What Is The Differences Between Soft Seat And Metal Seat

Both soft seated ball valves and metal seated ball valves are general valves. We can analyze their differences from five perspectives.

                                  Soft seat                                                                      Metal Seat

1.Different structure between soft seat and metal seat

Generally, for metal seated ball valves, it is metal to metal sealing, which means that the ball and seats are all metal material. However, for the soft seated ball valve, one or two seats use soft material.

2.Different material between soft seat and metal seat

For metal seated ball valves, the seat usually use stainless steel, carbon steel and copper materials. Metal seat materials require precision machining to ensure a precise fit with the ball. 

And for soft seated ball valve, the sealing material mounted on the valve seat is non-metallic. Becase there is a elasticity on the soft seat, therefore, its processing accuracy requirements are lower than that of hard-sealed seats.

3.Different application conditions between soft seat and metal seat

The soft seal is made of non-metallic material, and the hard seal is made of metal material

For the sealability, the sealing performance of soft seal is very good. However, the sealing performance of the hard seal can be determined according to the requirements.

Metal seat can be used in high pressure applications, but the soft seat can only used in medium and low pressure applications.

For soft seated ball valves, it need a fireproof structure, because the soft seat will have deformation and leakage while under high temperatures. But a metal seated ball valve does not require a fireproof structure. 

Soft seals are not as wear-resistant as hard seals, soft seals are not suitable for media containing particulate matter. 

The cost of hard sealed ball valves is higher than that of soft sealed ball valves.

4.Different manufacture standard between soft seat and metal seat

For metal to metal seat, we have to consider the hardness between ball and seats, and also the applications and media. The metal seat and ball need to spary the  hard coating. Continuous grinding is required between the ball and the seat to achieve seal. Thus, the metal seated ball valve has a longer production period and complex process.

Hard Coating

5.Different equipment selection between soft seat and metal seat

When the medium contains particulate matter, and temperature over 200 degrees, it is more suitable to choose a metal seat. When the diameter is larger than DN50, if the valve pressure difference is large, we also need to consider the torque. When the torque is large, we usually choose metal seat.

Above are the differences between soft seat and metal seat. If you still don’t know how to choose the seat, please feel free to contact us, our professional techncian will provide you the good advice.