Selection of valve material
There are many materials for manufacturing valve parts, including various brands of ferrous metals, non-ferrous metals and their alloys, various non-metallic materials, etc.
The materials for manufacturing valve parts shall be selected according to the following factors:
- 1. Pressure, temperature and characteristics of working medium.
- 2. The stress of the part and its role in the valve structure.
- 3. Good processability.
- 4. In the case of meeting the above conditions, there should be a lower cost.
Material of body, cover and disc
Table of Contents
- 1. Gray cast iron: gray cast iron is suitable for water, steam, air, gas, oil and other media with nominal pressure of PN ≤ 1.0MPa and temperature of – 10 ℃ ~ 200 ℃. The common grades of gray cast iron are HT200, HT250, HT300 and ht350.
- 2. Malleable cast iron: suitable for water, steam, air and oil medium with nominal pressure PN ≤ 2.5MPa and temperature of – 30 ~ 300 ℃. The common brands are kth300-06, kth330-08 and kth350-10.
- 3. Ductile iron: suitable for water, steam, air, oil and other media with PN ≤ 4.0Mpa and temperature of – 30 ~ 350 ℃. Common brands are: QT400-15, QT450-10, QT500-7.
- 4. Carbon steel (WCA, WCB, WCC): it is suitable for medium and high pressure valves with nominal pressure PN ≤ 32.0mpa and working temperature between – 29 ℃ and + 425 ℃. The working temperature of 16Mn and 30mn is – 29 ~ 595 ℃. It is commonly used to replace ASTM A105. The common grades are WC1, WCB, ZG25, high quality steel 20, 25, 30 and Low Alloy Structural Steel 16Mn.
- 5. Low temperature carbon steel (LCB): suitable for nominal pressure PN ≤ 6.4Mpa, temperature ≥ – 196 ℃, ethylene, propylene, liquid natural gas, liquid nitrogen and other media, commonly used brands are ZG1Cr18Ni9, 0Cr18Ni9, 1Cr18Ni9Ti, zg0cr18ni9
- 6. Alloy steel (wc6, wc9) is suitable for high temperature and high pressure valves in non corrosive medium with working temperature between – 29 ℃ and 595 ℃; wc5, wc9 are suitable for high temperature and high pressure valves in corrosive medium with working temperature between – 29 ℃ and 650 ℃.
- 7. Austenitic stainless steel, suitable for valves with corrosive medium between – 196 ℃ and + 600 ℃.
- 8. Monel alloy: mainly used for valves with hydrogen and fluorine medium.
- 9. Cast copper alloy: mainly used for oxygen pipeline valve with working temperature between – 29 ℃ and 595 ℃.
Table 1-1 common materials of valve shell
Shell material |
Standard |
Applicable temperature / ℃ |
Applicable pressure / MPa |
Applicable medium |
Grey cast iron |
-15–200 |
≤1.6 |
Water and gas |
|
Black core malleable iron |
-15–300 |
≤2.5 |
Water, seawater, gas, ammonia |
|
Ductile iron |
-30–350 |
≤4.0 |
Water, sea water, gas, air, steam |
|
Carbon steel(WCA、WCB、WCC) |
ASTM A216 |
-29–425 |
≤32.0 |
Non corrosive applications, including water, oil and gas |
Low temperature carbon steel(LCB、LCC) |
ASTM A352 |
-46–345 |
≤32.0 |
Low temperature application |
Alloy steel(WC6、WC9) (C5、C12) |
ASTM A217 |
-29–595 -29–650 |
High pressure |
Non corrosive medium and corrosive medium
|
ASTM A351 |
-196–600 |
Corrosive medium |
||
Monel alloy |
ASTM A494 |
400 |
Medium containing hydrofluoric acid |
|
Hastelloy |
ASTM A494 |
649 |
Strong corrosive medium such as dilute sulfuric acid |
|
Various strong corrosive media |
||||
Cast copper alloy |
-273–200 |
Oxygen, seawater |
||
Plastics, ceramics |
–60 |
≤1.6 |
Corrosive medium |
Code |
Material |
Standard |
Applicable conditions |
Temperature range |
WCB |
Carbon steel |
ASTM A216 |
Non corrosive applications, including water, oil and gas |
-29℃–+425℃ |
LCB |
Low temperature carbon steel |
ASTM A352 |
Low temperature application |
-46℃–+345℃ |
LC3 |
3.5% nickel steel |
ASTM A352 |
Low temperature application |
