X10NiCrSi35-191.4886 · Explained

Overview

What Is X10NiCrSi35-19 (1.4886)?

When a component has to survive glowing-hot service — inside a hardening furnace, a radiant tube, or a reformer in a petrochemical plant — ordinary stainless steel quietly runs out of road. X10NiCrSi35-19 is one of the grades engineers reach for once the temperature climbs toward 1100 °C and the atmosphere itself starts attacking the metal.

Better known by its European material number 1.4886, this is a fully austenitic, nickel-rich heat-resistant steel standardized under EN 10095, the specification covering heat-resisting steels and nickel alloys. It belongs to the same 35Ni–19Cr family as grades sold commercially under 330-type designations, and it is prized for a specific combination that is hard to get elsewhere: stable structure, dependable oxidation resistance, and unusually strong resistance to carburizing atmospheres.

The name itself is a recipe written in shorthand. The leading X flags a high-alloy steel; 10 points to roughly 0.10% carbon; and the trailing figures name the two dominant alloying elements and their approximate percentages — about 35% nickel and 19% chromium. Silicon earns its place in the name because it is deliberately added to reinforce the alloy's behavior at temperature. Everything about the designation is telling you this steel was designed for heat.

You will meet the same alloy under several labels. The EN material number 1.4886 and the name X10NiCrSi35-19 refer to the same specification, and buyers often cross-reference it against the 35Ni–19Cr, 330-type heat-resistant family. Because national standards define their ranges slightly differently, treat any cross-reference as a close match rather than a guaranteed one-for-one substitution, and confirm the exact grade on the material certificate.

Composition

What Is the Chemical Composition of 1.4886?

The typical composition specified for 1.4886 under EN 10095 is set out below. Iron makes up the balance, but with a third of the alloy given over to nickel, this is far from a plain iron-based stainless.

Each element pulls its weight. Chromium is what makes the steel oxidation-resistant at all — it forms the tight chromia film that shields the surface. Silicon works alongside it, helping that scale stay adherent through heating and cooling instead of flaking away. But the defining ingredient is nickel: at roughly 35% it does two things at once, locking the microstructure into a stable austenite and cutting the alloy's appetite for absorbing carbon from hot process gases.

Microstructure

Why Does 1.4886 Stay Austenitic?

Nickel is a powerful austenite stabilizer. With a third of the alloy given over to it, 1.4886 holds a face-centered-cubic austenitic structure across its entire working range, with no disruptive phase change on heating or cooling. That single fact drives most of its useful behavior.

A stable austenite means the steel keeps meaningful ductility and toughness both at cryogenic temperatures and while glowing hot, resists the embrittlement that troubles lower-alloy grades, and behaves predictably through thermal cycling. It is also essentially non-magnetic in the annealed condition. The trade-off is a higher thermal expansion coefficient than ferritic steels, which designers accommodate rather than fight.

Properties

Mechanical Properties You Can Design To

Parts are normally supplied in the solution-annealed (+AT) condition. The room-temperature figures below give the baseline; the real point of the alloy, though, is how gracefully it holds strength as the temperature climbs.

What sets 1.4886 apart is its creep resistance and lasting strength at elevated temperature. Absolute strength falls as any metal is heated, but this grade resists slow, load-driven deformation over long dwell times far better than commodity stainless. For furnace hardware expected to run for years under its own weight and thermal stress, that resistance to creep is often the property that actually decides service life.

Two more traits are worth building into a design. First, the alloy keeps a generous elongation of at least 40% in the annealed state, so it tolerates handling, thermal shock and forming without cracking. Second, its higher thermal expansion and lower thermal conductivity — normal for a high-nickel austenitic — mean clearances, guides and restraints should be sized to let hot parts grow and move freely rather than lock up against cooler structure.

Surface stability

Oxidation and Scaling Resistance

At high temperature the surface is the first line of defense, and this is where the chromium and silicon in 1.4886 earn their keep. Chromium builds a continuous, self-repairing chromia layer that slows further oxygen attack to a crawl; silicon promotes a thin silica-rich sub-layer that helps the scale grip the metal beneath.

The high nickel content keeps that protective scale stable through the expansion and contraction of repeated heating and cooling, so it resists spalling — the flaking that would otherwise expose fresh metal on every cycle. In clean, oxidizing air the grade is generally suited to continuous service approaching 1100 °C, with the practical ceiling set lower where components see heavy thermal cycling or sustained load.

Signature strength

The Carburization Resistance That Defines It

If there is a single reason to specify 1.4886 over a cheaper heat-resistant stainless, it is carburization resistance. In carbon-rich process atmospheres — the endothermic gas of a carburizing furnace, cracked hydrocarbons in a reformer — carbon diffuses into most steels, forming brittle carbides that embrittle the metal and, over time, destroy it from the inside.

