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What is Cold Cutting? Types of Cold Cutting Machines

Written by Anup Kumar Dey in Construction,Maintenance,Mechanical,Piping Interface

Cold cutting, as the name suggests, is a cutting operation without using heat. This is an effective cutting method used in various industries including material processing, pharmaceuticals, chemical, petrochemical, and oil & gas. In this article, we will explore more about the cold-cutting process, its definitions, reasons, benefits, and types of cold-cutting machines.

What is Cold Cutting?

Cold cutting can be defined as a material cutting procedure without using flame or heat, and without producing any spark. The cold-cutting process is one of the safest methods for cutting pipes, plates, and structures in hazardous environments.

Why Cold Cutting?

Cold cutting technology eliminates the majority of serious incidents due to the absence of heat from a torch. Heat and flame in hydrocarbon industries are serious hazards. So, the cold cutting process provides an edge in various works like pipe and pipeline repair, maintenance and shutdown activities, commissioning and decommissioning processes, etc.

Using cold cutting methods the hazards associated with thermal cutting or hot cutting are eliminated. This is the main reason that cold cutting of pipes and structural elements is ever-increasing. The main reasons for using the cold cutting procedure are:

  • Safety- The absence of heat makes the cold-cutting work environment safe for the tool operators.
  • Money- Cold cutting is cheaper as compared to hot cutting. Also, this can be performed in less time. So, cold cutting can easily fit into the budget.

Advantages of Cold Cutting

The cold cutting process provides a number of benefits like:

  • Prevention of Heat Affected Zone resulting in improved material properties.
  • Elimination of dangers associated with hot cutting. Cold cutting is safer.
  • Fast and quick operation.
  • Elimination of the difficult and laborious hand-grinding process to create weld ready surface makes the cold cutting operation cost-effective.
  • No chance of explosion.
  • No air-born contamination.
  • No spark and flame.
  • No hot work permit is required to start working.

Cold Cutting Machines

Cold cutting machines are the tools used for cold cutting operations. They are also known as cold cutters and usually are portable, lightweight, durable, and compact. Cold cutting machines are available in various configurations. The cold cutting technology is introduced in the year of 1949. Cold cutting machines are selected based on the application (what is to be cut), accuracy required, location, and economic viability.

Types of Cold Cutting Machines

Depending on the drive mechanism cold cutting machines are classified into the following two groups:

  • Pneumatic or Air-Driven cold cutting machines, and
  • Hydraulic cold cutting machines.

Refer to Fig. 1 below that provides a sample image of both types.

Pneumatic vs Hydraulic Cold Cutting Machine
Fig. 1: Pneumatic vs Hydraulic Cold Cutting Machine

Cold Cutting Procedure Steps

The cold cutting process is usually performed following the below-mentioned steps:

Preparation for the cutting process: Using the blade lowering/raising handle, the feed screw is turned until the cutter spindle is raised to the highest position. Then the start/stop control and machine directional control are set to OFF position. The machine speed and blade control are then positioned to a fully closed position. Air or hydraulic power requirements are checked as per manufacturer requirements.

Using the cold cutting machine for cold cutting operation: The machine is now positioned properly. The wheel holders must be properly positioned to provide stability and improved performance. Next, the cutting tool is turned on for operation. The cold cutting operation must be performed by trained operators and handled carefully. The cold cutting operation is performed by the rotation of a cutter.

Types of Pipe Cold Cutting Machines

Pipe cold cutting machines are also popular as clamshell lathe, split frame cutters, clamshell lathe, or clamshell cutters. Circular in construction, pipe cold cutting machines can easily wrap around the pipe in two halves and be attached together by a hinge. The rotating cutting tool works around the pipe circumference. Depending on the size and capability pipe cold cutting machines are of three types:

  • Low profile cold pipe cutter
  • Mid-size pipe cold cutting machine, and
  • Heavy-duty cold pipe cutting machine.

Pipe cold cutting machines perform the cutting operations for a range of pipe diameters and are suitable for precise and high-productivity requirements.

Examples of Cold Cutting Machines

There are various pipe cold cutting machines that are used for industrial applications. A Clamshell cutter is the most widely used pipe cutting tool.

