydrogen chloride, high temperature chlorine (425°C) and high temperature hydrogen chloride and other media, but it is not resistant to corrosion by sulfur-containing media and oxidizing media (such as nitric acid, media with high oxygen content), and it is nickel It reacts violently with sulfur and oxygen and easily forms Ni3S2 and NiO.

2. Performance of Monel alloy:
Monel alloy is a Ni-Cu solid solution, where Cu is used as a non-oxidizing resist added to Ni, which improves the corrosion resistance of nickel alloys and acts as a strengthening alloy. The addition of C can improve the casting performance of the alloy, but only 0.15% of C can be dissolved in the alloy at room temperature, and the excess C will be precipitated as a graphite phase. Adding 1.5%-3.5% Fe can also improve the casting performance of the alloy. Adding Mn and Si can improve the mechanical properties of the alloy, especially the content of Si has an important influence on the mechanical and physical properties of the Monel alloy.

3. Classification of Monel alloy:
Monel alloys are classified into casting alloys and deformed alloys.
3.1 Deformation alloy: There are more than 10 types of deformed Monel alloys in the United States, such as Monel400, MonelC, Monel403, Monel404, Monel R2405, Monel406, Monel411, MonelK500, MonelK501 and Monel502. Because Monel has its own representation methods in different American standard systems, SAE and ASTM jointly developed ASTM2SAE unified digital system (unified numbt system2 UNS) in order to facilitate the use and unified management of calculations. In the United States’ UNS, nickel alloys have 5 grades of deformed Monel alloys, including solid solution hardened No5500 (Monel400), No4404 (Monel404) and No4405 (MonelR2405), and precipitation hardened NO5500 (MonelK500) and NO5502 (Monel502). ) Etc. (refer to Table 1). Among them, the deformed Monel alloy commonly used in the manufacture of corrosion-resistant valves is Monel400 and MonelK500.
Table 1. Chemical composition of deformed Monel alloy in United States UNS

Grade name chemical composition/ %
C Si Mn S Ni Fe others
NO4400(Monel400) ≤0.3 ≤0.5 2 ≤0.024 63-70 ≤2.5 Cu base
No4404(Monel404) ≤0.15 ≤0.1 ≤0.1 ≤0.024 52-57 ≤0.5 Cu base, Al≤0.05
No4405(MonelR2405) ≤0.3 ≤0.5 ≤2.0 0.025-0.06 63-70 ≤2.5 Cu base
No5500(MonelK500) ≤0.25 ≤0.5 ≤1.5 ≤0.01 63-70 ≤2 Cu base, Al213-3115,Ti0135-0185
NO5502(Monel502) ≤0.10 ≤0.5 ≤1.5 ≤0.01 63-70 ≤2 Cu base, Al215-315

3.2 Casting alloy: The American cast Monel alloy has five grades of M35-1, M35-2, M-30H, M-25S and M-30C in ASTM A494 (Table 2), which is in the US Federal Standard QQ-N2-88 There are also 5 cast Monel alloys (Table 3).
Table 2. Cast Monel alloy in ASTM A494:

grade name chemical composition /% mechanical properties
C Mn Si P.S Cu Fe Ni Nb Compressive strength/Mpa Tensile strength/Mpa Elongation rate/% HB
M35-1(a) ≤0.35 ≤1.5 ≤1.25 ≤0.03 26-33 ≤3.5 Ba ≥450 ≥170 ≥25
M35-2 ≤0.35 ≤1.5 ≤2.00 ≤0.03 26-33 ≤3.5 Ba ≥450 ≥205 ≥25
M-30H ≤0.30 ≤1.5 2.7-3.7 ≤0.03 27-33 ≤3.5 Ba ≥690 ≥415 ≥10
M-25S ≤0.25 ≤1.5 3.5-4.5 ≤0.03 27-33 ≤3.5 Ba 243-294(b)
M-30C(a) ≤0.30 ≤1.5 1.0-2.0 ≤0.03 26-33 ≤3.5 Ba 1-3 ≥450 ≥225 ≥25 125-130(b)

Notes:
1.Ba=balance, means the balance is all Ni content.
2. To remove the weldability, it should be M3521 or M230C
3. This table is a data parameter
4. HB minimum is 300
Table 3 QQ2N2288 cast Monel alloy:

