What Is 1.4563 Steel?
Complete Guide to X1NiCrMoCu31-27-4

What Is 1.4563 Steel?

1.4563 is a super austenitic stainless steel standardized under European designation EN 10088-3 with the chemical symbol X1NiCrMoCu31-27-4. It belongs to an elite class of corrosion-resistant alloys engineered specifically for environments where conventional 300-series stainless steels and duplex steels fail — concentrated sulfuric acid, boiling phosphoric acid, deep-sea chloride-laden brine, and sour gas (H₂S + CO₂) systems.

While 316L handles most general industrial corrosion requirements and duplex steels extend those boundaries further, 1.4563 occupies the layer above both: environments where pitting index values below 40 are insufficient, where crevice corrosion attacks weld zones and flanged joints within months, and where stress corrosion cracking fractures load-bearing components without visible warning.

1.4563 delivers a PREN of approximately 48–52 — compared to ≈ 26 for 316L and ≈ 35 for 2205 duplex — making it one of the most corrosion-resistant wrought alloys available in forged form.

It is manufactured as rod, bar, plate, tube sheet, and — critically for pressure-bearing equipment — as open-die forgings and seamless rolled rings. The forged microstructure eliminates cast-in porosity and segregation banding that reduce corrosion uniformity in cast equivalents, which is why engineering specifications for chemical reactors, heat exchangers, and offshore equipment frequently mandate 1.4563 forged components over cast alternatives.

Naming Conventions & Cross-References

One of the most common sources of confusion when sourcing this alloy is the variety of designations used simultaneously across global markets. All of the following names refer to the same alloy chemistry:

Table 1 — Equivalent international designations for 1.4563 / X1NiCrMoCu31-27-4. ^* Sanicro® is a registered trademark of Sandvik AB. Jiangsu Liangyi Co., Limited has no affiliation with Sandvik AB and does not manufacture Sanicro® branded products. The alloy chemistry of 1.4563 / UNS N08028 is an open standard per EN 10088-3, produced independently by multiple mills worldwide.

When reviewing supplier mill test reports (MTRs) or purchase orders referencing "Alloy 28" or the Sanicro® 28 trade name (a Sandvik AB trademark), always verify the actual chemical composition against EN 10088-3 limits. "Sanicro®" is a registered trade name of Sandvik AB and is not affiliated with Jiangsu Liangyi Co., Limited. The alloy chemistry of 1.4563 / UNS N08028 is defined by EN 10088-3 as an open standard and is produced by multiple independent mills worldwide, including Jiangsu Liangyi Co., Limited in Jiangyin, China, supplying with full EN 10204 3.1 material test reports.

Chemical Composition

The corrosion performance of 1.4563 is inseparable from its alloying elements. Understanding what each element contributes is essential for specifying the correct grade and interpreting MTR chemistry results.

Table 2 — Chemical composition of 1.4563 per EN 10088-3. All values in weight percent.

Why Copper Is the Key Differentiator

The 0.6–1.4% copper content is often overlooked in competitor grades but is chemically decisive for 1.4563's application advantage. Copper depresses the corrosion rate in reducing acid environments — specifically, it raises the equilibrium potential in dilute sulfuric acid solutions, slowing the active dissolution of iron and nickel from the surface. This is why 1.4563 is specified for phosphoric acid production plants, sulfuric acid coolers, and urea synthesis loops where 904L and duplex steels fail within weeks.

Mechanical Properties

Mechanical properties of 1.4563 forgings tested in the solution-annealed condition, per EN 10088-3:

Table 3 — Mechanical and physical properties of 1.4563 forgings per EN 10088-3.

The austenitic microstructure and ultra-low carbon content (C ≤ 0.020%) produce excellent Charpy impact values even at sub-zero temperatures — important for cryogenic process equipment and cold-climate offshore installations. 1.4563 is usable to −196 °C without embrittlement.

Corrosion Resistance: Where 1.4563 Excels

Rather than optimizing for a single failure mode, the composition of X1NiCrMoCu31-27-4 addresses the four primary electrochemical mechanisms that destroy stainless steel components in industrial service.

1. Pitting Corrosion

Pitting initiates at surface defects and inclusion clusters in the presence of chloride ions. The low sulfur content (S ≤ 0.015%), high Cr and Mo, and controlled nitrogen of 1.4563 raise the critical pitting temperature (CPT) well above that of 316L and 904L. In ASTM G48 Method A ferric chloride immersion tests, 1.4563 typically passes at 50–60 °C, compared to ~35 °C for 904L and ~20 °C for 316L.