Clamshell Pipe Cutter

A clamshell pipe cutter is a portable pipe cold cutting machine used for cutting and bevelling pipes. They have reduced weight and dimensions and are available in a wide range of cutters. They are suitable for cutting Steel, SS, Hastelloy, SDSS, Inconel, Alloy Steel, and Cladded pipes. Their split-frame technology can cut pipes of high thicknesses and provides various unique features like:

  • Faster and Accurate process
  • Complete machining system with accessories
  • High-Quality precision cut
  • Tracking slides for uniform land.

The main components of a cold pipe cutting machine are:

  • Frame
  • Split Gear
  • Drive
  • Ball-bearing
  • Tool carriage
  • Clamping feet

Some other tools that work as cold cutters are

Band Saws and Diamond Wire Saws

Widely used in chemical industries, both Band Saws and Diamond Wire Saws are used when high-precision cutting is not a requirement. They are powered by hydraulics and suitable hose and hydraulic power packs are required.

While using a band saw cold cutting machine, the cutting surface gets heated and hence suitable coolant must be used during operation.

For cutting through pipelines, piles, and caissons, Diamond Wire Saws are a good choice. A beaded rope encrusted with small diamonds on the outside surface is used for cutting in a diamond wire saw. Because of this, the name diamond wire saws are given to this cold-cutting machine. The circular cross-section of the ropes avoids the problems of compression and jamming.

Abrasive Water Jet Cutting

Abrasive Water Jet Cold Cutting is used in environments where there is a risk of fire or explosion. A very high water pressure (in the range of 4137 bar) is used in this method. A hard abrasive material is crushed into the water for the cutting operation. This method is suitable for any metal, concrete, or composite material of high thicknesses.

What is a Sample Cooler? Design, Application, and Characteristics of Sample Coolers

Written by Anup Kumar Dey in Piping Design Basics

Sample Coolers cool the sample from a process/chemical stream to the required temperature conditions for safe analysis. They are basically small, compact shell and tube heat exchangers. Sample coolers form one of the most critical components of a sampling system. They are widely used for most applications in liquid, gas, or steam process.

The process sample requiring cooling passes through the tube side of the cooler. Whereas the cooling fluid (mostly water) passes through the shell side. The cooled sample is then collected from the tube side outlet and taken to a laboratory for analysis. Sometimes the sample is piped to in-line process instrumentation when continuous monitoring of process fluid properties such as conductivity, pH, or other chemical constituents is required.

Typical Sample Coolers
Fig. 1: Typical Sample Coolers

Sample coolers are also used to temper the sample to the required temperature for the analysis. This is very important as the fluid temperature can directly affect the analysis results. Usually, the sample is allowed to flow for a while before collection. This ensures that a true sample with proper temperature is collected for analysis.

Sample coolers are usually designed and constructed based on BS 5500, ASME Section Vlll, or TEMA standards. The selection of a sample cooler is usually done considering the application, specific type of fluid, temperature, pressure, and flow conditions.

Applications of Sample Coolers

Sample coolers are widely used in chemical process industries. The industries where sample coolers are frequently found are:

  • Oil & Gas
  • Refinery
  • Power generation (boiler sample cooler)
  • Fertilizer
  • Chemical and Petrochemical plants
  • Pharmaceutical
  • Process water sampling.
  • Sugar, Paper
  • Textile, Cement, Steel, etc.

Basic Design of Sample Cooler

Depending on the application, Sample coolers are designed in numerous sizes and configurations. In general, they consist of a single, one-piece heat transfer tube, wound as a coil. The tube is then housed in a cylindrical container called a shell. The process fluid stream is usually admitted to the coil from the top. The cooling fluid flows through the sample cooler shell in an opposite direction. This opposing flow ensures optimum efficiency for the sample cooler. The heat of the process sample is transferred to the cooling fluid making a decrease in the sample temperature.

The shell is mounted using flanged connections so that it can be removed without disturbing the sample lines. To facilitate convenient operation and collection, the sample cooler is installed as close as possible to the system take point. The sample coolers are usually installed in the vertical position.

