Valve Bonnet for Marine & Offshore
For shipyards, marine equipment builders and offshore operators. Specified to classification-society rules (DNV, ABS, LR) and NORSOK M-630 where offshore applies.
The Valve Bonnet is supplied to shipyards, marine equipment builders and offshore operators as an investment casting, in 9 catalogued sizes by nominal bore. In this sector the governing consideration is permanent seawater exposure, where a coating is a maintenance schedule rather than a strategy.
- Specified to
- classification-society rules (DNV, ABS, LR) and NORSOK M-630 where offshore applies
- Governing factor
- Permanent seawater exposure, where a coating is a maintenance schedule rather than a strategy
- Failure mode to design out
- Crevice corrosion under a gasket or inside a threaded joint, in the places nobody inspects
- Alloys
- CF8M, CF3M, CF8, CF3
Alloys Specified for This Part in Marine & Offshore
Which of these is right depends on the medium, the temperature and the pressure rather than on the sector alone — two plants in the same industry routinely specify different grades for the same part.
| Grade | Specification | Corrosion | Temperature |
|---|---|---|---|
| CF8M | ASTM A351 CF8M / UNS J92900 (cast 316) | Good pitting and crevice resistance in chlorides; standard choice for seawater-adjacent and chemical process duty. | approx. -196 C to +550 C, derated for pressure-retaining service above 425 C |
| CF3M | ASTM A351 CF3M / UNS J92800 (cast 316L) | As CF8M, with the low carbon that prevents sensitization at welds. | approx. -196 C to +425 C |
| CF8 | ASTM A351 CF8 / UNS J92600 (cast 304) | Good general corrosion resistance in fresh water, steam and mild chemicals; not for chlorides. | approx. -196 C to +550 C |
| CF3 | ASTM A351 CF3 / UNS J92500 (cast 304L) | As CF8 with low carbon for welded assemblies. | approx. -196 C to +425 C |
| CA6NM | ASTM A743 CA6NM / UNS J91540 | Moderate — better than carbon steel in water, well short of CF8M in chlorides. | approx. -73 C to +370 C |
| CA15 | ASTM A743 CA15 / UNS J91150 (cast 410) | Mild — suitable for fresh water and steam, not for chlorides. | approx. -30 C to +650 C |
| CB7Cu-1 (17-4 PH) | ASTM A747 CB7Cu-1 / UNS J92180 (17-4 PH) | Between CF8 and CF8M, depending on ageing condition; H1150 is more corrosion resistant than H900. | approx. -73 C to +316 C |
| CD3MN (2205) | ASTM A890 Gr 4A / UNS J92205 (cast 2205 duplex) | Substantially better than CF8M against chloride pitting and stress-corrosion cracking. | approx. -50 C to +280 C — the upper limit is set by 475 C embrittlement, not by strength |
| CE3MN (2507) | ASTM A890 Gr 5A / UNS J93404 (cast 2507 super duplex) | Excellent — PREN above 40, suitable for warm seawater and desalination brine. | approx. -50 C to +280 C |
| WCB | ASTM A216 WCB / UNS J03002 | None inherent — carbon steel castings are painted, plated or galvanized for corrosion protection. | approx. -29 C to +425 C |
| WCC | ASTM A216 WCC / UNS J02503 | None inherent; requires a protective coating. | approx. -29 C to +425 C |
| Inconel 625 (CW6MC) | ASTM A494 CW6MC / UNS N26625 (cast Inconel 625) | Outstanding — resists pitting, crevice attack and chloride stress-corrosion cracking. | approx. -196 C to +650 C |
| C95800 Nickel Aluminum Bronze | ASTM B148 C95800 (nickel aluminum bronze) | Excellent in seawater, with natural biofouling resistance; galvanically compatible with most marine steels. | approx. -200 C to +250 C |
Alloys & Grades
The Valve Bonnet is cast in 13 of the 63 grades we work in. Those are listed first; the full reference tree is underneath, with each designation shown alongside its ASTM/UNS, EN and GB equivalents.
