How to choose valves?

What are Valves?

As a general definition, valves are devices used to control, regulate and open/close the flow and/or the pressure of a pipeline and/or a piping system. Valves are highly critical and expensive components and one of the determining factors of pipelines reliability, safety, and performance.

There are many different types of valves, most often used in combination, which perform specific functions within the piping system or the pipeline.

The main types of valves used in the petrochemical and oil & gas industry are the following:

  • gate valve (API 600 cast gate, API 602 forged, API 603 cast stainless steel gate, API 6D expanding gate, API 6D slab gate valve, knife gate valve, pressure seal gate valve, etc.)
  • globe valve (BS 1873 cast globe valve, API 603 stainless steel globe valve, API 602 forged globe valve, y-globe valve, pressure seal globe valve…)
  • check valve (swing check valve, piston check valve, ball check valve, spring check valve, pressure seal check valve, etc.)
  • ball valve (floating, trunnion)
  • butterfly valve (concentric, double eccentric, triple eccentric)
  • strainers (y-shape, t-shape or basket strainers)
  • plug valve (API 6A plug valve, API 6D plug valve)
  • pinch valve
  • pressure relief/safety valve
  • diaphragm valve
  • control valves (ball, butterfly and globe type valve)
  • cryogenic valves (used when the operating temperature falls below 100° F – 73° C).
  • others less

Thousands of possible valve specifications are possible, originating from the combinations of mutliple parameters such as valve type, subtype, size (bore size and class), manufacturing norm (main ones are ANSI/ASME and EN/DIN), body and trim materials, type of valve operation (manual or actuated), etc. In terms of valve body construction, valves are classified in cast and forged type (forged bodies are used for valves below 2 inch. or for larger valves that require specific mechanical performance). Finally, valves may be operated manually (levers, wheels, gears) or via an automated actuator (the main types of actuators are: electric, pneumatic, hydraulic and gas over oil).

Standard valves are generally available on the market via distributors that stock products from global manufacturers. Custom, big-size and exotic materials valves follow instead the “make to order” manufacturing process and are sold directly from producers to end users and EPC contractors. The last distribution channel is the online valves websites, that are gaining traction for a couple of years.


The most common functions that can be executed by valves are:

  1. Start/stop the flow of the fluid (hydrocarbons, oil & gas, steam, water, acids) through the pipeline (example: gate type)
  2. Modulate the flow of the fluid through the pipeline (example: globe type)
  3. Control the flow of the fluid (control type)
  4. Change the direction of the flow (example 3-way ball)
  5. Regulate the pressure of a process (pressure reducing)
  6. Protect a piping system or a device (pump, motor, tank) from overpressures (safety or pressure relief) or back-pressures (check)


In this article, we illustrate the main types of valves used in the petrochemical and power generation industries:


Based on the movement of the disc, there are three main types of valves:

  • LINEAR MOTION: gate, globe, diaphragm, pinch, and check
  • ROTARY MOTION: butterfly valves, ball, plug, eccentric- and swing check
  • QUARTER TURN: valves that require approximately a quarter turn motion, from 0 to 90° of the stem to move from fully close to fully open position or vice versa.


1505908058 5447 Valve Gate - How to choose valves?

Gate valves open and close the flow of the fluid through the pipeline (and belong therefore to the family of the on-off valves). The wedge of the valve is positioned between two parallel (or oblique) seats positioned perpendicular to the flow. The fluid flows horizontally through gate valves and is not subject to pressure drops. Gate valves cannot be used to modulate and regulate the flow of the fluid, as the high speed of the fluid would damage the wedge and the seats of a partly open / partly closed gate valve. The main type of gate valves in the oil & gas industry are: API 600 (cast body carbon / alloy steel), API 603 (cast body stainless), API 6D (pipeline gate valve, expanding gate/slab gate type), API 602 (forged body gate valves), pressure seal gate valves (for high pressure applications). Knife-gate valves are the last type of gate valve with a very sharp sized and machined disc. Knife gate valves are manufactured according to the TAPPI standards. In terms of construction, gate valves may have rising / non-rising stems and different types of wedges (solid wedge, flexible wedge, and split wedge).


1505908060 2458 Valve Globe - How to choose valves?

Globe valves are used to regulate the fluid flowing through the pipeline (modulating valve) or in applications that require a frequent and quick opening/closing of the flow (as the movement required to close/open the valve is very short for this type of valve). Globe valves are available in various models (straight and y pattern), sizes and material grades (from cast steel to forged steel bodies) to cover the various requirements in terms of fluids, working temperatures, and pressures. A frequently asked question is what is the difference between gate and globe valves: gate valves are used to close/open the flow, whereas globe valves are used to modulate the flow. The most common types of globe valves in the petrochemical industry are BS 1873 (carbon/alloy cast body globe), API 603 (stainless steel cast body), API 602 (forged body). Pressure seal globes are used for high-pressure applications.


1505908061 6611 Valve Check - How to choose valves?

