THE REMOVABLE AND REPLACEABLE VALVE INTERNAL PARTS that come in contact with the flow medium are collectively termed as VALVE TRIM. These parts include valve seat(s), disc, glands, spacers, guides, bushings, and internal springs. The valve body, bonnet, packing, et cetera that also come in contact with the flow medium are not considered valve trim.

A Valve’s trim performance is determined by the disk and seat interface and the relation of the disk position to the seat. Because of the trim, basic motions and flow control are possible. In rotational motion trim designs, the disk slides closely past the seat to produce a change in flow opening. In linear motion trim designs, the disk lifts perpendicularly away from the seat so that an annular orifice appears.

Valve trim parts may be constructed of assorted materials because of the different properties needed to withstand different forces and conditions. Bushings and packing glands do not experience the same forces and conditions as do the valve disc and seat(s).

Flow-medium properties, chemical composition, pressure, temperature, flow rate, velocity and viscosity are some of the important considerations in selecting suitable trim materials. Trim materials may or may not be the same material as the valve body or bonnet.

API has standardized trim materials by assigning a unique number to each set of trim materials.

 1

NOMINAL TRIM410

TRIM CODEF6

STEM AND OTHER TRIM PARTS410 (13Cr) (200-275 HBN)

DISC/WEDGEF6 (13Cr) (200 HBN)

SEAT SURFACE410 (13Cr)(250 HBN min)

TRIM MATERIAL GRADE13Cr-0.75Ni-1Mn

SERVICEFor oil and oil vapors and general services with heat treated seats and wedges. General very low erosive or non-corrosive service between -100°C and 320°C. This stainless steel material lends itself readily to hardening by heat treatment and is excellent for contacting parts such as stems, gates, and discs. Steam, gas and general service to 370°C. Oil and Oil vapor 480°C.

 2

NOMINAL TRIM304

TRIM CODE304

STEM AND OTHER TRIM PARTS304

DISC/WEDGE304 (18Cr-8Ni)

SEAT SURFACE304 (18Cr-8Ni)

TRIM MATERIAL GRADE19Cr-9.5Ni-2Mn-0.08C

SERVICEFor moderate pressure in corrosive, low erosive service between -265°C and 450°C.

 3

NOMINAL TRIM310

TRIM CODE310

STEM AND OTHER TRIM PARTS(25Cr-20Ni)

DISC/WEDGE310 (25Cr-20Ni)

SEAT SURFACE310 (25Cr-20Ni)

TRIM MATERIAL GRADE25Cr-20.5Ni-2Mn

SERVICEFor moderate pressure in corrosive or non corrosive service between -265°C and 450°C.

 4

NOMINAL TRIM410 – Hard

TRIM CODEF6H

STEM AND OTHER TRIM PARTS410 (13Cr) (200-275 HBN)

DISC/WEDGEF6 (13Cr) (200-275 HBN)

SEAT SURFACEF6 (13Cr) (275 HBN min)

TRIM MATERIAL GRADE13Cr-0.75Ni-1Mn

SERVICESeats 275 BHN min. As trim 1 but for medium pressure and more corrosive service.

 5

NOMINAL TRIM410 – Full Hard faced

TRIM CODEF6HF

STEM AND OTHER TRIM PARTS410 (13Cr) (200-275 HBN)

DISC/WEDGEF6+St Gr6 (CoCr Alloy) (350 HBN min)

SEAT SURFACE410+St Gr6 (CoCr Alloy) (350 HBN min)

TRIM MATERIAL GRADE13Cr-0.5Ni-1Mn/Co-Cr-A

SERVICEHigh pressure slightly erosive and corrosive service between -265°C and 650°C and higher pressure. Premium trim service to 650°C. Excellent for high pressure water and steam service.

 5A

NOMINAL TRIM410 – Full Hard faced

TRIM CODEF6HF

STEM AND OTHER TRIM PARTS410 (13Cr) (200-275 HBN)

DISC/WEDGEF6+Hardf. NiCr Alloy (350 HBN min)

SEAT SURFACEF6+Hardf. NiCr Alloy (350 HBN min)

TRIM MATERIAL GRADE13Cr-0.5Ni-1Mn/Co-Cr-A

SERVICEAs trim 5 where Co is not allowed.

 6

NOMINAL TRIM410 and Ni-Cu

TRIM CODEF6HFS

STEM AND OTHER TRIM PARTS410 (13Cr) (200-275 HBN)

DISC/WEDGEMonel 400® (NiCu Alloy) (250 HBN min)

SEAT SURFACEMonel 400® (NiCu Alloy) (175 HBN min)

TRIM MATERIAL GRADE13Cr-0.5Ni-1Mn/Ni-Cu

SERVICEAs trim 1 and more corrosive service.

