Chemical Processing Weld Neck Flange

The Chemical Processing Weld Neck Flange is designed for aggressive chemical service where corrosion resistance and leak-tight integrity are critical. Forged from 304L and 316L stainless steel, these flanges resist attack from acids, chlorides and oxidizing media commonly found in chemical plants, petrochemical facilities and pharmaceutical processing lines.

Available to ASME B16.5 and DIN 2633 standards, each chemical processing weld neck flange features a raised face sealing surface and a butt weld hub that delivers a smooth, crevice-free bore. The low carbon content of 304L and 316L minimizes sensitization during welding, preserving corrosion resistance at the heat-affected zone and extending service life in demanding chemical environments.

Product Specifications

Key Advantages

• Forged 316L and 304L stainless steel for superior corrosion resistance
• Low carbon content minimizes sensitization during welding
• Resists acids, chlorides and oxidizing chemical media
• Raised face sealing surface for reliable gasket performance
• Crevice-free butt weld bore reduces contamination risk
• Conforms to ASME B16.5 and DIN 2633 dimensional standards
• Full material traceability with EN 10204 3.1 certificates
• Suitable for pharmaceutical and food-grade processing lines

Frequently Asked Questions

Q: Why choose 316L stainless steel for chemical processing weld neck flanges?

A: 316L stainless steel contains molybdenum, which significantly improves resistance to pitting and crevice corrosion in chloride-containing chemical environments. Its low carbon content also prevents sensitization during welding, making it the preferred choice for chemical plant piping.

Q: What chemical media can these flanges handle?

A: Chemical processing weld neck flanges in 316L resist a wide range of acids, alkalis and salt solutions, including dilute sulfuric acid, phosphoric acid and chlorides. For highly concentrated acids or elevated temperatures, we recommend upgrading to duplex or nickel alloy materials.

Q: Do you offer flanges to DIN standards for chemical plants?

A: Yes, our chemical processing weld neck flanges are available to DIN 2633 (PN series) as well as ASME B16.5 (Class series). We also support EN 1092-1 dimensions for European chemical projects.

Manufacturing & Quality Control

Chemical processing weld neck flanges are forged and then solution annealed to restore corrosion resistance after hot working. The raised face sealing surface is machined to a controlled finish for reliable gasket performance, and each flange is pickled and passivated to remove surface contaminants and form a protective oxide layer. Material traceability is maintained from raw bar stock through to final inspection.

Q: Do you provide passivation and surface treatment for chemical flanges?

A: Yes, all stainless steel chemical processing flanges are pickled and passivated as standard. For pharmaceutical and high-purity applications, we can also provide electropolished finishes and certified cleanliness levels on request.

Q: What size range do you offer for chemical processing weld neck flanges?

A: We supply chemical processing weld neck flanges from 1/2 inch up to 24 inch in Class 150 through Class 600 ratings. Larger sizes and custom dimensions are available on request to suit specific chemical plant piping layouts.

     TOBO GROUP sales head offce in Shanghai. 

     We are one of the Professional manufacturers Exporter  Pipeline products  in China .Our company was established in 1998, the plant covers 550, 000 square meters and a construction area of 6,8,000square meters, existing 260 workers and 45 technicians. 

      We have five branch factories which can supply the best quality pipes, tubes, fittings flanges and related accessories. Now, it owns a number of advanced pipe production equipments, metal, forging, machining, cold forming, hot extrusion, such as heat treatment process, producing 60, 000 tons of pipe fittings. Company with a variety of detection devices, such as nondestructive testing, chemical analysis, metallographic examination, physical experiments. The technical is very strength, our main products contain fittingsforged socket welding fittings and threaded fittings, pipe weld and the materials of the products contain stainless steel ,duplex-stainless steel alloy steel.

       In addition, we are authorized by more than 120 top-class mills from South Korea,Japan and China like JFE,SUMITOMO,POSCO,BAOSTEEL, TISCO,LISCO,.TPCO,HENGYANG VALIN and so on .

Our main products as follows:

• Stainless steel pipe & tube

(seamless pipe / welded pipe / square pipe /  rectangular tube,duplex stainless / inconel tube)

• Carbon / alloy steel pipe & tube

(seamless pipe / ERW / SSAW / LSAW / UOE / hollow section pipe / Galvanized Pipe)

• Tubing and casting

(line pipe,water pipeline,gas pipeline,oil pipeline)

• Special steel tube

(copper tube/titanium tube/aluminium tube/nickel alloy )

• steel bar 

(round bar/angle steel /flat steel/channel steel/steel wire)

• Pipe Fittings

(eblows, equal / reducing tees, concentric/eccentric reducers, caps, crosses, bends, dish end/end cup, stub ends, unions, couplings / hex couplings, swage nipples , nipples, hex. plug, sockolet, weldolet, thredolet, etc)

• Flange

(DIN flange/ AISI flange/blind flange/welding flange/stainless flange/slip on flange)

• steel sheet / coil

(stainless steel/carbon steel/alloy steel/galvanized steel/aluminium )

• Valve

(ball valve/gate valve/butterfly valve/globe valve/swing check valve/ check valve) 

      In order to comply with the global modernization services development trends and eliminating the varieties distress of the global enterprise‘s purchase in the consumables.. We coordinate the pressure pipe manufacturer which with the scale of production,quality control and high cost performance (has passed ISO 9001 quality series attestation, ccs, DNV,PED/97/23/EC,AD2000-WO,special equipment manufacturing license,ASME-SA182.through a variety of effective assort mechanism to make up the shortage of supply and Post-processing of VAT enterprise, and to supply high quality pipe fittings, because of the superior quality and good service, we have established long term business cooperation with more than 60 countries and areas,which covers Europe, Africa, South America, North America, Middle East, Taiwan and South East Asia and so on.

      With many years effort and support from our valuable customers, these products have obtained a big market share in the world. 

      Our business principle is "Superior quality, Competitive price, Timely delivery and Considerate service " Standing to the principle of “Enterprises focus on the core business”, TOBO will actively promotes the globalization of business strategy approach, using advanced supply chain management technology to service for clients with higher quality and more competitiveness ‘ s products. At the same time, we sincerely reply your inquiry, honesty waiting for your visiting and wish to have cooperation with you at the any time. We welcome all the customers to contact us for more information. We assure you, with our technical knowledge and experience, our company will be one of your Stable, Continuate business parters in China.

 info@tobo-group.com