SIST EN 3365:2025

Aerospace series - Steel X15CrNi17-3 (1.4057) - Air melted - Softened - Forging stock - a or D ≤ 300 mm

This document specifies the requirements relating to:
Steel X15CrNi17-3 (1.4057)
Air melted
Softened
Forging stock
a or D ≤ 300 mm
for aerospace applications.
NOTE   ASD-STAN designation: FE-PM3901
Material number: 1.4057

Luft- und Raumfahrt - Stahl X15CrNi17-3 (1.4057) - Lufterschmolzen - Weichgeglüht - Schmiedevormaterial - a oder D ≤ 300 mm

Dieses Dokument legt die Anforderungen an:
Stahl X15CrNi17 3 (1.4057)
Lufterschmolzen
Weichgeglüht
Schmiedevormaterial
a oder D ≤ 300 mm
für Anwendungen in der Luft- und Raumfahrt fest.
ASD-STAN-Bezeichnung: FE-PM3901
Werkstoffnummer: 1.4057

Série aérospatiale - Acier X15CrNi17-3 (1.4057) - Élaboré à l’air - Adouci - Produits destinés à la forge - a ou D ≤ 300 mm

Le présent document spécifie les exigences relatives à :
Acier X15CrNi17-3 (1.4057)
Élaboré à l’air
Adouci
Produits destinés à la forge
a ou D ≤ 300 mm
pour les applications aérospatiales.
Désignation ASD-STAN : FE-PM3901
Numéro de matériau : 1.4057

Aeronavtika - Jeklo X15CrNi17-3 (1.4057) - Taljeno - Mehčano - Material za kovanje - a ali D ≤ 300 mm

Ta dokument določa zahteve, ki se navezujejo na: jeklo X15CrNi17-3 (1.4057), taljeno, mehčano, material za kovanje, a ali D ≤ 300 mm za uporabo v aeronavtiki. OPOMBA: Oznaka ASD-STAN: FE-PM3901. Številka materiala: 1.4057.

General Information

• Status: Published
• Public Enquiry End Date: 25-Sep-2024
• Publication Date: 18-Sep-2025
• ICS: 49.025.10 - Steels
• Technical Committee: I13 - Imaginarni 13
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 18-Sep-2025
• Due Date: 23-Nov-2025
• Completion Date: 19-Sep-2025
• Ref Project: EN 3365:2025 - Aerospace series - Steel X15CrNi17-3 (1.4057) - Air melted - Softened - Forging stock - a or D ≤ 300 mm

Relations

• Revises: SIST EN 3365:2009 - Aerospace series - Steel FE-PM3901 (X15CrNi17-3) - Air melted, softened, forging stock a or D ≤ 300 mm
• Effective Date: 22-May-2024

Overview

SIST EN 3365:2025 is a European standard specifying the requirements for aerospace-grade steel X15CrNi17-3 (material number 1.4057). This steel type is air melted, softened, and supplied as forging stock with dimensions a or D up to 300 mm. Prepared by CEN and ASD-STAN, SIST EN 3365:2025 supersedes the 2007 edition and reflects updated material designations, technical tables, and normative reference alignments. It is a key document in the aerospace series of metallic materials standards designed to ensure consistent material quality and suitability for aerospace forging applications.

Key Topics

• Material Specification: Defines chemical composition limits for steel X15CrNi17-3, including carbon (0.12–0.20%), chromium (15.0–17.0%), nickel (2.00–3.00%), and other elements, ensuring corrosion resistance and mechanical performance.
• Manufacturing Process: Steel must be air melted and softened prior to supply as forging stock, guaranteeing optimal forgeability and structural integrity.
• Dimensional Limits: The standard applies to forging stock bars or billets with thickness (a) or diameter (D) less than or equal to 300 mm.
• Mechanical Properties: Specifies critical mechanical parameters including:
  • Proof stress ≥ 700 MPa
  • Tensile strength between 900 and 1,100 MPa
  • Minimum elongation of 12% in ambient temperature conditions
  • Hardness range between 262 and 331 HB
  • Impact energy ≥ 20 J with notch direction transverse (T)
• Testing and Inspection: Mandates compliance with EN 4700-005 for technical specifications and testing, EN 4050-1 for ultrasonic inspection of internal imperfections, and visual inspection for external defects.
• Heat Treatment: Details softened delivery condition code 'U', with additional guidelines for potential hardened and tempered reference heat treatments.

