How to reduce weight on valve blocks by using NNS HIP

Valve blocks are key components used to control flow in a variety of applications in several demanding industries such as O&G and chemical. The design and complexity of the valve blocks varies depending on the application. Using O&G as an example, large blocks can be found on well completions systems like Christmas Trees (XMT) as master valve blocks, annulus valve blocks or as production valve blocks.

Traditionally these valve blocks have been manufactured from forged blocks followed by extensive machining making them often square in shape as shown in the figure below.

As a direct consequence of the inability of the forging process to be able to produce complex shapes, in combination with the ambition to reduce machining in order to lower cost, often results in a large block with a lot of unnecessary material added. Material which adds weight on to the overall assembly which in turn impacts the total project cost negatively as installation costs normally go up with the increase in weight on subsea fields.  

Utilizing Powder Metallurgy Near Net Shape Hot Isostatic Pressing (PM NNS HIP) enables the possibility to create a more complex shaped blank. This technology provides the opportunity to remove unnecessary material and still keep machining costs low by giving the designer the control to design a valve block which has the same flow paths and functions with a drastically reduced weight. An example on a HIP:ed valve block with an identical function as a forged valve block can be seen in the figure below.

The weight of the raw blank, machined weight as well as the amount of material removed in machining can be seen in the table below.

If you want to learn more about the design mentality for PM NNS HIP we recommend to read our previous article “PM NNS HIP - The best additive manufacturing process in the world!” which covers the differences in design thinking when approaching forging vs HIP.

Another major benefit when using PM NNS HIP is the ability to integrate channels in the HIP blank reducing costly long hole drilling which is normally required when using traditionally manufacturing techniques such as forging. The channels inside the valve block could have a variety of complexity but even on blocks with fairly simple internal routings benefit with integrating channels using HIP can be found. Below you can see the same forged block as previously shown with the internal channels visible:

The exit at the bottom has no function and needs to be either blanked off by a blank or weld plugged. Both of these solutions introduce additional unnecessary costs into the project due to the forging process design.

Using a PM NNS HIP approach only necessary channels in the blank can be integrated without any “exits” which eliminates the need for additional costs. An example of this is shown in the figure below were the exit at the bottom has been removed as PM NNS HIP enables channels to be made without any machining.

Optimizing the flow channels inside the block can also be created with radiuses when using NNS HIP if deemed beneficial.

Using the O&G industry again as an example the valve blocks can also be utilized in harsh environments were corrosive medias is common and as a consequence introduces the need to use expensive Inconel cladding on wetted surfaces, or in some instances entire bores, depending on trim requirements. With complex internal flow paths the cost for the Inconel 625 weld overlay could exceed the cost for the raw material of the block itself.

Instead of a focus on the cost of the raw material there is a trend now shifting to look more closely at the entire cost of a product. For example using a HIP:ed 25Cr Super Duplex material like APM 2327 with excellent corrosive resistance would eliminate the necessity of an Inconel 625 overlay and ultimately reducing the total project cost. Also, removing operations impacts project risk and lead time in a positive way.

So whatever you are designing, be it an Xmas tree containing valve blocks, a manifold block, or valves used in the chemical industry you can make a positive choice and take the blocks to the next level. Get in touch with the experts in MTC Powder Solutions (MTC PS)!