- CF8M catalog grade ASTM A351 CF8M / UNS J92900 (cast 316)
- CF3M ASTM A351 CF3M / UNS J92800 (cast 316L)
- CF8 ASTM A351 CF8 / UNS J92600 (cast 304)
- CF3 ASTM A351 CF3 / UNS J92500 (cast 304L)
- CA6NM ASTM A743 CA6NM / UNS J91540
- CA15 ASTM A743 CA15 / UNS J91150 (cast 410)
- CB7Cu-1 (17-4 PH) ASTM A747 CB7Cu-1 / UNS J92180 (17-4 PH)
- CD3MN (2205) ASTM A890 Gr 4A / UNS J92205 (cast 2205 duplex)
- CE3MN (2507) ASTM A890 Gr 5A / UNS J93404 (cast 2507 super duplex)
- WCB ASTM A216 WCB / UNS J03002
- WCC ASTM A216 WCC / UNS J02503
- Inconel 625 (CW6MC) ASTM A494 CW6MC / UNS N26625 (cast Inconel 625)
- C95800 Nickel Aluminum Bronze ASTM B148 C95800 (nickel aluminum bronze)
Browse all 63 cast grades we work instainless · carbon & low-alloy · nickel & cobalt · copper · aluminium · titanium
Austenitic Cast Stainless Steel
- CF8 ASTM A351 CF8 · UNS J92600 · AISI 304 cast · EN 1.4308
- CF3 ASTM A351 CF3 · UNS J92500 · AISI 304L cast · EN 1.4309
- CF8M ASTM A351 CF8M · UNS J92900 · AISI 316 cast · EN 1.4408
- CF3M ASTM A351 CF3M · UNS J92800 · AISI 316L cast · EN 1.4409
- CF8C ASTM A351 CF8C · UNS J92710 · AISI 347 cast · EN 1.4552
- CG8M ASTM A351 CG8M · UNS J93000 · AISI 317 cast
- CN7M ASTM A351 CN7M · UNS N08007 · Alloy 20 cast · Carpenter 20
- CK3MCuN ASTM A351 CK3MCuN · UNS J93254 · 254 SMO cast · EN 1.4547
- CN3MN ASTM A351 CN3MN · UNS J94651 · AL-6XN cast
Martensitic Cast Stainless Steel
- CA15 ASTM A743 CA15 · UNS J91150 · AISI 410 cast · EN 1.4008
- CA40 ASTM A743 CA40 · UNS J91153 · AISI 420 cast · EN 1.4034
- CA6NM ASTM A743 CA6NM · UNS J91540 · EN 1.4313 · GX4CrNi13-4
- CA15M ASTM A743 CA15M · UNS J91151
- CA6N ASTM A743 CA6N · UNS J91650
Precipitation-Hardening Cast Stainless Steel
- CB7Cu-1 (17-4 PH) ASTM A747 CB7Cu-1 · UNS J92180 · 17-4 PH cast · AISI 630
- CB7Cu-2 (15-5 PH) ASTM A747 CB7Cu-2 · UNS J92110 · 15-5 PH cast
Duplex & Super Duplex Cast Stainless Steel
- CD3MN (2205) ASTM A890 Gr 4A · UNS J92205 · Duplex 2205 cast · EN 1.4470
- CE3MN (2507) ASTM A890 Gr 5A · UNS J93404 · Super Duplex 2507 cast · EN 1.4469
- CD4MCu ASTM A890 Gr 1A · UNS J93370
- CD3MWCuN (Zeron 100) ASTM A890 Gr 6A · UNS J93380 · Zeron 100 cast
Heat-Resistant Cast Stainless Steel
- HK30 ASTM A297 HK30 · UNS J94203 · GX40CrNiSi25-12
- HK40 ASTM A297 HK40 · UNS J94204 · EN 1.4848
- HH ASTM A297 HH · UNS J93503 · EN 1.4837 cast
- HT ASTM A297 HT · UNS J94605
- HP ASTM A297 HP · UNS J95705 · GX40NiCrSi35-25
Carbon Steel Castings