Applications

SIST EN 3365:2025 steel standard is designed primarily for aerospace components requiring:

• High-Performance Forgings: Components forged from X15CrNi17-3 steel exhibit excellent toughness, strength, and corrosion resistance suitable for critical aerospace structural parts.
• Aerospace Manufacturing: Used in aircraft and space vehicle parts manufacturing where material traceability, mechanical reliability, and consistent quality are vital.
• Quality Control in Aerospace Supply Chains: Enables manufacturers, suppliers, and quality assurance teams to verify conformity of steel forging stock with stringent aerospace requirements.
• Material Qualification: Facilitates agreements between manufacturers and purchasers for qualification programs per EN 2043 ensuring that semi-finished product standards are met for aerospace use.

Related Standards

• EN 2043 – General requirements for qualification of aerospace metallic semi-finished products, excluding forgings and castings.
• EN 4050-1 – Ultrasonic testing methods essential for detecting internal imperfections in forging stock.
• EN 4700-005 – Technical specifications and test methods specifically for steel forging stocks, including heat treatment and inspection procedures.
• EN 4258 – Defines the general organizational principles for the aerospace metallic material standards series, ensuring harmonized standardization approaches.
• EN 4500-005 – Provides drafting and presentation rules specialized for steel material standards in aerospace applications.

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By adhering to SIST EN 3365:2025, aerospace manufacturers ensure the reliable production of critical steel forging stock meeting the highest European standards for mechanical performance, quality control, and traceability-vital for safety and durability in aerospace engineering. This standard supports broader aerospace material standardization efforts, promoting international consistency and operational excellence.

Standards Content (Sample)

SLOVENSKI STANDARD
01-november-2025
Aeronavtika - Jeklo X15CrNi17-3 (1.4057) - Taljeno - Mehčano - Material za kovanje
- a ali D ≤ 300 mm
Aerospace series - Steel X15CrNi17-3 (1.4057) - Air melted - Softened - Forging stock -
a or D ≤ 300 mm
Luft- und Raumfahrt - Stahl X15CrNi17-3 (1.4057) - Lufterschmolzen - Weichgeglüht -
Schmiedevormaterial - a oder D ≤ 300 mm
Série aérospatiale - Acier X15CrNi17-3 (1.4057) - Élaboré à l’air - Adouci - Produits
destinés à la forge - a ou D ≤ 300 mm
Ta slovenski standard je istoveten z: EN 3365:2025
ICS:
49.025.10 Jekla Steels
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN 3365
EUROPEAN STANDARD
NORME EUROPÉENNE
September 2025
EUROPÄISCHE NORM
ICS 49.025.10 Supersedes EN 3365:2007
English Version
Aerospace series - Steel X15CrNi17-3 (1.4057) - Air melted
- Softened - Forging stock - a or D  300 mm
Série aérospatiale - Acier X15CrNi17-3 (1.4057) - Luft- und Raumfahrt - Stahl X15CrNi17-3 (1.4057) -
Élaboré à l'air - Adouci - Produits destinés à la forge - a Lufterschmolzen - Weichgeglüht -
ou D  300 mm Schmiedevormaterial - a oder D  300 mm
This European Standard was approved by CEN on 18 August 2025.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2025 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 3365:2025 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
Introduction . 4
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
4 Requirements . 5
Bibliography . 9

European foreword
This document (EN 3365:2025) has been prepared by ASD-STAN.
After enquiries and votes carried out in accordance with the rules of this Association, this document has
received the approval of the National Associations and the Official Services of the member countries of
ASD-STAN, prior to its presentation to CEN.
This document shall be given the status of a national standard, either by publication of an identical text
or by endorsement, at the latest by March 2026, and conflicting national standards shall be withdrawn
at the latest by March 2026.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN 3365:2007.
This document includes the following significant technical changes with respect to EN 3365:2007:
— EN 3365 (P2), 07/2007 – Update of the material designation, correction of the format of Table 1 to
comply with the requirements of the EN 4500 series, upda
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