Characteristic Features of a Sample Cooler

A sample cooler must possess the following characteristics:

  • They must be safe in operation.
  • They should provide an accurate sampling.
  • Highly efficient. The sample temperature from the cooler outlet shall be very close to the desired temperature.
  • Shall be robust to handle high pressure & high-temperature samples.
  • There should not be welded joints in the coil. Sample coolers shall be designed as a complete single-piece coil as this ensures trouble-free operations without risks of failure of joints inside the shell.
  • Sample coolers shall be made from corrosion-resistant materials.
  • Counter-current flow shall be achieved at a very close temperature approach of the sample to the cooling fluid.
  • The cooling fluid requirement must be minimum.
  • The size of the sample cooler must be small and compact to make the installation easy and minimize the cooling fluid utilization.
  • They should be mounted with proper access for easy maintenance. Installation should be such that the coils can be cleaned or replaced without any difficulty.
  • In-built safety relief valves are sometimes provided to prevent accidents in case of any unlikely coil failure.
  • The design shall be Self-draining to eliminate sample retention (the usual design is an inlet from the top and an outlet from the bottom).
  • Sample cooler shell must be possible to be easily removed without disconnecting the sample lines, for inspection or maintenance purposes.
  • It must be a low-pressure-drop system.

Sample Cooler Ordering Information

For ordering a sample cooler the following information should be mentioned in the datasheet:

  • Application of the cooler.
  • Continuous or intermittent operation.
  • Temperature and Pressure ranges.
  • Flow rate
  • Any associated valve requirement.
  • Material of shell, tube, and coils.
  • Required cooling capacity.
  • Inlet and Outley sizes.
  • Any pressure drop criteria
  • Pressure equipment directive (CE marking) requirements if any

Types of Sample Coolers

Depending on the construction of sample coolers, there are three types of sample coolers:

  • Single helical tube sample coolers.
  • Spiral tube sample coolers, and
  • Dual tube coil sample coolers.

Installation of Sample Coolers

For safety and efficient operation, a sample cooler needs to be installed as specified by the purchaser. While installing, the equipment should be isolated from all connected piping and depressurized. Sometimes, a relief valve is installed in the cooler line to protect against excessive pressure rise.

How to Become a Piping Designer?

Written by Anup Kumar Dey in Mechanical,Piping Design Basics

A Piping Designer is responsible for the basic design of overall pipe routing, plant layout, Overall plot plan, Unit Plot Plan, equipment layout, nozzle orientation, isometric generation, Piping MTO, developing 3D CAD models, and 2D drafting/extraction for any plant. They draft the drawings for piping and plumbing systems. For every chemical, petrochemical, power, refinery, food, and Oil & Gas industry piping designers serve an extremely important work role.

Who is a Piping Designer?

A piping designer is an engineering professional who utilizes computer-aided design and drafting systems to build and generate piping isometrics, plot plans, general arrangements, and various other drawings for construction professionals to erect the plant at the site. Piping designers are also known as drafters, draftsmen, CAD technicians, etc.

As per the Process piping Bible, ASME B31.3, a designer is a person in responsible charge of the engineering design. He assures the owner that the engineering design of piping complies with the requirements of the relevant Code (B31.3) along with any additional requirements established by the owner.

To put it simply, the Piping designer produces piping drawings and BOMs and makes use of engineering specifications such as piping material and fabrication specs, piping standard details, piping layout specifications, pipe support standards, and vendor drawings. The engineering specifications are published by the piping engineers, and the designer’s job is to make drawings in compliance with these specs. In the context of engineering projects Piping design is a collaboration between piping designers, piping engineers, process engineers, mechanical engineers, structural engineers, construction engineers, etc.

Per the ASME code, the person responsible for the design (legally liable) takes responsibility for the code compliance of the resulting design. Clearly, the piping designer is not responsible per ASME code compliance, since their job is to follow requirements given by others to produce the piping drawings. The person legally responsible for the code-compliant design is the Piping Engineer who must meet the minimum experience/qualifications set out in the ASME code. The ASME code-defined piping designer is quite different from the job title piping designers that we usually follow.

How to become a Piping Designer?