QQ-N-288 chemical composition /% mechanical properties
C Si Mn Cu Fe Ni Nb Compressive strength/Mpa Tensile strength/Mpa Elongation rate/% HB
A ≤0.35 ≤2.0 ≤1.5 26-33 ≤2.5 62-68 ≥448 ≥224 ≥25 125-150
B ≤0.30 2.7-3.7 ≤1.5 27-33 ≤2.5 61-68 ≥689 ≥455 ≥10 240-290
C ≤0.20 3.3-4.5 ≤1.5 27-31 ≤2.5 ≥60 ≥825 ≥550 ≥10 250-300
D ≤0.25 3.5-4.5 ≤1.5 27-31 ≤2.5 ≥60 ≥300
E ≤0.30 1.0-2.0 ≤1.5 26-33 ≤2.5 ≥60 1-3 ≥448 ≥221 ≥25 125-150

TH Valve is a professional manufacturer of butterfly valvegate valvecheck valveglobe valveknife gate valve, ball valve with API, JIS, DIN standard, used in Oil, Gas, Marine industry, Water supply and drainage, fire fighting, shipbuilding, water treatment and other systems, with Nominal Diameter of DN50 to DN1200, NBR/EPDM/VITON, Certificates & Approvals: DNV-GL, Lloyds, DNV, BV, API, ABS, CCS. Standards: EN 593, API609, API6D.

Related news /knowledge:
Valve material and valve standards-(8)- Monel alloy application;
Detailed introduction of soft sealing butterfly valve-(2);
Code of valve sealing or lining material;
Classification and advantages of gate valve;

 

Valve material and valve standards-(5)-packing material

Packing /Filler material:
On the valve, the packing is used to fill the space of the valve cover packing chamber to prevent the medium from leaking through the valve stem and the bonnet packing chamber.

ductile iron, DI, butterfly valve, manufacturer, center line, TH valve

ductile iron, DI, butterfly valve, manufacturer, center line, TH valve

Requirements for packing.

  • 1. Good corrosion resistance, the filler must be able to withstand the corrosion of the medium in contact with the medium.
  • 2. Good airtightness, the packing will not leak under the action of the medium and working temperature.
  • 3. The friction coefficient is small to reduce the friction torque between the valve stem and the packing.

Types of filler:

1. Soft filler: it is a string woven from plant matter, that is hemp, flax, cotton, jute, etc., or mineral, that is, asbestos fiber, or asbestos fiber with metal wire inside and graphite powder coated on the outside. Pressed molding fillers, and flexible graphite filler materials developed in recent years.
Vegetable packing is often used for low pressure valves below 100°C; mineral packing can be used for valves with 450-500°C. In recent years, the temperature of structural media using rubber O-rings as fillers is generally limited to below 60°C.
The packing on the high temperature and high pressure valve is also made of pure asbestos and flake graphite powder.

2. Hard filler: that is, filler made of metal or metal mixed with asbestos and graphite and filler formed by pressing and sintering of PTFE, metal filler is used less.

Selection of filling material:
The choice of packing should be based on the medium, temperature and pressure. The commonly used materials are as follows:

  • 1. Oil-impregnated asbestos rope, can be selected according to Table 5-2
  • 2. Rubber asbestos rope, can be selected according to 5-3
  • 3. Graphite asbestos rope: The asbestos rope is coated with graphite powder, the usable temperature is above 450°C, and the pressure can reach 16MPA, which is generally suitable for high-pressure steam. Lately, it gradually adopts the compressed herringbone type packing, which is placed in a single circle and has good sealing performance.
  • 4. Polytetrafluoroethylene: This is a kind of filler that is currently widely used. Especially suitable for corrosive media, but the temperature should not exceed 200°C. Generally, it is made by pressing or rod car.

Fig.5-2:

Material Grade name shape size(dia or square) Max Pressure kgf/cm2 max temp/ °C application
Oil-impregnated asbestos rope YS450 F 3,4,5,6,8,10,13,16,19,22,25 60 450 water, steam,air,petroleum products
Y 5,6,8,10,13,16,19,22,25
N 3,5,6,8,10,13,16,19,22,25
YS350 F,Y,N 3,5,6,8,10,13,16,19,22,25 45 350
YS250 F,Y,N 3,5,6,8,10,13,16,19,22,25 45 250

Note: The shape code F means square, through the heart or one or more layers of weaving; Y means round, with a twisted core in the middle and one or more layers of weaving on the outside; N means twisted.