-101℃–+340℃ |
WC6 |
1.25% Cr 0.5% Mo steel |
ASTM A217 |
Non corrosive applications, including water, oil and gas |
-30℃–+593℃ |
WC9 |
2.25 Cr |
|||
C5 |
5% Cr 0.5% Mo |
ASTM A217 |
Mild corrosive or aggressive applications and non corrosive applications |
-30℃–+649℃ |
C12 |
9% CR 1% Mo |
|||
CA15(4) |
12% chromium steel |
ASTM A217 |
Corrosive applications |
+704℃ |
CA6NM(4) |
12% chromium steel |
ASTM A487Corrosive applications |
|
-30℃–+482℃ |
CF8M |
ASTM A351 |
Corrosive or ultra low or high temperature non corrosive applications |
-From 268 ℃ to + 649 ℃ and above 425 ℃, carbon content of 0.04% or above shall be specified |
|
CF8C |
ASTM A351 |
Mainly used in high temperature, corrosive applications |
-From 268 ℃ to + 649 ℃, carbon content of 0.04% and above shall be specified above 540 ℃ |
|
CF8 |
ASTM A351 |
Corrosive or ultra low or high temperature non corrosive applications |
-From 268 ℃ to + 649 ℃ and above 425 ℃, carbon content of 0.04% or above shall be specified |
|
CF3 |
304 stainless steel |
ASTM A351 |
Corrosive or non corrosive applications |
+425℃ |
CF3M |
316L stainless steel |
ASTM A351 |
Corrosive or non corrosive applications |
+454℃ |
CN7M |
Alloy steel |
ASTM A351 |
It has good corrosion resistance to hot sulfuric acid |
+425℃ |
M35-1 |
Monel |
ASTM A494 |
Weldable grade. It has good corrosion resistance to all common organic acids and brine. It also has high corrosion resistance to most alkaline solutions |
+400℃ |
N7M |
Hastelloy B |
ASTM A494 |
It is especially suitable for hydrofluoric acid of various concentrations and temperatures. It has good corrosion resistance to sulfuric acid and phosphoric acid |
+649℃ |
CW6M |
ASTM A494 |
It has good corrosion resistance in strong oxidation environment. It has good corrosion resistance to formic acid (formic acid), phosphoric acid, sulfite and sulfuric acid |
+649℃ |
|
CY40 |
Inconel |
ASTM A494 |
Good performance in high temperature applications. It has good corrosion resistance for strong corrosive fluid medium |
Sealing surface material
The sealing surface is the most critical working surface of the valve. The quality of the sealing surface is related to the service life of the valve. Usually, the material of the sealing surface should consider factors such as corrosion resistance, abrasion resistance, erosion resistance and oxidation resistance. It is usually divided into two categories:
Soft material
- 1. Rubber (including polybutadiene rubber, fluororubber, etc.)
- 2. Plastics (PTFE, nylon, etc.)
Hard sealing material
- 1. Copper alloy (for low pressure valves)
- 2. Chromium stainless steel (for common high and medium pressure valves)
- 3. Stellite Alloy (used for high temperature and high pressure valve and strong corrosion valve)
- 4. Nickel base alloys (for corrosive media)
Stem material
In the process of valve opening and closing, the valve stem bears tensile, compressive and torsional forces, and is in direct contact with the medium. At the same time, there is relative friction movement between the valve stem and the packing. Therefore, the material of the valve stem must have sufficient strength and impact toughness at the specified temperature, certain corrosion resistance and scratch resistance, and good processability. Commonly used stem materials are as follows.
Carbon steel
For water and steam medium with low pressure and medium temperature less than 300 ℃, A5 ordinary carbon steel (now Q275, A3 is Q235) is generally selected.
For medium pressure and medium temperature not more than 450 ℃ water, steam medium, generally choose 35 high quality carbon steel.
Alloy steel
For medium pressure and high pressure, medium temperature does not exceed 450 ℃ of water, steam, oil and other media, generally choose 40Cr (chromium steel).