Check valves (also named “non-return”) are used to protect equipment as pumps, as they prevent potentially damaging backflows. These valves provide a tight seal as well as a fast closing in case of unwanted back-flows. The swing check type is the most common and is designed to produce a low-pressure drop in the pipeline. Compared to the API 600 type, widely used for petrochemical applications, API 603 valves are used with the corrosive media and abrasive conditions. High-pressure check valves are also available on the market, and they have pressure seal cover with different configurations. API 602 check valves (piston check, ball check) are made of forged steel. Dual plate check valves are special types that are used to protect pumps and compressors from potentially damaging backflows (they conform to the API 594 norm).


1505908060 1238 Valve Ball - How to choose valves?

Ball valves have a spherical disc that is able to modulate the flow of a fluid in the pipeline. The ball inside the valve has a hole through which the flow passes as the hole is aligned with the two ends of the device. Otherwise, when the hole is in a perpendicular position to the ends, the flow is interrupted. The lever of the valve is aligned to the position of the ball, so the open/close status is clearly visible. The two main types are the floating ball and the trunnion mounted type. Both types can be either side or top entry. Three-way ball valves and wafer ball valves are also available on the market. The key norm for ball valves is API 6D and BS 5351 (forged type). Ball valves, as well as butterfly valves and plug valves, belong to the quarter turn family. Stainless steel ball valves are used for corrosive pipeline applications. A specific type is the so-called “double block and bleed ball valves ” (DBB): they feature a double seating surface that seals the pressure on both sides of the device.


1505908061 2055 Valve Butterfly - How to choose valves?

Butterfly valves are used to cut off or modulate the flow of a fluid. Manual butterfly is often preferred to other valves as they are cheaper, lighter and easier to maintain (but for some application, actuated types are also available). The key part of this type of valve, the disc, is positioned at the center of the pipe and the disc is connected via a rod to an external actuator. Differently, from a ball valve, the disc is always present within the flow and creates a specific pressure drop. Resilient butterfly valves (otherwise defined “concentric”) have seats in soft material (EPDM, VITON, NBR, BUNA-N seats or similar) and have lowest pressure ratings than high-performance type (also called double eccentric). The third type that has a metal to metal seal is the triple eccentric type (a type that competes with ball valves for some applications). Butterfly valves used in petrochemical are manufactured in accordance with the API 609 Norm.


1505908061 1650 Valve Strainer - How to choose valves?

Y-strainers and basket strainers are used to filter solids from a fluid flowing in a pipeline by means of a perforated or wire-mesh filtering element (i.e. the strainer). These devices are relatively cheap equipment to protect downstream mechanical equipment from damages due to debris like rust, pipe scale, sediment, and other solids that flow together with the conveyed fluid. Strainers are available with both cast and forged body materials.


1505908058 5821 Valve plug - How to choose valves?

There are three different designs of plug valves. The short pattern design type has a compact face to face dimensions and port areas accounting for 40% to 60% of a full-bore valve. The regular pattern has a longer face to face dimensions and a port area of 50-70% the full-bore plug valves and is designed to provide minimal loss of flow. Full bore design has long face to face dimensions and a round port. This last configuration provides unrestricted flow and allows pigging operations of the pipeline. Modern plug valves are an evolution of a basic design that was developed back in the Roman empire. API 6A design is used for upstream operations.


1505908059 5483 Valve Pressure relief - How to choose valves?

The goal of a pressure relief valves (PRV or safety) is to release possible overpressures of specific equipment (example boilers, pressure vessels) or pipelines; they open automatically as a set pressure (or temperature) is exceeded and the overpressure is released. Pressure relief valves are available in most material grades from carbon steel to stainless steel and can manage overpressure of any fluid (hydrocarbons, gas, steam or water). One of the main components of this type of valves is the spring. PRV valves can be used as a safety valve or a relief valve depending on the application. What is the difference between a pressure relief valve and a safety valve? The term pressure relief to valves used to control overpressures in vessels that contain liquids (the opening of the valve is not sudden, but proportional to the increase of the pressure in the vessel). The term safety valve is instead used for mechanical devices that have compressed fluids or for vessels filled with gas (safety valves open all of a sudden, as the set pressure of the valve is reached). It is any way possible that these terms are interchangeable. Safety valves are available either in the API 526 and ASME construction.


A control valve is used to control parameters such as process pressure, temperature, level, flow, pressure. These valves open or close the flow (partly or totally) on the basis of signals captured by specific sensors that compare actual to target process values. Control functions can be implemented by globe, butterfly and ball valves. Solenoid valves generally provide control functions in a small size piping or instrumentation system.

Most of the above valves may have different types of connections with tubes and process equipment:

  • flanged: connected to other piping equipment by means of single or double flanges.
  • butt weld: connected to piping by welded joints
  • screwed (NPT connections): the connection is in this case screwed (typical for forged valves)
  • socket: connected by fillet welds


Valves are rather complex mechanical devices, consisting of multiple parts and components:


The body is a key part of any valve: it contains the other critical components and it has to withstand pressure loads from the connected piping system. Valve are joined to other piping components by different connections as, for instance, butt weld or socket weld, threaded or flanged types. The body can be manufactured out of cast steel or forged steel in a variety of shapes, designs and material grades. The most common grades are high temperature carbon steel, low temperature carbon steel and austenitic stainless steel (SS304, SS316, SS321, etc). For specific applications, special material grades with stronger corrosion resistance are used, such as super austenitic stainless steels (SMO 254), duplex and super duplex steels, and nickel alloys (Inconel, Incoloy, Hastalloy). For marine applications, non ferrous materials or alloys are used (Monel, cupronickel, aluminum bronze). Iron bodies are used in less critical applications as water distribution systems.


