Stainless steel flange

Stainless steel flange is made from stainless steel, a corrosion-resistant alloy that is known for its strength, durability, and aesthetic appeal.

Stainless steel flanges come in various grades, such as 304, 304L, 316, 316L, and 310, each with its own specific properties and applications.

Common material standards and Grades are ASTM A182 Grade F304/L and F316/L, with pressure ratings from Class 150, 300, 600 etc and to 2500.

Types of stainless steel flanges Which one is best for you?

Stainless steel flanges also ranged with slip on flange, weld neck flange, blind flange, socket weld flange and threaded pipe flange.

Stainless steel flanges are available in various sizes, shapes, and designs, and they can be classified based on their face type or pressure class. Common types of stainless steel flanges include:

1. Weld Neck Flanges: Weld Neck Flange has a long tapered neck that is welded to the pipe, providing excellent strength and support for high-pressure applications.
2. Slip-On Flanges: Slip-On Flange slips over the end of the pipe and is then welded in place, making them easy to install and suitable for low-pressure applications.
3. Blind Flanges: Blind Flange is used to seal the end of a pipe or fitting, rather than connecting it to another component.
4. Threaded Flanges: Threaded Flange has threads on the inside bore, allowing them to be connected to pipes or fittings with matching threads.

Stainless steel flanges are commonly used in industries such as oil and gas, chemical processing, and food and beverage processing, where resistance to corrosion, high-temperature and pressure is required. The choice of stainless steel grade depends on several factors, including the application, the environment, and the required performance characteristics.

Overall, stainless steel flanges are an essential component of industrial piping systems, providing a means to connect pipes and other equipment components in a secure and leak-proof manner.

Why choose stainless steel flanges?

You want to get value for your money. Here is why stainless steel flanges are worth the investment.

Resistance to Corrosion

In every metal application, corrosion is an important consideration. In the U.S., around $9 billion goes to handling pipeline corrosion incidences. Metals are acted upon by rust, chemicals, as well as other environmental factors. Therefore, it would be best if you chose flanges that can withstand these factors. Stainless steel becomes a perfect choice since it has a high resistance to corrosion.

Durability

Stainless steel is durable and can withstand a lot of pressure. Although aluminum could be a cheaper option, it cannot withstand as much stress.

Withstanding High Temperatures

In industries, the temperatures could get a bit extreme. However, stainless steel flange fittings can withstand the temperatures without deformation or warping. Therefore, at no point will your system be compromised.

What is the ASTM A403?

ASTM A403 Stainless Steel Pipe Fittings refers to the material of forged and rolled austenitic stainless fittings for pressure pipes. Common grades are WP304/L, WP316/L. They can be used into many fields as engineering industry, energy conversion plants etc.

ASTM A403 Standard specification covers the standard for wrought austenitic stainless steel fittings for pressure piping applications.

Chemical Composition (%) of ASTM A403

Notes:

For each reduction of 0.01% below the specified C maximum, an increase of 0.06% Mn above the specified maximum will be permitted, up to a maximum of 1.35%.

The sum of Cu, Ni, Cr, and Mo shall not exceed 1.00%.

The sum of Cr and Mo shall not exceed 0.32%.

The maximum carbon equivalent (C.E.) shall be 0.50, based on heat analysis and the formula C.E.=C+Mn/6+(Cr+Mo+V)/5+(Ni+Cu)/15.

Mechanical properties of ASTM A403

Material Furnished to this specification shall conform to the requirements of specifications A960/A960M including any supplementary requirements that are indicates in the purchase order. Failure to company with the common requirements of Specification A960/A960M constitutes non-conformance with this specification . In case of conflict between this specification and Specification A960/A960M , this specification shall prevail.

Material Furnished to this specification shall conform to the requirements of specifications A960/A960M including any supplementary requirements that are indicates in the purchase order. Failure to company with the common requirements of Specification A960/A960M constitutes non-conformance with this specification. In case of conflict between this specification and Specification A960/A960M , this specification shall prevail.

What grade of steel is ASTM A403?

The standard includes several grades of austenitic stainless steel alloys, and uses the WP or CR prefix to mark the grade of steel, depending on the applicable ASTM or MSS size and rated pressure standards. ASTM A403 is designed for forged steel pipe fittings, Cast pipe fittings are not suitable.

Comparison table of stainless steel brands of various countries

In order to solve the cumbersome and difficult to remember stainless steel grades, improve the practicability of the brand representation, and the contrast with the international standard grades, China has formulated the "Universal Code System for Steel and Alloy Grades", such as 06Cr19Ni10, corresponding to 304. Different grades of stainless steel have different ingredients, but they all have a national standard. The standards of each country are also different.

