Duplex Steel Lap joint flange is having two components, a stub end, and a loose backing flange. Stub end is butt welded to the pipe and Backing flange freely move over the pipe. The backing flange can be of different material than stub material and normally of the carbon steel to save the cost. Lap flange is used where frequent dismantling is required, and space is constrained.
The lap joint flange is practically identical to a slip-on flange except it has a radius at the intersection of the bore and flange face. The lap joint flange is practically identical to a slip-on flange except it has a radius at the intersection of the bore and flange face. This radius is necessary to have the flange accommodate a lap joint stub end. Normally, a lap joint flange and a lap joint stub end are mated together is an assembly system.
Duplex Steel Lap Joint Flanges have all the same common dimensions as any other flange named on this page however it does not have a raised face, they used in conjunction with a "Lap Joint Stub End". These flanges are nearly identical to a Slip On flange with the exception of a radius at the intersection of the flange face and the bore to accommodate the flanged portion of the Stub End. Their pressure-holding ability is little, if any, better than that of Slip On flanges and the fatigue life for the assembly is only one tenth that of Welding Neck flanges.
Grade: 2205 (1.4507)
|Tensile strength||620MPa min||Density||7,805kg/m3|
|Yield strength||450MPa mi||Elastic modulus||200GPa|
Stainless Steel :
Grade: 304 (1.4301), 304L (1.4307), 304H (1.4948), 309 (1.4828), 309S, 310, 310S (1.4845) , 316 ( 1.4401), 316H, 316L( 1.4404 /1.4432) , 317, 317L (1.4438), 321 (1.4541), 321 H(1.4878), 347 (1.4550), 347H (1.4961), 904L (1.4539)
Grade: Nickel 200, Nickel 201
Super Duplex Steel:
Grade: 2507 (UNS S32750) (1.4410) (UNS S32750), Z100
Grade: Inconel 600 (2.4640), Inconel 601 (2.4851), Inconel 625 (2.4856), Inconel 718(2.4668)
Grade: Gr.1 (3.7025) , Gr.2 (3.7035) , Gr.3:(3.7055) , Gr.5(3.7164/65), Gr. 7(3.7235) , Gr. 11 (3.7225)
Grade: Monel 400 ( 2.4360), Monel K500, Monel R-405
Grade: Hastalloy B2, Hastalloy B3, Hastalloy C22, Hastalloy C276, Hastalloy X
Grade: Incoloy 800 (2.4958), Incoloy 800H, Incoloy 800HT
The manufacturing process of flange mainly is divided into forging, casting, cutting and rolling. .
The casting and forging flanges have advantages that the blanks of them have accurate shape, size and low costs and only need simple process. But forging flanges have manufacturing defects such as blowholes, cracks, etc and have not very smooth internal organization streamline. The obvious advantages of forging flanges are that they can be forged in various shapes and they have low costs. .
Forging flanges generally have lower carbon content than the casting flanges and are not easy to rust. They have smooth streamline, uniform internal organization, and better mechanical performance than that of casting flanges. There are no defects, such as blowholes and cracks existing in the casting flanges. Forging flanges are able to withstand higher shear and drawing forces than casting flanges. However, if adopting improper forging process, it will also cause appearance of large, uneven grains and solidification cracking phenomenon, resulting in higher cost than the casting flanges. .
We can distinguish between the casting flanges and forging flanges from the different production process. To take the centrifugal flange as an example, it is a kind of casting flange. Centrifugal flanges are produced by a precision casting method, which makes the flanges’ organization smaller than those commonly produced by sand casting and improves the quality of flanges, making fewer occurrences of loose tissue, pore, sand hole etc.
Cutting process refers to producing flanges by directly cutting a round plate with the inner diameter, outer diameter and thickness which can be further processed later from the middle plate, and then processing the bolt hole and waterline. The maximum diameter of such flanges is limited by the width of the middle plate.
Cutting process refers to producing flanges by cutting stripes from the middle plate and then rolling them into round shape. This process is mainly used for the production of large flange. After the rolling process, weld and then flatten the round shape, and finally process the serrated spiral finish and bolt hole.