The high nickel content of 1.4886 sharply lowers both the solubility and the inward diffusion of carbon, so the alloy simply takes up far less of it. That translates directly into longer service life for parts living in carburizing and reducing environments, where lower-nickel grades fail early. The grade also stands up well to nitriding attack. One caution belongs on the record: like other high-nickel alloys, it is more vulnerable in sulfur-bearing atmospheres, so sulfidation risk should be assessed for the specific process gas.

Applications

What Is X10NiCrSi35-19 Used For?

The alloy shows up wherever heat, load and aggressive atmosphere meet at once. Common forged applications include:

• Industrial furnace internals — retorts, muffles, radiant tube components, burner hardware and roller-hearth parts
• Heat-treatment fixtures — fan hubs, support posts, shafts and structural members for trays, grids and baskets
• Petrochemical & refining — tube supports, hangers, thermowell bodies and other hot-section fittings
• Kiln and calcination hardware exposed to continuous high temperature
• High-temperature shafts, sleeves and fasteners that must keep their strength while glowing

Typical forged forms are stepped shafts, discs, rings, flanges, sleeves and blanks — geometries that later machine into finished furnace and process components.

Process

Why Forge This Grade Instead of Casting or Cutting From Bar?

Forging does more than shape 1.4886 — it improves it. Hot working refines the grain, closes internal porosity, and aligns the metal's flow lines with the part's loaded directions. For rotating, pressure-bearing or heavily loaded hot components, that sound, worked structure gives better creep integrity and fatigue life than a cast or a machined-from-billet equivalent.

There is an economic argument too. This is an expensive, hard-to-machine alloy, so forging to a near-net shape removes a great deal of costly metal cutting and reduces the raw tonnage of nickel-rich material that ends up as chips.

Fabrication

Machining and Welding Notes

Machining

Like most austenitic grades, 1.4886 work-hardens readily and cuts with a tough, gummy chip. Rigid setups, sharp carbide tooling with positive rake, and steady feeds that keep the cutting edge below the previously work-hardened layer all help. Generous coolant manages the heat that this poor-conducting alloy would otherwise dump into the tool.

Welding

The grade is weldable by standard methods using matching or over-alloyed high-nickel fillers. Clean joints, controlled heat input and sound technique keep hot-cracking risk in check. Post-weld heat treatment is not generally required, though a solution anneal can be applied where structure or stress relief needs to be restored.

Comparison

How Does 1.4886 Compare to 310S and Alloy 800H?

Against 310S (1.4845), the familiar 25Cr–20Ni workhorse: 310S is more economical and an excellent oxidation performer, but its far lower nickel leaves it exposed in carburizing atmospheres, exactly where 1.4886's 35% nickel pulls ahead. Against creep-optimized grades such as Alloy 800H/800HT, those alloys use additions like titanium and aluminium to win in high-stress, pressure-boundary creep service; 1.4886 is the stronger pick where oxidation and carburization resistance dominate and mechanical stress is moderate. The right grade is always the one matched to the actual temperature, load and process gas — not the highest number on a datasheet.

Procurement

How to Specify and Order Forged 1.4886 Parts

A clean enquiry gets a faster, more accurate quotation. When requesting forged 1.4886 components, it helps to state:

• Form and dimensions — shaft, disc, ring, flange or drawing, with finished and rough sizes
• Standard and grade — EN 10095, 1.4886 / X10NiCrSi35-19, plus any equivalent called out
• Delivery condition — normally solution annealed (+AT)
• Material certificates — EN 10204 3.1 (3.2 by third-party arrangement on request)
• Testing & NDT — chemistry, mechanicals, ultrasonic inspection and any project-specific checks

With those points pinned down, a forge can move straight from material through forging, heat treatment and machining to a certified, ready-to-fit part. To see stock forms and start a request, visit our custom 1.4886 forgings.

FAQ

Frequently Asked Questions

The takeaway

Key Takeaways

Need the grade turned into a real part? Request a quote for finished forged parts and send us your drawing.

Sources

References & Standards

1. EN 10095 — Heat resisting steels and nickel alloys, European Committee for Standardization (CEN). Defines grade X10NiCrSi35-19 / 1.4886, composition and mechanical property requirements.
2. EN 10204 — Metallic products — Types of inspection documents (e.g. 3.1 and 3.2 certificates) referenced for material certification.
3. Background on austenitic stainless steel and carburizing as general reference concepts.
4. Alloying element roles: nickel and chromium in heat-resistant steels.

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