Overview

Graphite packing with Inconel wire is the packing you specify when the duty is beyond what ordinary packing can survive: superheated steam, high-pressure valve stems, and hydrocarbon service at temperature. It is braided from high-purity expanded graphite (typically >99% carbon) with Inconel wire woven through the structure — Inconel being a nickel-based superalloy (over 70% nickel) that holds its strength at temperatures where ordinary steel wire would soften.

The graphite does the sealing. It is self-lubricating, chemically resistant across the full pH range, and thermally conductive, so it does not burn or carbonise the way a fibre packing would at 500°C+. The Inconel wire does the holding: it reinforces the braid so that under extreme pressure the soft graphite cannot extrude out through the gland clearance or blow out of the stuffing box. Published datasheets for this construction give steam service to around 650°C and valve pressures up to roughly 550 bar.

One thing to be clear about before ordering: this is fundamentally a high-pressure valve stem packing — a static and reciprocating duty. It is not designed as a high-speed rotating pump packing. For a rotating pump shaft, standard Graphite Gland Packing is the right product (rated around 450°C on rotating equipment). The Inconel-reinforced grade is what you fit to a boiler isolation valve, a superheated steam valve, or a high-pressure hydrocarbon valve.

Because graphite is electrically conductive and sits against a metal stem in the presence of moisture, galvanic corrosion of the stem is a genuine risk. Quality Inconel-reinforced graphite packings include a sacrificial corrosion inhibitor that corrodes preferentially and protects the stem — a detail worth confirming on any graphite packing you buy for critical valves.

Specifications

Typical properties for expanded graphite packing with Inconel wire reinforcement. Ratings differ substantially between valve (static/reciprocating) and rotating duty — confirm against your application.

Property	Value	Test Standard
Material	Expanded graphite, >99% carbon purity	—
Reinforcement	Inconel wire (nickel-based superalloy, >70% Ni)	—
Construction	Braided graphite foil / yarn with Inconel wire woven through	—
Corrosion Inhibitor	Sacrificial inhibitor included — protects the stem	—
Colour	Black (graphite)	—
Max Temperature — Steam	up to ~650°C	—
Max Temperature — Oxidising Atmosphere	~450°C (graphite oxidises above this in air)	—
Min Temperature	−200°C (cryogenic capable)	—
Max Pressure — Valves	up to ~550 bar	—
Max Pressure — Rotating	~20 bar (not its intended duty)	—
pH Range	0 – 14 (except strong oxidizers)	—
Max Shaft Speed	~2 m/s (valve / low-speed duty)	—
Thermal Conductivity	High — conducts frictional heat away from the stem	—
Self-Lubricating	Yes — graphite is inherently lubricating	—
Extrusion Resistance	Excellent — the purpose of the Inconel wire	—
Electrical Conductivity	Conductive (graphite)	—
Standard Sizes	3 mm – 25 mm square section	—
Supply Form	Coil / spool by weight, or pre-cut and pre-formed die-moulded rings	—

Properties in Detail

Thermal Properties

Max Temp (Steam): up to ~650°C
Max Temp (in Air): ~450°C (oxidation limit)
Min Temperature: −200°C
Thermal Conductivity: High — carries heat away from the stem
Fire Safety: Graphite does not melt or burn away — suits fire-safe valve designs

Pressure & Mechanical

Max Pressure (Valves): up to ~550 bar
Extrusion Resistance: Excellent (Inconel reinforced)
Max Speed: ~2 m/s (valve duty)
Self-Lubrication: Excellent — low stem friction
Intended Duty: Valve stems: static & reciprocating

Chemical & Other

pH Range: 0 – 14
Weak Point: Strong oxidizers (nitric, chromic acid) attack graphite
Corrosion Inhibitor: Sacrificial — protects the stem galvanically
Electrical: Conductive — note in instrumentation service

Manufacturing

The packing starts as high-purity expanded (flexible) graphite — graphite foil that has been exfoliated so it compresses and conforms like a soft foil rather than behaving as a brittle mineral. This is what lets it seal tightly against an imperfect stem surface.