Fig.5-3:

Material Grade name size(dia or square) Max Pressure kgf/cm2 max temp/ °C application
Rubber, asbestos, packing XS450 3,4,5,6,8,10,13,16,19,22,25,28 60 450 steam,petroleum products
XS350 45 350
XS250 45 250

TH Valve is a professional manufacturer of butterfly valvegate valvecheck valveglobe valveknife gate valve, ball valve with API, JIS, DIN standard, used in Oil, Gas, Marine industry, Water supply and drainage, fire fighting, shipbuilding, water treatment and other systems, with Nominal Diameter of DN50 to DN1200, NBR/EPDM/VITON, Certificates & Approvals: DNV-GL, Lloyds, DNV, BV, API, ABS, CCS. Standards: EN 593, API609, API6D

Related news /knowledge:
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Valve material and valve standards-(1)

What material is WCB/LCB/LCC/WC6/WC in the valve?
W, wrought casting; C, Carbon steel; A, B, C indicate the strength value of steel grades from low to high.

lug type butterfly valve-ductile iron

lug type butterfly valve-ductile iron

WCA, WCA, WCC represent carbon steel, ABC represents the strength level, and WCB is commonly used. The corresponding pipe material of WCB should be A106B, and the corresponding forging material should be A105.
WC6 is an alloy steel casting, the corresponding pipe material is about A355 P11, and the forging is A182 F11; there is also WC9, high temperature resistant alloy steel, the corresponding pipe material is about A355 P22, and the corresponding forging is A182 F22.
WC: weldable casting
LCB/LCC (ASTM A352) low temperature carbon steel
ITCS is carbon steel with impact toughness; impact test C=carbon S=steel (A350)
Split body split type, side entry side mounted (referring to the actuator), corresponding to TOP entry top mounted type

Commonly used valve casting and forging carbon steel material table

material country standard material grade name
Casting China GB/T 12229 WCA WCB WCC
ZG205-415 ZG250-485 ZG275-485
USA ASTM A216/A216M WCA WCB WCC
UNS J02502 UNS J03002 UNS J02503
Forged China GB/T 12228 GB/T 699 25 25Mn 35 40 A105
USA ASTM A105/A105M A105

Low temperature casting parts material name and temperature range

C C C-Mn C-Mo 2.5Ni Ni-Cr-Mo 3.5Ni 4.5Ni 9Ni Cr-Ni-Mo
LCA LCB LCC LC1 LC2 LC2-1 LC3 LC4 LC9 CA6NM
J02504 J03303 J02505 J12522 J22500 j42215 j31550 j41500 j31300 j91540
-32 -46 -46 -59 -73 -73 -101 -115 -115 -73

Commonly used valve ASTM Casting and Forged material sheet (ASME B16.5)

ASTM Casting ASTM Forged China name Temp °C suitable medium
Carbon steel
A216 WCB A105 20 -29/427 water,steam,air,petroleum products
Low temp Carbon steel
A352 LCB A350 LF2 16Mn -46/343
A352 LCC A350 LF2 16Mn -46/343
High temp alloy
A217 WC1 A182 F1 20MnMo -29/454 High temp, High pressure medium
A217 WC6 A182 F11 15CrMo -29/552 High temp, High pressure medium
A217 WC9 A182 F22 10Cr2Mo1 -29/593 High temp, High pressure medium
A217 C5 A182 F5 1Cr5Mo -29/650 Corrosive high temperature medium
A217 C12 A182 F9 Cr9Mo1 -29/593 High sulfur oxidizing medium
Martensitic stainless steel
A217 CA15 A182 F6a Cr9Mo1 -29/593 High sulfur oxidizing medium
Austenitic stainless steel(C≤0.08)
A351 CF8 A182 F304 0Cr18Ni9 -196/537 corrosive medium
A351 CF3 A182 F304L -196/425 corrosive medium
A351 CF8M A182 F316 0Cr18Ni12Mo2Ti -196/537 corrosive medium
A351 CF3M A182 F316L -196/425 corrosive medium
low carbon Austenitic stainless steel(C≤0.03)
A351 CF3 A182 F304L 00Cr18Ni10 -0.459016393 corrosive medium
A351 CF3M A182 F316L 00Cr18Ni14Mo2 -196/454 corrosive medium
Special alloy
A351 CN7M B462Gr.NO8020 (ALLOY20) -29/149 Oxidizing medium and various concentrations of sulfuric acid
A494 M-30C (Monel alloy) B4564 Gr.NO4400 -29/482 Hydrofluoric acid, Sea water
Hastelloy H.B H.C Strong corrosive medium such as dilute sulfuric acid

Notes:
1. Forged valve body material is dense, not easy to have defects, the structure size is not limited by the mold, and the pressure bearing performance is reliable. It is mostly used for high pressure, oxygen working conditions, small diameter or other small batch valve manufacturing, generally at high temperature, Choose forgings under high pressure or low temperature or special medium; castings are generally only suitable for medium and low pressure, and are mostly used for mass production of standardized molded valves.

2. The difference between material A351 CF3M and A182 F316L: the materials corresponding to the two standards are 316 stainless steel. CF3M stands for castings and is often used as valve material. The corresponding forging steel code is A182 F316L. ASTM A216 WCB is a casting, and its forging is A105; the casting of SS304 is A351-CF8, and the forging is A182-F304.