2. Crevice Corrosion

Crevice corrosion attacks stagnant zones at flanged joints, gasket faces, tube-to-tubesheet interfaces, and under deposits. The critical crevice temperature (CCT) for 1.4563 is approximately 35–45 °C in seawater — sufficient for heat exchanger and pipeline applications in tropical offshore environments where lower-alloyed steels fail at ambient temperature.

3. Stress Corrosion Cracking (SCC)

Chloride-induced SCC fractures conventional 300-series steels without visible progressive corrosion. The high nickel content (30–34%) of 1.4563 places it firmly in the SCC-resistant region of the Copson curve. In laboratory tests, 1.4563 has demonstrated resistance to chloride SCC up to 200 °C — far exceeding 316L, which fails above ~60 °C in concentrated chloride solutions.

4. Reducing Acid Corrosion

The 0.6–1.4% copper content is the capability that separates 1.4563 from 904L. Copper provides genuine chemical resistance to sulfuric acid (H₂SO₄) across a wide concentration range, phosphoric acid (H₃PO₄), and moderate concentrations of hydrochloric acid (HCl).

PREN Comparison Across Stainless Steel Grades

1.4563 vs. 316L, 904L, and 2205 Duplex

The comparison below positions 1.4563 against the grades it most commonly competes with or replaces in engineering specifications:

Table 4 — Grade comparison. ★ highlighted row = 1.4563 (subject of this guide).

The primary trade-off versus 2205 duplex is yield strength: at 220 MPa minimum proof strength, 1.4563 cannot match duplex's structural efficiency (450 MPa+). Engineers may need to increase wall thickness — a cost typically offset by the elimination of corrosion-related maintenance and replacement over a 25-year asset life.

Forging 1.4563: Process Considerations

The combination of high nickel content and ultra-low carbon makes 1.4563 formable but demanding during hot working. Its deformation resistance is significantly higher than 304 or 316L, requiring greater press force and tighter thermal control.

Hot Forging Temperature Window

The recommended hot working range for X1NiCrMoCu31-27-4 is 1,100 °C to 1,230 °C. Below 1,050 °C, flow stress rises steeply and surface cracking risk increases. Above 1,250 °C, incipient grain-boundary melting can occur in high-Ni heats with elevated phosphorus. Leading manufacturers use 2,000–6,300-tonne hydraulic forging presses to maintain sufficient force with controllable ram speeds, minimizing adiabatic temperature rise.

Available 1.4563 Forging Products

Heat Treatment of 1.4563

All 1.4563 forgings are delivered in the solution-annealed condition. No precipitation-hardening or age-hardening treatments are applicable to this fully austenitic grade.

Solution Annealing Parameters

The standard solution anneal requires heating to 1,100–1,180 °C, holding for sufficient time to dissolve sigma phase and carbide precipitates formed during hot working (minimum 1 minute per mm of section thickness, minimum 30 minutes total), then rapid water quenching. The rapid quench is essential: slow cooling through 600–900 °C allows sigma-phase precipitation at grain boundaries, dramatically reducing both toughness and corrosion resistance.

Thermal Sensitization Risk

Although ultra-low carbon (C ≤ 0.020%) minimizes sensitization during welding, prolonged exposure to 650–900 °C in service can lead to sigma-phase embrittlement over years of operation. Process engineers should review operating temperature histories when setting inspection intervals for 1.4563 components in borderline temperature zones.

Weldability

1.4563 is weldable by TIG (GTAW), MIG (GMAW), and plasma arc processes. Preheat is not required. The recommended filler metal is AWS/ASME SFA-5.14 ERNiCrMo-3 (Alloy 625) or the matching ERNiCrMo-8 type. Post-weld heat treatment is not required for most applications, but a full solution anneal at 1,100 °C+ is advisable for critical pressure-boundary welds in severe corrosive service to restore full corrosion resistance at the HAZ.

Applications by Industry

1.4563 is the material of choice whenever the lifecycle cost of corrosion-induced failure exceeds the premium material cost. Its combination of super-austenitic corrosion resistance, high ductility, and weldability makes it uniquely suited to the following sectors:

Frequently Asked Questions: 1.4563 Steel