Valves are mechanical devices able to control, regulate and interrupt the flow and the pressure of a pipeline or a process that conveys liquids, gasses, vapors, slurries, etc. A valve is an essential component of a piping system and one of the most critical components determining its reliability, safety, and performance.
COMMON TYPES OF VALVES
The main types of valves are gate valves, globe valves, check valves, ball valves, butterfly valves, y strainers, basket strainers, plug valves, pinch, pressure relief and safety valves, diaphragm valves etc. Each type has then several subtypes (example ball valves may be floating or trunnion). A valve may be self-operated or manual or actuated (electric, pneumatic, hydraulic actuators and gas over oil actuators are available). Piping designers shall choose the correct valve type, size, rating, construction materials (body and trim) by analyzing the required valve functions within the piping system, the type of media to be conveyed (oil, gas, water, steam, solids) and the working pressure and working temperature of the pipeline.
VALVES BASIC FUNCTIONS
Valves may be used to execute the following basic functions:
- Start/stop the flow of a fluid like hydrocarbons, gas, steam, water, acids (on/off)
- Reduce/increase a fluid flow
- Control the direction of a fluid flow (control valve)
- Regulate a flow or the pressure of a petrochemical process
- Protect a piping system in case of overpressures (pressure relief valve, safety valve)
FLANGED, WELDED AND THREADED CONNECTIONS
To operate properly, valves shall be connected to pipes to ensure that the pipeline doesn’t leak. The three main pipe/valve connections are summarized in the table below:
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
WELDED ENS (SOCKET, BUTT WELD)
In case of welded connections, the valve is welded directly onto the pipe. This type of connection is generally more expensive but guarantees 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, the repair chances are limited in case of threaded connections.
Generally, a valve is manufactured by assembling the following key parts: the body, the bonnet, the trim, the actuator and the packing:
The body, sometimes called the shell, is a key component of a pressure valve. It serves as the main element of a valve assembly because it keeps the other parts together. The body shall resist fluid pressure loads from the connecting piping system. Valve ends are designed to connect the valve to the piping or the nozzles using several types of connections, as for instance butt weld or socket weld, threaded or flanged. Valve bodies may be manufactured out of cast steel or forged steel in a variety of forms and material grades. The most common are Carbon steel, austenitic stainless steel (SS304, SS316, SS321, etc), superaustenitic stainless steels (SMO 254), duplex and super duplex stainless steels, martensitic stainless steel, duplex, Inconel, Incoloy, Monel, non ferrous materials such as aluminum bronze or less noble materials as cast iron.Back to top
The bonnet (sometimes called “valve cover”) is the second most important element of a valve, after the body, to have a good seal of the valve and pressure rating. One of the key scopes of the bonnet is to allow the access to the internal parts of the valve (disc, seat, stem, etc) if the maintenance of the valve is required. Alike the body of the valve, bonnets are available in many designs and models (the most typical are: bolted bonnet, round bolted bonnet, welded bonnet, pressure seal bonnet). Bonnets are manufactured in cast steel or forged steel, and the same material of the body valve is used. The bonnet is connected to the body of the valve by a threaded, bolted, or welded joint connection – and gaskets are used to ensure a tight seal. Manufacturers strive to optimize the bonnet design and its tightness. Bonnets are indeed an important element of the overall valve design and have a direct impact on the manufacturing and assembly process as well as on the overall size and dimensions of the valve. Furthermore, bonnets represent a remarkable portion of overall cost of a valve.Back to top
The valve trim is a collective name for all the parts of the valve that can be substituted or replaced in case of maintenance of the valve. Typically, the trim includes components as the disc, the seat, the stem and the sleeves needed to guide the stem (but the trim composition may vary from valve to valve, example the trim of a gate valve differs from the trim of a ball valve). Valves performance is impacted by the quality of the disc / seat interface. The trim allows a valve to control the fluid flow: in the case of valves where the trim executes a rotational motion, the disc slides on the seat determines specific outlets for the flow (ball valves); in the cas of valves that have linear motion trims (example gate valves) the disc slides perpendicularly on the seat to open or close the flow of the fluid.Back to top
The disc is the component that permits, throttles or stops the flow of the fluid, depending on its relative position to the seat. In the case of a plug or a ball valve, the disc is named plug or a ball.
The disc is the third most important primary pressure part of a valve, after the body and the bonnet. When the valve is closed, the disc shall withstand the full pressure of the fluid. Discs are generally manufactured out of forged steel, and in some designs, are hard faced to provide stronger wear properties to the valve. Most valves are named by the specific design of their disc.Back to top
Seats accommodate the movements of the disc, and valves may have one or multiple seats. Globe or a swing-check valve usually have one seat that, in connection with the disc, creates a seal able to stop the flow of the fluid. Gate valves instead have two seats, one on the upper side and the other on the bottom side. To enhance the wear resistance of the seats their surface is often hard-faced by welding and the contact surface of the seal rings are finely machined. A proper finish of the seating area surface is required to have a good seal when the valve is in the closed position. Seal rings are not usually considered pressure retaining parts of the valve.Back to top
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:
- 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.
