Press Releases

Oftentimes, piping installation on a major project site like a desalination plant or a chemical refinery at high-pressure is done by experienced procurement managers whose work does not go wrong during an early quotation meeting. Rather, these projects usually have problems several months later during pressure testing.

Suppose there is a case in which a procurement officer accepts forged stainless steel flanges supplied by a company which is cheaper than the market average by 12%. The material test reports (MTRs) seem perfect, the furnace numbers coincide, and all dimensions match well with the standard ASME requirements. Nevertheless, a little leakage will occur from a critical heat exchanger when pressurized with a fluid at 1.5 times the design limit. At that point of pressurization, micro-porosity in the body of the forging will cause a small leak, resulting in a complete loss of chemical media in the system; the chemical plant will need to be shut down, and the delay will make the original 12% savings completely negligible.

When a system consists of critical piping, selecting a substandard component might result in an industrial hazard, while getting just a little bit of a good component can also lead to great operational savings. From the perspective of design, plant operation, and procurement leaders, choosing reliable ss flanges manufacturers must not rely only on the unit price, as it should. It must involve thorough assessment of the use of material, metallurgical knowledge, forging discipline, precision machining, and non-destructive testing capabilities.

The Definition of a Flange that meets high-quality standards

Essentially, a stainless steel flange serves as a connector or joiner of different pieces of pipe through mechanical means while providing a leakage-proof seal at the same time.

In addition to offering a mechanical joint, flanges allow for very easy clean-up, access for maintenance, and modification.

The geometry of a standard flange is defined in the ASME B16.5, EN 1092-1, or DIN specifications internationally. But when we talk about a "high-quality" flange, it's the internal soundness that is meant here.

It is a fact that only very few defects can spoil the entire quality of a stainless steel flange. Thus, a high-quality stainless steel flange is one in which the metal has been thoroughly forged or cast with the best possible uniformity; it is free from defects such as cracks or holes on the surface; the sealing area has the most appropriate accuracy and alignment of the threaded holes is absolutely perfect and the chemistry of the metal is fully in accordance with one of the standards like for example: UNS S30403(S30400) 304L; UNS S31603(S32168) S31600; 316L; or even duplex types such as UNS S31803(S32205) 31800.

Cast flanges are typically made for low-pressure and non-essential purposes only; however, when high pressure or corrosive conditions are required, then, of course, only forged flanges can be the right choice. Forging of metals leads to denser grains, voids inside the metals are removed, and dynamic loads are significantly handled by both fatigue strength and mechanical toughness.

The Importance of Quality Flanges in an Industrial Setting

There are industries where pipelines are always working under a tremendous variety of heavy-duty environmental conditions. Here, a small problem on a major flange joint is not just going to cause a leak, but more importantly, result in a significant loss of production, a major accident, or a total failure of the whole system.

The Main Reason Why Industrial Flange Failures Can't Be Predicted

During industrial production, the pressurized liquid/gas is circulated in the system, and temperature variations are inevitable. The system is also subjected to a variety of vibrations due to the pumps that operate the system. When the piping is subjected to cyclic pressure and thermal shock, if the flange cannot withstand such stress due to, for example, improper heat treatment or internal forging defects in the flange, one should expect a failure at that joint.

Quality of manufacturing must guarantee that the ultimate load and the yield strength are in line with the pressure-temperature limits which are defined in the ASME B16.5 standards.

Protecting Equipment against Severe Corrosion by Using Flanges made up of High Quality Steel.

The term "stainless" does not imply that the steel cannot corrode. On the contrary, stainless steel becomes corrosion-resistant through the right combination of alloying elements and suitable post-forging heat treatment. Stainless steel exposed to a chloride-rich medium or an acidic processing flow will be prone to intergranular corrosion or pitting if not properly treated. Austenitic grade stainless steels should be through-annealed (usually the temperature is 1040-1150°C and then quenched quickly in water) to get the grain boundaries free of any chromium carbides. Negligence or a hasty approach will leave the grain boundaries open for localized corrosion.

Keeping Downtime and Overall Cost to a Minimum

Finding materials suppliers only based on the lowest purchase price ignores the concept of Total Cost of Ownership (TCO). The procedure of swapping out a broken flange entails: disconnecting the pipe section, evacuating fluid content, disassembling the joints via cutting or unbolting, and carrying out the welding or fitting operation of new parts and then testing the system for approval. Often, the personnel cost and productivity loss would be several times more than the value of the component bought.

