Shanxi Hongkai Forging Co.,Ltd.

Company Profile

Shanxi Hongkai specializes in Forged flanges & Forging Parts, with integrated capabilities covering forging, heat treatment, machining, physical/chemical testing, surface treatment, and logistics. We comply with ASME B16.5, EN1092-1, DIN, UNI, BS4504, JIS, and GOST standards. Main products include High Neck, Lap Joint, Socket Weld, Slip-On, Threaded, Blind, and Flat flanges, size DN15–DN4000. We are mainly exported to Europe, American, and other regions. With superior quality, comprehensive packaging/logistics, and scientific technical support, we have earned strong market recognition.

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  ASTM A105 Carbon Steel Forged Blind Flange

  ASTM A105 Carbon Steel Blind Flange – ASME B16.5 – Class 150 to 2500 Our ASTM A105 carbon steel blind flanges are manufactured to ASME B16.5, serving as reliable pipe end closures for oil & gas, petrochemical, power plants, and pressure testing applications. Available from ½" to 48" (DN15–DN1200), with pressure ratings Class 150 through Class 2500 (PN20–PN420). Solid disc design ensures complete isolation, enabling safe maintenance and system expansion. We source premium ingots from Baosteel and TISCO with full mill certificates. PMI verification confirms chemical composition per ASTM A105/A105N. Using 2,500–6,300 ton forging presses and ring-rolling mills, we refine grain structure, eliminate porosity, and achieve tensile strength ≥485 MPa, yield ≥250 MPa, elongation ≥22%. For low-temperature service down to -46°C, A350 LF2 grade is available with Charpy impact testing. All flanges undergo full normalizing (870–930°C) in programmable furnaces with digital time-temperature curves per batch. This eliminates residual stress, ensures uniform hardness (HB 137–187), and improves machinability. Q&T treatment also offered for higher strength grades. CNC vertical lathes and boring mills deliver high accuracy: Sealing faces: RF, FF, MFM, TG, RTJ per ASME B16.5. Surface roughness Ra ≤3.2 μm for RF, and ≤1.6 μm for RTJ grooves. Bolt circle tolerance ±0.5 mm, hole diameter H14 grade for easy field alignment. Thickness calculated per ASME VIII with safety factor ≥3.0, plus +1.0 mm machining allowance. 100% Non-Destructive Examination UT (ultrasonic) on all flanges DN150 & above per ASME V. MT (magnetic particle) on sealing faces and bolt holes to detect surface cracks. PT for stainless grades. Hardness testing per piece; hydrostatic (1.5× rated) or pneumatic (1.1×) tests available upon request. Every inspection record is compiled into a traceable quality dossier. Each flange is laser-marked with standard, material, class, size, heat number, and batch code for full traceability from raw material to finished product. Customer-specific markings also available. Standard coating: anti-rust varnish + protective pads on sealing faces. Options: hot-dip galvanizing, zinc plating, or epoxy powder coating for corrosive environments. Export packaging: VCI paper + polyethylene bag + foam padding, stacked on ISPM-15 plywood pallets with steel strapping. Large sizes bolted to steel cradles. Container stuffing secured with dunnage bags for sea freight safety. Documentation Each shipment includes: commercial invoice, packing list, bill of lading, COO, EN 10204 Type 3.1/3.2 MTC, NDE reports, heat treatment charts, and compliance declaration. Third-party inspection (SGS, BV, TÜV) coordinated upon request.
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  ASME Carbon Steel Forged Weld Neck Flange

  Weld Neck Flange (also called as WN Flange) is a high-integrity, heavy-duty piping connection component widely used in industrial systems.  Characterized by a long, tapered hub that transitions smoothly to the pipe, it forms a permanent and robust joint through butt welding with the pipeline. This design ensures exceptional structural strength and leak-tight performance, making it the preferred choice for critical applications involving high pressure, high temperature, and volatile or corrosive media. Compliant with global standards such as ASME, EN, GOST, and JIS, our WN flanges are manufactured with precision to meet the diverse requirements of international projects.
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  ASME carbon steel forged plate Slip On flange

  Slip On Flange (also called as SO Flange) is a widely used piping connection component characterized by a hollow, cylindrical design that slips over the outer surface of a pipeline. It forms a secure joint through fillet welding on both the inner and outer sides of the flange hub, balancing reliability, ease of installation, and cost-effectiveness. As one of the most popular flange types in industrial applications, it is designed for moderate pressure and temperature conditions, with dimensions and specifications compatible with global standards such as ASME, EN, GOST, and JIS. Our SO flanges are widely adopted in general industrial pipelines due to their simple structure, convenient alignment, and economical cost.
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  ASME carbon steel forged Thread flange

  Threaded flanges are mechanical components that achieve non-welded connections between pipe threads and threaded pipes through internal hole processing. They belong to a detachable connection method. They are convenient for installation and maintenance, especially suitable for alloy steel pipeline systems where welding is prohibited and for special material connections with poor welding performance, effectively avoiding the additional stress caused by welding deformation. They are mostly used in low-pressure or dangerous liquid scenarios where welding is not allowed. They are typically limited to Class 300 and below, or PN40 and below.
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  ASME/EN1092/DIN/JIS Carboon Steel Forged Lap Joint Flange

  The Lap Joint flange is a movable flange plate. Its structure is divided into two parts. One end of the pipe section is connected to the pipeline, and the other end is made into a socket weld ring.  This structure can effectively save costs. However, it can withstand relatively low pressure. It is commonly used in situations where the medium temperature and pressure are not high, but the medium is highly corrosive.It is suitable for low-pressure environments and can be frequently disassembled.
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  ASME/EN1092/DIN/JIS Carboon Steel Socked Weld Forged Flange

  The socket weld flange has a similar appearance to the Slip-On Flange, but there is a socket step inside the flange. After the pipe is inserted, welding connects them together.  It is suitable for low-temperature and low-pressure applications, with pipe diameters less than 80.  The advantages of the socket weld flange are that the flange can be quickly removed, which is suitable for systems that require frequent maintenance and replacement. However, its sealing performance is poor, and it is suitable for use in drainage systems with water accumulation.  The pressure rating is Class 150 to Class 1500, or PN10 to PN160. It is a common choice for small-diameter high-pressure pipes.