38CrMoAlA nitriding steel can be used for high pressure, medium temperature not exceeding 540 ℃ water, steam and other media.
25Cr2MoVA chromium molybdenum vanadium steel is generally used for steam medium with high pressure and medium temperature not exceeding 570 ℃.
Stainless acid resistant steel
For medium pressure and high pressure, medium temperature does not exceed 450 ℃ non corrosive medium and weak corrosive medium, can choose 1Cr13, 2Cr13, 3Cr13 chromium stainless steel.
When used in corrosive medium, stainless acid resistant steel such as Cr17Ni2, 1Cr18Ni9Ti, Cr18Ni12Mo2Ti, cr18ni12mo3ti and precipitation hardening steel ph15-7mo can be selected.
Heat resistant steel
4Cr10Si2Mo martensitic heat resistant steel and 4Cr14Ni14W2Mo austenitic heat resistant steel can be used for high temperature valves with medium temperature less than 600 ℃.
Stem nut material
In the process of valve opening and closing, the stem nut directly bears the axial force of the stem, so it must have a certain strength. At the same time, it and the valve stem are threaded transmission, requiring small friction coefficient, no rust and avoid biting phenomenon.
Copper alloy
Copper alloy is one of the commonly used materials because of its low friction coefficient and no rust. Zhmn58-2-2 cast brass can be used for low pressure valve with PG < 1.6Mpa. ZQAl9-4 bronze can be used for medium pressure valve with pg16-6.4mpa. For high pressure valves, zhal66-6-3-2 cast brass can be used.
Steel
When the working conditions do not allow the use of copper alloy, high quality carbon steel such as 35 and 40, stainless acid resistant steel such as 2Cr13, 1Cr18Ni9 and Cr17Ni2 can be selected. The following conditions are not allowed under working conditions.
- 1. For electric valve, stem nut with melon clutch needs heat treatment to obtain high hardness or surface hardness.
- 2. When the working medium or surrounding environment is not suitable for the selection of copper alloy, such as ammonia medium with corrosion to copper.
When selecting steel stem nut, special attention should be paid to the phenomenon of thread seizure.
Fastener, packing and gasket materials
Fastener material
Fasteners mainly include bolts, stud bolts and nuts. The fastener bears the pressure directly on the valve, which plays an important role in preventing the outflow of medium. Therefore, the selected material must ensure sufficient strength and impact toughness at the service temperature.
When selecting fastener materials according to medium pressure and temperature, it can be selected according to the table.
Name |
Nominal pressure PG (MPA) |
Medium temperature (℃) |
|||||
300 |
350 |
400 |
425 |
450 |
530 |
||
Bolt
|
1.6-2.5 |
Q235(A3) |
35 |
30CrMoA |
– |
||
4.0-10.0 |
35 |
35CrMoA |
25Cr2MoVA |
||||
16.0-20.0 |
30CrMoA |
35CrMoA |
25Cr2MoVA |
||||
Nut |
1.6-2.5 |
Q235(A3) |
30 |
35 |
– |
||
4.0-10.0 |
30 |
35 |
35CrMoA |
||||
16.0-20.2 |
35 |
35CrMoA |
The alloy steel material must be heat treated. When there are special corrosion resistance requirements for fasteners, stainless acid resistant steel such as Cr17Ni2, 2Cr13 and 1Cr18Ni9 can be selected.
Filler material
In the valve, the packing is used to fill the space of the valve cover packing chamber to prevent the medium from leaking through the space of the valve stem and the valve cover packing chamber.
Requirements for fillers
- 1) Good corrosion resistance, filler and medium contact, must be able to resist the corrosion of the medium.
- 2) Good sealing performance, no leakage of packing under the action of medium and working temperature.
- 3) The friction coefficient is small to reduce the friction torque between the valve stem and packing.
Types of fillers
The fillers can be divided into soft fillers and hard fillers
1) Soft filler: it is made of plant material, such as hemp, flax, cotton, jute, etc., or mineral material, such as asbestos fiber, or cord woven by asbestos fiber with metal wire inside and coated with graphite powder outside, as well as molded filler and flexible graphite filler developed in recent years.
Plant packing is commonly used in low pressure valve below 100 ℃, mineral packing can be used in 450-500 ℃.
