Overlay welded flange and flat welded ring loose flange

Disadvantages of flat welding ring loose flange:
1. Low pressure.
2. Low strength at the welding ring (especially when the thickness is below 3mm)
Production standard of flat welded ring loose flange:
National standard: GB/T9112-2000 (GB9113·1-2000～GB9123?4-2000)
American Standard: ANSI B16.5 Class150, 300, 600, 900, 1500 (WN, SO, BL, TH, LJ, SW)
Japanese standard: JIS 5K, 10K, 16K, 20K (PL, SO, BL, WN, TH, SW)
German standard: DIN2573, 2572, 2631, 2576, 2632, 2633, 2543, 2634, 2545 (PL, SO, WN, BL, TH)
Ministry of Chemical Industry Standards: HG5010-52～HG5028-58, HGJ44-91～HGJ65-91
Flange standard: HG20592-2009 (PN series)\HG20615-2009 (Calss series)
Ministry of Machinery Standards: JB81-59～JB86-59, JB/T74-1994, JB/T79-94～JB/T86-94
Pressure vessel standards: NB/T47020-2012～NB/T47027-2012, JB1157-82～JB1160-82 B16.47A/B B16.39 B16.48
Overlay/Overlay Flange
Standard number of marine lap welded steel flanges: This standard applies to marine products and marine engineering products. The main materials are: carbon steel, alloy steel, low temperature steel, stainless steel.
Forged flange connection is to connect two pipes, fittings or equipment, and forged flange connection is an important connection method for pipeline construction. Forged flange connection is easy to use and can withstand greater pressure.　In industrial pipelines, forged flange connections are widely used. In the family, the pipe diameter is small, and it is low pressure, and the connection of the flange stamping elbow is invisible. If it is in a boiler room or production site, flanged pipes and equipment are everywhere. The chromium content is 0.1%～0.5% (forged flanges generally do not contain chromium), the carbon content is below 1.0% and the forged flanges are manufactured by high-temperature forging, although some forged flanges have surface hardness (HRC) It can reach more than 56 (the hardenable layer is only about 15mm). Because the hardenability of the forged flange material is poor, the hardness of the core is generally only more than 30 degrees. Under normal circumstances, the forged flange is often treated with water quenching.