Inconel wire is then braided through the graphite structure, not merely wrapped around the outside. That distinction matters: an internally-reinforced braid holds the soft graphite in place under pressure from every direction, so it cannot be squeezed out through the gland clearance. Inconel is used rather than stainless steel because it retains its mechanical strength at the 600°C+ temperatures this packing is designed for.

A sacrificial corrosion inhibitor is incorporated during manufacture. Because graphite is electrically conductive and sits in contact with a metal stem, a galvanic cell can form in the presence of moisture and pit the stem. The inhibitor corrodes preferentially, protecting the stem instead — a genuinely important feature on expensive valves, and worth confirming on any graphite packing you buy.

Sizes & Availability

Supplied in standard square cross-sections. Packing size is set by your stuffing box: (bore − stem diameter) ÷ 2. Our Gland Packing Calculator will size it and total the metres for you.

Section Size	Typical Use	Availability
3 mm	Small instrument & control valves	Stock
4 mm	Small valves	Stock
5 mm	Small / medium valves	Stock
6 mm	Medium valves	Stock
8 mm	Medium valves, steam isolation	Stock
9.5 mm	Steam & process valves	Stock
10 mm	Steam & process valves	Stock
12 mm	Large valves, boiler isolation	Stock
14 mm	Large valves	Stock
16 mm	Large / high-pressure valves	Stock
19 mm	Heavy high-pressure valves	Stock
20 mm	Heavy high-pressure valves	Stock
22 mm	Heavy duty	To order
25 mm	Heavy duty	To order

Also available as pre-formed die-moulded graphite rings, which give a denser, more consistent seal than field-cut braid on critical high-pressure valves. Tell us stem diameter, bore and ring count.

Chemical Resistance

Graphite is chemically resistant across the full pH 0–14 range. Its one real weakness is strong oxidizing agents, which attack graphite chemically — and, in air, oxidation above roughly 450°C.

Medium	Resistance	Notes
Steam (saturated & superheated)	Excellent	The core application — up to ~650°C
Hot Water & Boiler Feed	Excellent	Standard duty
Hydrocarbons / Petrochemicals	Excellent	Refinery and process valve service
Strong Alkalis / Caustic	Excellent	Fully resistant
Solvents	Excellent	Fully resistant
Mineral Oils & Fuels	Excellent	Fully resistant
Strong Acids (non-oxidising)	Good	Generally good — confirm concentration
Nitric / Chromic Acid (oxidising)	Poor	Strong oxidizers attack graphite — use PTFE packing instead
Chlorine & Oxidizers	Poor	Not recommended — specify PTFE for this duty

General guidance for the material family at normal industrial concentrations. See the full Chemical Compatibility Chart, and confirm your exact chemical, concentration and temperature with us before final selection.

Applications

This packing is built for the hottest, highest-pressure valve duty in the plant.

Superheated Steam Valves The primary application. Main steam, reheat and superheater isolation valves running at temperatures where fibre packing would simply carbonise. Rated to around 650°C in steam service.

High-Pressure Boiler Isolation Valves The Inconel reinforcement is what makes valve pressures up to roughly 550 bar achievable — it holds the soft graphite in place so it cannot extrude through the gland clearance.

Refinery & Petrochemical Valves Hydrocarbon and process valve stems at temperature. Graphite is chemically resistant across the full pH range and does not degrade in hydrocarbon service.

Power Plant Valve Stems Turbine, feedwater and steam-side valves in power generation, where a leaking stem is both an energy loss and a safety hazard.

Fire-Safe Valve Designs Graphite does not melt or burn away in a fire the way a polymer packing does, which is why graphite-based packing is used in fire-safe valve constructions.

Cryogenic Valve Service Graphite also performs at the other extreme — down to around −200°C — making it suitable for LNG and cryogenic valve stems as well as high-heat duty.

Industries

Why Graphite Packing With Inconel Wire is specified in each of the industries we serve.