The specific standards of each country are as follows:

Standard

Pipe Flange Standards mainly include three systems in the world, ANSI/ASME flange system(American), DIN flange system(European system), JIS flange system, other system made according to this three systems, like GB flange standard, which mainly made according to ANSI/ASME and DIN flange standard, Duwa Piping supplies those flanges with top quality and soonest delivery time.

ASME standards

• ASME B16.1 – Gray Iron Pipe Flanges and Flanged Fittings: Classes 25, 125, and 250
• ASME B16.5 – Pipe Flanges and Flanged Fittings: NPS 1/2 through NPS 24 Metric/Inch Standard
• ASME B16.20 – Ring Joint Gaskets and Grooves for Steel Pipe Flanges
• ASME B16.21 – Nonmetallic Flat Gaskets for Pipe Flanges
• ASME B16.24 – Cast Copper Alloy Pipe Flanges and Flanged Fittings: Classes 150, 300, 600, 900, 1500, and 2500
• ASME B16.34 – Large Diameter Steel Flanges (NPS 26 through NPS 60)
• ASME B16.36 – Orifice Flanges
• ASME B16.42 – Ductile Iron Pipe Flanges and Flanged Fittings: Classes 150 and 300
• ASME B16.47 – Large Diameter Steel Flanges (NPS 26 Through NPS 60)

ASTM standards

• ASTM A105 – Specification for Carbon Steel Forgings for Piping Applications
• ASTM A182 – Specification for Forged or Rolled Alloy Steel Pipe Flanges, Forged Fittings, and Valves and Parts for High Temperature Service
• ASTM A193 – Specification for Alloy Steel and Stainless Steel Bolting Materials for High Temperature Service
• ASTM A194 – Specification for Carbon and Alloy Steel Nuts for Bolts for High Pressure and High Temperature Service
• ASTM A694 – Specification for Carbon and Alloy Steel Forgings for Pipe Flanges, Fittings, Valves, and Parts for High-Pressure Transmission Service
• ASTM A707 – Specification for Flanges, Forged, Carbon and Allow Steel for Low Temperature Service

AWWA standards

• AWWA C115 – Standard for Flanged Ductile Iron Pipe with Ductile-Iron or Gray-Iron Threaded Flanges

ISO standards

• ISO 5251 – Stainless steel butt-welding fittings

MSS standards

• MSS SP-6 – Standard Finishes for Contact Faces Pipe Flanges and Connecting End Flanges of Valves and Fittings
• MSS SP-9 – Spot Facing for Bronze, Iron and Steel Flanges
• MSS SP-25 – Standard Marking Systems for Valves, Fittings, Flanges, and Unions
• MSS SP-44 – Steel Pipeline Flanges
• MSS SP-53 – Quality Standards for Steel Castings and Forgings for Valves, Flanges and Fittings and Other Piping Components – Magnetic Particle
• MSS SP-54 – Quality Standards for Steel Castings and for Valves, Flanges and Fittings and Other Piping Components – Radiographic
• MSS SP-55 – Quality Standards for Steel Castings and for Valves, Flanges and Fittings and Other Piping Components – Visual
• MSS SP-75 – High Test Wrought Butt Welding Fittings
• MSS SP-106 – Cast Copper Alloy Flanges and Flanged Fittings Class 125,150, and 300
• ASME B16.5 and ASME B16.47 cover pipe flanges up to NPS 60 (B16.5 from 1/2″ to 24″ and B16.47 from 26″ to 60″). ANSI
• B16.47 covers two series of flanges, Series A is equal to MSS SP-44-44, and Series B is equal to API 605 (API 605 has been canclled).

The most frequently asked questions regarding flanges and flange fittings have to do with how flanges fit on specific steel tube and steel pipe ends.

How flanges operate?

Flanges have flat or flush surfaces that are vertical to the pipe to which they are attached. The attachment process involves mechanically joining two or more faces using bolts, adhesives, collars, or welds. Due to the attachment requirements, a flange must fit the equipment or pipe that it’s designed. That’s why it’s necessary to check all the possible specifications and dimensions to ascertain that it’s of the right size, type, and material.

What are the three parts of a flanged connection?

Pipe flanges, gaskets, and bolts are the three parts that comprise a flanged connection. Gaskets and bolts are typically made of the same flange materials or a material approved for the pipe components. Each component comes in various materials that suit specific applications and must be matched correctly for proper functioning. The gaskets come in two conventional types: full-face gaskets and ring gaskets. Full-face gaskets have the bolt holes visible and pair up with raised-face gaskets. Ring gaskets tend to be smaller rings minus the bolt holes and pair up with flat-faced flanges. Securing the flange components requires matching the surfaces evenly and plumb, adjusting as needed for a uniform fit. Once all surfaces match, bring the flanges together and secure at least two of the bolts. Refine the alignment, so the remaining bolt holes match and their corresponding bolts are tightly secured.

How do I properly size a flange for pipe use?