 7

NOMINAL TRIM410 – Very Hard

TRIM CODEF6HF+

STEM AND OTHER TRIM PARTS410 (13Cr) (200-275 HBN)

DISC/WEDGEF6 (13Cr) (250 HBN min)

SEAT SURFACEF6 (13Cr) (750 HB)

TRIM MATERIAL GRADE13Cr-0.5Ni-1Mo/13Cr-0.5Ni-Mo

SERVICESeats 750 BHN min. As trim 1 but for higher pressure and more corrosive/erosive service.

 8

NOMINAL TRIM410 – Hard faced

TRIM CODEF6HFS

STEM AND OTHER TRIM PARTS410 (13Cr) (200-275 HBN)

DISC/WEDGE410 (13Cr) (250 HBN min)

SEAT SURFACE410+St Gr6 (CoCr Alloy) (350 HBN min)

TRIM MATERIAL GRADE13Cr-0.75Ni-1Mn/1/2Co-Cr-A

SERVICEUniversal trim for general service requiring long service life up to 593°C. As trim 5 for moderate pressure and more corrosive service. Steam, gas and general service to 540°C. Standard trim for gate valves.

 8A

NOMINAL TRIM410 – Hard faced

TRIM CODEF6HFS

STEM AND OTHER TRIM PARTS410 (13Cr) (200-275 HBN)

DISC/WEDGEF6 (13Cr) (250 HBN min)

SEAT SURFACE410+Hardf. NiCr Alloy (350 HBN min)

TRIM MATERIAL GRADE13Cr-0.75Ni-1Mn/1/2Co-Cr-A

SERVICEAs trim 5A for moderate pressure and more corrosive service.

 9

NOMINAL TRIMMonel®

TRIM CODEMonel®

STEM AND OTHER TRIM PARTSMonel® (NiCu Alloy)

DISC/WEDGEMonel 400® (NiCu Alloy)

SEAT SURFACEMonel 400® (NiCu Alloy)

TRIM MATERIAL GRADE70Ni-30Cu

SERVICEFor corrosive service to 450°C such as acids, alkalies, salt solutions, etc. Very corrosive fluids.
Erosive-corrosive service between -240°C and 480°C. Resistant to sea water, acids, alkalies. Has excellent corrosion resistance in chlorine and alkylation service.

 10

NOMINAL TRIM316

TRIM CODE316

STEM AND OTHER TRIM PARTS316 (18Cr-Ni-Mo)

DISC/WEDGE316 (18Cr-Ni-Mo)

SEAT SURFACE316 (18Cr-Ni-Mo)

TRIM MATERIAL GRADE18Cr-12Ni-2.5Mo-2Mn

SERVICEFor superior resistance to corrosion for liquids and gases which are corrosive to 410 stainless steel up to 455°C. As trim 2 but a higher level of corrosive service. Provides excellent resistance to corrosive media at high temperatures and toughness for service at low temperatures. Low temperature service standard for 316SS valves.

 11

NOMINAL TRIMMonel – Hard faced

TRIM CODEMonelHFS

STEM AND OTHER TRIM PARTSMonel® (NiCu Alloy)

DISC/WEDGEMonel® (NiCu Alloy)

SEAT SURFACEMonel 400®+St Gr6 (350 HBN min)

TRIM MATERIAL GRADE70Ni-30Cu/1/2Co-Cr-A

SERVICEAs trim 9 but for medium pressure and more corrosive service.

 11A

NOMINAL TRIMMonel – Hard faced

TRIM CODEMonelHFS

STEM AND OTHER TRIM PARTSMonel® (NiCu Alloy)

DISC/WEDGEMonel® (NiCu Alloy)

SEAT SURFACEMonel 400T+HF NiCr Alloy (350 HBN min)

TRIM MATERIAL GRADE70Ni-30Cu/1/2Co-Cr-A

SERVICEAs trim 9 but for medium pressure and more corrosive service.

 12

NOMINAL TRIM316 – Hard faced

TRIM CODE316HFS

STEM AND OTHER TRIM PARTS316 (Cr-Ni-Mo)

DISC/WEDGE316 (18Cr-8Ni-Mo)

SEAT SURFACE316+St Gr6 (350 HBN min)

TRIM MATERIAL GRADE18Cr-12Ni-2.5Mo-2Mn1/2Co-Cr-A

SERVICEAs trim 10 but for medium pressure and more corrosive service.

 12A

NOMINAL TRIM316 – Hard faced

TRIM CODE316HFS

STEM AND OTHER TRIM PARTS316 (Cr-Ni-Mo)

DISC/WEDGE316 (18Cr-8Ni-Mo)

SEAT SURFACE316 Hardf. NiCr Alloy (350 HBN min)

TRIM MATERIAL GRADE18Cr-12Ni-2.5Mo-2Mn1/2Co-Cr-A

SERVICEAs trim 10 but for medium pressure and more corrosive service.