- 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.
- 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.
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.
A 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 desirable use a manual valve:
- 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 most commonly used valve actuators are:
- Gear Actuators
- Electric actuators
- Pneumatic actuators (pneumatic control valves use this type frequently)
- Hydraulic actuators
- Gas over oil actuators
- Solenoid Actuators
Rotork actuators and Auma actuators have the largest marketshares within the petrochemical industry.
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Vallves can be classified based on the specific movement of the disc:
- LINEAR MOTION VALVES: Valves in which the closing element moves in a straight line to allow, stop, or throttle the flow (gate, globe, diaphragm, pinch and check Valves)
- ROTARY MOTION VALVES: Valves in which the closing element moves with an angular or a circular path, as it happens for butterfly valves, ball, plug, eccentric- and swing check valves
- QUARTER TURN VALVES: Those are the 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.
More in detail, the main types of petrochemical valves (API valves, ASME valves, EN valves) are:
Gate valves are designed to manage the cut off of a fluid's flow (on-off). Gate valves close / open the flow of the fluid by the slide of a gate, that is called wedge, between two parallel or oblique seats rings positioned perpendicular to the flow. The flow, in the case of a gate valve, is horizontal and straight through; therefore, frictional losses (pressure drops) are low. Gate valves are not suited to modulate the flow as the high speed of the fluid may create damage at the wedge and the seats when the valve is partly open. Under normal conditions, the valve remains either fully open or fully closed. The installation of a gate valve is independent of the flow direction. Knife gate valves are special types of gate valves. In specific cases, pressure seal gate valves are used.Back to top
Globe valves are on / off valves in which the disc moves on and off the seat, therefore the port is open or closed in proportion to the motion and position of the disc. Globe valves are used to regulate the flow rate of the fluid in the pipeline. Globe valves are also suited for on/off duties that require the frequent opening and closing of the flow, due to the short distance of the disc between the open and the closed position. Globe valves are unidirectional valves and are installed so that fluid pressure happens under the disc. Globe valves are supplied in various models, sizes and material grades to cover the various requirements in terms of fluids, working temperatures and pressures. A last consideration about gate valve vs globe valves: gate valves are generally preferred for on/off functions, whereas globe valves are used for flow modulation. For high pressure applications, pressure seal globe valves are generally used to modulate the flow of the media.Back to top
Check valves (also called non-return valve) are typically used to protect equipment as pumps, as they impede the reversal of the flow in case of pipelines back pressures. Check valves provide a tight seal as well as a fast closing reaction in case of unwanted back-flows. Swing type check valves are the most common type of check valves and are designed to produce a low-pressure drop in the pipeline. Compared to API 600 design, widely used for petrochemical applications, API 603 are suited with the corrosive media and abrasive conditions normally happening within the fine chemical processes. High-pressure check valves are also available on the market, and they have pressure seal cover with different configurations. Dual plate valves are generally considered within the check valves family of valves.Back to top
Ball valves are fitted with a spherical disc, that controls the flow of the fluid in the pipeline. Indeed, the ball has a hole through which the flow passes once the hole is aligned with the two ends of the valve. Otherwise, when the hole is in a perpendicular position to the valve ends, the flow is closed. The lever of the valve is aligned to the position of the ball, so the open / close status of a ball valve is clearly visible. The two main types of ball valves are the floating ball valves and the trunnion mounted ball valves. Floating ball valves have no support for the ball, whereas the ball of trunnion ball valves is held in place by a support (trunnion). Both types can be side entry or top entry. Three-way ball valves (3-way ball valve) are also available on the market.
