Most valves carry marks in two places: a stainless nameplate riveted to the body, and marks on the body itself. Many valve plants mark nameplates every day, with a tag engraver or a fiber laser. Bodies and flange rims get dot peen, which still reads after blasting and paint.
Valve plants ask HeatSign two questions: what do we have to mark, and which machine marks it? This page answers both, starting with the nameplate.
Two kinds of machine come up all the way through. A dot peen marker taps rows of small dents into the steel, deep enough to read under paint, and a fiber laser darkens a thin surface layer for sharp text, logos and codes.
Already know your marking list?
Send it with a photo of the part. We will tell you which machine fits and what it costs. Or jump to the machines and prices ↓
Where do valve marks go: on the body or on a nameplate?
Your valve standard splits the marks between the two. Size, class and material usually go on the body, often cast in by the foundry. The pressure-temperature rating, trim materials and date go on the nameplate, and the serial number goes on both.
Here is how API 6D, the standard for pipeline valves, splits them:
What to mark | On the body | On the nameplate | How it gets there | Changes per valve? |
|---|---|---|---|---|
Maker’s name or logo | Body or plate | Yes | Cast or plate | No |
Size (e.g. NPS 4 or DN 100) | Yes | Yes | Cast | No |
Pressure class (e.g. Class 300) | Yes | Yes | Cast | No |
Body material (e.g. WCB, A105) | Yes | Yes | Cast or dot peen | No |
Heat number (the steel’s batch ID) | Yes | — | Dot peen or stamp | Yes, per batch |
Serial number | Yes | Yes | Dot peen + plate | Yes |
Pressure-temperature rating | — | Yes | Plate | No |
Trim materials (stem, ball or disc, seat) | — | Yes | Plate | Sometimes |
Date of manufacture | — | Yes | Plate | Yes |
Ring groove number (e.g. R49, the metal seal ring a ring-joint flange takes) | Ring-joint flanges only | — | Dot peen | No |
Flow arrow | Check valves only | — | Cast | No |
Source: API Specification 6D, valve body and nameplate marking tables. Check your own edition and your customer’s specification.
Three points explain why the nameplate matters so much:
- The plate is allowed to carry the body marks. Public marking standards based on MSS SP-25 (the common US marking standard for valves) let the mandatory marks be cast, forged or stamped on the body, or shown on a plate fixed securely to it.
- Some data only goes on the plate. ASME B16.34 asks for the pressure rating at 100 °F (38 °C) on the identification plate, its name for the nameplate. When a small valve body has no room, marks are dropped from the body in a set order, so most of the data ends up on the plate.
- Every valve gets its own plate. The serial number and date change on every valve, so the nameplate is the part a valve plant marks every day.
Two rules surprise many buyers:
API 6D: no outsourcing
Marking, tagging and nameplates have to be done by the valve maker, so a 6D plant needs its own marking machine.
EN 19: painted-on marks do not count
The European valve marking standard wants marks cast, forged or stamped into the body, plus a plate that resists corrosion, along with its rivets or screws.
For your quality team
These standards apply to your valves, not to our machines. No marking machine is “certified” to API 6D or MSS SP-25. The machine just has to make the mark your standard asks for.
How do you mark valve nameplates?
Mark the plates flat, before they are fixed to the valve. A tag engraver (dot peen) suits a few dozen plates a day. A desktop fiber laser adds logos, QR codes and crisp black text, and an auto-feed fiber laser handles hundreds a day from an Excel file.
Each numbered line on the example plate:
- Maker and standard: your name or logo, and the standard the valve is built to.
- Size, pressure class and end type: often cast on the body too.
- Body material.
- Trim materials: stem, ball or disc, and seat.
- Pressure-temperature rating: usually only on the plate.
- Serial number and date: different on every valve. The serial is on the body too.
- Buyer’s order and tag number: only when the purchase order asks for it.
- Country and sealing type: extra items some standards and buyers ask for.
Lines 1 to 5 and line 8 stay the same for a valve model. Lines 6 and 7 (orange) change, so the software should read them from a list instead of an operator typing them.
Pick the machine by how many plates you mark a day:
Plates a day | Machine | Why |
|---|---|---|
A few to a few dozen | No air, no computer. Marks you can feel, so oil and scratches do not hide them. | |
A few dozen, with logos or codes | Desktop fiber laser, HS-FL20 / FL30 | Dark, sharp text, logos and Data Matrix codes on stainless plates |
Hundreds | Feeds blank plates from a stack and reads serial numbers from Excel |
How a typical valve plant runs it:
- Export the order data. Serial numbers, date, PO number and tag numbers go into one Excel file.
- Mark the plates flat. The machine fills each plate from the next row of the file.
- Check the serial against the body. The serial on the plate must match the one marked on the body.
