VALVE TRIM

Last updated: 28 Aug 2026

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Valve trim refers to the internal components of a valve that directly influence fluid flow performance and the likelihood of operational incidents.

Valve trim consists of four key components that must be considered: the seat, disc, back seat, and stem. These components are replaceable. Selection of the valve trim must be appropriate for the specific application, taking into account factors such as the type of fluid, operating pressure, and temperature.

Designers can currently select a Trim Number from the API 600 Trim Number table to suit the specific application. The Trim Numbers commonly used in the industry are as follows:

API600 Trim Number 13th Edition
Trim Number	Material	Seat	Disc	Back Seat	Stem	Service
5	Hard Faced	Hard Faced	Hard Faced	13%Cr	13%Cr	Suitable for high-pressure applications; offers superior wear resistance compared to Trim #8. Recommended for high-pressure steam service at temperatures not exceeding 450°C.
8	13%Cr+ Hard Faced	Hard Faced	13%Cr	13%Cr	13%Cr	Suitable for general applications; capable of withstanding high pressure and offering excellent resistance to corrosion and wear. Ideal for use with steam, gas, oil, and hot water. Recommended for operating temperatures not exceeding 250°C.
10	316	316	316	316	316	Suitable for use with highly corrosive fluids and at sub-zero temperatures.
12	316+Hard Faced	Hard Faced	316	316	316	It functions similarly to Trim #10 but offers superior corrosion resistance due to hard-facing on the seat; it is suitable for use in both high-temperature and cryogenic applications.
16	Hard Faced	Hard Faced	Hard Faced	316	316	Suitable for high-pressure, ultra-high-temperature steam applications, as well as cryogenic or high-temperature gas service. It offers excellent resistance to corrosion and wear, and is recommended for operating temperatures exceeding 450°C.