Ball valves, as well as butterfly valves and plug valves, belong to the family of quarter turn valves.Back to top
Butterfly valves are used to cut off or modulate a fluid's flow. They are preferred to other valves since they are cheaper and lighter. The key part of a butterfly 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. A butterfly valve is classified as a quarter-turn valve. Resilient butterfly valves (otherwise defined “concentric butterfly valves”) have seats in sodt material (EDPM, VITON, NBR, BUNA-N seats or similar) and have lowest pressure ratings than high-performance valves (also called double eccentric butterfly valves). A third type of butterfly valve that has a metal to metal seal is the triple eccentric butterfly valves (sometimes also called triple offset butterfly valve). Butterfly valves used in petrochemical are manufactured in accordance with the API 609 Norm.Back to top
Y STRAINER and BASKET STRAINER
Y-strainers are used to filter solids from a the fluid flowing in a pipeline by using a perforated or wire mesh filtering element (i.e. the strainer). Strainers are relatively cheap means of protecting downstream mechanical equipment from damages due to debris like rust, pipe scale, sediment, and other solids that may flow together with the conveyed fluid.Back to top
There are three different designs of plug valves. Short pattern design plug valves have a compact face to face dimensions and port areas accounting for 40% to 60% of a full bore plug valve. Regular pattern plug valves have longer face to face dimensions and a port area of 50-70% the full bore plug valves and are designed to provides minimal loss of flow. Full bore design: full bore plug valves have long face to face dimensions and round port that above the minimum diameter specified in the annex of ASME B16.34 or/and API 6D. This configuration provides unrestricted flow and allows pigging operations of the pipeline. The industrial plug valve is one of the oldest types of valves, the first applications are found back during the times of the Roman Empire.Back to top
PRESSURE RELIEF VALVE
The goal of a pressure relief valves (PRV valve or safety valve) is to release over pressures happening within equipment (example boilers, pressure vessels) or pipelines; indeed pressure relief valves 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 are suitable to manage over pressure of any fluid (hydrocarbons, gas, steam or water). One of the main components of pressure relief valves is the spring. PRV valves can be used as a safety valve or a relief valve depending on the application.Back to top
VALVES CONTROL VALVES
A control valve, otherwise defined as flow control valve, is used to control parameters such as process pressure, temperature, level, flow, pressure. Control valves open or close the flow (partly or totally) on the basis of signals captured by specific sensors that compare actual process to target values. Control functions can be attributed to globe valves (globe control valve or “S-shaped” control valve), butterfly (butterfly control valve) and ball valves (ball control valve). Solenoid valves generally provide control functions in a piping system.Back to top
VALVES DIMENSION AND WEIGHTS
|VALVE TYPE||NPS||RATING / CLASS|
|CAST BODY||1/4 ’’- 64’’ (and above)||The pressure / temperature rating of a valve is defined by the valve class.
ASME B16.34 foresees three types of classes: standard, special, and limited. ASME B16.34 designates classes 150, 300, 400, 600, 900, 1500, 2500, and 4500 valves.
|FORGED BODY||3/8’’ and above|
API, ASME, BS VALVE NORMS
|GATE VALVE||API 600, API 603, API 6D latest edition, ASME B16.34 latest revision, TAPPI (knife gate).|
|GLOBE VALVE||BS 1873, API 603, ASME B16.34|
|CHECK VALVE||API 594 (dual plate check valve), API 603, BS 1868|
|GATE, GLOBE, CHECK VALVE (FORGED)||API 602-ISO 15761, ASME B16.34, BS 5351/5352|
|BALL VALVE||API 6D, ASME B16.34, BS 5351|
|BUTTERFLY VALVE||API 609, MSS SP 67, MSS SP 68|
|PLUG VALVE||API 6A, API 6D|
|PRESSURE RELIEF API||API 526|
Main ASME norms related to valves:
- ASME B16.10 Valves’ face to face dimension: This Standard covers the face-to-face dimensions of straight flow valves as well as the end center-to-face and center-to-end dimensions of angular flow valves. The scope of the norm is to ensure standardization and interchangeability of valves produced by different factories.
- ASME B16.34 Flanged, Threaded and Welded Ends Valves: This standard refers to the construction, the dimensions, the tolerances, the materials, the nondestructive examination, the testing and marking for cast and forged valves. The norm applies to valves with any end connection, such as flanged, threaded, wafer, flangeless and any material grade such as steel, nickel-base alloys, and other alloys.