- Fit the plate after painting. Rivet or screw it on last, so paint never covers the text.
Laser or dot peen for the plate? A fiber laser gives the cleanest look and can add a logo or a code. Dot peen marks have depth you can feel, so they stay readable when the surface gets scratched or oily.
Nameplate or valve tag?
A nameplate is fitted by the valve maker and carries the valve’s own data. A valve tag is the small round or square tag a plant hangs on the valve with its own number, like FV-1203. The same tag engraver marks both. If you are deciding whether to buy tags or make them, the payback math with real tag prices is in our nameplate engraving machine guide.
Which HeatSign machine fits your valves?
Start with the nameplate, then add a body marker if your plant marks bodies or flange rims:
Valve nameplates and tags, a few dozen a day: tag engraverHS-DE04 / DE05, no air or computer needed. About $1,300–1,900.See the tag engraving machine → 
Hundreds of nameplates a day: auto-feed nameplate laser (HS-FL60MA)Feeds plates from 30 × 30 to 150 × 150 mm and reads serial numbers from Excel. About $6,500.See the nameplate laser → 
Flange rims and round bodies: rotary dot peen (HS-DP200-R)Marks 360° around parts that fit on a bench. About $3,000–5,000.See the rotary dot peen marker → 
Large valve bodies, big flanges, site work: portable or handheld dot peenHeatSign portable and handheld models cost about $1,500–2,850.See the handheld dot peen marker → 
Stainless stems and fittings, logos and codes: fiber laser with rotaryHS-FL30-R / 60-R. About $2,250–5,300.See the rotary fiber laser →How much does a valve marking machine cost?
At HeatSign, a nameplate tag engraver costs about $1,300–1,900, a desktop fiber laser $1,950–5,000, and an auto-feed nameplate laser about $6,500. Body markers run from about $1,500 for a portable dot peen head to $5,300 for a fiber laser with a rotary axis.
Machine | Price range | Best for |
|---|---|---|
Tag engraver (dot peen) | $1,300–1,900 | Nameplates and valve tags, a few dozen a day |
Desktop fiber laser | $1,950–5,000 | Nameplates with logos and codes, stainless parts |
Auto-feed nameplate laser | About $6,500 | Hundreds of nameplates a day |
Portable / handheld dot peen marker | $1,500–2,850 | Large bodies, flanges, site work |
Rotary dot peen marker | $3,000–5,000 | Flange rims, round bodies |
Fiber laser with rotary | $2,250–5,300 | Stainless stems and fittings |
What moves the price: marking area, air or electric drive, a rotary axis, automatic feeding, and the software. More detail is in our dot peen marking machine prices guide.
How do you mark the valve body, and is it safe on the pressure wall?
The foundry usually casts the size, class and material into the body, and the plant adds the serial and heat numbers with a dot peen marker. On pressure-holding walls, the mark must have no sharp notch and must not make the wall thinner.
Dot peen writes with separate round dots. That follows the same idea as the “low-stress” stamps that several valve and defense specifications ask for. What that means on the shop floor:
- Dots, not sharp grooves. A sharp V-shaped stamp can start a crack under pressure. Dot peen writes each letter as a row of separate small dents.
- Mark the right spot. Specifications point marks to flange rims, raised pads and low-stress areas, not to thin sections of the wall.
- Don’t go too deep. A mark must never take the wall below its minimum thickness. HeatSign dot peen markers usually mark 0.1–0.5 mm (0.004–0.020 in) deep.
- Lost a cast mark during machining? A stamped or dot peen mark can replace it.
Your own valve specification and your customer always have the final word. If they name a method, follow it, and send us a sample part if you are not sure.
Dot peen or fiber laser: which fits each valve part?
Use dot peen on cast and forged steel bodies and flange rims that will be blasted, painted or heat treated later. Use a fiber laser on nameplates, stainless bodies, stems and fittings, and wherever text, logos or QR and Data Matrix codes must be small and sharp.
Valve part | Best method | How deep | After blasting or paint |
|---|---|---|---|
Nameplate | Fiber laser or tag engraver (dot peen) | Surface mark (laser), shallow dots (dot peen) | Fitted after painting, so not affected |
Cast steel or iron body | Dot peen | 0.1–0.5 mm (0.004–0.020 in); go deeper if painted | Readable if deep enough |
Forged steel body | Dot peen | 0.1–0.5 mm (0.004–0.020 in) | Readable if deep enough |
Stainless body, stem or fitting | Fiber laser | Surface mark, up to about 0.1 mm | Paint covers it |
Flange rim | Dot peen on a rotary chuck or a portable head | 0.1–0.5 mm | Readable if deep enough |
The rule of thumb: if paint or blasting comes after the mark, choose dot peen. If the part is a plate or finished stainless and the mark must look clean, choose a laser marker.
