Trim of Valves

Note: Data provided about API Trim numbers is for informational purposes only. Always consult current API publications to verify information and trim date.

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, etcetera 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 TRIM 1

NOMINAL TRIM
410
TRIM CODE
F6
STEM AND OTHER TRIM PARTS
410 (13Cr) (200-275 HBN)
DISC/WEDGE
F6 (13Cr) (200 HBN)
SEAT SURFACE
410 (13Cr)(250 HBN min)
TRIM MATERIAL GRADE
13Cr-0.75Ni-1Mn
SERVICE
For 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.
API TRIM 2

NOMINAL TRIM
304
TRIM CODE
304
STEM AND OTHER TRIM PARTS
304
DISC/WEDGE
304 (18Cr-8Ni)
SEAT SURFACE
304 (18Cr-8Ni)
TRIM MATERIAL GRADE
19Cr-9.5Ni-2Mn-0.08C
SERVICE
For moderate pressure in corrosive, low erosive service between -265°C and 450°C.
API TRIM 3

NOMINAL TRIM
310
TRIM CODE
310
STEM AND OTHER TRIM PARTS
(25Cr-20Ni)
DISC/WEDGE
310 (25Cr-20Ni)
SEAT SURFACE
310 (25Cr-20Ni)
TRIM MATERIAL GRADE
25Cr-20.5Ni-2Mn
SERVICE
For moderate pressure in corrosive or non corrosive service between -265°C and 450°C.
API TRIM 4

NOMINAL TRIM
410 - Hard
TRIM CODE
F6H
STEM AND OTHER TRIM PARTS
410 (13Cr) (200-275 HBN)
DISC/WEDGE
F6 (13Cr) (200-275 HBN)
SEAT SURFACE
F6 (13Cr) (275 HBN min)
TRIM MATERIAL GRADE
13Cr-0.75Ni-1Mn
SERVICE
Seats 275 BHN min. As trim 1 but for medium pressure and more corrosive service.
API TRIM 5

NOMINAL TRIM
410 - Full Hard faced
TRIM CODE
F6HF
STEM AND OTHER TRIM PARTS
410 (13Cr) (200-275 HBN)
DISC/WEDGE
F6+St Gr6 (CoCr Alloy) (350 HBN min)
SEAT SURFACE
410+St Gr6 (CoCr Alloy) (350 HBN min)
TRIM MATERIAL GRADE
13Cr-0.5Ni-1Mn/Co-Cr-A
SERVICE
High 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.
API TRIM 5A

NOMINAL TRIM
410 - Full Hard faced
TRIM CODE
F6HF
STEM AND OTHER TRIM PARTS
410 (13Cr) (200-275 HBN)
DISC/WEDGE
F6+Hardf. NiCr Alloy (350 HBN min)
SEAT SURFACE
F6+Hardf. NiCr Alloy (350 HBN min)
TRIM MATERIAL GRADE
13Cr-0.5Ni-1Mn/Co-Cr-A
SERVICE
As trim 5 where Co is not allowed.
API TRIM 6

NOMINAL TRIM
410 and Ni-Cu
TRIM CODE
F6HFS
STEM AND OTHER TRIM PARTS
410 (13Cr) (200-275 HBN)
DISC/WEDGE
Monel 400® (NiCu Alloy) (250 HBN min)
SEAT SURFACE
Monel 400® (NiCu Alloy) (175 HBN min)
TRIM MATERIAL GRADE
13Cr-0.5Ni-1Mn/Ni-Cu
SERVICE
As trim 1 and more corrosive service.
API TRIM 7

NOMINAL TRIM
410 - Very Hard
TRIM CODE
F6HF+
STEM AND OTHER TRIM PARTS
410 (13Cr) (200-275 HBN)
DISC/WEDGE
F6 (13Cr) (250 HBN min)
SEAT SURFACE
F6 (13Cr) (750 HB)
TRIM MATERIAL GRADE
13Cr-0.5Ni-1Mo/13Cr-0.5Ni-Mo
SERVICE
Seats 750 BHN min. As trim 1 but for higher pressure and more corrosive/erosive service.
API TRIM 8

