Flanged Gate Valve Welding Technical Requirements and Connection Mode

1. What are the technical requirements for welding flanged gate valves?

Many people know that the working environment of flanged gate valve is more demanding, there are certain technical requirements in welding, of course, on the one hand, but also because there are many factors that affect welding, today we will understand together.

Flanged gate through the weld and the influence factors of weld metal mechanical properties, as well as the analysis of welding test results, a reasonable design of body structure, weld groove forms, the structure of the valve seat, strictly control the chemical composition of body material, choose reasonable welding wire flux and process parameters, timely control of the process of welding interlayer temperature, It can meet the welding production requirements of flanged gate valve.

In the design of fully welded joint of flanged gate valve body, for alignment and positioning, there is a ring assembly crack in the weld root. This crack will produce stress concentration several times the normal working stress under the action of internal pressure and external load, which also makes it difficult for engineers to deal with.

Directly buried welding ball valve can be directly buried in the ground, without building a large valve well, only set up a small shallow well on the ground, greatly saving construction costs and engineering time. The length of the valve body and the height of the stem can be adjusted according to the construction and design requirements of the pipeline.

2. Flanged gate valve several ways of connection

In general, our common valve connection mode mainly has these kinds of flange connection, thread connection, welding connection. Do you know the difference between the three?

Flanged valves are easier to install and remove, but flanged valves are bulkier and more expensive than threaded valves, so they are suitable for pipe connections of all sizes and pressures.

Threaded valves are mainly valves with nominal diameters under 50mm. If the diameter size is too large, it is very difficult to install and seal the joint.

Threaded connections are usually made of tapered or straight pipe threads at the valve inlet and outlet ends, which can be connected to tapered pipe thread joints or lines.

In the nominal diameter is large, the use of harsh conditions, high temperature occasions, flanged gate valve body often use groove welding, at the same time, welding joints have strict requirements, must choose a strong technical welder to complete the work.

Welded valves with nominal diameters up to 50mm usually have welded jacks to hold the pipe at the flat end of the load. Welded valves can be difficult to disassemble and reinstall.

Therefore, its use is limited to usually long-term reliable operation, or the use of harsh conditions, high temperature occasions. Such as thermal power station, nuclear energy project, ethylene project on the pipeline.