The steps for becoming a piping designer are listed below:

  • Step 1: Obtain a High School Education/ITI Certificate
  • Step 2: Obtain a Diploma in Mechanical Engineering
  • Step 3: Plant Design and Piping Engineering Course (Online or from any institute)
  • Step 4: Learn the following software:
    • AutoCAD for a 2D piping designer or Piping drafter
    • Any of PDMS, E3D, Revit, or SP3D for 3D piping designer
  • Step 5: Acquire Industry Experience: Gain working experience by working on live projects utilizing the software you learned from training institutes.

Once you get sufficient experience by working on live projects you will be able to grow your career to the next level as Senior Piping Designer, Lead Piping Designer, Principal piping designer, and so on. After an experience of at least 10 years, you will be considered a proper piping designer and can move on your career ladder to become a senior piping designer.

The process piping code ASME B31.3 has some stringent requirements for designers. As per that Code, depending on the system criticality and complexity of the job, the owner’s approval for piping designers will be required if he does not meet any one of the following four criteria:

  1. Completion of a degree, accredited by an independent agency, in engineering, science, or technology, requiring the equivalent of at least 4 years of full-time study that provides exposure to a fundamental subject matter relevant to the design of piping systems, plus a minimum of 5 years of experience in the design of related pressure piping.
  2. Professional Engineering registration, recognized by the local jurisdiction, and experience in the design of related pressure piping.
  3. Completion of an accredited engineering technician or associate’s degree, requiring the equivalent of at least 2 years of study, plus a minimum of 10 years of experience in the design of related pressure piping.
  4. Fifteen years of experience in the design of related pressure piping.

Piping Designer Jobs

An experienced piping designer is an asset for many organizations. Wherever there are piping systems to transfer or transport fluids (liquids or gases) from one place to another, piping designers are required. So, piping designers are always required for the following industries:

  • Oil & Gas (Both Offshore and Onshore)
  • Chemical
  • Petrochemical
  • Mineral
  • Food Processing
  • Steel
  • Power Generation
  • Solar Plants
  • Refinery
  • Water Sector (Water treatment plant, Sewage treatment plant, Water Desalination plant, etc)
  • Marine
  • Shipyards

Piping Designer Salary

The salary of entry-level piping designers is quite less. In India, the average salary of entry-level piping designers is in the range of 15,000 to 20,000 INR per month. However, once they gain experience and achieve the required experience their salary increases. In the mid-range (10+ years of experience), a piping designer earns in the range of 60,000-70,000 per month.

However, the salary varies from region to region. A large number of piping designers are required in the Gulf region, Singapore, Malaysia, South Korea, Norway, Europe, and the USA. In these countries, piping designers earn handsome money. In the USA, the average salary of a piping designer annually is $50,000.

Piping Design Courses

Various institutes provide online and in-person piping designer courses to help candidates learn the piping design software packages and the basics of piping design. In general, the aspirant planning to become a piping designer should learn the following basics from a piping design course:

Piping Designer Skills

The important skills that a piping designer required are:

  • CAD software knowledge (Both 2D and 3D)
  • Reading and Understanding drawings
  • Analytical skills
  • Planning skills
  • Imagination skills

What is Inconel Material? Composition, Properties, Grades, and Applications of Inconel

Written by Anup Kumar Dey in Engineering Materials

When thinking of materials for high performance in rigorous applications, the name of Inconel material automatically comes to mind. As the Inconel material is very expensive, the use is of limited nature. Because of this Inconel material is generally less familiar as compared to Steel or Aluminum. In this article, we will explore some basics of this unique nickel alloy.

What is Inconel?

Inconel materials are nickel-chrome-based superalloys. Inconel has high corrosion resistance, oxidation resistance, strength at high temperatures, and creep resistance. Inconel is able to withstand elevated temperatures and extremely corrosive environments.

The term “Inconel” is a registered trademark of Special Metals Corporation, USA. In 1932, the first Inconel alloy was formulated.