Power Plants

A power station is where this packing earns its cost. Main steam, reheat and feedwater valves run at temperatures and pressures that destroy conventional packing outright, and a leaking valve stem on a superheated steam line is simultaneously an energy loss, a maintenance headache and a genuine safety hazard. Expanded graphite reinforced with Inconel wire is specified for exactly these stems: the graphite seals and self-lubricates at temperatures up to around 650°C without carbonising, while the Inconel wire prevents the soft graphite from extruding out of the gland under pressures that can reach several hundred bar. Because graphite is also fire-safe — it does not melt or burn away — it suits the fire-safe valve designs required on critical steam and fuel systems. The one thing to specify carefully is the corrosion inhibitor, which protects the expensive valve stem from galvanic pitting.

Oil & Gas / Refineries

Refinery and petrochemical valves combine hot hydrocarbons, high pressure and, frequently, fire-safety requirements — a combination that rules out most packing materials. Inconel-reinforced graphite packing handles all three. Graphite is chemically inert to hydrocarbons, solvents and the full pH range, so the process media does not degrade it; the Inconel wire gives the extrusion resistance needed for high-pressure valve stems; and graphite’s inherent fire resistance supports fire-safe valve designs where a polymer packing would melt out and release inventory. It also works at the opposite extreme, down to about −200°C, which makes the same material family suitable for LNG and cryogenic valve service. The one media to avoid is strong oxidizers — nitric and chromic acid attack graphite chemically, and PTFE packing should be used for those specific lines instead.

Chemical Plants

Graphite’s appeal in chemical processing is its breadth: it is resistant across the full pH 0–14 range, so a single packing handles acid, caustic and solvent valve service that would otherwise require several different materials. Inconel-reinforced grades add the high-pressure and high-temperature capability needed on reactor isolation and steam-jacketed valve stems. The critical exception, and it is one worth stating plainly, is strong oxidizing agents. Concentrated nitric acid, chromic acid and similar oxidizers attack graphite chemically — this is not a temperature or pressure limit but a straightforward material incompatibility, and the correct choice for those lines is Pure PTFE packing. Where oxidizers are not present, Inconel-reinforced graphite is the most capable valve stem packing in the plant.

Cement & Sugar Mills

Heavy process industries run their own boiler houses and steam distribution systems, and the isolation and control valves on those steam lines face the same high-temperature duty as a power station, if at lower pressure. Inconel-reinforced graphite packing is specified on the hottest of those valve stems, where standard packing would carbonise and fail. In a sugar mill in particular it is important to match the packing to the line: the abrasive juice, mud and massecuite pumps need aramid packing for its abrasion resistance, while the boiler and steam-side valves need graphite for its heat resistance. Fitting either material to the other’s duty is a common and costly error, and it is the single most useful thing to get right when specifying packing across a mill.

Inconel-Reinforced Graphite vs Other Packings

This is the top of the range for heat and pressure. Note it is a valve-stem packing — not a high-speed rotating pump packing.

Property	Graphite + Inconel	Graphite (standard)	Aramid	Pure PTFE
Max Temperature	~650°C (steam)	450°C rotating / 650°C valve	250 – 260°C	260°C
Max Pressure (Valve)	~550 bar	~100 bar	~100 bar	Lower
Extrusion Resistance	Excellent (wire reinforced)	Good	Excellent	Fair
Intended Duty	Valve stems (static/recip.)	Pumps & valves	Rotating pumps	Pumps & valves
Chemical Range	pH 0–14 (not oxidizers)	pH 0–14 (not oxidizers)	pH 2–12	pH 0–14 (all)
Abrasion Resistance	Fair	Fair	Excellent	Fair
Strong Oxidizers	Poor — avoid	Poor — avoid	Poor	Excellent
Choose It For	Superheated steam, HP valves	General steam & heat	Abrasive slurry	Chemicals, food

Advantages & Limitations

Advantages

The highest temperature capability in our packing range — steam service to around 650°C.
Very high valve pressure rating (up to roughly 550 bar) thanks to the Inconel wire reinforcement.
Excellent extrusion and blow-out resistance — the wire holds the soft graphite in place.
Chemically resistant across the full pH 0–14 range.
Self-lubricating, with high thermal conductivity that carries frictional heat away from the stem.
Sacrificial corrosion inhibitor protects the valve stem from galvanic pitting.
Fire-safe: graphite does not melt or burn away, supporting fire-safe valve designs.
Also performs at cryogenic temperatures, down to about −200°C.

