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How to Select Gate Valve Materials

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The material selection of gate valve mainly depends on the fluid medium and working environment. According to the different medium and environment, the material selection is also different. Generally speaking, the material selection of valve is divided into three aspects; the sealing surface of valve disc, in which the valve body is generally made of carbon steel cast iron (gray cast iron ductile iron) stainless steel (304 316) and the valve plate is made of carbon steel stainless steel (304 316) dual phase steel (2507 316) Generally, the sealing surface of nylon coating lining fluorine has: NBR EPDM PDEF ppl. Customers can choose the corresponding material according to their actual needs. Please contact our sales staff and look forward to cooperating with you.

BODY

The body of gate valves below 2 inches is generally made of forged steel (the most common body material grades are ASTM A105 for high-temperature service, ASTM A350 for low-temperature service and, ASTM A182 F304/F316 for corrosive service).
The bodies of gate valves of bore sizes above 2 inches are, instead, made of cast steel (the main cast grades are ASTM A216 WCB for high-temperature service, ASTM A351 for low-temperature conditions and ASTM A351 CF8 and CF8M – i.e. stainless steel 304 and 316 gate valves).

TRIM

The removable and replaceable parts of the valve are collectively defined as “trim” (for a gate valve: seat, disc, backseat and, stem).
The API 600 specification foresees a number of standard trim combinations, as illustrated below

API TRIM # BASE MATERIAL MATERIAL FOR SEAT MATERIAL FOR DISC BACKSEAT
MATERIAL		 MATERIAL FOR STEM
1 410 410 410 410 410
2 304 304 304 304 304
3 F310 310 310 310 310
4 Hard 410 Hard 410 410 410 410
5 Hardfaced Stellite Stellite 410 410
5A Hardfaced Ni-Cr Ni-Cr 410 410
6 410 and Cu-Ni Cu-Ni Cu-Ni 410 410
7 410 and Hard 410 Hard 410 Hard 410 410 410
8 410 and Hardfaced Stellite 410 410 410
8A 410 and Hardfaced Ni-Cr 410 410 410
9 Monel Monel Monel Monel Monel
10 316 316 316 316 316
11 Monel Stellite Monel Monel Monel
12 316 and Hardfaced Stellite 316 316 316
13 Alloy 20 Alloy 20 Alloy 20 Alloy 20 Alloy 20
14 Alloy 20 and Hardfaced Stellite Alloy 20 Alloy 20 Alloy 20
15 304 and Hardfaced Stellite Stellite 304 304
16 316 and Hardfaced Stellite Stellite 316 316
17 347 and Hardfaced Stellite Stellite 347 347
18 Alloy 20 and Hardfaced Stellite Stellite Alloy 20 Alloy 20

MATERIAL SELECTION

TRIM RECOMMENDED SERVICE
13% Cr, Type 410 Stainless Steel For oil and oil vapors and general services with heat treated seats and wedges.
13% Cr, Type 410 plus Hardfacing Universal trim for general service requiring long service life up to 1100°F (593°C).*
Type 316 Stainless For liquids and gases which are corrosive to 410 Stainless Steel, up to 1000°F (537°C).*
Monel For corrosive service to 842°F (450°C) such as acids, alkalies, salt solutions, etc.
Alloy 20 For corrosive service such as hot acids -49°F to 608oF (-45°C to 320°C).
NACE Specially treated 316 or 410 trim combined optionally with B7M Bolts and
2HM nuts to meet NACE MR-01-75 requirements.
Full Stellite Full hard faced trim, suitable for abrasive & severe services up to 1200°F (650°C).