Main Technical Aspects on Which Your Selection of SS Flange Manufacturer Relies Completely

Checking the capability of manufacturing Stainless Steel (SS) Flanges should be done on several levels, including technical, metallurgical, and operational aspects, by procurement teams.

Metal Quality and Quality Forging

Sufficient quality is required for raw steel billets to guarantee the performance of the flange. A good steelmaker will get vacuum-degassed billet material from certified steel mills with full traceability. When working with steel forgings, the closed-die or ring-rolling method must be controlled so that material grains are in continuous flow along the flange hub contour and flange face.

An essential parameter for evaluating metal quality includes:

• Heat-treatment Procedure: The manufacturer should have heat-treatment furnaces that are not just calibrated but also automated with full temperature monitoring; for instance, solution annealing of austenitic grades and hardening of precipitation-hardened grades should be precisely done.
• Mixed-up Grain Size and Inclusion: Top forging grades consist of very fine yet consistent grain sizes so that under pressure variations, they do not crack earlier.

Measurement Accuracy and Machining Tolerances

Even if the metal of the flange is perfect, it might still be the case that if the finish of the flange face does not satisfy the requirement, the joint may result in a leak. Tolerance for the machining directly determines how far the seal of the gasket would cover the flange joint.

• Rough Finish of the Raised Face (RF): Per ASME B16.5, RF flanges may have either stock finish or smooth finish with surface roughness (Ra) ranging from 3.2µm to 6.3µm (125-200 µ-inches). The spiral/concentration pattern should appear clean, seamless, and free from tool marks, if any.
• Cutting circle of Bolt holes: The accuracy of hole positioning and pitch circle diameter (PCD) remains one of the critical factors controlled through CNC machining; any shift in bolt hole positions results in the field technicians having to do a forced fit, which is harmful and causes pipeline joints to introduce unwanted shear forces.

Material Tracking and Material Testing

Make no mistake, but only flanges that are fully accompanied by documents can be accepted at all. Quality SS Flange producers usually issue either EN 10204 3.1/3.2 Material Test Certificates (MTCs) that have full details on metal content and characteristics.

How to Judge an SS Industrial Flange Supplier

When you assess a potential supplier, you need to be looking at much more than just the advertisements and the products that come with them.

Examine Manufacturer's Capabilities vs. Subcontractors

Manufacturers with their own forging equipment and facilities for heat treatment and testing are much more likely to produce consistent, high-quality products. When a supplier relies on third-party companies that they haven't checked out to provide heat treatments or machining services, the quality control is no longer in their hands, and the time it takes to deliver your order can become highly unpredictable. The risk of material traceability also increases in such situations.

Make sure they have International Certifications.

Based on your industry and where your product is going to be installed, you need to check that the manufacturer holds applicable accreditations:

• ISO 9001:2015: A fundamental quality management system.
• PED 2014/68/EU: A directive to ensure safe pressure equipment in the EU for European exports or projects following EU standards.
• IBR Approval: This is required for the setup of steam lines under high- pressure conditions in India.
• API 6A / 17D: For the operation of high-pressure offshore and oilfield equipment, these specifications are an absolute requirement.

Gather Information on Packaging and Protection

Stainless steel can be contaminated by a surface that is touched by carbon steel, even temporarily, during transport or storage. The premier Flanges Manufacturers for SS maintain strict policies that the carbon and stainless steel products shall be kept in completely different areas. Moreover, the finished flanges should be packed well by using end caps and anti-rust coating (in case of non-passivated) and seaworthy packaging to safeguard the machined faces from getting damaged during transit.

Frequent Procurement Errors

The sourcing team at an expert vendor, if at all, can be expected to commit errors. Here are a few of them:

• A focus on Unit Price: Purchasers of cheap flanges that are either not made by brand name or do not include heat numbers will face a very high rejection rate during hydro-tests or onsite installations.
• Overlook Carbon Content in Stainless Steel Alloys: If standard stainless steel (Grade 304 or 316) is being purchased for welding applications, and not the low-carbon versions (304L/316L), welding will result in carbide precipitation that in turn can lead to accelerated corrosion at or very near the weld-affected zone (HAZ).
• Receiving Incomplete Test Reports: Heat analysis MTCs that give a 'typical' value for every parameter instead of an actual value will be a red flag and must be rejected straightaway.
• Failing to Look Up Gasket Face Serrations: When there is a discrepancy between the gasket material and the gasket face finish (like using a smooth face if a spiral-wound gasket needs a serrated face), there is an impact on the integrity of the seal.