VALVES DESIGN AND MANUFACTIRING STANDARDS ISO, ASME, API
|ISO 5208:1993||Pressure testing of valves - Industrial|
|ISO 5209:1977||Marking - General purpose industrial valves|
|ISO 5752:1982||Metal valves for use in flanged pipe systems - Face-to-face and centre-to-face dimensions|
|ISO 5996:1984||Cast iron gate valves|
|ISO 6002:1992||Bolted bonnet steel gate valves|
|ISO 7121:1986||Flanged steel ball valves|
|ISO 7259:1988||Key-operated cast iron gate valves for underground use|
|ISO 10423:2003||API 6A||Wellhead and Christmas Tree Equipment Specification|
|ISO 10434:2004||API 600||Bolted bonnet steel gate valves for the petroleum, petrochemical and allied industries|
|ISO 10497:2004||API 607||Testing of valves - Fire type-test requirements (Fire Test for Soft-Seated Quarter-Turn Valves)|
|ISO 10631:1994||Metallic butterfly valves for general purposes|
|ISO 12149:1999||Bolted bonnet steel globe valves for general-purpose applications|
|ISO 14313||API 6D||Specification for Pipeline Valves|
|ISO 15156||NACE MR0175||NACE MR0175, Petroleum and natural gas industries - Materials for use in H2S-containing environments in oil and gas production|
|ISO 15761:2002||API 602 - (Incorporates BS5352)||Steel gate, globe and check valves for sizes DN 100 and smaller, for the petroleum and natural gas industries|
|ISO 15848-1:2006||Industrial valves - Measurement, test and qualification procedures for fugitive emission Part 1: Classification system and qualification procedures for type testing of valves|
|ISO 17292:2004||Metal ball valves for petroleum, petrochemical and allied industries|
|API 591||User Acceptance of Refinery Valves|
|API 598||Valve Inspection and Testing|
|API 600||Steel Gate Valves|
|API 602||Compact Carbon Steel Gate Valves|
|API 603||Cast, Corrosion Resistant Gate Valves|
|API 608||Metal Ball Valves-Flanged, Threaded and Butt-Welding Ends (150&300)|
|API 17D||Specification for Subsea Wellhead and Christmas Tree Equipment|
|API 6FA||Specification for Fire Test for Valves|
|API 622||Type Testing of Process Valve Packing for Fugitive Emissions|
|ASME B16.34||Valves 2 Flanged, Threaded, and Buttwelded End|
|ASME B16.10||Face-to-Face and End-to-End Dimensions of Valves|
|ASME B16.5||Pipe Flanges and Flanged Fittings|
|ASME B16.25||Buttwelded Ends|
|ASME B16.11||Forged Fittings, Socket Welding and Threaded|
VALVES FACE TO FACE DIMENSIONS ASME B16.10 (in mm)
ASME B16.10 CLASS 150
|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|
ASME B16.10 CLASS 300
|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|
ASME B16.10 CLASS 600
|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|
ASME B16.10 CLASS 900
|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|
ASME B16.10 CLASS 1500
|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|
ASME B16.10 CLASS 2500
|2500#||Gate Solid Wedge Double Disc and Conduit Long Pattern||Plug Regular Pattern||Globe Lift Check and Swing Check Long Pattern||Ball Long Pattern|
P&ID SYMBOLS FOR VALVES
VALVES MATERIAL GRADES
COMMON CASTING MATERIALS FOR PETROCHEMICAL VALVES
|COMMON DESIGNATION||ASTM CASTING||SERVICE|
|Carbon Steel||ASTM A216 Grade WCB||Non-corrosive fluids as water, oil and gases at temperatures range -20°F (-30°C) and +800°F (+425°C)|
|Low Temp Carbon Steel||ASTM A352 Grade LCB||Low temperature to -50°F (-46°C). Use excluded above +650°F (+340°C).|
|Low Temp Carbon Steel||ASTM A352 Grade LC1||Low temperature to -75°F (-59°C). Use excluded above +650°F (+340°C).|
|Low Temp Carbon Steel||ASTM A352 Grade LC2||Low temperature to -100°F (-73°C). Use excluded above +650°F (+340°C).|
|3.1/2% Nickel Steel||ASTM A352 Grade LC3||Low temperature to -150°F (-101°C). Use excluded above +650°F (+340°C).|
|1.1/4% Chrome 1/2% Moly Steel||ASTM A217 Grade WC6||Non-corrosive fluids as water, oil and gases at temperatures range -20°F (-30°C) and +1100°F (+593°C).|
|2.1/4% Chrome||ASTM A217 Grade C9||Non-corrosive fluids as water, oil and gases at temperatures range -20°F (-30°C) and +1100°F (+593°C).|
|5% Chrome 1/2% Moly||ASTM A217 Grade C5||Mild corrosive or erosive applications and non-corrosive applications at temperatures between -20°F (-30°C) and +1200°F (+649°C).|
|ASTM A217 Grade C12||Mild corrosive or erosive applications and non-corrosive applications at temperatures between -20°F (-30°C) and +1200°F (+649°C).|
|12% Chrome Steel||ASTM A487 Grade CA6NM||Corrosive application at temperatures between -20°F (-30°C) and +900°F (+482°C).|
|12% Chrome||ASTM A217 Grade CA15||Corrosive application at temperatures up to +1300°F (+704°C)|
|316SS||ASTM A351 Grade CF8M||Corrosive or either extremely low or high temperature non-corrosive services between -450°F (-268°C) and +1200°F (+649°C). Above +800°F (+425°C) specify carbon content of 0.04% or greater.|
|347SS||ASTM 351 Grade CF8C||Mainly for high temperature, corrosive applications between -450°F (-268°C) and +1200°F (+649°C). Above +1000°F (+540°C) specify carbon content of 0.04% or greater.|
|304SS||ASTM A351 Grade CF8||Corrosive or extremely high temperatures non-corrosive services between -450°F (-268°C) and +1200°F (+649°C). Above +800°F (+425°C) specify carbon content of 0.04% or greater.|
