Classification of marine flanges

Haihao Group manufacture & supply forged flanges in different dimensions,specifications,standards,materials,our forged flanges are used in many fields,such as shipbuilding,oil & gas,chemical,water treatment,power plant,steam,construction and so on.We produce the marine flanges in different types,which contain flat flange,weld neck flange,lap joint flange,hydraulic flange.

Stainless steel SS316 weld neck flanges and slip on flanges

Stainless steel SS316 weld neck flanges and slip on flanges

Marine flat welded flanges

Flanges are welded by inserting pipes into inner rings of flanges. Flat welded flanges are divided into flanges with necks and flanges with lap welding. Flat welded flange has the advantages of simple manufacture, low production cost,but not high temperature and high pressure resistance.It is mainly used in normal temperature pipelines with pressure less than 2.5 MPa,and is the most widely used flange in ships.

Marine weld neck flanges

Marine weld neck flange is one of the butt welding product,refers to the flange with neck,which has the transition of circular pipe and is butt welded with the tube.The marine weld neck flange is rigid,not easy to deform,well sealed and widely used. It is suitable for high pressure and temperature situations. The nominal pressure PN is about 16 MPa. Mainly used for compressed air piping and carbon dioxide piping.

Lap joint flange or loose flange finished in Haihao Group

Lap joint flange or loose flange finished in Haihao Group


Marine lap joint flanges

Generally,the material cost of pipeline is very high.In order to reduce the cost,we adopt the same material as the pipeline’s internal fittings and different materials of flange combination.That is to say,flange is sleeved on the end of the pipeline by flanging,steel ring and so on. The flange can move on the end of the pipeline.Lap joint flanges are generally used in copper-nickel alloy pipes and expansion joints.

Marine hydraulic flanges

The pressure of ship hydraulic piping system is very high,so special socket high-pressure method is adopted.The thickness of hydraulic flange is about 30mm-45mm according to the diameter of the pipe.This kind of flange generally adopts a concave flange and a convex flange,using O-ring as sealing material.

We are specialized in the production of forged steel flanges,and we also have engaged in research and design in flanges,rings,customized forgings,and have made excellent achievements in the high quality flange industry.If you want to know more about our flange products,please email


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