Selection of valve material:
There are many materials for manufacturing valve parts, including various types of ferrous and non-ferrous metals and their alloys, and various non-metallic materials. The materials for manufacturing valve parts are selected
16 U-type-flange-butterfly-vlave-body
according to the following factors:
1. The pressure, temperature and characteristics of the working medium.
2. The force of the part and its function in the valve structure.
3. Have better manufacturability.
4. If the above conditions are met, there must be a lower cost.
Section one: the material of the valve body, bonnet and valve plate
1. Gray cast iron: Gray cast iron is suitable for water, steam, air, gas, oil and other media with a nominal pressure of PN≤1.0MPa and a temperature of -10°C–200°C. The commonly used grades of gray cast iron are: HT200, HT250, HT300, HT500.
2.. Malleable cast iron: suitable for water, steam, air and oil media with a nominal pressure of PN≤2.5Mpa and a temperature of -30-300°C. Commonly used grades are: KTH300-06, KTH330-08, KTH350-10.
3. Nodular cast iron: suitable for water, steam, air and oil with PN≤4.0Mpa and temperature of -30-350°C. Commonly used grades are: QT400-15, QT450-10, QT500-7.
4. Carbon steel (WCA, WCB, WCC): Suitable for nominal pressure PN≤32MPa, suitable for medium and high pressure valves with operating temperature between -29°C and +425°C. Among them, 16Mn and 30Mn work at -29-595°C, and are often used to replace ASTM A105. Commonly used grades are WC1, WCB, ZG25 and high-quality steel 20, 25, 30 and low-alloy structural steel 16Mn.
5. Low temperature carbon steel (LCB): suitable for ethylene, propylene, liquid natural gas, liquid nitrogen and other media with nominal pressure PN≤6.4MPa and temperature ≥-196°C. Commonly used grades are ZG1Cr18Ni9, 0Cr18Ni9, 1Cr18Ni9Ti, ZG0Cr18Ni9.
6. Alloy steel (WC6, WC9), suitable for high temperature and high pressure valves with non-corrosive medium working temperature between -29-595°C; WC5, WC9 are suitable for working temperature between -29-659°C High temperature and high pressure valves for corrosive media.
7. Austenitic stainless steel, suitable for valves with corrosive media with working temperature between -196-600°C.
Eight. Monel alloy: mainly suitable for valves with hydrofluoric medium.
nine. Cast copper alloy: Mainly suitable for valves for oxygen pipelines whose operating temperature is between -29 and 595°C
Fig.1-1 Commonly used valve body material:
valve body material |
standard |
temp |
PN/Mpa |
medium |
Grey cast Iron |
|
-15/200 |
≤1.6 |
water,gas |
Black Heart Malleable Cast Iron |
|
-15/300 |
≤2.5 |
water, seawater, gas, Ammonia |
ductile cast iron |
|
-30/350 |
≤4.0 |
water,seawater,gas,air,steam |
carbon steel (WCA,WCB,WCC) |
ASTM A216 |
-29/425 |
≤32 |
non-corrosive water, oil, gas |
Low temp carbon steel (LCB,LCC) |
ASTM A352 |
-46/345 |
≤32 |
low temp application |
Alloy(WC6,WC9,C5,C12) |
ASTM A217 |
-29/595 -29/650 |
High pressure |
non-corrosive corrosive medium |
Austenitic stainless steel |
ASTM A351 |
-196/600 |
|
corrosive medium |
Monel alloy |
ASTM A494 |
400 |
|
Hydrofluoric acid medium |
Hastelloy |
ASTM A494 |
649 |
|
Strong corrosive medium such as dilute sulfuric acid |
Titanium alloy |
|
|
|
Various strong corrosive media |
Cast copper alloy |
|
-273/200 |
|
Oxygen, sea water |
Plastic, Ceramic |
|
-60 |
≤1.6 |
corrosive medium |
Name |
material |
standard |
temp range °C |
application |
WCB |
carbon steel |
ASTM A216 |
-29/425 |
non-corrosive water, oil and gas |
LCB |
low temp carbon steel |
ASTM A352 |
-46/345 |
low temp applicaion |
LC3 |
3.5% nickel steel |
ASTM A352 |
-101/340 |
low temp applicaion |
WC6 |
1.25% chromium, 0.5% molybdenum |
ASTM A217 |
-30/593 |
non-corrosive water, oil and gas |
WC9 |
2.25% chromium |
C5 |
5% chromium,0.5% molybdenum |
ASTM A217 |
-30/649 |
light or non-corrosive application |
C12 |
9% chromium 1% molybdenum |
CA15(4) |
12% chromium |
ASTM A217 |
704 |
corrosive application |
CA6NM(4) |
12% chromium |
ASTM A487 |
-30/482 |
corrosive application |
CF8M |
stainless steel 316 |
ASTM A351 |
-268/649 when <425, need C=0.04% info |
corrosive,ultra low/high temp with no corrosive application |
CF8C |
stainless steel 347 |
ASTM A351 |
-268/649 when <425, need C=0.04% info |
high temp, corrosive application |
CF8 |
stainless steel 304 |
ASTM A351 |
-268/649 when <425, need C=0.04% info |
corrosive,ultra low/high temp with no corrosive application |
CF3 |
stainless steel 304L |
ASTM A351 |
425 |
corrosive or non-corrosive |
CF3M |
stainless steel 316L |
ASTM A351 |
454 |
corrosive or non-corrosive |
CN7M |
alloy |
ASTM A351 |
425 |
Good resistance to hot sulfuric acid corrosion |
M35-1 |
monel |
ASTM A494 |
400 |
Weldable grade, good resistance to common organic acid and salt water corrosion, resistance to most alkaline solutions |
N7M |
Hastelloy B |
ASTM A494 |
649 |
Suitable for treating various concentrations and temperatures of hydrofluoric acid, with good resistance to corrosion by sulfuric acid and phosphoric acid |
CW6M |
Hastelloy C |
ASTM A494 |
649 |
Very good resistance to strong oxidation, resistance to phosphoric acid, sulfurous acid and sulfuric acid at high temperatures |
CY40 |
Inconel alloy |
ASTM A494 |
|
Resistant to strong corrosive fluids at high temperatures |
TH Valve is a professional manufacturer of butterfly valve, gate valve, check valve, globe valve, knife 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
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