Mechanical seal sealing ring (non-graphite ring) hot mounting

In the previous article, we focused on the hot mounting of graphite rings. This article talks about the hot  mounting of non-graphite rings for mechanical seals.

1.Tungsten carbide and silicon carbide rings

Ring seat of the mechanical seal heating temperature are dependant on the particular materials: various types of austenitic stainless steel, duplex steel, HastB/C: 350℃～400℃; titanium material: 450℃～500℃; The heating temperature is related to the diameter D of the ring seat. The upper limit is taken when D≦100mm, and the lower limit is taken when D>100mm.

2.MFL type ring seat made of 4J42 

In order to avoid reprocessing on the ring seat after mounting, (because the welding tip cannot be welded for finishing turning) the hot mounting procedure for tungsten carbide and silicon carbide is as follows:

The heating temperature of the ring seat is 240℃~290℃; use a pressing machine (pressure 0.5t~1.5t) to press the insert ring into the ring seat of the mechanical seal. Note: A support ring is added to the surface of the ring seat welding nozzle, the inlaid ring is below, and the bottom surface is protected by a polished support plate. After the component has cooled, check the gap between the bearing surface and the insert ring of the mechanical seal.

3.Insert rings for high-pressure mechanical seals (carbon graphite and silicon carbide rings) 

For all ring seats and insert rings used for high-pressure mechanical seals, their supporting surfaces need to be ground and mounted under pressure in a (hydraulic) pressing machine. Attention should be paid to selecting the supporting gasket suitable for the ring seat and the insert ring of the mechanical seal.

If the mounting pressure is indicated on the drawing, after the mounting parts of the mechanical seals reach the specified level in the pressing machine, the pressure should be kept for 2 to 5 minutes for large batches of parts, and for single parts and large-diameter parts (diameter D>100mm), the pressure should be kept for 10 minutes. .

If the mounting pressure is not indicated on the drawing of the mechanical seal the following provisions are valid: Diameter D＜50mm, pressure 2~5t. Diameter D=50~100mm, pressure 5~10t. Diameter D＞100mm, pressure 10~25t. Depending on the size of the ring, the holding time in the pressing machine is 2 to 10 minutes.