In recent years, the temperature of structural medium using rubber O-ring as filler is generally limited below 60 ℃.
The packing on high temperature and high pressure valve is also made of pure asbestos and flake graphite powder.
2) Hard filler: that is, the filler made of metal or metal mixed with asbestos and graphite, and the filler formed by pressing and sintering of polytetrafluoroethylene. Metal filler is rarely used.
Selection of fillers
The selection of fillers 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: it can be selected according to table 5-3.
3) Graphite asbestos rope: the asbestos rope is coated with graphite powder. The temperature can be above 450 ℃ and the pressure can reach 16MPa. It is generally suitable for high pressure steam. In recent years, it has gradually adopted the pressed herringbone packing, which is placed in a single ring and has good sealing performance.
4) Polytetrafluoroethylene: This is a kind of filler widely used at present. Especially suitable for corrosive media, but the temperature should not exceed 200 ℃. Generally, it is made by pressing or bar stock car, and the shape is shown in Figure 5-1.
Figure 5-1
Name | Grade | Shape | Specifications | Applicable limit pressure | Applicable limit temperature | Purpose |
(diameter or square side length) | kgf/cm² | (℃) | ||||
Oil impregnated asbestos rope | YS450 | F |
3.4.5.6.8.10
13.16.19.22.25
|
60 | 450 | For 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 | ||
Table 5-2
Note: shape code f means square, through the center or one to multi-layer braiding; y means round, with a twisted core in the middle and one to multi-layer braiding on the outside; n means twisted.
Name | Grade | Specification (straight formula or square side length) | Applicable limit pressure kgf / cm 2 | Applicable limit temperature (℃) | Purpose |
Rubber | XS450 |
3 . 4 . 5 . 6 . 8
10 . 13 . 16 . 19
|
60 | 450 | For steam, petroleum products |
Asbestos | XS350 | 45 | 350 | ||
Packing | XS250 | 22 . 25 . 28 | 45 | 250 |
Table 5-3
Gasket material
The gasket is used to fill all the unevenness between the two joint surfaces (such as the sealing surface between the valve body and the valve cover), so as to prevent the medium from leaking from the joint surface.
Requirements for gaskets
The gasket material has certain elasticity and plasticity at working temperature and enough strength to ensure sealing. At the same time, it should have good corrosion resistance.
Types and selection of gasket materials
Gasket can be divided into soft and hard two kinds, soft generally for non-metallic materials, such as cardboard, rubber, asbestos rubber, PTFE, etc. Hard materials are generally metal materials or metal coated asbestos, metal and asbestos winding, etc.
There are many shapes of gaskets, including flat, round, oval, toothed, lens and other special shapes.
The metal gasket is made of 08, 10, 20 high-quality carbon steel and 1Cr13, 1Cr18Ni9 Stainless steel. It is suitable for high-temperature and high-pressure valves with high machining accuracy and surface finish.
Non metallic gasket material is generally good plasticity, with little pressure can achieve sealing. Suitable for low temperature and low pressure valves.
Gasket materials can be selected according to table 5-4.
