• Steel Flanges

    A flange is a method of connecting pipes, valves, pumps and other equipment to form a piping system, provides easy access for cleaning, inspection or modification. read more

  • Pipe Fittings

    The ends of all buttweld fittings are bevelled.The shape of the bevel depending upon the actual wall thickness.This bevelled ends are needed to be able to make a "Butt weld". read more

  • Steel Pipes

    Pipe is a hollow tube with round cross section for the conveyance of products. The products include fluids, gas, pellets, powders and more. read more


This Standard specifies steel pipe flanges (hereafter referred to as “flanges”) of nominal size 10A to 1500A for nominal pressure 5K, 10K, 10K light type,16K, 20K and 30K which are used to join parts for piping, such as steel pipes and valves, in ordinary(1),pressure (2), high pressure (3), high temperature (4), alloy steel pipes (5), strainless steel pipes (6) piping for steam, air, gas, water, oil, etc. (7).


  • Piping using Carbon steel pipes for ordinary piping of JIS G 3452 and arc welded carbon steel pipes of JIS G 3457.
  • Piping using Carbon steel pipes for pressure service of JIS G 3454.
  • Piping using Carbon steel pipes for high pressure service of JIS G 3455.
  • Piping using Carbon steel pipes for high temperature serivce of JIS G 3456.
  • Piping using Alloy steel pipes of JIS G 3458.
  • Piping using stainless steel pipes of JIS G 3459 and large diameter welded stainless steel pipes of JIS G 3468.
  • Integral flange, which is to be used as part of some other equipment or components, shall also be within the scope of this Standard.

Weld Neck Flange
Integral Flange
Blind Flange
Socket Weld Flange
Threaded Flange
Plate Flange
Slip On Flange Type A
Slip On Flange Type B
Slip On Flange Type C
Loose Flange/Lap Joint Flange

Classification of flanges and the designation

Classification of flange Designation Figure
Welding flange Silp on plate flange SOP Silp-on-plate-flange
Slip on hubbed flange SOH Socket-welding-flange
Socket welding flange SW Socket-welding-flange
Welding neck flange WN Welding-neck-flange
Lap joint flange LJ Lap-joint-flange
Threaded flange TR Threaded-flange1
Intergral flange IT Intergral-flange
Blank flange BL Blank-flange

Types of nominal pressure 20 K and 30 K slip on hubbed flanges

Classification of flange Type Figure
Slip on hubbed flange Type A Slip-on-hubbed-flange-A
Type B Slip-on-hubbed-flange-b
Type C Slip-on-hubbed-flange-c

Latest Products

08 2016 04
07 2016 04
19 2016 03
15 2016 03

Our Markets

haihao has been a professional supplier of pipes,fittings and flanges, serving the world industry piping since 1982.
oil and gas industry

as a leading manufacturer,stockist and supplier, our knowledgeable and experienced technical team can understand well what you need . help you find the best solution for your regular and specific requirement.
contact us


Serving the world flowing! Aiming to be the best in the field! Improving level of “Made in China”!”

Tom , Haihao Group

Our References