Composition of Inconel Alloy

The chemical composition of Inconel material varies with grade. As this is a nickel alloy, the Nickel percentage is more. Other elements present in Inconel alloy material are:

  • Chromium
  • Iron
  • Cobalt
  • Molybdenum
  • Titanium
  • Niobium

Refer to table 1 below which provides the chemical composition of some of the common Inconel material grades (Reference: https://en.wikipedia.org/wiki/Inconel). All values of elements are provided in mass %.

Inconel GradeNickel (Ni)Chromium (Cr)Iron (Fe)Molybdenum (Mo)Niobium (Nb) & Tantalum(Ta)Cobalt (Co)Manganese (Mn)Copper (Cu)Aluminum (Al)Titanium (Ti)Silicon (Si)Carbon (C)Sulphur (S)Phosphorous (P)Boron (B)
600≥7214-176-10–––≤1.0≤0.5––≤0.5≤0.15≤0.015––
61744.2–6120-24≤38-10–10-15≤0.5≤0.50.8-1.5≤0.6≤0.50.05-0.15≤0.015≤0.015≤0.006
625≥5820-23≤58-103.15-4.15≤1≤0.5–≤0.4≤0.4≤0.5≤0.1≤0.015≤0.015–
690≥5827-317-11–––≤0.5≤0.5––≤0.5≤0.05≤0.015––
Nuclear grade 690≥5828-317-11––≤0.1≤0.5≤0.5––≤0.5≤0.04≤0.015––
71850–5517-21Balance2.8-3.34.75-5.5≤1.0≤0.35≤0.30.2-0.80.65-1.15≤0.35≤0.08≤0.015≤0.015≤0.006
X-750≥7014-175-9–0.7-1.2≤1.0≤1.0≤0.50.4-1.02.25-2.75≤0.5≤0.08≤0.01––
Table 1: Composition of Inconel Alloy

Properties of Inconel Material

Inconel is characterized by its ability to withstand very high temperatures. Inconel alloy maintains excellent strength even at elevated temperatures. A thick and stable protective oxide layer is formed when heated which provides excellent corrosion resistance even at high temperatures. For very high-temperature applications when steel material succumbs to creep, Inconel material is an ideal choice.

The main reason for Inconel’s very high-temperature resistance is due to the formation of an intermetallic compound Ni3Nb in the gamma double prime (ɣ’’) phase. This intermetallic phase acting as a ‘glue’ on the grain boundaries, prevents the grains from increasing in size when heated to high temperatures. Gamma prime forms small cubic crystals that inhibit slip and creep effectively at elevated temperatures.

The Mechanical and Physical properties of Inconel alloy 625 are provided below in Fig. 1:

Physical and Mechanical Properties of Inconel 625 alloy
Fig. 1: Physical and Mechanical Properties of Inconel 625 alloy

Inconel Alloy Material Grades

Inconel material has a variety of grades varying in composition and properties developed for specific applications. The common Inconel grades are as follows:

  • Inconel 188: Used widely for commercial gas turbine and aerospace applications.
  • Inconel 230: Used mainly by the power, aerospace, chemical processing, and industrial heating industries.
  • Inconel 600: Solid solution strengthened.
  • Inconel 601
  • Inconel 617: Used in ASME Boiler and Pressure Vessel Code for high-temperature nuclear applications such as molten salt reactors.
  • Inconel 625: Acid resistant, good weldability.
  • Inconel 690: For nuclear applications, and low resistivity
  • Inconel 706
  • Inconel 713C: It is a precipitation hardenable nickel-chromium base cast alloy.
  • Inconel 718: This alloy is a gamma double prime strengthened with good weldability.
  • Inconel X-750: Widely used for gas turbine components, blades, seals, and rotors.
  • Inconel 751: Increased aluminum content for improved rupture strength in the 1600 °F range.
  • Inconel 792: Added with increased aluminum content for improved high-temperature corrosion-resistant properties, used especially in gas turbines.
  • Alloy 825
  • Inconel 907
  • Inconel 909
  • Inconel 925: Inconel 925 is a nonstabilized austenitic stainless steel with low carbon content.
  • Inconel 939: Gamma prime strengthened to increase weldability.