Gasket material | Medium | Scope of application | |
Pressure (MPA) | Temperature (℃) | ||
Cardboard | Water and oil | ≤10 | 40 |
Oil impregnated paperboard | Water and oil | ≤10 | 40 |
Rubber sheet | Water, air | ≤6 | 50 |
Asbestos board | Steam, gas | ≤6 | 450 |
Teflon | Corrosive medium | ≤25 | 200 |
Rubber asbestos board xb-450 | Steam, air, gas | ≤60 | 450 |
XB-350 | Steam, air, gas | ≤40 | 350 |
XB-200 | Steam, air, gas | ≤15 | 200 |
Oil resistant rubber asbestos board | Oils | 160 | 30 |
08 steel and xb-450 filling | Steam | 100 | 450 |
08 steel and xb-350 filling | Steam | 40 | 350 |
1Cr13, 0Cr13 asbestos filling | Steam | 100 | 600 |
08 steel and oil resistant rubber asbestos filling | Oils | 100 | 350 |
Copper | Water vapor, air | 100 | 250 |
Aluminium | Water vapor, air | 64 | 350 |
#10 steel, #20 steel | Water vapor, oil | 200 | 450 |
1Cr13 | Steam | 200 | 550 |
1Cr13Ni9 | Steam | 200 | 600 |
Table 5-4
Table 5-5 common materials of valve internals
Interior material |
Applicable temperature / ℃ |
Interior material |
Applicable temperature / ℃ |
304 |
-268 – 316 |
Type 400 stainless steel 60RC |
-29–427 |
316 |
-268–316 |
17-4PH |
-40–427 |
Bronze |
-273–232 |
No.6 alloy steel (Co-Cr) |
-273–816 |
Inconel alloy |
-240–649 |
Electroless nickel plating |
-268–427 |
K Monel alloy |
-240–482 |
Chromium plating |
-273–316 |
Monel alloy |
-240–482 |
Nitrile rubber |
-40–93 |
Hastelloy alloy B |
-198–371 |
Fluororubber |
-23–204 |
Hastelloy alloy C |
-198–538 |
teflon |
200 |
titanium alloy |
-29–316 |
nylon |
-73–93 |
Nickel base alloy |
-198–316 |
polyethylene |
-73–93 |
No.20 alloy |
-46–316 |
Chloroprene rubber |
-40–82 |
Type 416 stainless steel 40RC |
-29–427 |
Schedule 5-6 Common materials and applicable temperature of valve sealing surface
Sealing surface material |
Applicable temperature / ℃ |
Hardness |
Applicable media |
Bronze |
-273~232 |
Water, sea water, air, oxygen, saturated steam, etc |
|
316L |
-268~316 |
14HRC |
Steam, water, oil, gas, liquefied gas, etc. with slight corrosion and no erosion |
17-4PH |
-40 – 400 |
40 – 45HRC |
Medium with slight corrosion but erosion |
Cr13 |
-101~400 |
37 – 42HRC |
Medium with slight corrosion but erosion |
Stellite Alloy |
-268~650 |
40 – 45HRC (normal temperature) 38HRC ( 650 ℃ ) |
Erosive and corrosive media |
Monel alloy KS |
-240~482 |
27 – 35HRC 30 – 38HRC |
Alkali, salt, food, acid solution without air, etc |
Hastelloy CB |
371 538
|
14HRC 23HRC |
Corrosive mineral acid, sulfuric acid, phosphoric acid, wet hydrochloric acid gas, no chloric acid solution, strong oxidizing medium |
-45.6~316 |
-253~427 |
Oxidizing medium and sulfuric acid of various concentrations |
Material list of cast iron valve stem, sealing surface, gasket, packing and fastener
Name |
Standard |
Material grade |
Remarks |
Stem |
ASTM A 182 |
F6a |
|
ASTM A 276 |
410 、420 |
||
GB/T 1220 |
1Cr13 、 2Cr13 |
||
Sealing surface |
GB/T 1176 |
ZCuZn25Al6Fe3Mn3 |
Cast aluminum brass |
ZCuZn38Mn2Pb2 |
Cast manganese brass |
||
ZCuAl9Mn2 、 ZCuAl10Fe3 |
Cast aluminum bronze |
||
GB/T 1220 |
1Cr13 、 2Cr13 、 1Cr18Ni9 、 1Cr18Ni9Ti |
||
Polytetrafluoroethylene( PTFE ) |
|||
Rubber |
|||
shim |
GB/T 3985 |
XB350 、 XB450 |
Rubber asbestos board |
1Cr13 / XB450 |
Spiral wound gasket |
