SIST EN 4374:2023

Overview

SIST EN 4374:2023 is a European standard developed by CEN that specifies technical requirements for the heat-resisting alloy NI-PH1301 (NiCr19Co18Mo4Ti3Al3). This alloy is designed for aerospace applications where exceptional heat resistance and mechanical performance are critical. The standard covers solution treated and precipitation treated forms of the alloy, specifically in bars and sections with external diameters (De) up to 200 mm.

This standard ensures quality, consistency, and suitability of NI-PH1301 alloy products for high-temperature aerospace environments. It forms part of the wider aerospace metallic materials series, aligned with other CEN standards focused on aerospace steel and heat-resistant alloys.

Key Topics

• Material Composition: Covers detailed chemical composition of NI-PH1301 alloy with specified minimum and maximum limits for elements such as Nickel (Ni), Chromium (Cr), Cobalt (Co), Molybdenum (Mo), Titanium (Ti), Aluminum (Al), Carbon (C), Silicon (Si), and others, ensuring optimal heat resistance and structural integrity.

• Heat Treatment Processes: Defines solution treatment at 1175 °C ± 10 °C followed by air cooling, and precipitation treatment involving controlled heating cycles at 1080 °C and aging at 850 °C and 760 °C to enhance mechanical properties.

• Product Form and Dimensions: Applicable to wrought bars and sections with external diameters not exceeding 200 mm, providing flexibility in manufacturing for a variety of aerospace components.

• Mechanical Properties: Specifies minimum requirements for proof stress (Rp0.2 ≥ 340 MPa), rupture stress (≥ 370 MPa), and elongation at rupture (≥ 8%), to guarantee mechanical robustness under operational conditions.

• Quality and Inspection: References EN 4700-002 for testing methods, inspection procedures for internal and external imperfections, grain size, microstructure, and dimensional accuracy to maintain strict aerospace quality standards.

• Product Qualification: Emphasizes the need for agreed qualification programs between manufacturers and purchasers per EN 2043, ensuring products meet intended aerospace application demands.

Applications

SIST EN 4374:2023's heat-resisting alloy NI-PH1301 is primarily utilized in aerospace industries requiring components that endure extreme temperatures and mechanical stresses, such as:

• Aerospace engine components: Turbine blades, combustion chambers, and exhaust systems where heat resistance and strength at elevated temperatures are vital.

• Structural elements in aircraft and spacecraft: Bars and sections used in high-temperature zones, contributing to the safety and durability of airframes and propulsion systems.

• High-temperature mechanical systems: Any aerospace assembly demanding alloys with superior creep resistance, oxidation resistance, and mechanical integrity under cyclic thermal loading.

The standard's precise requirements enable manufacturers and engineers to select and validate NI-PH1301 alloy components for critical aerospace applications, balancing material performance and reliability.

Related Standards

• EN 4258: Aerospace series general organization of metallic materials standardization, outlining the framework for the series EN 4374 belongs to.

• EN 4700-002: Technical specification for steel and heat resisting alloys in wrought products, detailing testing and inspection methods applied within EN 4374.

• EN 2043: General requirements for aerospace semi-finished product qualification, including qualification protocols critical for NI-PH1301 bars and sections.

• EN 4500-003: Rules for drafting and presentation of aerospace metallic material standards, ensuring consistent and clear documentation for heat-resisting alloys.

By adhering to SIST EN 4374:2023, aerospace manufacturers ensure NI-PH1301 alloy components meet the stringent quality, mechanical, and thermal performance required in modern aerospace engineering. Compliance with this standard supports enhanced safety, durability, and efficiency of aerospace systems exposed to high-temperature operational environments.