Gate valves hot forging: Mecolpress solution

Gate valves hot forging can present some criticalities. Mecolpress hydraulic presses could brilliantly overcome these, reducing production costs and consenting to obtain a forged part without flash.

The most commonly hot forged brass parts are the ones used for the liquids control.

The parts can be, for example:

• water meters bodies,
• ball valves,
• water and gas fittings,
• gate valves.

These latter ones have the function of fluid flow adjusting and stopping onto a tube and they fulfill it by controlling through an handwheel (or a motorized actuator) the interposition of a disc between the in- and out- sections of the valve. In order to better visualize their movement, you can image it like the closing of a gate slide in the middle of a tunnel.

Also depending on application typology, every manufacturer develops his own drawing for valves that are characterized by contours, dimensions and always different thicknesses.

The range of measures of the valve is very wide. These measures are usually defined in inches and are related to the useful section of fluid passage when the valve is totally open.

Also the working pressures, the valve control and the working environment determine the need to have valves with hose joints that are more or less distant from the valve center, with circular section neck valve o irregular hexagon section neck valve, with greater of minor neck height.

Normally the hot forging of a gate valve is not very easy to realize, above all if you want to forge the part without possible defects, using little material (therefore with most possible depth of all the holes) or without flash as well.

The traditional forging with eccentric mechanical presses of gate valves requires a greater energy compared to the forging of ball valves having the same dimensions, and a punches stroke, in particular of one, much higher.

For example, for the realization of gate valves of 2 inches or more, eccentric mechanical presses of minimum 450 tons capacity and a forging tool (defined as bell tool) that allows the realization of holes of great diameter are normally used.

This technology has been valid and successfully used for many years, and Mecolpress as well proposes it to its customers through its SEO and SEO CVE CS presses series.

But there is also a much more efficient way for gate valves hot forging: the hydraulic press.

Gate valves can be hot forged even by means of Mecolpress hydraulic press of ME series.

Our ME presses allow to forge these valves completely flashfree, with very high precision, without risk of defects due to the brass flow in the die.

Moreover, also the productivity is higher than the one allowed by traditional method with eccentric mechanical presses and bell tool.

An hydraulic Mecolpress press ME350-4G240, for example, can forge 2 inch gate valves flashfree, without the help of special tools, with a productivity of about 800 parts/hour.

Exactly for this application in January 2019 we supplied a hydraulic press ME350 to one of the most important valve manufacturers of Far East.

We started the collaboration with the customer by studying the “traditional” valve geometry and after the forging simulations carried out by our technical office, we could verify that some improvements connected to the shape were possible.

Indeed, the study showed that the thicknesses could be reduced and therefore it was possible to reduce the weight and the cost of the forged part. Moreover, our technicians considered useful to modify corners and corner rounding to ease the brass flow. These modifications grant a longer die duration.

Once the approval from the customer for the new geometry was obtained, we realized the die and then a sample of these valves that were sent to the customer both for dimensional checks and for mechanical machining tests.

All the tests gave successful outcome and now the customer is impatient to receive the hydraulic press and to start producing this with this new much more efficient method that will reduce considerably the necessary brass quantity to realize the hot forged valve.

Over the years Mecolpress has developed a considerable experience in gate valves hot forging field and for every valve shape, or brass alloys to be used, including, for example, brass without lead or anti-dezincification brass.