|304L SS||ASTM A351 Grade CF3||Corrosive or non-corrosive services to +800F (+425°C).|
|316L SS||ASTM A351 Grade CF3M||Corrosive or non-corrosive services to +800F (+425°C).|
|Alloy-20||ASTM A351 Grade CN7M||Good resistance to hot sulfuric acid to +800F (+425°C).|
|Monel||ASTM 743 Grade M3-35-1||Weldable grade. Good resistance to corrosion by all common organic acids and salt water. Also highly resistant to most alkaline solutions to +750°F (+400°C).|
|Hastelloy B||ASTM A743 Grade N-12M||Well suited for handling hydrofluoric acid at all concentrations and temperatures. Good resistance to sulphuric and phosphoric acids to +1200°F (+649°C).|
|Hastelloy C||ASTM A743 Grade CW-12M||Good resistance to span oxidation conditions. Good properties at high temperatures. Good resistance to sulphuric and phosphoric acids to +1200°F (+649°C).|
|Inconel||ASTM A743 Grade CY-40||Very good for high temperature service. Good resistance to spanly corrosive media and atmosphere to +800°F (+425°C).|
|Bronze||ASTM B62||Water, oil or gas: up to 400°F. Excellent for brine and seawater service.|
CHEMICAL COMPOSITION ASTM A216 – CARBON STEEL CASTINGS SUITABLE FOR FUSION WELDING
ASTM A216 grade WCB chemical composition
|Composition, % max|
|WCA UNS J02502||0.25(1)||0.70(1)||0.04||0.045||0.60||0.30||0.50||0.50||0.20||1.00|
|WCB UNS J03002||0.30(2)||1.00(2)||0.04||0.045||0.60||0.30||0.50||0.50||0.20||1.00|
|WCC UNS J02503||0.25(3)||1.20(3)||0.04||0.045||0.60||0.30||0.50||0.50||0.20||1.00|
- For each reduction of 0.01% below the specified maximum Carbon content, an increase of 0.04% manganese above the specified maximum is allowed up to a maximum of 1.10%.
- For each reduction of 0.01% below the specified maximum Carbon content, an increase of 0.04% Mn above the specified maximum is allowed up to a maximum of 1.28%.
- For each reduction of 0.01% below the specified maximum Carbon content, an increase of 0.04% manganese above the specified maximum is allowed to a maximum of 1.40%.
CHEMICAL COMPOSITION ASTM A351 – CASTINGS AUSTENITIC STAINLESS STEEL FOR PRESSURE CONTAINING PARTS
|Composition. % (max. except whers range is given)|
|CF8C||J92710||0.08||1.5||2.0||0.040||0.040||18.0-21.0||9.0-12.0||0.50||( 1 )|
|CF10MC||0.10||1.50||1.50||0.040||0.040||15.0-18.0||13.0-16.0||1.7-2.25||( 2 )|
- Grade CF8C shall have a Niobium content 8 times above the Carbon but not over 1.00%.
- Grade CF10MC shall have a Niobium content 10 times above the Carbon but not over 1.20%.
COMMON FORGING MATERIALS FOR PETROCHEMICAL VALVES
|ASTM DESIGN||DESCRIPTION||SERVICE||CASTING COMPARISON|
|A105(1)||Carbon Steel||General service such as oil, oil vapor, gas, steam and water at temperatures -20°F to 1000°F (-28°C to 537°C).||A216-WCB|
|A350-LF2 CL1||Low Temperature Carbon Steel||Suitable for temperatures -50°F and not above 650°F (-46°C and not above 343°C).||A352-LCB|
|A182-F11 CL2||1 1/4% Cr, 1/2% Mo Alloy Steel||High temperatures from -20°F to 1100°F to minimize graphitization (-28°C to 593§C).||A217-WC6|
|A182-F22 CL3 (2)||2 1/4% Cr, 1% Mo Alloy Steel||For services requiring greater strength than F11 at temperatures from -20°F to 1100°F (-28°C to 593°C).||A217-WC9|
|A182-F5||5% Cr, 1/2% Mo Alloy Steel||For corrosive/erosive refinery use requiring resistance at temperatures from -20°F to 1100§F (-28°C to 590°C).||A217-C5|
|A182-F9||9% Cr, 1% Mo Alloy Steel||For services involving media with higher Sulphur content to combat oxidation to 1100oF (593°C).||A217-C12|
|A182-F304||18% Cr, 8% Ni Stainless Steel||For corrosive services and atmospheres from -450°F to 1000°F (-268°C to 537°C).||A351-CF8|
|A182-F316||18% Cr, 8% Ni, 2% Mo Stainless Steel||For superior resistance to corrosion from -450°F to 1000°F (-268°C to 537°C).||A351-CF8M|
- Allowed but not recommended for long term use above 800oF (425oC)
- Warning to the possibility of excessive oxidation (scaling) when used above 1050oF (563oC)
SPECIAL FORGING MATERIALS FOR PETROCHEMICAL VALVES
(C2, C4, B2, C276…)
|Nickel Alloy||Good high temperature properties. Excellent corrosion resistance in hydrochloric acid.|
|INCONEL 600 / INCONEL 625 / INCOLOY 800||Nickel Alloy||For high temperature service. Nuclear applications.|
|MONEL 400 / MONEL K500||Nickel-Copper Alloy||For corrosive service up to 842oF (450oC). Resistant to sea water, acids, alkalies.|
|TITANIUM GR 1-GR 11||Transition Metal||Good resistance to corrosion together with low specific weight.|
|ASTM A182 F20||Alloy 20 - Specialty Alloy||For corrosive service such as hot sulphuric acid. Resists -49oF to 600oF (-45oC to 316oC).|
|ASTM A182 F51||Ferritic-Austenitic Stainless Steel||Very high strength, resistance to corrosion, pitting and stress corrosion in chloride media.|
|ASTM A182 F44||Austenitic Stainless Steel||Very high strength, high resistance to corrosion.|
CHEMICAL COMPOSITION ASTM A105 – CARBON STEEL FORGINGS FOR PIPING APPLICATIONS
|0.35 max||0.60-1.05||0.035 max||0.040
- The total of Cu, Ni, Niobium, Moly and Vanadium shall not exceed 1.00%.