Limitations

Attacked by strong oxidizers — nitric acid, chromic acid and similar. This is a chemical incompatibility, not a rating limit. Use Pure PTFE packing for oxidizer service.
Oxidises in air above roughly 450°C. The 650°C figure applies to steam/inert service; in an oxidising atmosphere the practical ceiling is lower.
A valve-stem packing, not a rotating pump packing. Speed capability is low (~2 m/s). For a rotating pump shaft, use standard graphite gland packing.
Electrically conductive — worth noting in instrumentation and certain electrical service.
Graphite is messy to handle and marks hands and surfaces.
Higher cost than standard packing — specify it where the temperature and pressure genuinely demand it.

Installation, Storage & Maintenance

Installation

Cut rings squarely on a mandrel of the correct stem diameter and fit them one at a time, staggering successive ring joints by 90° or 120° so no straight leak path exists through the set. Seat each ring fully before adding the next. On critical high-pressure valves, pre-formed die-moulded graphite rings give a denser and more consistent seal than field-cut braid — ask us for these. Tighten the gland evenly and do not over-compress: graphite seals at modest load, and over-tightening increases stem friction and can make the valve hard to operate.

Storage

Store in the original packaging in a clean, dry place. Graphite is chemically stable with an effectively indefinite shelf life and does not age or degrade. Keep coils clean — grit picked up in storage will be carried straight onto the valve stem during installation.

Maintenance

Graphite packing is self-lubricating and largely maintenance-free in service. Check for stem leakage and take up the gland gradually if needed, rather than in one large step. Inspect the stem surface at every repack: a scored or pitted stem will leak through any packing. If you see galvanic pitting on the stem, confirm that the packing you are fitting contains a corrosion inhibitor — not all graphite packings do.

Buying Guide

What to tell us so we quote the right grade first time.

Valve or pump? This is the single most important question. Inconel-reinforced graphite is a valve-stem packing. If you are packing a rotating pump shaft, standard graphite gland packing is the correct product.
Stem diameter and stuffing box bore. These set the packing section: (bore − stem) ÷ 2. Our Gland Packing Calculator will size it and total the metres.
Operating temperature — and is the atmosphere oxidising? Graphite goes to ~650°C in steam, but oxidises in air above roughly 450°C. Tell us the real service condition, not just the peak number.
Operating pressure. The Inconel reinforcement is what buys you the very high valve pressure rating. If your pressure is modest, standard graphite packing may be sufficient and cheaper.
Any strong oxidizers in the media? Critical. Nitric acid, chromic acid and similar oxidizers attack graphite. If these are present, you need PTFE packing instead — tell us and we will redirect you.
Braided or pre-formed die-moulded rings? For critical high-pressure valves, pre-formed graphite rings give a denser, more consistent seal than field-cut braid. Worth specifying on important valves.

Standards & Compliance

Expanded graphite of >99% carbon purity, reinforced with Inconel wire (a nickel-based superalloy, typically >70% Ni).
Supplied to standard commercial square cross-sections (3 mm to 25 mm).
Sacrificial corrosion inhibitor included to protect the valve stem from galvanic corrosion — confirm this requirement at the point of order.
Suitable for use in fire-safe valve constructions, as graphite does not melt or burn away.
Inconel® is a registered trademark of its owner; we supply nickel-alloy-reinforced graphite packing to the specification described and do not imply supply of any specific branded alloy unless stated on the order.
Certificates of conformity available on request.

Downloads

Product Datasheet (PDF) Specifications, applications and industries served.

