SIST EN 4137:2009

• Abstract:

  This standard specifies the characteristics of bolts, normal bi-hexagonal head, stepped shank, long thread, in titanium alloy, anodized, MoS2 lubrificated.; Classification: 1 100 MPa ) / 315 °C )

• Status: Published
• Publication Date: 17-Aug-2009
• ICS: 49.030.20 - Bolts, screws, studs
• Technical Committee: I13 - Imaginarni 13
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 13-Jul-2009
• Due Date: 17-Sep-2009
• Completion Date: 18-Aug-2009
• Ref Project: EN 4137:2009 - Aerospace series - Bolts, normal bi-hexagonal head, stepped shank, long thread, in titanium alloy, anodized, MoS2 lubricated - Classification: 1 100 MPa (at ambient temperature) / 315 °C

• Refers: SIST EN 14035-19:2003 - Fireworks - Part 19: Hand-held sparklers - Specification and test methods
• Effective Date: 28-Jan-2026
• Refers: SIST EN 9100:2018 - Quality Management Systems - Requirements for Aviation, Space and Defense Organizations
• Effective Date: 28-Jan-2026
• Refers: SIST EN 9133:2018 - Aerospace series - Quality Management Systems - Qualification Procedure for Aerospace Standard Products
• Effective Date: 28-Jan-2026
• Refers: SIST EN 2491:2011 - Aerospace series - Molybdenum disulphide dry lubricants - Coating methods
• Effective Date: 28-Jan-2026
• Refers: SIST EN 840-6:2004+A1:2008 - Mobile waste containers - Part 6: Safety and health requirements
• Effective Date: 28-Jan-2026
• Refers: SIST EN 2424:2008 - Aerospace series - Marking of aerospace products
• Effective Date: 28-Jan-2026
• Refers: SIST EN 14460:2006 - Explosion resistant equipment
• Effective Date: 28-Jan-2026

SIST EN 4137:2009 is the Slovenian adoption of EN 4137:2009 from CEN. It specifies aerospace bolts with a normal bi-hexagonal head, stepped shank, long thread, in titanium alloy, anodized and MoS2 lubricated. The standard is for people who need a fixed definition for design, procurement, manufacture, inspection, and qualification of these fasteners.

What does SIST EN 4137:2009 specify?

SIST EN 4137:2009 specifies the characteristics of a particular aerospace bolt type and organizes them in six clauses, supported by Figure 1 and Tables 1 and 2. The document covers the bolt configuration, dimensions, materials, surface treatment, designation, marking, and technical specification.

Clause 1 gives the scope and the classification of 1 100 MPa at ambient temperature and 315 °C. Clause 2 lists the standards used to apply the document. Clause 3 defines the required characteristics, while Clauses 4 to 6 cover how the bolt is designated, marked, and technically specified.

What are the key requirements of SIST EN 4137:2009?

Geometry, dimensions, and tolerances

SIST EN 4137:2009 ties the bolt geometry to Figure 1 and the dimensional data in Table 1. The dimensions and tolerances are stated in millimetres and apply after anodizing but before lubricating, which matters because measured size must reflect the surface condition expected at delivery.

The standard also uses ISO 7913 for tolerances of form and position. In practice, this means the bolt must not only have the right nominal sizes, but also the right shape and positional accuracy for aerospace assembly.

Material and surface treatment

SIST EN 4137:2009 requires titanium alloy material in the classification 1 100 MPa, with the material reference given through TR 3775. It also requires anodizing and then lubrication with MoS2, with the lubricant application given by EN 2491 and a coating thickness of 5 µm to 10 µm.

This matters because the bolt’s mechanical class and surface condition are part of its defined performance. Buyers and suppliers need to control both the base material and the surface process, not just the thread size.

Thread and head features

SIST EN 4137:2009 uses MJ threads, with limit dimensions referenced to ISO 5855-2. The wrenching configuration is tied to ISO 4095, and the lead and runout thread requirements refer to ISO 3353-1.

In practice, this fixes the thread profile and drive geometry so the bolt fits the intended aerospace nuts and tooling. It reduces ambiguity when parts are sourced from different manufacturers.

Surface finishing details

SIST EN 4137:2009 requires sharp edges to be broken within the stated range and identifies optional features shown in Figure 1. The figure also shows the head shape, the thread region, and optional holes.

This is important for manufacturing and inspection because edge condition, optional features, and the exact bolt form all affect assembly, durability, and conformity checking.

Designation, holes, and length coding

SIST EN 4137:2009 builds the designation from a description block and an identity block, with codes for holes, diameter, length, and lubricant. Table 2 assigns the hole code, and Table 1 gives the diameter and length codes.

For users, this means the part can be specified in a compact standardized way on drawings, purchase orders, and inspection records. The designation must match the actual bolt configuration.