- WCB ASTM A216 WCB · UNS J03002 · GP240GH · EN 1.0619
- WCC ASTM A216 WCC · UNS J02503
- WCA ASTM A216 WCA · UNS J02502
- LCB ASTM A352 LCB · UNS J03003
- LCC ASTM A352 LCC · UNS J02505
- AISI 1045 Cast ASTM A732 Gr 1045 · UNS G10450 · C45 · 45#
Low-Alloy Steel Castings
- AISI 4140 Cast ASTM A732 Gr 4140 · UNS G41400 · 42CrMo4 · EN 1.7225
- AISI 8620 Cast ASTM A732 Gr 8620 · UNS G86200 · 20CrNiMo
- WC6 ASTM A217 WC6 · UNS J12072 · 1.25Cr-0.5Mo · G17CrMo5-5
- WC9 ASTM A217 WC9 · UNS J21890 · 2.25Cr-1Mo · G17CrMo9-10
- C5 ASTM A217 C5 · UNS J42045 · 5Cr-0.5Mo
- C12A ASTM A217 C12A · UNS J84090 · Grade 91 · 9Cr-1Mo-V
- AISI 4340 Cast ASTM A732 Gr 4340 · UNS G43400 · 40CrNiMoA
Nickel-Base Alloy Castings
- Inconel 625 (CW6MC) ASTM A494 CW6MC · UNS N26625 · Inconel 625 · Alloy 625
- Inconel 718 AMS 5383 · UNS N07718 · Alloy 718 · GH4169
- Inconel 713C AMS 5391 · UNS N07713 · Alloy 713C
- Hastelloy C (CW6M) ASTM A494 CW6M · UNS N30107 · Hastelloy C cast
- Hastelloy C-276 (CW12MW) ASTM A494 CW12MW · UNS N30002 · Alloy C-276 cast
- Monel M-35-1 ASTM A494 M35-1 · UNS N24135 · Monel 400 cast
Cobalt-Base Alloy Castings
- CoCrMo (ASTM F75) ASTM F75 · UNS R30075 · CoCr28Mo6
- Stellite 6 UNS R30006 · CoCr-A · Alloy 6
- Stellite 12 UNS R30012 · Alloy 12
- X-40 (Co-Cr-W) AMS 5382 · UNS R30031 · Haynes 31
Bronze Castings
- C95800 Nickel Aluminum Bronze ASTM B148 C95800 · UNS C95800 · NAB · CuAl10Fe5Ni5
- C95500 Nickel Aluminum Bronze ASTM B148 C95500 · UNS C95500
- C90300 Tin Bronze ASTM B584 C90300 · UNS C90300 · 88-8-0-4
- C93200 Bearing Bronze ASTM B584 C93200 · UNS C93200 · SAE 660
Brass Castings
- C83600 Red Brass ASTM B584 C83600 · UNS C83600 · 85-5-5-5
- C87600 Silicon Brass ASTM B584 C87600 · UNS C87600
- C86300 Manganese Bronze ASTM B584 C86300 · UNS C86300
Aluminum Alloy Castings
- A356 / A356-T6 ASTM B26 A356 · UNS A13560 · AlSi7Mg0.3 · EN AC-42000
- A357 ASTM B26 A357 · UNS A13570 · AlSi7Mg0.6
- 355 / C355 ASTM B26 355 · UNS A03550 · AlSi5Cu1Mg
- A201-T7 ASTM B26 A201 · UNS A02010 · AlCu4MgTi
Titanium Castings
- Ti-6Al-4V (Grade 5) ASTM B367 Gr C-5 · UNS R56400 · TC4 · Ti-6-4
- CP Titanium Grade 2 ASTM B367 Gr C-2 · UNS R50400
Special & Wear Alloys
- Ni-Resist D-2 ASTM A439 D-2 · UNS F43000
- High-Chrome White Iron ASTM A532 Class III · 25Cr white iron
Technical Drawing
Every parameter below is editable, and the drawing redraws to match the values you choose. Picking a size snaps the other fields to that size's values; you can then override any one of them.