 13

NOMINAL TRIMAlloy 20

TRIM CODEAlloy 20

STEM AND OTHER TRIM PARTSAlloy 20 (19Cr-29Ni)

DISC/WEDGEAlloy 20 (19Cr-29Ni)

SEAT SURFACEAlloy 20 (19Cr-29Ni)

TRIM MATERIAL GRADE29Ni-19Cr-2.5Mo-0.07C

SERVICEVery corrosive service. For moderate pressure between -45°C and 320°C.

 14

NOMINAL TRIMAlloy 20 – Hard faced

TRIM CODEAlloy 20HFS

STEM AND OTHER TRIM PARTSAlloy 20 (19Cr-29Ni)

DISC/WEDGEAlloy 20 (19Cr-29Ni)

SEAT SURFACEAlloy 20 St Gr6 (350 HBN min)

TRIM MATERIAL GRADE29Ni-19Cr-2.5Mo-0.07C/1/2Co-Cr-A

SERVICEAs trim 13 but for medium pressure and more corrosive service.

 14A

NOMINAL TRIMAlloy 20 – Hard faced

TRIM CODEAlloy 20HFS

STEM AND OTHER TRIM PARTSAlloy 20 (19Cr-29Ni)

DISC/WEDGEAlloy 20 (19Cr-29Ni)

SEAT SURFACEAlloy 20 Hardf. NiCr Alloy (350 HBN min)

TRIM MATERIAL GRADE29Ni-19Cr-2.5Mo-0.07C/1/2Co-Cr-A

SERVICEAs trim 13 but for medium pressure and more corrosive service.

 15

NOMINAL TRIM304 – Full Hard faced

TRIM CODE304HS

STEM AND OTHER TRIM PARTS304 (18Cr-8Ni-Mo)

DISC/WEDGE304St Gr6

SEAT SURFACE304+St Gr6 (350 HBN min)

TRIM MATERIAL GRADE19Cr-9.5Ni-2Mn-0.08C/1/2Co-Cr-A

SERVICEAs trim 2 but more erosive service and higher pressure.

 16

NOMINAL TRIM316 – Full Hard faced

TRIM CODE316HF

STEM AND OTHER TRIM PARTS316 HF (18Cr-8Ni-Mo)

DISC/WEDGE316+St Gr6 (320 HBN min)

SEAT SURFACE316+St Gr6 (350 HBN min)

TRIM MATERIAL GRADE18Cr-12Ni-2.5Mo-2Mn/Co-Cr-Mo

SERVICEAs trim 10 but more erosive service and higher pressure.

 17

NOMINAL TRIM347 – Full Hard faced

TRIM CODE347HF

STEM AND OTHER TRIM PARTS347 HF (18Cr-10Ni-Cb)

DISC/WEDGE347+St Gr6 (350 HBN min)

SEAT SURFACE347+St Gr6 (350 HBN min)

TRIM MATERIAL GRADE18Cr-10Ni-Cb/Co-Cr-A

SERVICEAs trim 13 but more corrosive service and higher pressure. Combines good corrosion resistance with high temperature resistance up to 800°C.

 18

NOMINAL TRIMAlloy 20 – Full Hardfaced

TRIM CODEAlloy 20 HF

STEM AND OTHER TRIM PARTSAlloy 20 (19Cr-29Ni)

DISC/WEDGEAlloy 20+St Gr6 (350 HBN min)

SEAT SURFACEAlloy 20+St Gr6 (350 HBN min)

TRIM MATERIAL GRADE19 Cr-29Ni/Co-Cr-A

SERVICEAs trim 13 but more corrosive service and higher pressure. Water, gas or low pressure steam to 230°C.

 Special

NOMINAL TRIMBronze

TRIM CODEBronze

STEM AND OTHER TRIM PARTS410 (CR13)

DISC/WEDGEBronze

SEAT SURFACEBronze

TRIM MATERIAL GRADE…

SERVICEWater, oil, gas, or low pressure steam to 232°C.

 Special

NOMINAL TRIMAlloy 625

TRIM CODEAlloy 625

STEM AND OTHER TRIM PARTSAlloy 625

DISC/WEDGEAlloy 625

SEAT SURFACEAlloy 625

TRIM MATERIAL GRADE…

SERVICE…

 NACE

Specially treated 316 or 410 trim combined with B7M bolts and 2HM nuts to meet NACE MR-01-75 requirements.

 Full Stellite

Full Hardfaced trim, suitable for abrasive and severe services up to 1200°F (650°C).