- The sum of Niobium and Molybdenum shall not exceed 0.32%.
CHEMICAL COMPOSITION ASTM A182 FORGED STAINLESS STEEL FOR VALVES
|F316Ti||0.08||2.0||0.045||0.030||1.0||10.0-14.0||16.0-18.0||2.0-3.0||(3)||N 0.10 max|
- Grades F304, F304L, F316, and F316L shall have a maximum Nitrogen of 0.10%.
- Grades F304N, F316N, F304LN, and F316LN shall have a Nitrogen of 0.10 to 0.16%.
- Grade F316Ti shall have a Titanium content five times above the Carbon plus Nitrogen and not more than 0.70%.
- Grade F321 shall have a Titanium content five times above the Carbon and not more than 0.70%.
- Grade F321H shall have a Titanium content four times above the Carbon and not more than 0.70%.
- Grades F347 and F348 shall have a Niobium content ten times above the Carbon and not more than 1.10%.
- Grades F347H and F348H shall have a Niobium content above than eight times the Carbon and not more than 1.10%.
API 600 VALVE TRIM CHART
|API TRIM #||MATERIAL||SEAT||DISC||BACKSEAT||STEM|
|4||Hard 410||Hard 410||410||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|
|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|
VALVE SERVICE AND TRIM SELECTION
|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).*|
* Depends upon base material grade
COMPARISON CHART ASTM, DIN BODY/BONNET MATERIALS
|Carbon Steel||CS||C-Mn-Fe||K03504||A105N||A216-WCB||C22.8 DIN 17243||1.0460||General non-corrosive service from -20F(-29C) to 800F(427C)|
|Low Temperature Carbon Steel||LTCS||C-Mn-Fe||K03011||A350-LF2||A352-LCA A352-LCB A352-LCC||TSTE 355 DIN 18103||1.0566||General non-corrosive service from -50F
(-46C) to 650F(340C), LF2 to 800F(427C).
|Low Temperature Alloy Steel||Nickel Steel||3.1/2Ni||K32025||A350-LF3||A352-LC3||10Ni14||1.5637||-150F(-101C) to 650F(340C)|
|Low Alloy Steel||Moly Steel||C-1/2Mo||K12822||A182-F1||A217-WC1||15MO3||1.5415||Up to 875F (468C)|
|Alloy Steel Chrome Moly||1.1/4Cr-1/2Mo||K11572||A182-F11 cl2||A217-WC6||13CRMO44||1.7335||Up to 1100F (593C)|
|2.1/4Cr-1Mo||K21590||A182-F22 cl3||A217-WC9||10CRMO910||1.7380||Up to 1100F(593C), HP steam|
|5Cr-1/2Mo||K41545||A182-F5||A217-C5||12CRMO195||1.7362||High temp refinery service|
|9Cr-1Mo||K90941||A182-F9||A217-C12||X 12 CrMo 9 1||1.7386||High temp erosive refinery service|
|9Cr-1Mo-V||A182-F91||A217-C12A||X 10 CrMoVNb 9 1||1.4903||High pressure steam|
|Stainless Steel||Austenitic S.Steel 300 series S.Steel||304 : 18Cr-8Ni||S30400||A182-F304||A351-CF8||DIN X5CrNi 18 9||1.4301||0.04% min. carbon for temp.>1000F(538C)|
|304L : 18Cr-8Ni||S30403||A182-F304L||A351-CF3||X 2 CrNi 19 11||1.4306||Up to 800F(427C)|
|316 : 16Cr-12Ni-2Mo||S31600||A182-F316||A351-CF8M||DIN X5CrNiMo 18 10||1.4401||0.04% min. carbon for temp.>1000F(538C)|
|316L : 16Cr-12Ni-2Mo||S31603||A182-F316L||A351-CF3M||X 5 CrNiMo 17 12 2||1.4404||Up to 800F(427C)|
|316Ti:||S31635||A182-F316Ti||X 6 CrNiMoTi 17 12 2||1.4571|