The bonnet is an another important part of most valves. When dismantled from the body, it allows the access to the internal components of the valve to execute maintenance activities or replacement of parts (such as the disc, seat, stem, etc).  Valve bonnets are available in many designs and models (the most typical are: bolted, round bolted, welded, pressure seal) and are manufactured in cast steel or forged steel (generally using the same material grade of the body). The bonnet is connected with the body by a threaded, bolted, or welded joint connections – and gaskets are used in between the body and the bonnet. Manufacturers strive to optimize the design of this part (to reduce the overall dimension of the device and to ensure that the connection is tight and leakage-proof).


The valve trim is a collective name for all the internal parts of the valve that can be removed and replaced and that have a direct contact with the fluid flowing through the pipeline. Typically, the trim includes components as the disc, the seat, the stem, the glands, the bushings and the sleeves needed to guide the stem (but the specific elements that constitute the trim of a valve depends on the valve type). The trim is a fundamental component of the performance and the operation of the valve and the trim materials combination shall be choosen with care. The most used trim combinations for gate, globe and check valves are defined by the API trim chart.


The disc is the part of the valve that opens, closes or modulate the flow of the fluid within the pipeline, depending on its relative position to the seat. In the case of a gate valve, the gate (wedge) is the disc of the valve (whereas the disc is called “ball” for ball valves).

After the body and the bonnet, the disc is the third most important element that determines the performance of the valve and its tight seal.  Discs are generally manufactured in forged steel and are often reinforced (hard faced) to enhance the mechanical properties of the base material.


Seats accommodate the movements of the disc, and valves may have one or multiple seats. Globe or a swing-check valve are fitted with one seat that, in connection with the disc, creates the seal that interrupts the flow of the fluid. Gate valves have instead two seats, one on the upper side and the other on the lower side of the valve. Seats are often hard-faced. A proper finish of the seats is required to ensure a good seal when the valve is in the closed position.


The stem of a valve is used to maneuver the valve (open / close) because it moves the disc inside the valve. The stem is linked to the valve actuator or to the manual hand wheel (or lever) at one end, and is connected to the valve disc on the other end. In the case of gate and globe valves, the stem exercises a linear motion on the disc, whereas for ball, butterfly and plug valves the disc rotates to open or close the valve (therefore such valves are called “quarter turn valves”). Stems are made of forged steel and are connected to the disc by threading or other means. To prevent the leakages of the valve, a proper finish of the stem surface is necessary.

There are five types of valve stems:

  • Rotary Stem: This is a standard type for ball, plug, and butterfly valves. A quarter-turn motion of the stem opens or closes the valve.
  • Sliding Stem: In this case the stem does not execute any rotation. The stem slides in and out the valve to open or close it. This design is common in hand-operated lever rapid opening valves. It is also used in control valves are operated by hydraulic or pneumatic cylinders.
  • Rising type with outside screw and yoke (“OS&Y”): the external side of the stem is threaded while the part of the stem which is inside the valve is plain. The threads of the stem are isolated from the medium by the packing. Two alternative designs are available. The “OS&Y” design is common for valves above 2″.
  • Rising type with an inside screw (“IS&Y”): The threaded part of the stem is positioned inside the valve body, whereas the stem packing lays outside. With this design, the stem threads are in touch with the medium flowing through the pipeline. Once rotated, the stem and the hand wheel rise together and open the valve.
  • Non-rising stem type with inside screw: The threaded part of the stem is inside the valve and does not rise. The valve disc floats on the stem, like a nut if the stem is rotated. Stem threads are in contact with the media of the pipeline, and as such, may be exposed to its corrosive impact. This is the reason why such design is used when the available space to position the valve is too narrow to permit linear movement, and the media does not cause erosion, corrosion or abrasion of the stem material.


1505908242 5406 Valvepacking - How to choose valves?

The gasket that seals the stem with the bonnet is called packing, and comprises the following components:

  • Gland follower, which is a sleeve that compresses the packing, by a gland into the stuffing box.
  • Gland, a type of bushing, which compresses the packing into the stuffing box.
  • Stuffing box, a chamber in which the packing gets compressed.
  • Packing, available in different materials, like PTFE, elastomers, fibrous material, etc.
  • A backseat is a seating inside the bonnet. The backseat provides a seal between the stem and bonnet and prevents system pressure from building against the valve packing once the valve is fully open. Back seats are often used in gate and globe valves.
  • The valve packaging shall be properly designed and manufacture to minimize the possible damages to the stem and minimize the risk of leakages of fluids. On the other hand, it is necessary to observe that a too tight packing may affect the stem.