Things to Know before Sourcing from India

India is already one of the world's biggest manufacturing bases for industrial quality stainless steel forgings. There is a perfect combination of good products, metallurgical expertise, and manufacturing that can support large orders. So, procurement teams dealing with or outsourcing from the Indian market are advised to consider several elements that are specific to the Indian market situation.

Manufacturing Zones

Maharashtra, Gujarat, and the National Capital have been chosen as the main hubs for SS flange production. The area around the Mumbai-Thane-Navi Mumbai belt & Pune are major centers of steel manufacturing in Maharashtra.

The Gujarat state has Ahmedabad, Rajkot, & Vadodara as main manufacturing hubs. In addition, there are a few manufacturing clusters around the National Capital where manufacturers are located.

The manufacturing belt has a well-developed infrastructure, supply-chain logistics, availability of raw materials, and is close to major sea ports like JNPT, Hazira, and Mundra. Procurement teams can get the most up-to-date information about manufacturers and supply chains in the belt.

Indian Boilers Regulation (IBR) Compliance

Flanges in India that are part of high-pressure steam systems cannot be used without Indian Boiler Regulations (IBR) being followed strictly. Sourcing departments should ensure that prior to shipment, a Form III-C certificate signed by an authorised IBR inspector is made available by the manufacturer.

Domestic Sourcing vs. Import Dynamics

While it may be the case that low-cost flanges from imports are sometimes supplied to the market, local Indian manufacturers that have obtained NABL laboratory approvals, hold PED certificates, and global EPC approvals are able to provide a higher level of quality control, shorter lead time, and clear material traceability to the origin of the material.

Frequently Asked Questions

What is the difference between a forged flange and a plate flange?

A forged flange is a forging done by hammer or roll forging a billet into a desired shape, having a very fine grain structure ideal for high pressure and thermal stress. The plate flange is a section cut from a rolled flat plate. It is generally not suitable for high pressure as it lacks the fatigue strength and mechanical properties of a forged one.

Under what scenario is it advised to use dual-certified material grades like 304/304L or 316/316L?

Dual-certified stainless steel is that which satisfies both the very low carbon content of "L" grade to prevent carbide precipitation during welding (max 0.030% carbon) and, at the same time, meets the higher strength needs of the base grade. Therefore, specifying dual-certified flanges allows the department to purchase a single component with multiple abilities that can handle extremely high-pressure welding at high temperatures without causing mechanical failure of the component.

Why is it so important that PMI (Positive Material Identification) be carried out prior to shipping?

PMI is carried out by means of X-ray Fluorescence (XRF) or Optical Emission Spectrometry (OESP) that allow very quick confirmation of the elemental composition of the final flange. The main function of PMI analysis is the prevention of costly alloy mix-ups through its operation as a final stage in the quality control process. An example would be mixing Grade 304 and Grade 316, due to which expensive mistakes could be made.

What flange facing type is best suited for high pressure applications?

While, in general, Raised Face (RF) flanges are suitable for standard industrial pressure classes (Class 150 to Class 600), Ring-Type Joint (RTJ) facings are typically used in high-pressure (Class 900 and above) and high-temperature applications. Metal-to-metal contact capable of withstanding high pressure is achieved using RTJ flanges that use a precisely machined ring metallic gasket fitting a deep groove on the flange face.

Choose Procurement Strategy Wisely

Getting essential items required for piped systems in a factory is essentially a risk-mitigation activity. A flange is not simply a flat piece of metallic material; it is a safety barrier of great importance that is designed to safely contain hazardous/pressurized or very hot contents.

Select only suppliers with full materials and product certifications that have a system of thorough quality checks. Don't get carried away by low prices; rather, go for stainless steel flanges that have been fabricated to strict standards and are accompanied by all their necessary technical documents. Thus, the head purchaser of a company avoids unexpected breakdowns, ensures continuous operations, and maximizes profits in the long run.