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.

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
		PTFE
		rubber
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 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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