An hand operated or manual valve is generally equipped with a hand wheel that can be rotated clockwise or counter-clockwise to open and / or close the valve (typical for gate and globe valves). Ball, plug or butterfly are actuated using a lever (manual quarter turn valves).

In the following cases, it is not either possible nor advisable to use manual valves:

  • Large dimension valves that operate at high pressures
  • Valves that need to be controlled from a remote location
  • Valves that require, for the nature of the process, a very fast open or close operation

In all these cases, a valve actuator is needed. The actuator produces linear and rotary motion able to open ot close a valve (the actual movement depends of course on the type of the valve, linear or quarter turn). The main types of valves actuators are:

  • Gear Actuators
  • Electric actuators
  • Pneumatic actuators (pneumatic control valves use this type frequently)
  • Hydraulic actuators
  • Gas over oil actuators
  • Solenoid Actuators


There are three main types of valve end (that impact the way a valve can be connected to a pipe or other mechanical devices in the piping arrangement). Valves should be tightly connected to pipes to ensure a tight sealing. The most used types of pipe/valve connections are:


A flanged connection requires the use of two flanges with the related bolts, nuts, and washers. Flanged connections are widely used in pipeline systems regardless the pressure and the bore of the valves and the connected pipes. Flanged connections are generally a cheap solution to join pipes with valves


In case of welded connections, the valve is welded directly onto the pipe. This type of connection is generally more expensive but ensures a good protection against leakages. Weld connections are used in high-pressure pipelines and can be of two types, butt weld and socket weld (the valve has a socket and the pipe is welded therein, generally in case of pipelines below 2 inches of diameter).


In this case, the valve is connected to the pipe by a thread (tapered thread). This type of connection is generally used for low-pressure pipelines with bore size lower than 2 inches. It is also a very cheap connection, because no other material, then the pipe and the valve are necessary, and no flanges, no bolts, and no weld operation are needed. In case of leakage, however, repair chances are limited for threaded connections.

Based on the materials of construction:

The valves could also be classified based on the materials of construction. There can be any number of combinations possible with the materials of construction. It is for the piping engineer to select the same in consultation with the process engineer to suit the process fluid.

The environment in which the valves are installed is also to be considered for selection of materials of construction. However, the most commonly available materials are:

  • Cast Iron
  • Bronze
  • Gun metal
  • Carbon Steel
  • Stainless Steel
  • Alloy Carbon Steel
  • Poly Propylene UHMW-PE,UHMW-HDPE etc
  • Special Alloys


ASME B16.34 Valves Flanged, Threaded and Welding End applies to new construction. It covers pressure-temperature ratings, dimensions, tolerances, materials, nondestructive examination requirements, testing, and marking for cast, forged, and fabricated flanged, threaded, and welding end and wafer or flangeless valves of steel, nickel-base alloys, and other alloys.  Wafer or flangeless valves, bolted or through-bolt types, that are installed between flanges or against a flange are treated as flanged-end valves.  Alternative rules for NPS 2½ and smaller valves are given in Mandatory Appendix V.

This Standard is to be used in conjunction with equipment described in other volumes of the ASME B16 Series of Standards as well as with other ASME standards, such as the Boiler and Pressure Vessel Code and the B31 Piping Codes. Careful application of these B16 standards will help users to comply with applicable regulations within their jurisdictions, while achieving the operational, cost and safety benefits to be gained from the many industry best-practices detailed within these volumes.


The ASME valve standard B16.34 is a standard accepted globally by end-users, engineering contractors, and valve mills as the cornerstone reference to design valves, test them and assess operational performance. Back in 1988, the scope of this standard was modified to include threaded-end and weld-end valves in addition to flanged-end valves. It is often used as a minimum requirement when purchasing valves internationally, to make sure that minimum requirements are met. ASME B16.34 is also mentioned in the more general ASME spec ASME B31.1, “Power Piping Design”.

When does a valve comply to ASME B16.34?

  • Body & shell materials comply with ASME and ASTM material standards for chemistry and strength
  • Body & shell materials are heat-treated to ensure proper grain structure, corrosion resistance, and hardness.
  • Wall thicknesses of body and other pressure-containing components meet ASME B16.34 specified minimum values for each pressure class.
  • NPT and SW end connections comply with ASME B1.20.1 or ASME B16.11.
  • Stems are internally loaded and blowout proof.
  • All bolting will be ASTM grade with maximum applied stress controlled by B16.34.
  • Each valve is shell tested at 1,5x rated pressure for a specific test time duration.
  • Each valve is tested for seat leakage in both directions for a specific test time duration.
  • Each valve is permanently tagged with materials of construction, operating limits and name of the manufacturer.

Any buyer shall check with the manufacturer the compliance of the offered valves to ASME B16.34 before placing a purchase order.