Marking and technical specification

SIST EN 4137:2009 requires marking in accordance with EN 2424, style B. Clause 6 states that the technical specification follows ISO 9152 except for manufacturer approval, which uses EN 9100, and bolt qualification, which uses EN 9133.

In practice, marking supports traceability, and the technical reference set tells manufacturers and quality teams which standards govern production control and qualification.

What terms does SIST EN 4137:2009 define?

• Bi-hexagonal head - A 12-point wrenching head shape used so a tool can engage the bolt in aerospace applications.
• Stepped shank - A shank with a change in diameter along its length, as shown in the bolt configuration.
• MJ threads - The aerospace metric thread form used for these bolts, with limit dimensions taken from ISO 5855-2.
• Classification - The strength and temperature class given in the scope: 1 100 MPa at ambient temperature and 315 °C.
• Diameter code - The code in Table 1 that identifies the nominal bolt diameter for designation.
• Length code - The code in Table 1 that identifies the bolt length for designation.
• Hole code - The designation element that states whether the bolt has holes or not.
• Lubricant code - The designation element that identifies the MoS2 lubricant product from TR 4070.

Who uses SIST EN 4137:2009?

SIST EN 4137:2009 is used by aerospace designers, fastener manufacturers, procurement teams, and quality personnel. It is also relevant to inspection and qualification teams who need a common definition for bolt geometry, material, surface treatment, marking, and designation.

In practice, it helps when specifying parts, checking supplier conformity, writing purchase requirements, and verifying that delivered bolts match the approved aerospace standard.

Which standards are used with SIST EN 4137:2009?

• EN 2424 - defines marking of aerospace products.
• EN 2491 - gives coating methods for molybdenum disulphide dry lubricants.
• EN 9100 - provides the quality management system requirements used here for manufacturer approval.
• EN 9133 - gives the qualification procedure for aerospace standard parts.
• ISO 3353-1 - covers lead and runout threads for rolled external threads.
• ISO 4095 - defines the bihexagonal wrenching configuration.
• ISO 5855-2 - gives MJ thread limit dimensions for bolts and nuts.
• ISO 7913 - covers tolerances of form and position.
• ISO 9152 - gives the procurement specification used as the base technical specification.
• TR 3775 - identifies materials for aerospace bolts and pins.
• TR 4070 - lists commercial products for molybdenum disulphide coatings.

What does the SIST EN 4137:2009 document contain?

The document contains Figure 1, which shows the bolt configuration and key features, and Table 1, which gives the diameter and length coding, related dimensions, wrenching dash numbers, and approximate mass values. Table 2 gives the hole codes used in the designation.

It also contains the designation example, which shows how the standard number, hole code, diameter code, length code, and lubricant code are combined. Clause 5 gives the marking reference, and Clause 6 connects the bolt to the technical specification and the associated approval and qualification standards.

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Aeronavtika - Sorniki, normalna dvanajstroba glava, tanko steblo, dolg navoj, iz titanove zlitine, anodizirani, namazani z MoS2 - Klasifikacija: 1100 MPa (pri temperaturi okolice)/315 °CLuft- und Raumfahrt - Zwölfkantschrauben, Dünnschaft, langes Gewinde, aus Titanlegierung, anodisiert, MoS2-geschmiert - Klasse: 1100 MPa (bei Raumtemperatur)/315 °CSérie aérospatiale - Vis à tête bihexagonale normale, à tige dégagée, filetage long, en alliage de titane, anodisées, lubrifiées MoS2 - Classification: 1100 MPa (à température ambiante)/315 °CAerospace series - Bolts, normal bi-hexagonal head, stepped shank, long thread, in titanium alloy, anodized, MoS2 lubricated - Classification: 1100 MPa (at ambient temperature)/315 °C49.030.20Sorniki, vijaki, stebelni vijakiBolts, screws, studsICS:Ta slovenski standard je istoveten z:EN 4137:2009SIST EN 4137:2009en,de01-september-2009SIST EN 4137:2009SLOVENSKI
STANDARD
EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN 4137
July 2009 ICS 49.030.20 English Version
Aerospace series - Bolts, normal bi-hexagonal head, stepped shank, long thread, in titanium alloy, anodized, MoS2 lubricated - Classification: 1 100 MPa (at ambient temperature) / 315 °C
Série aérospatiale - Vis à tête bihexagonale normale, à tige dégagée, filetage long, en alliage de titane, anodisées, lubrifiées MoS2 - Classification : 1 100 MPa (à température ambiante) / 315 °C
Luft- und Raumfahrt - Zwölfkantschrauben, Dünnschaft, langes Gewinde, aus Titanlegierung, anodisiert, MoS2-geschmiert - Klasse: 1 100 MPa (bei Raumtemperatur) / 315 °C This European Standard was approved by CEN on 6 June 2009.
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 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 Management Centre has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
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B-1000 Brussels © 2009 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 4137:2009: ESIST EN 4137:2009
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