How do you mark flange rims, round bodies and large valves?
Small round parts go on a rotary chuck (a turning clamp), so the head marks all the way around the rim. Large flanges and heavy valve bodies stay put. A portable dot peen head clamps on with a V-block (a V-shaped holder) or a magnet, or the operator uses a handheld marker.
Your part | Setup | Why |
|---|---|---|
Flanges and round bodies up to bench size | Benchtop dot peen marker with a rotary chuck | The part turns, so text follows the curve at an even depth |
Large flanges, big valve bodies, pipe | Portable dot peen head with a V-block or magnet | You bring the marker to the part; no crane needed |
Parts already installed, or awkward spots | No air hose, no cable to the bench |
From our files
A flange maker in Kazakhstan marked flanges from small to very large. HeatSign suggested a small fiber laser marking machine for the small flanges and a portable pneumatic dot peen marker for the big ones.
A common problem on curved parts: some characters come out deeper than others, because the distance from the pin to the surface changes along the curve. A rotary axis, or a head set square to the rim, fixes this. Our guide to choosing a flange marking machine and the page on marking large round parts go into the setups.
A 20 W mini fiber laser marking machine marking chrome angle valves.
A dot peen marker writing a product code on a steel flange.
How do you mark serial numbers, heat numbers and order data?
Let the software change the data, not the operator. Serial numbers count up by one on each valve, and heat, order and tag numbers load from a list or an Excel file. Use the same file for the nameplate machine and the body marker, so the serial on the plate always matches the body.
This matters more than it sounds. Some buyers ask for their purchase order number and “Manufactured for …” on every valve, and an inspector checks it. With steel stamps, that means changing letters by hand for each order. With a dot peen or laser marker, it is a new line in the file.
Two tips from valve plants we work with:
- Keep the heat number next to the serial number. Inspectors match the heat number to the material certificate (an EN 10204 3.1 certificate), so it must be easy to read.
- Mark the body and the disc separately if their heat numbers differ. The disc comes from a different melt, so it carries its own heat number.
If your customer also wants something to scan, the same data can go into a Data Matrix code (a small square barcode) on the nameplate. Our page on marking serial numbers on metal parts covers the numbering features.
FAQ
Does a valve need a nameplate if the body is already marked?
Usually yes. ASME B16.34, API 6D and EN 19 all ask for a nameplate or identification plate, and some data, like the pressure-temperature rating, only goes on the plate. Check your own standard and your buyer’s purchase order.
Should valve nameplates be laser marked or dot peened?
Both work. A fiber laser gives sharp, dark text and can add a logo or a QR code. A dot peen tag engraver costs less and leaves marks you can feel, which stay readable on scratched or oily plates.
Should you mark the nameplate before or after it is fitted?
Before. Mark the plate flat on the machine, then rivet or screw it on after painting. If a fitted plate needs new data, a portable fiber laser or a handheld dot peen marker can mark it in place.
Does a valve marking machine need to be certified to API 6D or MSS SP-25?
No. These standards apply to your valves, not to the marking machine. The machine only has to make the mark your standard asks for, in the right place and at a readable depth.
Will a dot peen heat number still read after shot blasting or painting?
Yes, if it is deep enough. On cast steel bodies, mark toward the deep end of the usual 0.1–0.5 mm (0.004–0.020 in) range. Then send one part through your full blasting and painting process before you sign off.
Is dot peen a low-stress marking method?
It writes with separate dots instead of a sharp groove, the same idea as the round-bottom, low-stress stamps that several valve specifications ask for. Your specification and your customer have the final say on the method.
Can HeatSign test-mark my nameplates or valve parts?
Yes. Send a few blank plates, a part, or a drawing with your marking list. HeatSign will tell you which machine fits and what the mark will look like.
What should you prepare before you choose a machine?
Write down four things first: the marks your standard asks for, how many nameplates you mark a day and their size, the size and material of your biggest and smallest valve body, and what happens after marking (blasting, painting, heat treatment). Those answers pick the method and the machine for you.
Then send them to HeatSign by email or WhatsApp, with a photo of the part or plate. We will reply with a machine recommendation and a price.
Sources
- API Specification 6D, Addendum 2: valve body and nameplate marking tables; marking, tagging and nameplates may not be outsourced
- ASME B16.34 and API 602 marking summary: what goes on the valve identification plate
- EN 19: marking of metallic valves; painted-on markings are not permitted
- MSS SP-25: standard marking system for valves, fittings, flanges and unions
- IS 9866: public marking standard that draws on MSS SP-25; marks may be on the body or a securely fixed plate; stamping must not crack the body or thin the wall
- EN 10204 certificate types: what a 3.1 material certificate contains