Applications of Inconel Material

INCONEL alloy is designated as UNS N06625, Werkstoff Number 2.4856, and ISO NW6625. The NACE MR-01-75 standards list Inconel material. The Inconel material products are manufactured in all standard mill forms including rod, bar, wire, wire rod, plate, sheet, strip, shapes, pipes, tubular products, and forging stock.

The most widespread application of Inconel alloys is found in the aerospace industry. The space shuttle, Rocket engines, 3D printing technology, etc use Inconel. The nuclear industry also uses a lot of various Inconel grades. Other uses of Inconel alloys include:

  • Jet Engines
  • Fuel Nozzles
  • Engine Components
  • Afterburner Rings
  • Saltwater marine applications
  • Oil and Gas extraction
  • Industrial Processing
  • Pharmaceutical Industry

Inconel vs Monel

Both Inconel and Monel have Nickel as their primary element. However, there are many differences between the two nickel alloys. The main differences between Inconel and Monel are provided in Table 2 below:

ParameterInconelMonel
DefinitionInconel is a nickel-chromium based superalloyMonel is Nickel-copper based alloy
Maximum Nickel ContentInconel roughly has 72% nickel in the base material.Monel has around 67% nickel in the composition.
PriceInconel is more expensive than Monel.Monel is relatively cheaper than Inconel.
Elevated temperature corrosion resistance propertiesInconel has superior corrosion resistance properties at elevated temperatures.At lower temperatures, the corrosion resistance of Monel is preferred because of its low cost.
Melting Point Range2500 to 2600 Deg F2372 to 2462 Deg F
Density8.8 gm per cubic cm8.22 gm per cubic cm
HardnessHarderRelatively softer.
Temperature rangeThe maximum temperature range is 2200 Deg FThe maximum temperature range is 1000 Deg F
StrengthThe strength of Inconel is higher than Monel.Lower
Table 2: Monel vs Inconel

Butterfly Valve vs Ball Valve: Major Differences between a Ball Valve and a Butterfly Valve

Written by Anup Kumar Dey in Piping Design Basics

When designing a system that controls the fluid flow, you’ll probably need to choose between a ball valve and a butterfly valve. Both these valves find applications in various industries, and each has its set of benefits. To choose the right product for your system, you must understand the butterfly vs ball valve features, working principles, advantages, and disadvantages.

Ball Valve vs Butterfly Valve
Fig. 1: Ball Valve vs Butterfly Valve

Understanding Ball Valves and Butterfly Valves

Ball valves and butterfly valves are considered some of the simplest control valves in the market. They are compatible with different fluid mediums and are used across a broad range of temperatures and pressure. Both valves are quarter-turn, meaning a 90-degree rotation will take the valve from fully open to fully close and vice versa. They can also be controlled manually or using electric, pneumatic and hydraulic actuators. Affordability, easy maintenance, reliability, and durability make these valves more widely accepted than the other types. Let’s look at each of these valves.

Butterfly Valve

Butterfly valves have a disc driven by a hand wheel or lever. The disc sits perpendicular to the fluid flow direction when it’s closed, while a seal sits on the valve body to ensure tight and secure closure. The stem position while opening or closing the valve is often directly proportional to the flow rate.

Butterfly Valve
Fig 2: Butterfly Valve (A) Handwheel, (B) Gearbox, (C) Stem, (D) Body, (E) Disc, (F) Seal, (G) Packing.

Butterfly valves are lightweight, have the least parts, and require little support. Similarly, they are cheaper than ball valves, especially beyond a certain diameter size. However, they aren’t suitable for high-pressure applications since high-pressure differences between the valve’s seal and the sides make it difficult to open the valve. A solution is to use a bypass valve to balance this pressure difference and enhance a smooth operation.

Since the disc interrupts fluid flow even when it’s fully open, there’s some pressure drop across the valve, limiting its ability for use in certain applications, e.g., pigging. They are also limited to ON/OFF operation and cannot be used for high-precision fluid control.

Ball Valve

Ball Valve
Fig. 3: Ball Valve (A) Handle, (B) Handle screw/Bolt, (C) Shaft, (D) Packing, (E) Seat, (F) Ball, (G) Body.