|321: 18Cr-10Ni-Ti||S32100||A182-F321||X 6 CrNiTi 18 10||1.4541||0.04% min. carbon (grade F321H) and heat treat at 2000F(1100C) for service temps.>1000F(538C)|
|347: 18Cr-10Ni-Cb(Nb)||S34700||A182-F347||A351-CF8C||DIN 8556||1.4550||0.04% min. carbon (grade F347H) and heat treat at 2000F(1100C) for service temps.>1000F(538C)|
|Alloy 20||28Ni-19Cr-Cu-Mo||N08020||A182-F20||A351-CN7M||DIN 1.4500||2.4660||service to 600F(316C)|
|Duplex 2205||22Cr-5Ni-3Mo-N||S31803 S32205||A182-F51||A890-J92205||X2CrNiMON22-5-3 DIN 10088-1 (95)||1.4462||service to 600F(316C) -The original S31803 UNS designation has been supplemented by S32205 which has higher minimum N, Cr, and Mo.|
|Super Duplex 2507||25Cr-7Ni-4Mo-N||S32750||A182-F53||A351-CD4MCu A890 5A||X2CrNiMoN25-7-4 DIN 10088-1 (95)||1.4501||service to 600F(316C)|
|Super Austenitic 6Mo||20Cr-18Ni-6Mo||S31254||A182-F44||A351-CK3MCuN||X1CrNiMoCuN20-18-7 DIN 10088-1 (95)||1.4547||service to 600F(316C)|
|Nickel-Iron Alloy||Incoloy 800||33Ni-42Fe-21Cr||N08800||B564-N08800||X10NiCrAlTi32-20||1.4876||service to 1000F(538C)|
|Incoloy 825||42Ni-21.5Cr-3Mo-2.3Cu||N08825||B564-N08825||A494-CU5MCuC||DIN 17744||2.4858||service to 600F(316C) for N02200, 1200F(648C) for N02201|
|Nickel-Copper||Monel 400||67Ni-30Cu||N04400||B564-N04400||A494-M35-1||DIN 17730||2.4360|
|Nickel-Alloy||904L||N08904||904L||n/a||Z2 NCDU 25-20||1.4539|
|Nickel Superalloys||Inconel 600||72Ni-15Cr-8Fe||N06600||B564-N06600||A494-CY40||DIN 17742||2.4816|
|Inconel 625||60Ni-22Cr-9Mo-3.5Cb||N06625||B564-N06625*||A494-CW-6MC||2.4856||*Difficult to forge in close dye|
|Hastelloy C-276||54Ni-15Cr-16Mo||N10276||B564-N10276*||A494-CW-2M||NiMo 16 Cr 15 W||2.4819||*Difficult to forge in close dye|
PIPING ASTM GRADES (PIPES, BUTT WELD FITTINGS, FORGED FITTINGS, VALVES, BOLTS)
|MATERIAL||PIPES||BW FITTINGS||FORGINGS||VALVES||BOLT SETS|
|Carbon Steel||A106 Gr A||A234 Gr WPA||A105||A216 Gr WCB||A193 Gr B7
A194 Gr 2H
|A106 Gr B||A234 Gr WPB||A105||A216 Gr WCB|
|A106 Gr C||A234 Gr WPC||A105||A216 Gr WCB|
|A335 Gr P1||A234 Gr WP1||A182 Gr F1||A217 Gr WC1||A193 Gr B7
A194 Gr 2H
|A335 Gr P11||A234 Gr WP11||A182 Gr F11||A217 Gr WC6|
|A335 Gr P12||A234 Gr WP12||A182 Gr F12||A217 Gr WC6|
|A335 Gr P22||A234 Gr WP22||A182 Gr F22||A217 Gr WC9|
|A335 Gr P5||A234 Gr WP5||A182 Gr F5||A217 Gr C5|
|A335 Gr P9||A234 Gr WP9||A182 Gr F9||A217 Gr C12|
|A333 Gr 6||A420 Gr WPL6||A350 Gr LF2||A352 Gr LCB||A320 Gr L7
A194 Gr 7
|A333 Gr 3||A420 Gr WPL3||A350 Gr LF3||A352 Gr LC3|
|A312 Gr TP304||A403 Gr WP304||A182 Gr F304||A182 Gr F304||A193 Gr B8
A194 Gr 8
|A312 Gr TP316||A403 Gr WP316||A182 Gr F316||A182 Gr F316|
|A312 Gr TP321||A403 Gr WP321||A182 Gr F321||A182 Gr F321|
|A312 Gr TP347||A403 Gr WP347||A182 Gr F347||A182 Gr F347|
MECHANICAL PROPERTIES OF COMMON VALVES MATERIALS
|Material Code and Description||Minimum Physical Properties||Modulus||Approximate|
|(psi)||Point (psi)||in 2" (%)||of Area (%)|
|1||Carbon Steel||ASTM A216 Grade WCB||70,000||36,000||22||35||27.9||137-1 87|
