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Valve material and valve standards-(6)-gasket material

Valve 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 bonnet) to prevent the medium from leaking between the joint surfaces.

lug type butterfly valve, ductile iron, center lined,

lug type butterfly valve, ductile iron, center lined,

1. Requirements for gaskets: The gasket material has a certain degree of elasticity, plasticity and sufficient strength at working temperature to ensure sealing. At the same time, it must have good corrosion resistance.

2. Types and selection of gasket materials: gaskets are divided into two types: soft and hard. The soft is generally non-metallic materials, such as cardboard, rubber, asbestos rubber sheet, and PTFE. Hardness is generally metal material or metal-coated asbestos, metal and asbestos entangled, etc.

There are many forms of gaskets, including flat, round, oval, tooth-shaped, lens-shaped and other special shapes.
Metal gaskets are generally made of 08, 10, 20 high-quality carbon steel and 1Cr13, 1Cr18Ni9 stainless steel, which require high machining accuracy and surface finish, and are suitable for high temperature and high pressure valves.
Non-metallic gasket materials generally have good plasticity and can be sealed with less pressure, which is suitable for low temperature and low pressure valves.
The gasket material can be selected according to Table 5-4.

Gasket material medium Pressure/Mpa Temp/°C
cardboard water, oil ≤10 40
Oil-impregnated cardboard water, oil ≤10 40
rubber board water,air ≤6 50
asbestos board steam, gas ≤6 450
PTFE corrosive ≤25 200
rubber asbestos board XB-450 water steam, air, gas ≤60 450
XB-350 water steam, air, gas ≤40 350
XB-250 water steam, air, gas ≤15 200
Oil-resistant rubber asbestos sheet oil 160 30
08 steel and XB-450 filling steam 100 450
08 steel and XB-350 filling steam 40 350
1Cr13,0Cr13 and asbestos filling steam 100 600
08 steel and oil-resistant rubber and asbestos filling oil 100 350
copper water steam,air 100 250
aluminium water steam,air 64 350
10steel, 20steel water steam, oil 2– 450
1Cr13 steam 200 550
1Cr3Ni9 steam 200 600

Attached Table 1-2 Common Materials for Valve Trim:

internal parts material suitable temp/°C internal parts material suitable temp/°C
304 -268/316 SS440 60RC -29/427
316 -268/316 17-4PH -40/427
bronze -273/232 6 alloy(Co-Cr) -273/816
inconel alloy -240/649 Electroless Nickel -268/427
K monel alloy -240/482 chrome -273/316
monel alloy -240/482 NBR -40/93
hastelloy B -198/371 Viton -23/204
hastelloy C -198/538 PTFE 200
Titanium alloy -29/316 Nylon -73/93
Nickel alloy -198/316 Polyethylene -73/93
20 alloy -46/316 Neoprene -40/82
SS416 40RC -29/427

Attached Table 1-3 Common materials and operating temperature of valve sealing surface:

Sealing surface material temp range / °C hardness suitable medium
bronze -273/232 water, seawater, air,oxygen,saturated vapor
316L -268/316 14HRC Slightly corrosive and non-impact media like steam, water, oil, gas,liquid gas
17-4PH -40/400 40-50HRC slightly corrosive and impact medium
Cr13 -101/400 37-42HRC slightly corrosive and impact medium
Stellite alloy -268/650 40-45HRC (normal temp); 38HRC (650°C) impact and corrosive medium
Monel alloy KS -240/482 27-35HRC, 30-38HRC Air-free acid solution like alkali, salt,food
Hastelloy CB 371, 538 14HRC, 23HRC Corrosive mineral acid, sulfuric acid, phosphoric acid, wet hydrochloric acid gas, chlorine-free acid solution, strong oxidizing medium
20 alloy -45.6/316 36-61HRC Oxidizing medium and various concentrations of sulfuric acid

Material table of stem, sealing surface, gasket, packing and fastener of cast iron valve:

name standard material name remarks
Vlave stem ASTM A182 F6a
ASTM A276 410,420
GB/T 1220 1Cr13, 2Cr13
sealing surface GB/T 1176 ZCuZn25A15Fe3Mn3 Cast aluminum brass
ZCuZn38Mn2Pb2 Cast manganese brass
ZCuS19Mn2, ZCuAl10Fe3 cast aluminum bronze
GB/T 1220 1Cr13,2Cr13,1Cr18Ni9,1Cr18Ni9Ti
gasket GB/T 3985 XB350,XB450 rubber asbesto sheet
1Cr13/XB450 Spiral wound gasket
GB/T 3985 1Cr18Ni9/XB450
filler PTFE
JB/T 6617 flexible graphite ring
fastener GB/T 699 bolt 35/nut25
GB/T 3077, GB/T 699 bolt 30CrMo, 35CrMo/nut 35,45

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-(5)-packing material;
Valve material and valve standards-(9)- general valve & parts materials;
What is the material of the main parts of the butterfly valve?-(1);
Fasteners, fillers and gasket materials of valves;