Need a drawing or a specific size? Send your requirement on WhatsApp and we will confirm what is achievable in this material.

Frequently Asked Questions

What is Inconel wire doing in graphite packing?

Holding the graphite in place. Expanded graphite seals beautifully but is soft, and under high pressure it would extrude out through the gland clearance. Inconel wire is braided through the structure to reinforce it. Inconel is used rather than steel because it keeps its strength at the 600°C+ temperatures this packing works at.

What temperature can it handle?

Around 650°C in steam service. Important caveat: in an oxidising atmosphere (open air), graphite begins to oxidise above roughly 450°C, so the practical ceiling is lower there. Tell us the real service condition.

What pressure can it handle?

Up to roughly 550 bar on valves. That very high rating is precisely what the Inconel reinforcement buys you.

Can I use this on a rotating pump?

It is not designed for it. This is a valve-stem packing — a static and reciprocating duty with a low speed capability (~2 m/s). For a rotating pump shaft, use standard Graphite Gland Packing, which is rated around 450°C on rotating equipment.

What is the difference from standard graphite packing?

The Inconel wire reinforcement. It buys you far higher pressure capability and much better extrusion resistance, at the cost of being specialised for valve duty rather than general pump-and-valve service.

Which chemicals attack graphite packing?

Strong oxidizers — concentrated nitric acid, chromic acid and similar. This is a genuine chemical incompatibility, not a rating limit. For oxidizer service, use Pure PTFE Gland Packing instead.

What pH range does it handle?

The full pH 0–14 range, with the strong-oxidizer exception noted above.

Why does graphite packing need a corrosion inhibitor?

Graphite is electrically conductive. Sitting against a metal stem with moisture present, it can form a galvanic cell and pit the stem. A sacrificial corrosion inhibitor corrodes preferentially and protects the stem instead. Not all graphite packings include one — ours does, and it is worth confirming on any graphite packing you buy for expensive valves.

Is it fire-safe?

Graphite does not melt or burn away in a fire the way a polymer packing does, which is why graphite-based packings are used in fire-safe valve constructions. Confirm the specific fire-safe certification you need at the point of order.

Can it be used at cryogenic temperatures?

Yes — graphite performs down to around −200°C, so the same material family covers LNG and cryogenic valve stems as well as superheated steam.

What size do I need?

Packing size = (stuffing box bore − stem diameter) ÷ 2, rounded to the nearest standard section. Our Gland Packing Calculator works it out and totals the metres required.

Braided packing or pre-formed rings?

For critical high-pressure valves, pre-formed die-moulded graphite rings give a denser and more consistent seal than field-cut braided packing. On less critical valves, braid cut into rings is fine and more economical.

How many rings should I fit?

Typically 4 to 6, depending on the stuffing box depth. Count what came out, or send us the box dimensions.

Should I stagger the ring joints?

Yes — always. Rotate each successive ring joint by 90° or 120° from the one below it. A set of rings with aligned joints has a straight leak path right through it.

Is graphite packing messy?

Yes, it marks hands and surfaces. That is cosmetic rather than functional, but wear gloves and keep it away from finished surfaces during installation.

Does it need lubrication?

No. Graphite is inherently self-lubricating, which is one of its main advantages — it keeps stem friction low without any added lubricant that could burn off at temperature.

Why is my valve hard to operate after repacking?

Almost always over-tightening. Graphite seals at a modest gland load; over-compressing it dramatically increases stem friction. Back the gland off and take it up gradually.

Is it electrically conductive?

Yes, graphite conducts. This is rarely an issue on a valve, but it is worth being aware of in instrumentation or certain electrical applications.

What is the shelf life?

Effectively indefinite. Graphite is chemically stable and does not age. Just keep it clean and dry — grit picked up in storage would go straight onto the valve stem.

Graphite + Inconel vs aramid — which do I need?

Completely different problems. Heat and high-pressure valve duty → graphite with Inconel. Abrasive slurry on a rotating pump → aramid. Neither will do the other’s job.

Graphite Packing With Inconel Wire