Properly sizing a flange for pipe use depends not only on the type of flange but its compatible piping. The pipe must slip into the flange’s inside diameter easily and securely, and the outside diameter should cover wall holes. Once you determine the specific flange type and material you need for the job, you’ll need to take several measurements. The four measurements you’ll need are the inside diameter, outside diameter, bolt hole count, and bolt hole center. You’ll need to align each of these measurements from opposing bolt holes to get the most accurate readings. Take all measurements from edge to edge and try to get as precise as possible to match the correct product. Round up bolt diameter to the next half or whole step since bolts measure half or whole inches. Once you have all four measurements, check them against the manufacturer’s table to find the correct flange. Most manufacturers list these specifications on their websites for easy reference.

Flange Inspection

Before dispatching from manufacture each flange is inspected to ensure quality. During an inspection you have to check the following;

• Outer & Inner Diameter of body
• Bolt Circle & Bolt hole Diameter
• Hub Diameter & thickness of weld end
• Length of the Hub
• Straightness and alignment of the bolt hole

ASME B16.5 and B16.47 standards cover permissible tolerances for inspection.

Flange material standards

Flanges are used to connect pipes or other equipment components in various industries, and they come in a variety of materials and sizes. Flange material standards are developed by standard-setting organizations and describe the properties and characteristics of different materials that can be used to make flanges. Some examples of commonly used flange material standards include:

1. ASTM A105: This standard covers forged carbon steel piping components, including flanges, that are suitable for use in high-pressure applications.
2. ASTM A182: This standard covers forged or rolled alloy steel pipe flanges, forged fittings, and valves and parts intended for high-temperature service.
3. ANSI B16.5: This standard specifies the dimensions, tolerances, and markings for steel pipe flanges and flanged fittings.
4. DIN 2632-2638: This standard defines the dimensions and tolerances for flanges made from steel, including carbon steel, stainless steel, and other alloys.
5. ASME B16.47: This standard covers large diameter steel flanges, typically used in high-pressure applications where larger bore sizes are needed.
6. BS 4504: This British standard covers circular flanges for pipes, valves, and fittings, with nominal sizes ranging from 15 to 600 mm.

The choice of flange material standard will depend on various factors such as the application, the environment, the fluid being transported, and the required performance characteristics. For example, high-pressure applications may require flanges made from materials with high strength and durability, while corrosive environments may require flanges made from materials with good resistance to corrosion.

Flanged connection

There are many ways to connect flanges, including threading, welding or bolting. The threaded flange is best for low pressure or smaller pipelines because it can maintain its seal. When your pipeline is larger or high pressure, then the welded flange is preferable. A boiler room is one place where welded blind flanges might be used, due to the high pressure involved.

Flanged joints: flanges, bolts and nuts and gaskets

A flange is a external rib at the end of pipes, valves and other flow devices to assemble them.

Dimensions of the flanges are up to specific Standards : DIN, ANSI, AS, BS, JIS

A flanged connection requires two flanges (the “main” and the “companion”), a set of bolts and nuts (whose number depends on the flange diameter and class) and two sealing gaskets. Flanged connections have to be executed and supervised by trained personnel, as the quality of the joint has a critical impact on the performance of the piping system / pipeline (the standard TSE – TS EN 1591 Part 1-4, “Flanges and their joints”, defines a number of requirements for the execution of proper flanged connections). Whereas all elements of the joint are critical, experience shows most leaks are originated by the improper installation of the sealing elements, i.e. the gaskets.

The typical pipe to flange connections are welded or threaded. Welded flanges are used for pipelines and piping systems with high pressures and temperatures, and with diameters above 2 inches.

Threaded connections are instead used for installations of smaller diameter and not subject to severe mechanical forces such as expansion, vibration, contraction, oscillation (forces that would crack the threaded joint). In all these critical cases, butt weld connections are recommended.

Delivery

Steel flanges must be packed with seaworthy packing method then delivery to customers, usually the packing way include wooden box, wooden pallet, iron & steel cage, iron & steel pallet etc.

Flange Marking

Flange markings are governed by ANSI ASME codes. Flange marking includes;

• Manufacturer logo
• ASTM material code
• Material Grade
• Service rating (Pressure-temperature Class))
• Size
• Thickness (Schedule)
• Heat No
• Special marking if any QT (Quenched and tempered) or W (Repair by welding)

PMI-raw material inspection

Size inspection

ASME B16.5 and B16.47 standards cover permissible tolerances for inspection.

• Outer & Inner Diameter of body
• Bolt Circle & Bolt hole Diameter
• Hub Diameter & thickness of weld end
• Length of the Hub
• Straightness and alignment of the bolt hole

Packing

Because of the normal wooden boxes or wooden pallets have to do fumigation treatment, we usually use plywood pallet or plywood case or box to pack steel flanges without fumigation treatment.