ASME B16.34 classifies also the material grades for forged and cast valves, matching them with other critical material grades used for the manufacturing of piping products. ASME B16 34 classified materials in 3 main groups (carbon / alloy steel, stainless steel and nickel-alloy steel). Find following the matching tables proposed by the norm:


Material Material Nominal Forging Casting Plate Bar Tubular
Group No. Designation
1.1 C A216 Gr. WCB A675 Gr. 70 A672 Gr. B70
C-SI A105 A515 Gr. 70 A105 A672 Gr. C70
C-MN-SI A350 Gr. LF2 A516 Gr. 70 A350 Gr. LF2
A537 Gr. Cl.1 A696 Gr. C
C-MN-SI-V A350 Gr. LF6 Cl.1
1.2 C-SI A106 Gr. C
2 1/2NI A352 Gr. LC2 A203 Gr. B
3 1/2NI A350 Gr. LF3 A352 Gr. LC3 A203 Gr. E A350 Gr. LF3
C-MN-SI A216 Gr. WCC
A352 Gr. LCC
C-MN-SI-V A350 Gr. LF6 Cl.2
1.3 C A352 Gr. LCB A675 Gr. 65
C-SI A515 Gr. 65 A672 Gr. B65
2 1/2NI A203 Gr. A
3 1/2NI A203 Gr. D
C-MN-SI A516 Gr. 65 A672 Gr. C65
1.4 C A675 Gr. 60 A106 Gr. B
C-SI A515 Gr. 60 A672 Gr. B60
A350 Gr. LF1 A672 Gr. C60
C-MN-SI A516 Gr. 60 A350 Gr. LF1
A696 Gr. B
1.5 C-1/2MO A182 Gr. F1 A217 Gr. WC1 A204 Gr. A A182 Gr. F1 A691 Gr. CM-70
A352 Gr. LC1 A204 Gr. B
1.6 C-1/2MO A335 Gr. P1
A369 Gr. FP1
1/2CR-1/2MO A387 Gr. 2 Cl.1 A691 Gr. 1/2CR
A387 Gr. 2 Cl.2
1CR-1/2MO A387 Gr. 12 Cl.1
1.7 C-1/2MO A204 Gr. C A691 Gr. MC-75
1/2CR-1/2MO A182 Gr. F2 A182 Gr. F2
NI-1/2CR-1/2MO A217 Gr. WC4
3/4NI-MO-3/4CR A217 Gr. WC5
1.8 1CR-1/2MO A387 Gr. 12 Cl.2 A691 Gr. 1CR
A335 Gr. P12
A369 Gr. FP12
1 1/4CR-1/2MO-SI A387 Gr. 11 Cl.1 A691 Gr. 1 1/4CR
A335 Gr. P11
A369 Gr. FP11
2 1/4CR-1MO A387 Gr. 22 Cl.1 A691 Gr. 2 1/4CR
A335 Gr. P22
A369 Gr. FP22
1.9 1CR-1/2MO A182 Gr. F12 Cl.2 A182 Gr. F12 Cl.2
1 1/4CR-1/2MO-SI A182 Gr. F11 Cl.2 A387 Gr. 11 Cl.2 A182 Gr. F11 Cl.2
1 1/4CR-1/2MO A217 Gr. WC6 A739 Gr. B11
1.1 2 1/4CR-1MO A182 Gr. F22 Cl.3 A217 Gr. WC9 A387 Gr. 22 Cl.2 A182 Gr. F22 Cl.3
A739 Gr. B22
1.11 3CR-1MO A182 Gr. F21 A387 Gr. 21 Cl.2 A182 Gr. F21
MN-1/2MO A302 Gr. A & B
MN-s1/2MO-1/2NI A302 Gr. C
MN-1/2MO-3/4NI A302 Gr. D
C-MN-SI A537 Gr. CL2
1.12 5CR-1/2MO A387 Gr. 5 Cl.1 A691 Gr. 5CR
A387 Gr. 5 Cl.2 A335 Gr. P5
A369 Gr. FP5
5CR-1/2MO-SI A335 Gr. P5b
1.13 5CR-1/2MO A182 Gr. F5a A217 Gr. C5 A182 Gr. F5a
A182 Gr. F5 A182 Gr. F5
1.14 9CR-1MO A182 Gr. F9 A217 Gr. C12 A182 Gr. F9
1.15 9CR-1MO-V A182 Gr. F51 A217 Gr. C12A A387 Gr. 91 Cl.2 A182 Gr. F91 A335 Gr. P91