||
GB/T 3985 |
1Cr18Ni9 / XB450 |
||
filler |
Polytetrafluoroethylene( PTFE ) |
||
JB/T 6617 |
Flexible graphite ring |
||
Screw fastener |
GB/T 699 |
Bolt 35 / Nut 25 |
|
GB/T 3077 GB/T 699 |
General valve material
General valve material API 600 Required trim material combination
Stem material type |
hardness HB |
Sealing surface |
||
Seal No |
Material type |
Hardness |
||
13Cr |
two hundred – two hundred and seventy-five |
1 |
13Cr |
≥HB250 |
4 |
13Cr |
≥HB750 |
||
5 or 5A |
HF |
≥HB350 |
||
6 |
13Cr/NiCu |
≥HB750/≥HB175 |
||
7 |
13Cr/13Cr |
≥HB250/≥HB750 |
||
8- 8A |
13Cr/HF |
≥HB250/≥HB350 |
||
18Cr-8Ni |
Not specified |
2 |
18Cr-8Ni |
Not specified |
25Cr-20Ni |
3 |
25Cr-20Ni |
||
Nickel copper alloy |
9 |
Nickel copper alloy |
||
11 or 11A |
Nickel copper alloy /HF |
Not specified /≥HB350 |
||
18Cr-8Ni-Mo |
10 |
18Cr-8Ni-Mo |
Not specified |
|
12 or 12A |
18Cr-8Ni-Mo/HF |
Not specified /≥HB350 |
||
19Cr-29Ni |
13 |
19Cr-29Ni |
Not specified |
|
14 or 14A |
19Cr-29Ni/HF |
Not specified /≥HB350 |
Common material combination of Internals
Stem material |
Sealing surface material |
Stem material |
Sealing surface material |
13Cr |
13Cr/13Cr |
321 |
321/321 |
13Cr |
13Cr/STL |
321 |
321/STL |
13Cr |
STL/STL |
321 |
STL/STL |
13Cr |
13Cr/Monel |
1Cr18Ni9Ti |
1Cr18Ni9Ti/1Cr18Ni9Ti |
17-4PH |
STL/STL |
1Cr18Ni9Ti |
1Cr18Ni9Ti/STL |
17-4PH |
17-4PH/17-4PH |
1Cr18Ni9Ti |
STL/STL |
Monel |
Monel/Monel |
1Cr18Ni12Mo2Ti |
1Cr18Ni12Mo2Ti/1Cr18Ni12Mo2Ti |
304 |
304/304 |
1Cr18Ni12Mo2Ti |
1Cr18Ni12Mo2Ti/STL |
304 |
304/STL |
1Cr18Ni12Mo2Ti |
STL/STL |
304 |
STL/STL |
twenty No.2 alloy |
twenty No.2 alloy /20 No.2 alloy |
316 |
316/316 |
Hastelloy B |
Hastelloy B /Hastelloy B |
316 |
316/STL |
Hastelloy C |
Hastelloy C /Hastelloy C |
316 |
STL/STL |
F51 |
F51/F51 |
304L |
304L/304L |
F51 |
F51/STL |
304L |
304L/STL |
38CrMoALA |
STL/STL |
304L |
STL/STL |
25Cr2MoIV A |
STL/STL |
316L |
316L/316L |
4Cr10Si2Mo |
STL/STL |
316L |
316L/STL |
4Cr14Ni14W2Mo |
STL/STL |
316L |
STL/STL |
Inconel |
Inconel/Inconel |
Common fastener materials
Stud |
Nut |
temperature max ℃ |
Stud |
Nut |
Temperature max ℃ |
35 |
25 |
425 |
0Cr18Ni9 |
0Cr18Ni9 |
600 |
35CrMo |
35、45 |
425 |
0Cr17Ni12Mo2 |
0Cr17Ni12Mo2 |
600 |
35CrMo |
30CrMo |
500 |
25Cr2Mo1VA |
25Cr2MoVA |
600 |
25Cr2MoVA |
30CrMo |
550 |
25Cr2MoVA |
35CrMo |
600 |
Matching of bolt and nut materials for American Standard valve
Bolt |
Nut |
Scope of application |
||
standard |
Brand |
standard |
Brand |
|
ASTM A 193 |
B7 |
ASTM A 194 |
2H |
-29-425℃ |
B7M |
2HM |
Anti sulfur valve of NACE standard at –29 – 425 ℃ |
||
B16 |
seven |
-29-593℃ |
||
B8 |
eight |
-196-700℃ |
||
B8M |
8M |
|||
ASTM A 320 |
L7 |
four |
-46 – 101 ℃ low temperature valve |
Source: China Valve Supplier: www.epowermetals.com
(Yaang Pipe Industry is a leading manufacturer and supplier of nickel alloy and stainless steel products, including Super Duplex Stainless Steel Flanges, Stainless Steel Flanges, Stainless Steel Pipe Fittings, Stainless Steel Pipe. Yaang products are widely used in Shipbuilding, Nuclear power, Marine engineering, Petroleum, Chemical, Mining, Sewage treatment, Natural gas and Pressure vessels and other industries.)
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