Trim of Valves
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.
410
F6
410 (13Cr) (200-275 HBN)
F6 (13Cr) (200 HBN)
410 (13Cr)(250 HBN min)
13Cr-0.75Ni-1Mn
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.
304
304
304
304 (18Cr-8Ni)
304 (18Cr-8Ni)
19Cr-9.5Ni-2Mn-0.08C
For moderate pressure in corrosive, low erosive service between -265°C and 450°C.
310
310
(25Cr-20Ni)
310 (25Cr-20Ni)
310 (25Cr-20Ni)
25Cr-20.5Ni-2Mn
For moderate pressure in corrosive or non corrosive service between -265°C and 450°C.
410 - Hard
F6H
410 (13Cr) (200-275 HBN)
F6 (13Cr) (200-275 HBN)
F6 (13Cr) (275 HBN min)
13Cr-0.75Ni-1Mn
Seats 275 BHN min. As trim 1 but for medium pressure and more corrosive service.
410 - Full Hard faced
F6HF
410 (13Cr) (200-275 HBN)
F6+St Gr6 (CoCr Alloy) (350 HBN min)
410+St Gr6 (CoCr Alloy) (350 HBN min)
13Cr-0.5Ni-1Mn/Co-Cr-A
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.
410 - Full Hard faced
F6HF
410 (13Cr) (200-275 HBN)
F6+Hardf. NiCr Alloy (350 HBN min)
F6+Hardf. NiCr Alloy (350 HBN min)
13Cr-0.5Ni-1Mn/Co-Cr-A
As trim 5 where Co is not allowed.
410 and Ni-Cu
F6HFS
410 (13Cr) (200-275 HBN)
Monel 400® (NiCu Alloy) (250 HBN min)
Monel 400® (NiCu Alloy) (175 HBN min)
13Cr-0.5Ni-1Mn/Ni-Cu
As trim 1 and more corrosive service.
410 - Very Hard
F6HF+
410 (13Cr) (200-275 HBN)
F6 (13Cr) (250 HBN min)
F6 (13Cr) (750 HB)
13Cr-0.5Ni-1Mo/13Cr-0.5Ni-Mo
Seats 750 BHN min. As trim 1 but for higher pressure and more corrosive/erosive service.
410 - Hard faced
F6HFS
410 (13Cr) (200-275 HBN)
410 (13Cr) (250 HBN min)
410+St Gr6 (CoCr Alloy) (350 HBN min)
13Cr-0.75Ni-1Mn/1/2Co-Cr-A
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.
410 - Hard faced
F6HFS
410 (13Cr) (200-275 HBN)
F6 (13Cr) (250 HBN min)
410+Hardf. NiCr Alloy (350 HBN min)
13Cr-0.75Ni-1Mn/1/2Co-Cr-A
As trim 5A for moderate pressure and more corrosive service.
Monel®
Monel®
Monel® (NiCu Alloy)
Monel 400® (NiCu Alloy)
Monel 400® (NiCu Alloy)
70Ni-30Cu
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.
316
316
316 (18Cr-Ni-Mo)
316 (18Cr-Ni-Mo)
316 (18Cr-Ni-Mo)
18Cr-12Ni-2.5Mo-2Mn
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.
Monel - Hard faced
MonelHFS
Monel® (NiCu Alloy)
Monel® (NiCu Alloy)
Monel 400®+St Gr6 (350 HBN min)
70Ni-30Cu/1/2Co-Cr-A
As trim 9 but for medium pressure and more corrosive service.
Monel - Hard faced
MonelHFS
Monel® (NiCu Alloy)
Monel® (NiCu Alloy)
Monel 400T+HF NiCr Alloy (350 HBN min)
70Ni-30Cu/1/2Co-Cr-A
As trim 9 but for medium pressure and more corrosive service.
316 - Hard faced
316HFS
316 (Cr-Ni-Mo)
316 (18Cr-8Ni-Mo)
316+St Gr6 (350 HBN min)
18Cr-12Ni-2.5Mo-2Mn1/2Co-Cr-A
As trim 10 but for medium pressure and more corrosive service.
316 - Hard faced
316HFS
316 (Cr-Ni-Mo)
316 (18Cr-8Ni-Mo)
316 Hardf. NiCr Alloy (350 HBN min)
18Cr-12Ni-2.5Mo-2Mn1/2Co-Cr-A
As trim 10 but for medium pressure and more corrosive service.
Alloy 20
Alloy 20
Alloy 20 (19Cr-29Ni)
Alloy 20 (19Cr-29Ni)
Alloy 20 (19Cr-29Ni)
29Ni-19Cr-2.5Mo-0.07C
Very corrosive service. For moderate pressure between -45°C and 320°C.
Alloy 20 - Hard faced
Alloy 20HFS
Alloy 20 (19Cr-29Ni)
Alloy 20 (19Cr-29Ni)
Alloy 20 St Gr6 (350 HBN min)
29Ni-19Cr-2.5Mo-0.07C/1/2Co-Cr-A
As trim 13 but for medium pressure and more corrosive service.
Alloy 20 - Hard faced
Alloy 20HFS
Alloy 20 (19Cr-29Ni)
Alloy 20 (19Cr-29Ni)
Alloy 20 Hardf. NiCr Alloy (350 HBN min)
29Ni-19Cr-2.5Mo-0.07C/1/2Co-Cr-A
As trim 13 but for medium pressure and more corrosive service.
304 - Full Hard faced
304HS
304 (18Cr-8Ni-Mo)
304St Gr6
304+St Gr6 (350 HBN min)
19Cr-9.5Ni-2Mn-0.08C/1/2Co-Cr-A
As trim 2 but more erosive service and higher pressure.
316 - Full Hard faced
316HF
316 HF (18Cr-8Ni-Mo)
316+St Gr6 (320 HBN min)
316+St Gr6 (350 HBN min)
18Cr-12Ni-2.5Mo-2Mn/Co-Cr-Mo
As trim 10 but more erosive service and higher pressure.
347 - Full Hard faced
347HF
347 HF (18Cr-10Ni-Cb)
347+St Gr6 (350 HBN min)
347+St Gr6 (350 HBN min)
18Cr-10Ni-Cb/Co-Cr-A
As trim 13 but more corrosive service and higher pressure. Combines good corrosion resistance with high temperature resistance up to 800°C.
Alloy 20 - Full Hardfaced
Alloy 20 HF
Alloy 20 (19Cr-29Ni)
Alloy 20+St Gr6 (350 HBN min)
Alloy 20+St Gr6 (350 HBN min)
19 Cr-29Ni/Co-Cr-A
As trim 13 but more corrosive service and higher pressure. Water, gas or low pressure steam to 230°C.
Bronze
Bronze
410 (CR13)
Bronze
Bronze
...
Water, oil, gas, or low pressure steam to 232°C.
Alloy 625
Alloy 625
Alloy 625
Alloy 625
Alloy 625
...
...
Specially treated 316 or 410 trim combined with B7M bolts and 2HM nuts to meet NACE MR-01-75 requirements.
Full Hardfaced trim, suitable for abrasive and severe services up to 1200°F (650°C).
Note:
Data provided about API Trim numbers is for informational purposes only. Always consult current API publications to verify information and trim date.
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