NOMINAL TRIM
410 - Hard faced
TRIM CODE
F6HFS
STEM AND OTHER TRIM PARTS
410 (13Cr) (200-275 HBN)
DISC/WEDGE
410 (13Cr) (250 HBN min)
SEAT SURFACE
410+St Gr6 (CoCr Alloy) (350 HBN min)
TRIM MATERIAL GRADE
13Cr-0.75Ni-1Mn/1/2Co-Cr-A
SERVICE
Universal 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.
API TRIM 8A

NOMINAL TRIM
410 - Hard faced
TRIM CODE
F6HFS
STEM AND OTHER TRIM PARTS
410 (13Cr) (200-275 HBN)
DISC/WEDGE
F6 (13Cr) (250 HBN min)
SEAT SURFACE
410+Hardf. NiCr Alloy (350 HBN min)
TRIM MATERIAL GRADE
13Cr-0.75Ni-1Mn/1/2Co-Cr-A
SERVICE
As trim 5A for moderate pressure and more corrosive service.
API TRIM 9

NOMINAL TRIM
Monel®
TRIM CODE
Monel®
STEM AND OTHER TRIM PARTS
Monel® (NiCu Alloy)
DISC/WEDGE
Monel 400® (NiCu Alloy)
SEAT SURFACE
Monel 400® (NiCu Alloy)
TRIM MATERIAL GRADE
70Ni-30Cu
SERVICE
For 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.
API TRIM 10

NOMINAL TRIM
316
TRIM CODE
316
STEM AND OTHER TRIM PARTS
316 (18Cr-Ni-Mo)
DISC/WEDGE
316 (18Cr-Ni-Mo)
SEAT SURFACE
316 (18Cr-Ni-Mo)
TRIM MATERIAL GRADE
18Cr-12Ni-2.5Mo-2Mn
SERVICE
For 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.
API TRIM 11

NOMINAL TRIM
Monel - Hard faced
TRIM CODE
MonelHFS
STEM AND OTHER TRIM PARTS
Monel® (NiCu Alloy)
DISC/WEDGE
Monel® (NiCu Alloy)
SEAT SURFACE
Monel 400®+St Gr6 (350 HBN min)
TRIM MATERIAL GRADE
70Ni-30Cu/1/2Co-Cr-A
SERVICE
As trim 9 but for medium pressure and more corrosive service.
API TRIM 11A

NOMINAL TRIM
Monel - Hard faced
TRIM CODE
MonelHFS
STEM AND OTHER TRIM PARTS
Monel® (NiCu Alloy)
DISC/WEDGE
Monel® (NiCu Alloy)
SEAT SURFACE
Monel 400T+HF NiCr Alloy (350 HBN min)
TRIM MATERIAL GRADE
70Ni-30Cu/1/2Co-Cr-A
SERVICE
As trim 9 but for medium pressure and more corrosive service.
API TRIM 12

NOMINAL TRIM
316 - Hard faced
TRIM CODE
316HFS
STEM AND OTHER TRIM PARTS
316 (Cr-Ni-Mo)
DISC/WEDGE
316 (18Cr-8Ni-Mo)
SEAT SURFACE
316+St Gr6 (350 HBN min)
TRIM MATERIAL GRADE
18Cr-12Ni-2.5Mo-2Mn1/2Co-Cr-A
SERVICE
As trim 10 but for medium pressure and more corrosive service.
API TRIM 12A

NOMINAL TRIM
316 - Hard faced
TRIM CODE
316HFS
STEM AND OTHER TRIM PARTS
316 (Cr-Ni-Mo)
DISC/WEDGE
316 (18Cr-8Ni-Mo)
SEAT SURFACE
316 Hardf. NiCr Alloy (350 HBN min)
TRIM MATERIAL GRADE
18Cr-12Ni-2.5Mo-2Mn1/2Co-Cr-A
SERVICE
As trim 10 but for medium pressure and more corrosive service.
API TRIM 13