Ball valves have a hollow spherical ball held in position at one or both ends. A shaft is attached to the top end of the ball, allowing for a rotation that either opens or closes the valve. When the valve is fully open, the hole lies parallel to the fluid flow direction. The ball sits on a seat inside the valve body and can have a two-way, three-way, or four-way flow directions.

The hole in a ball valve will vary depending on the application. This hole will also feature different designs, such as a V-port and a full-port design. A V-port design guarantees stable flow control while a full port valve allows zero or near-zero pressure drop. If the bore size is less than the pipe diameter, the flow will experience some pressure drop.

Compared to butterfly valves, ball valves don’t experience leakages when fully closed. They also open easily when there’s a high differential pressure on the valve’s sides; hence do not require a bypass valve.

Advantages and Disadvantages of Butterfly Valve vs Ball Valve

While butterfly valves and ball valves have several similarities, some differences make one valve stand out in certain applications. We have rounded up the main pros and cons of both valves below.

Weight and size:

Ball valves are heavy and require significant support, while butterfly valves are lighter even at larger pipe diameters. Butterfly valves are highly recommended for applications that require larger pipe diameters (i.e., those above DN 150). The ball valve works well for size diameters below DN 50.

Leakage:

Ball valves offer a tight seal for high-pressure applications, while butterfly valves are prone to leakages at relatively high pressures.

Installation Space:

Butterfly valves have a smaller installation footprint than ball valves.

Cost:

Butterfly valves are cheaper than ball valves, especially for larger-diameter sizes.

Connection Style:

Ball valves have a wide range of connection types with flanges or threads, while butterfly valves are limited to flange style with a wafer or lug design.

Flow Control:

Ball valves are ideal for ON/OFF control and modulation purposes. It also comes with a full port valve design option that eliminates pressure drop in the valve. On the other hand, butterfly valves are only suitable for ON/OFF control, plus the valve disc restricts fluid flow, creating some pressure drop.

Butterfly Valve vs Ball Valve

The above discussions on the major differences between butterfly valves and ball valves can be provided in a tabular format as below:

ParameterButterfly ValveBall Valve
WeightButterfly Valves are Light Weight Valves. Hence, transfers less load to pipe supports.Heavy Weight is the characteristic of Ball Valves
StructureThe butterfly valve consists of a thin disk in a thin body. Simpler design.Ball valves have a sphere-like disc inside a bulky body. Complex design.
Space RequirementThe installation Space requirement of the butterfly valve is less.Ball valves need more installation space than butterfly valves.
LeakageAt high differential pressure, butterfly valves are prone to leakage.Ball valves provide a tight seal.
Flow RestrictionThe butterfly valve disc restricts the flow by creating a large pressure drop.Ball valves have less pressure drop as compared to butterfly valves.
ApplicationSuitable for ON/OFF control and proportional controlSuitable for modulating and ON/OFF Control. However, they are more used for isolation purposes.
CostButterfly valves are cheaperBall valves are expensive
ConnectionButterfly valves have a flange style with a lug or wafer designA range of connections is available for ball valves.
UsesUsed for Liquid service applicationsBall valves are capable of handling both liquid and gas.
Operating ConditionMainly used for low-temperature and pressure servicesSuitable for high temperature and pressure services
No of PortsButterfly valves can have only two portsBall valves can have more than two ports.
Table 1: Butterfly Valve vs Ball Valve

Summary

When selecting between a ball valve and a butterfly valve, you should consider all the product features, ideal use cases, and pros and cons. Understanding your system requirements and valve design expectations will also help you in decision-making.

The number of ports required, flow regulation, flow capacity, and operating conditions is the key factors to consider. You also want to choose a product from a reputed manufacturer that has a positive track record in the market. Seeking professional guidance during the selection process is highly recommended, especially if you are new to fluid control.

References and Further Studies

P-Number, F-Number, and A-Number in Welding

Written by Anup Kumar Dey in Construction,Engineering Materials,Mechanical

To ease welding procedure creation and welding procedure management, the ASME Weld Number tables provide a well-defined numbering system methodology. These numbers are assigned to the Weld base metals and filler metals. Grouping materials reduces the number of welding procedures and welder performance qualification tests for a wide range of materials. ASME Boiler and Pressure Vessel Code (ASME BPVC Section IX) has assigned a grouping scheme for base metals that consists of the P numbers and Group Numbers. Earlier there were ASME S Numbers that were removed by the code from the year 2009. Similarly, the filler metal grouping scheme consists of the F-Numbers and A-Numbers. Refer to Fig. 1, which clarifies what these numbers relate to.