         Material   Material Nominal Forging Casting Plate Bar Tubular
Group No. Designation
2.1 18CR-8NI A182 Gr. F304 A351 Gr. CF3 A240 Gr. 304 A182 Gr. F304 A312 Gr. TP304
A182 Gr. F304H A351 Gr. CF8 A240 Gr. 340H A182 Gr. F304H A312 Gr. TP304H
A479 Gr. 304 A358 Gr. 304
A479 Gr. 304H A376 Gr. TP304
A376 Gr. TP304H
A430 Gr. FP304
A430 Gr. FP304H
2.2 16CR – 12N I- 2MO A182 Gr. F316 A240 Gr. 316 A182 Gr. F316 A312 Gr. TP316
A182 Gr. F316H A240 Gr. 316H A182 Gr. F316H A312 Gr. TP316H
A479 Gr. 316 A358 Gr. 316
A479 Gr. 316H A376 Gr. TP316
A376 Gr. TP316H
A430 Gr. FP316
18CR-8NI A351 Gr. CF3A A430 Gr. FP316H
A351 Gr. CF8A A240 Gr. 317
18CR – 13NI – 3MO A312 Gr. TP317
16CR – 12NI – 2MO A351 Gr. CF3M
A351 Gr. CF8M
19CR – 10NI – 3MO A351 Gr. CG8M
2.3 18CR – 8NI A182 Gr. F304L A240 Gr. 304L A182 Gr. F304L A312 Gr. TP304L
A479 Gr. 304L
16CR -12NI – 2MO A182 Gr. F316L A240 Gr. 316L A182 Gr. F316L A312 Gr. TP316L
A479 Gr. 316L
2.4 18CR – 10N I- TI A182 Gr. F321 A240 Gr. 321 A182 Gr. F321 A312 Gr. TP321
A182 Gr. F321H A240 Gr. 321H A479 Gr. 321 A312 Gr. TP321H
A182 Gr. F321H A358 Gr. 321
A479 Gr. 321H A376 Gr. TP321
A376 Gr. TP321H
A430 Gr. FP321
A430 Gr. FP321H
2.5 18CR – 10NI – CB A182 Gr. F347 A351 Gr. CF8C A240 Gr. 347 A182 Gr. F347 A312 Gr. TP347
A182 Gr. F347H A240 Gr. 347H A182 Gr. F347H A312 Gr. TP347H
A182 Gr. F348 A240 Gr. 348 A182 Gr. F348 A358 Gr. TP347
A182 Gr. F348H A240 Gr. 348H A182 Gr. F348H A376 Gr. TP347
A479 Gr. 347 A376 Gr. TP347H
A376 Gr. TP348
A479 Gr. 347H A430 Gr. FP347
A479 Gr. 348 A430 Gr. FP347H
A479 Gr. 348H A312 Gr. TP348
A312 Gr. TP348H
2.6 25CR-12NI A351 Gr. CH8
A351 Gr. CH20
23CR-12NI A240 Gr. 309S A312 Gr. TP309H
A240 Gr. 309H A358 Gr. 309H
2.7 25CR-20NI A182 Gr. F310H A351 Gr. CK20 A240 Gr. 310S A182 Gr. F310H A312 Gr. TP310H
A240 Gr. 310H A479 Gr. 310H
A479 Gr. 310S A358 Gr. 310H
2.8 20CR – 18NI – 6MO A182 Gr. F44 A351 Gr. CK3MCuN A240 Gr. S31254 A312 Gr. S31254
A479 Gr. S31254 A358 Gr. S31254
22CR – 5NI- 3MO – N A182 Gr. F51 A240 Gr. S31803 A479 Gr. S31803 A789 Gr. S31803
A479 Gr. S32750 A790 Gr. S31803
25CR – 7NI – 4MO -N A182 Gr. F53 A240 Gr. S32750 A789 Gr. S32750
A790 Gr. S32750
24CR-10NI – 4MO – V A351 Gr. CE8MN
25CR – 5NI -2 MO -2CU A351 Gr. CD4MCu
25CR- 7NI -3.5MO -W-CB A351 Gr. CD3MWCuN A789 Gr. S32760
25CR – 7NI-3.5 MO – N- CB -W A182 Gr. F55 A240 Gr. S32760 A790 Gr. S32760