|2||Carbon Steel||ASTM A352 Grade LCB||65,000||35,000||24||35||27.9||137-1 87|
|3||Chrome Moly Steel||ASTM A217 Grade C5||90,000||60,000||18||35||27.4||241 Max.|
|4||Carbon Moly Steel||ASTM A217 Grad e WC1||65,000||35,000||24||35||29.9||215 Max.|
|5||Chrome Moly Steel||ASTM A217 Grade WC6||70,000||40,000||20||35||29.9||215 Max.|
|6||Chrome Moly Steel||ASTM A217 Grade WC9||70,000||40,000||20||35||29.9||241 Max.|
|7||3 1/2% Nickel Steel||ASTM A352 Grade LC3||65,000||40,000||24||35||27.9||137|
|8||Chrome Moly Steel||ASTM A217 Grade C12||90,000||60,000||18||35||27.4||180-240|
|9||Stainless Steel Type 304||ASTM A351 Grade CF-8||65,000||28,000||35||-||28||140|
|10||Stainless Steel Type 316||ASTM A351 Grade CF-8M||70,000||30,000||30||-||28.3||156-170|
|11||Cast Iron||ASTM A126 Class B||31,000||-||-||-||-||160-220|
|12||Cast Iron||ASTM A126 Class C||41,000||-||-||-||-||160-220|
|13||Ductile Iron||ASTM A395 Type 60-45-15||60,000||45,000||15||-||23-26||143-207|
|14||Ductle Ni-Resist Iron (500 KG Load)||ASTM A439 Type D-2B||58,000||30,000||7||-||-||148-211|
|15||Standard Valve Bronze||ASTM B62||30,000||14,000||20||17||13.5||55-65*|
|16||Tin Bronze||ASTM B143 Alloy 1A||40,000||18,000||20||20||15||75-85*|
|17||Manganese Bronze||ASTM B147 Alloy 8A||65,000||25,000||20||20||15.4||98*|
|18||Aluminum Bronze||ASTM B148 Alloy 9C||75,000||30,000||12 min.||12||17||150|
|19||Mondel Alloy 411||(Weldable Grade)||65,000||32,500||25||-||23||120-170|
|20||Nickel Moly Alloy B||ASTM A494 (Hastelloy B)||72,000||46,000||6||-||-||-|
|21||Nickel Moly Chrome Alloy C||ASTM A494 (Hastelloy C)||72,000||46,000||4||-||-||-|
|22||Cobalt-base Alloy No. 6||Stellite No. 6||121,000||64,000||01.feb||-||30.4||-|
|23||Aluminum Bar||ASTM B211 Alloy 20911-T3||44,000||36,000||15||-||10.2||95|
|24||Yellow Brass Bar||ASTM B16 1/2 Hard||45,000||15,000||7||50||14||-|
|25||Naval Brass Bar||ASTM B21 Alloy 464||60,000||27,000||22||55||-||-|
|26||Leaded Steel Bar||AISI 12L 14||79,000||71,000||16||52||-||163|
|27||Carbon Steel Bar||ASTM A108 Grade 1018||69,000||48,000||38||62||-||143|
|28||AISI 4140 Chrome Moly Steel||(Suitable for ASTM A193 Grade B7 bolt material)||135,000||115,000||22||63||29.9||255|
|29||Stainless Steel Type 302||ASTM A276 Type 302||85,000||35,000||60||70||28||150|
|30||Stainless Steel Type 304||ASTM A276 Type 304||85,000||35,000||60||70||-||149|
|31||Stainless Steel Type 316||ASTM A276 Type 316||80,000||30,000||60||70||28||149|
|32||Stainless Steel Type 316L||ASTM A276 Type 316L||81,000||34,000||55||-||-||146|
|33||Stainless Steel Type 410||ASTM A276 Type 410||75,000||40,000||35||70||29||155|
|34||Stainless Steel Type 17-4PH||ASTM A461 Grade 630||135,000||105,000||16||50||29||275-345|
|35||Nickel Copper Alloy Bar||Alloy K500 (K Monel)||100,000||70,000||35||-||26||175-260|
|36||Nickel Moly Alloy B Bar||ASTM B335 (Hastelloy B)||100,000||46,000||30||-||-||-|
|37||Nickel Moly Alloy C Bar||ASTM B336 (Hastelloy C)||100,000||46,000||20||-||-||-|