P-Number, F-Number, and A-Number in Welding
Fig. 1: P-Number, F-Number, and A-Number in Welding

What is the P Number in Welding?

Depending on the material characteristics like composition, weldability, brazeability, design consideration, heat treatment, and mechanical properties, ASME BPVC assigned P-Numbers to the base metals. The code assigned the same P-number for the materials with similar material characteristics. These are listed in Table QW/QB-422 of ASME. While changing the base metal from a qualified WPS to a new base metal, requalification or a new PQR is not required if the new base metal falls in the same P-Number.

These base metals are grouped by material and the assigned P-Numbers are constant for that specific material group. For example, the base metals of Low Carbon Steel or Carbon Manganese material fall in P-Number 1. The following table (Table-1) provides the P-number ranges for various metals and alloys.

Sr. No.Type of  Steel, Metal, AlloyP-Number
1.Carbon Steel (C-Mn )1
2.Low Alloy Steel (Cr-Mo Steels)4, 5A, 5B, 5C, 15E
3.Stainless  Steels (Cr-Ni steels)8, 10H
4.Nickel & Ni-base alloys41 to 49
5.Aluminum & Aluminum alloys21 to 26
6.Copper & copper alloys31 to 35
7.Titanium & titanium alloys51 to 53
8.Zirconium & zirconium alloys61 and 62
Table 1: ASME P-Number Table

From the ASME Sec IX table, QW/QB-422 can find the P-number of a specific grade of material, i.e. which material falls under which P-number and what is product form i.e. plate, forging, sheets, fittings, etc.

P-number is generally mentioned in WPS & PQR for procedure qualification and in WPQ for performance qualification.

What is the F-Number in Welding?

As the name suggests, F stands for Filler number. Depending on the composition, the microstructure of the material F-number is assigned to welding consumables i.e. filler wires, and electrodes to reduce the procedure and performance qualifications. F-number is generally mentioned in WPS & PQR for procedure qualification and in WPQ for performance qualification. The ASME Sec IX (QW-432 assigned the F-number on the basis of type of consumable, usability of consumable, metallurgical compatibility, heat treatment, and other mechanical properties. The same F no is assigned to carbon steel as well as stainless steel filler wires. For example. ER70S-6 & ER308 have the same F no. i.e. F no. 6. The following table (Table-2) provides the F-number ranges for various consumables as classified in ASME Section.

Sr. No.Type of  Steel consumablesF-Number
1.Carbon Steel1 to 6
2.Low Alloy Steel (Cr-Mo Steels)1 to 6
3.Stainless  Steels (Cr-Ni steels)5, 6
4.Nickel & Ni-base alloys41 to 46
5.Aluminum & Aluminium alloys21 to 26
6.Copper & copper alloys31 to 37
7.Titanium & titanium alloys51 to 56
8.Zirconium & zirconium alloys61
9.Hard-facing weld metal overlays71 and 72
Table 2: ASME F-Number Chart

From the ASME Sec IX, table QW-432 can find the F-number of specific consumables classified as per ASME Sec IIC. With the F-number there is a reduction of procedure and performance qualification as the same F-number of material does not require requalification.

From the ASME Sec IX, table QW-433 can be referred to for the welder performance qualification range. A snapshot is given below:

What is the A-Number in Welding?

As from the name, A stands for analysis. A-number is designated by ASME to weld metal deposition composition analysis to reduce the number of procedure qualifications in Welding. From the ASME Sec IX table QW-442 can be referred to for different A  number is given to different groups of metals/alloys. A-number is generally mentioned in WPS & PQR. It is not essential for performance qualification i.e. not mentioned in WPQ.

Note that the A-Number gives the chemical composition of the weld metal in the “as-welded” state, not of the filler metal product in its raw form.

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Video Courses in Welding

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