        Material Material Nominal Forging Casting Plate Bar Tubular
Group No. Designation
3.1 35NI-35FE-20CR-CB B462 Gr. N08020 B463 Gr. N08020 B473 Gr. N08020 B464 Gr. N08020
B468 Gr. N08020
3.2 99NI B160 Gr. N02200 B162 Gr. N02200 B160 Gr. N02200 B161 Gr. N02200
B163 Gr. N02200
3.3 99NI-Low C B160 Gr. N02201 B162 Gr. N02201 B160 Gr. N02201
3.4 67NI-30CU B564 Gr. N04400 B127 Gr. N04400 B164 Gr. N04400 B165 Gr. N04400
B163 Gr. N04400
67NI-30CU-S B564 Gr. N04405 B164 Gr. N04405
3.5 72NI-15CR-8FE B564 Gr. N06600 B168 Gr. N06600 B166 Gr. N06600 B167 Gr. N06600
B163 Gr. N06600
3.6 33NI-42FE-21CR B564 Gr. N08800 B409 Gr. N08800 B408 Gr. N08800 B163 Gr. N08800
3.7 65NI-28MO-2FE B335 Gr. N10665 B333 Gr. N10665 B335 Gr. N10665 B662 Gr. N10665
3.8 54NI-16MO-15CR B564 Gr. N10276 B575 Gr. N10276 B574 Gr. N10276 B622 Gr. N10276
60NI-22CR-9MO-3.5CB B564 Gr. N06625 B443 Gr. N06625 B446 Gr. N06625
62NI-28MO-5FE B335 Gr. N10001 B333 Gr. N10001 B335 Gr. N10001 B622 Gr. N10001
70NI-16MO-7CR-5FE B573 Gr. N10003 B434 Gr. N10003 B573 Gr. N10003
61NI-16MO-16CR B574 Gr. N06455 B575 Gr. N06455 B574 Gr. N06455 B622 Gr. N06455
42NI-21.5CR-3MO-2.3CU B425 Gr. N08825 B424 Gr. N08825 B425 Gr. N08825 B423 Gr. N08825
3.9 47NI-22CR-9MO-18FE B572 Gr. N06002 B435 Gr. N06002 B572 Gr. N06002 B622 Gr. N06002
3.1 25NI-47FE-21CR-5MO B672 Gr. N08700 B599 Gr. N08700 B672 Gr. N08700
3.11 44FE-25NI-21CR-MO B649 Gr. N08904 B625 Gr. N08904 B649 Gr. N08904 B677 Gr. N08904
3.12 26NI-43FE-22CR-5MO B621 Gr. N08320 B620 Gr. N08320 B621 Gr. N08320 B622 Gr. N08320
47NI-22CR-20FE-7MO B581 Gr. N06985 B582 Gr. N06985 B581 Gr. N06985 B622 Gr. N06985
3.13 49NI-25CR-18FE-6MO B581 Gr. N06975 B582 Gr.N06975 B581 Gr. N06975 B622 Gr. N06975
NI-FE-CR-MO-CU-Low C B564 Gr. N08031 B625 Gr. N08031 B649 Gr. N08031 B622 Gr. N08031
3.14 47NI-22CR-19FE-6MO B581 Gr. N06007 B582 Gr. N06007 B581 Gr. N06007 B622 Gr. N06007
3.15 33NI-2FE-21CR B564 Gr. N08810 B409 Gr. N08810 B408 Gr. N08810 B407 Gr. N08810
NI-MO B494 Gr. N-12MW
NI-MO-CR B494 Gr. CW-12MW
3.16 35NI-19CR-1 1/4SI B511 Gr. N08330 B536 Gr. N08330 B511 Gr. N08330 B535 Gr. N08330
3.17 29NI-20.5CR-3.5CU-2.5MO A351 Gr. CN-7M


What is the face to face dimension? In a valve (or fitting), the face to face to face dimension is the distance in mm from the face of the inlet port to the face of the outlet port.

CLASS 150 | CLASS 300 | CLASS 600 | CLASS 900 | CLASS 1500 | CLASS 2500

face to face valve - How to choose valves?


150# Ball Long Pattern Ball Short Pattern Gate Solid Wedge and Double Disc Gate Conduit Plug Short Pattern Plug Regular Pattern Plug Venturi Pattern Plug Round Port Full Bore Globe Lift and Swing Check Y-Globe and Y-Swing Check
1/2 108 108 108 108 140
3/4 117 117 117 117 152
1 127 127 127 140 176 127 165
1 1/4 140 140 140 140 184
1 1/2 165 165 165 165 222 165 203
178 178 178 178 178 178 267 203 229
190 190 190 190 190 298 216 279
3 203 203 203 203 203 203 343 241 318
4 229 229 229 229 229 305 229 432 292 368
5 254 254 381 356
6 394 267 267 267 267 394 394 406 470
8 457 292 292 292 292 457 457 495 597
10 533 330 330 330 330 533 533 622 673
12 610 356 356 356 356 610 610 698 775
14 686 381 381 381 686 686 787
16 762 406 406 406 762 762 914
18 864 432 432 864 864 978
20 914 457 457 914 914 978
22 508 1067
24 1067 508 508 1067 1067 1295
26 559 559 1295
28 610 610 1448
30 610 660 1524
32 711
34 762 1016
36 711 813 1956


300# Ball Long Pattern Ball Short Pattern Gate Solid Wedge and Double Disc and Conduit Plug Short and Venturi Pattern Plug Regular Pattern Plug Round Port Full Bore Globe and Lift Check Swing Check
1/2 140 140 140 152
3/4 152 152 152 178
1 165 165 165 159 190 203 216
1 1/4 178 178 178 216 229
1 1/2 190 190 190 190 241 229 241
216 216 216 216 282 267 267
241 241 241 241 330 292 292
3 282 282 282 282 387 318 318
4 305 305 305 305 457 356 356
5 381 400 400
6 403 403 403 403 403 559 444 444
8 502 419 419 419 502 686 559 533
10 568 457 457 457 568 826 622 622
12 648 502 502 502 711 965 711 711
14 762 572 762 762 762 838
16 838 610 838 838 838 864
18 914 660 914 914 914 978
20 991 711 991 991 991 1016
22 1092 1092 1092 1092 1118
24 1143 813 1143 1143 1143 1346
26 1245 1245 1245 1245 1346
28 1346 1346 1346 1346 1499
30 1397 1397 1397 1397 1594
32 1524 1524 1524 1524
34 1626 1626 1626 1626
36 1727 1727 1727 1727 2083


