Flange, also known as flange flange disc or flange. Flange is a part connected between shaft and shaft, which is used to connect pipe ends. Flange is also used in the import and export of equipment, which is used to connect two equipment, such as reducer flange. Flange connection or flange joint refers to the removable connection of flange, gasket and bolt as a group of combined sealing structures. Pipeline flange refers to the flange used in piping equipment, and the flange used in equipment refers to the import and export flange of equipment. There are holes in the flange, and the bolts connect the flanges tightly. The flanges are sealed with gaskets. Flange is divided into threaded connection (screw connection) flange, welding flange and clamp flange. Flanges are used in pairs. Wire-jointed flanges can be used in low-pressure pipelines, and welding flanges can be used under pressure of more than four kilograms. A gasket is added between the two flanges and then bolted. The thickness of flanges under different pressures is different, and the bolts they use are also different. When the pump and valve are connected with the pipeline, the parts of these equipment are also made into corresponding flange shape, also known as flange connection. Where bolts are used around two planes to connect joints that are closed at the same time, they are generally referred to as "flanges", such as the connection of ventilation pipes, which can be called "flanges". But this connection is only part of a device, such as the connection between flange and pump, so it is difficult to call the pump "flange parts". Comparatively small, such as valves, can be called "flange parts".
Material analysis
The vessel inner diameter Di=4000mm, the calculated pressure Pc=0.4MPa, the design temperature t=50 C, the standard elliptical head, the material 16MnR (the allowable stress of material is 170MPa at the design temperature), the negative deviation of steel is not more than 0.25mm and does not exceed 6% of nominal thickness, the corrosion margin C2=1mm, the welding joint coefficient of tailor welded head?=1. The calculated thickness, design thickness and nominal thickness of elliptical head are calculated.
KpDi
Calculated thickness delta=------------------------= 4.73mm
2 [_] t-0.5pc
Calculated thickness delta d = delta + C2 = 4.73 + 1 = 5.73 mm
Considering that the effective thickness of standard elliptical head should not be less than 0.15% of the inner diameter of head Di, and the effective thickness should be 0.15% of Di=6mm.
Delta E > Delta d, C1 = 0, C2 = 1, nominal thickness delta n = delta e + C1 + C2 = 6 + 0 + 1 = 7mm
Considering the standard gauge thickness of steel, the thickness of the first design circle 1 = 1 is floating 1 mm, so the value of delta n = 8 mm is chosen.
According to the technical data of professional head manufacturer, Di = 4000 and delta n = 8 head thinning C3 = 1.5mm are processed. The second round integral value of thickness is delta 2 = 0.5.
If the forming thickness of the head must not be less than the nominal thickness of the head and the negative deviation of the steel plate C1 is reduced, the feeding thickness shall be as follows:
Delta s = Delta n + C1 + C3 + Delta 2 = 8 + 0 + 1.5 + 0.5 = 10mm, and the minimum thickness after forming is 8.5mm. If the forming thickness of the head is not less than the design thickness, the feeding thickness is as follows: delta S = delta D (delta e) +C3 + Delta 2 = 8mm, and the minimum thickness after forming is 6.5mm, which is larger than the effective thickness, the design thickness, delta D and the calculated thickness.
It can be seen from the above that two different requirements make the feed thickness of the head differ by 2 mm and the weight difference is as much as 300 kg.
Definition of thickness
The thickness definition of GB150 and related standards is not very reasonable, mainly reflected in the thickness requirement of container and head after forming. The thickness requirement of convex head and hot drum should not be less than the nominal thickness minus negative deviation of steel plate (delta n-C1). This may lead to the increase of thickness on the basis of design thickness twice in design and manufacture. To ensure the forming thickness. For this reason, the concept of minimum forming thickness has been put forward: "The thickness of hot-rolled cylinder or convex head should be guaranteed after processing and forming, and its value is not less than the design thickness". That is to say, the designer should mark the nominal thickness and the minimum forming thickness (i.e. the design thickness Delta d) on the drawing, so that the manufacturer can decide whether to add the manufacturing thinning according to the manufacturing process and the design roundness of the original design. The definition and marking of thickness is a popular method in the international pressure vessel industry up to 2013, which has its rationality. However, there are two problems to be solved in the current standards in China.
Connection mode editing
Flange connection is to fix two pipes, fittings or equipment on a flange separately, between the two flanges, plus flange pad, and fasten them together with bolts to complete the connection. Some pipe fittings and equipment have their own flange, also belong to the flange connection. Flange connection is an important connection mode in pipeline construction. Flange connection is easy to use and can withstand greater pressure. In industrial pipelines, in the family, the diameter of the pipeline is small, and it is low pressure, so the flange connection can not be seen. If you are in a boiler room or production site, there are flanged pipes and equipment everywhere.
1. According to the types of flange connection, flange connection can be divided into: plate flange, necked flange, necked butt welding flange, socket flange, thread flange, flange cover, necked butt welding ring flange, flat welding ring flange, ring groove flange and flange cover, large-diameter flat flange, large-diameter high-neck flange, eight-character flange. Blind plate, loose flange of butt welding ring, etc.
Welding Quality Editor
As iron plate welding flange, many customers question whether the quality of iron plate welding flange is better than forging welding flange. In fact, the quality of welded flange is the same as that of forged welded flange, but where on earth can't the welded flange be guaranteed, that is, the material of welded flange is the least guaranteed, because in the general process, the density of welded flange is not a problem, but in the process of production. In the process of production, the blank of welded flange of iron plate