Request a Quotation
The form follows the drawing configuration above. Attaching a drawing or a STEP file is the fastest route to a firm price.
Dimensions & Parameters
Nominal casting dimensions before machining allowance. Every row is a starting point for the customizer above.
| Size | Overall Length L (mm) | Overall Width W (mm) | Overall Height H (mm) | Wall Thickness T (mm) | Port Diameter ØD1 (mm) | Flange Diameter (mm) | Fillet Radius R (mm) | Casting Weight (kg) |
|---|---|---|---|---|---|---|---|---|
| DN15 | 59.4 | 89 | 80.2 | 3.6 | 15 | 89 | 3 | 0.34 |
| DN20 | 64.4 | 99 | 86.9 | 3.9 | 20 | 99 | 3 | 0.44 |
| DN25 | 69.9 | 108 | 94.4 | 4.2 | 25 | 108 | 3.5 | 0.56 |
| DN32 | 77 | 117 | 104 | 4.6 | 32 | 117 | 3.5 | 0.73 |
| DN40 | 90.8 | 127 | 122.6 | 5 | 40 | 127 | 4 | 1.04 |
| DN50 | 97.9 | 152 | 132.2 | 5.5 | 50 | 152 | 4.5 | 1.44 |
| DN65 | 104.5 | 178 | 141.1 | 6.4 | 65 | 178 | 5 | 2.04 |
| DN80 | 111.7 | 190 | 150.8 | 7.2 | 80 | 190 | 6 | 2.62 |
| DN100 | 126 | 229 | 170.1 | 8.3 | 100 | 229 | 6.5 | 4.04 |
Frequently Asked Questions
What matters most for a valve bonnet in Marine & Offshore?
Permanent seawater exposure, where a coating is a maintenance schedule rather than a strategy. The failure this sector designs out is crevice corrosion under a gasket or inside a threaded joint, in the places nobody inspects.
Which specifications apply in Marine & Offshore?
Commonly classification-society rules (DNV, ABS, LR) and NORSOK M-630 where offshore applies. Name the one your drawing works to on the RFQ — it changes the testing, the documentation and the price, and it is cheaper to agree before tooling than after.
Which alloys are used for a valve bonnet in Marine & Offshore?
Commonly CF8M, CF3M, CF8, CF3 and CA6NM. The right one depends on the medium, the temperature and the pressure rather than on the sector alone — two plants in the same industry routinely specify different grades for the same part.
How do I request a quotation?
Configure the drawing on this page — size, alloy, finish — and submit the form. Attaching a drawing or a STEP file is the fastest route to a firm price, and it lets us flag a castability issue before you commit to tooling.
More on the Valve Bonnet
The full record for the valve bonnet — every catalogued size, the parametric drawing and the quote form — is on the Valve Bonnet product page.
Each grade changes the price, the weight and what the part survives, so there is a page per grade for this part: CF8M (the catalog grade), WCB (the carbon-steel cost baseline), CF3M (low carbon, for welded assemblies), CF8 (cheaper, where chlorides are absent), WCC (stronger carbon steel for larger parts) and CA6NM (tough and cavitation resistant).
How it is shelled decides the tolerance and the surface you get, and the tolerance band is worked out against this part's own dimensions on each: Silica Sol Casting (DCTG 5 – 7, Ra 3.2 – 6.3 µm), Water Glass Casting (DCTG 7 – 9, Ra 6.3 – 12.5 µm) and Composite Shell Casting (DCTG 6 – 8, Ra 6.3 – 12.5 µm).
The specification and the testing change by sector more than the geometry does, so the valve bonnet is written up separately for Valve Manufacturing, Oil & Gas, Chemical Processing, Power Generation and Water & Wastewater.
If the question is still whether a casting is the right way to make this part at all, the Valve Bonnet application guide covers where it is used, what has to be decided before a price exists, and where investment casting is the wrong answer.