600# Ball Long Pattern Gate Solid Wedge and Double Disc and Conduit Long Pattern Plug Regular and Venturi Pattern Plug Round Port Full Bore Globe Lift Check and Swing Check Long Pattern
1/2 165 165 165
3/4 190 190 190
1 216 216 216 254 216
1 1/4 229 229 229 229
1 1/2 241 241 241 318 241
292 292 292 330 292
330 330 330 381 330
3 356 356 356 444 356
4 432 432 432 508 432
5 508 508
6 559 559 559 660 559
8 660 660 660 794 660
10 787 787 787 940 787
12 838 838 838 1067 838
14 889 889 889 889
16 991 991 991 991
18 1092 1092 1092 1092
20 1194 1194 1194 1194
22 1295 1295 1295 1295
24 1397 1397 1397 1397
26 1448 1448 1448 1448
28 1549 1549 1600
30 1651 1651 1651 1651
32 1778 1778 1778
34 1930 1930 1930
36 2083 2083 2083 2083


900 # Gate Solid Wedge and Double Disc and Conduit Long Pattern Plug Regular and Venturi Pattern Plug Round Port Full Bore Globe Lift Check and Swing Check Long Pattern Ball Long Pattern
3/4 229
1 254 254 254 254
279 279 279 279
305 305 356 305 305
2 368 368 381 368 368
419 419 432 419 419
3 381 381 470 381 381
4 457 457 559 457 457
5 559 559
6 610 610 737 610 610
8 737 737 813 737 737
10 838 838 965 838 838
12 965 965 1118 965 965
14 1029 1029 1029
16 1130 1130 1130 1130
18 1219 1219 1219
20 1321 1321 1321 1321
24 1549 1549 1549


1500# Gate Solid Wedge Double Disc and Conduit Long Pattern Plug Regular and Venturi Pattern Plug Round Port Full Bore Globe Lift Check and Swing Check Short Pattern Ball Long Pattern
1/2 216
3/4 229
1 254 254 254
279 279 279
305 305 305
2 368 368 391 368 368
419 419 454 419 419
3 470 470 524 470 470
4 546 546 625 546 546
5 673 673
6 705 705 787 705 705
8 832 832 889 832 832
10 991 991 1067 991 991
12 1130 1130 1219 1130 1130
14 1257 1257 1257
16 1384 1384 1384 1384
18 1537 1537
20 1664 1664
24 1943 1943


2500# Gate Solid Wedge Double Disc and Conduit Long Pattern Plug Regular Pattern Globe Lift Check and Swing Check Long Pattern Ball Long Pattern
1/2 264 264
3/4 273 273
1 308 308 308
349 349
384 384 384
2 451 451 451 451
508 508 508 508
3 578 578 578 578
4 673 673 673 673
5 794 794 794
6 914 914 914 914
8 1022 1022 1022 1022
10 1270 1270 1270 1270
12 1422 1422 1422 1422

How to choose a valve?

The valve is a control component in the fluid delivery system, with diversion, shutoff, regulation, throttling, to prevent backflow, the valve is a control component in the fluid delivery system, with diversion, shutoff, regulation, throttling, reverse flow, Overflow relief and other functions. The valve acts as an important control element for the pipe. Pipeline system

Choose the most suitable valve is very important, related to the safety of the pipeline, loss of traffic, cost, etc., must be familiar with the characteristics of the valve and select the valve steps and basis.

At present, China’s valve industry has been able to produce a wide range of gate valves, globe valves, check valves, ball valves, butterfly valves, throttle valves, plug valves, diaphragm valves, safety valves, regulating valves, traps and special valves; The maximum working pressure is 600MPa, the maximum nominal diameter of 5350mm, the maximum working temperature of 1200 ℃, the minimum working temperature of -196 ℃, the media for water, steam, oil, natural gas, strong corrosive media (such as concentrated nitric acid, Concentration of sulfuric acid, etc.), flammable media (such as stupid, ethylene, etc.), toxic media (such as hydrogen sulfide), explosive media and radioactive media (metal sodium, – pure water, etc.). Stainless steel cast iron, cast iron, forged steel, high and low alloy steel, stainless steel acid resistance, Hastelloy alloy,

Inquire nickel ore, Monel alloy, duplex stainless steel, titanium and so on. And to supporting the production of various electric, pneumatic, hydraulic valve drive device.

In the face of such a large number of valve varieties and such a variety of complex conditions, to choose the most suitable for the installation of the pipeline system valve products, first of all should understand the characteristics of the valve; Second, the master should select the steps and basis of the valve; the rules.

How to order valves?

To correctly specify a valve to suppliers, the following details have to be provided:

  • Valve family (example ball valve), subfamily (example ball/trunnion) and exact type (ball/trunnion/top entry)
  • Bore size, generally expressed in NPS or DN (main bore and reducing bore, if applicable)
  • Valve rating/class (class range from 150# to 4500#)
  • Manufacturing norm (example API 6D)
  • Body material/trim material/packing etc
  • Testing requirements
  • Type of connection (flanged, threaded, butt weld, lug and others)
  • Fluid in the pipeline (>oil, gas, water, steam, solids)
  • Working temperature
  • Working pressure
  • Quantity
  • Delivery time
  • Origin restrictions

Source: China Valves Manufacturer – Yaang Pipe Industry Co., Limited (

(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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