NOMINAL TRIM
Alloy 20
TRIM CODE
Alloy 20
STEM AND OTHER TRIM PARTS
Alloy 20 (19Cr-29Ni)
DISC/WEDGE
Alloy 20 (19Cr-29Ni)
SEAT SURFACE
Alloy 20 (19Cr-29Ni)
TRIM MATERIAL GRADE
29Ni-19Cr-2.5Mo-0.07C
SERVICE
Very corrosive service. For moderate pressure between -45°C and 320°C.
API TRIM 14

NOMINAL TRIM
Alloy 20 - Hard faced
TRIM CODE
Alloy 20HFS
STEM AND OTHER TRIM PARTS
Alloy 20 (19Cr-29Ni)
DISC/WEDGE
Alloy 20 (19Cr-29Ni)
SEAT SURFACE
Alloy 20 St Gr6 (350 HBN min)
TRIM MATERIAL GRADE
29Ni-19Cr-2.5Mo-0.07C/1/2Co-Cr-A
SERVICE
As trim 13 but for medium pressure and more corrosive service.
API TRIM 14A

NOMINAL TRIM
Alloy 20 - Hard faced
TRIM CODE
Alloy 20HFS
STEM AND OTHER TRIM PARTS
Alloy 20 (19Cr-29Ni)
DISC/WEDGE
Alloy 20 (19Cr-29Ni)
SEAT SURFACE
Alloy 20 Hardf. NiCr Alloy (350 HBN min)
TRIM MATERIAL GRADE
29Ni-19Cr-2.5Mo-0.07C/1/2Co-Cr-A
SERVICE
As trim 13 but for medium pressure and more corrosive service.
API TRIM 15

NOMINAL TRIM
304 - Full Hard faced
TRIM CODE
304HS
STEM AND OTHER TRIM PARTS
304 (18Cr-8Ni-Mo)
DISC/WEDGE
304St Gr6
SEAT SURFACE
304+St Gr6 (350 HBN min)
TRIM MATERIAL GRADE
19Cr-9.5Ni-2Mn-0.08C/1/2Co-Cr-A
SERVICE
As trim 2 but more erosive service and higher pressure.
API TRIM 16

NOMINAL TRIM
316 - Full Hard faced
TRIM CODE
316HF
STEM AND OTHER TRIM PARTS
316 HF (18Cr-8Ni-Mo)
DISC/WEDGE
316+St Gr6 (320 HBN min)
SEAT SURFACE
316+St Gr6 (350 HBN min)
TRIM MATERIAL GRADE
18Cr-12Ni-2.5Mo-2Mn/Co-Cr-Mo
SERVICE
As trim 10 but more erosive service and higher pressure.
API TRIM 17

NOMINAL TRIM
347 - Full Hard faced
TRIM CODE
347HF
STEM AND OTHER TRIM PARTS
347 HF (18Cr-10Ni-Cb)
DISC/WEDGE
347+St Gr6 (350 HBN min)
SEAT SURFACE
347+St Gr6 (350 HBN min)
TRIM MATERIAL GRADE
18Cr-10Ni-Cb/Co-Cr-A
SERVICE
As trim 13 but more corrosive service and higher pressure. Combines good corrosion resistance with high temperature resistance up to 800°C.
API TRIM 18

NOMINAL TRIM
Alloy 20 - Full Hardfaced
TRIM CODE
Alloy 20 HF
STEM AND OTHER TRIM PARTS
Alloy 20 (19Cr-29Ni)
DISC/WEDGE
Alloy 20+St Gr6 (350 HBN min)
SEAT SURFACE
Alloy 20+St Gr6 (350 HBN min)
TRIM MATERIAL GRADE
19 Cr-29Ni/Co-Cr-A
SERVICE
As trim 13 but more corrosive service and higher pressure. Water, gas or low pressure steam to 230°C.

Ball Valves, Butterfly Valves, Check Valves, Diaphragm Valves, Float Valves, Gate Valves, Globe Valves, Needle Valves, Plug Valves, Y-Pattern Valves, Pressure Regulators, Safety & Relief Valves, Wye Strainers