SIST EN 3385:2012

SIST EN 3385:2012 is the Slovenian adoption of EN 3385:2012, published by SIST. It specifies steel external retaining rings for axial mounting, vacuum cadmium plated, for aerospace applications, so engineers, buyers, and inspectors can identify the ring type, its dimensions, material condition, surface treatment, marking, and mounting references.

What does SIST EN 3385:2012 specify?

SIST EN 3385:2012 defines the characteristics of axial mounting external retaining rings made of steel and vacuum cadmium plated for aerospace applications. In practice, the standard is used to select a ring by diameter code, check its physical form and finish, and apply the correct marking and installation references.

SIST EN 3385:2012 is organized into clauses 1 to 7:

• Scope and field of application
• Normative references
• Required characteristics
• Designation
• Marking
• Technical specification
• Mounting

Clause 3 is the main technical section. It points to the figure and table for geometry and mass, gives the material hardness ranges, and sets the cadmium plating requirement.

What are the key requirements of SIST EN 3385:2012?

SIST EN 3385:2012 requires the ring geometry and mass to follow Figure 1 and the table in Clause 3.1. That matters because the ring must fit the shaft groove and installed condition defined for its diameter code.

Configuration, dimensions, and mass

Clause 3.1 links each diameter code to the ring shape, dimensions, and approximate mass. The table is the selection and inspection reference for production, receiving inspection, and drawing definition.

Material condition

Clause 3.2 specifies spring steel hardness ranges by diameter code group: one range applies to diameter codes 008 to 038 and another to diameter codes 040 to 165. For users, this means the ring material must be controlled to the correct hardness for the size range being supplied.

Surface treatment

Clause 3.3 requires vacuum cadmium plating to EN 2535. A plating thickness of 5 µm to 9 µm applies on all surfaces that can be contacted by a 20 mm ball, and the other surfaces must have a continuous deposit. In practice, this gives a clear coating check for coated areas that can be reached and a general coverage requirement for the rest.

Designation

Clause 4 gives the designation format with a description block and an identity block, using the EN standard number and the diameter code. This helps purchasers, planners, and stores identify the exact ring size without ambiguity.

Marking, technical specification, and mounting

Clause 5 requires marking to EN 2424, style G. Clause 6 points to EN 3380 for the technical specification, and Clause 7 points to EN 3426 for mounting. That means the ring is not used in isolation - marking, product requirements, and installation all refer to companion aerospace standards.

What terms does SIST EN 3385:2012 define?

• Axial mounting - the ring is fitted in the axial direction rather than being mounted in another orientation, which matters for how the groove and installation tool are used.
• External retaining ring - a ring that retains a part from the outside of a shaft or similar component, which is the part type covered by the standard.
• Vacuum cadmium plated - cadmium is deposited under vacuum conditions, giving the surface treatment required by Clause 3.3.
• Diameter code - the code used in the designation and table to identify the ring size and the corresponding shaft nominal diameter.
• EN 2424 - the aerospace marking standard used for the ring marking style.
• EN 2535 - the aerospace standard for vacuum deposition of cadmium used for the surface treatment.
• EN 3380 - the technical specification standard for aerospace retaining rings.
• EN 3426 - the standard for groove dimensions for axial mounting external type retaining rings.

Who uses SIST EN 3385:2012?

SIST EN 3385:2012 is used by aerospace designers, manufacturers, suppliers, inspectors, and purchasing teams that work with shaft retention hardware. It is especially relevant when a ring has to be specified by size, plated condition, marking, and mounting method. Quality teams use it to verify delivered parts against the required dimensions, hardness, and plating condition.

Which standards are used with SIST EN 3385:2012?

SIST EN 3385:2012 names these normative references:

• EN 2424 - gives the marking style required for the product.
• EN 2535 - gives the vacuum cadmium deposition requirement used for the surface treatment.
• EN 3380 - gives the technical specification for aerospace retaining rings.
• EN 3426 - gives the groove dimensions used for axial mounting external type retaining rings.

What does the SIST EN 3385:2012 document contain?

SIST EN 3385:2012 contains one figure for the ring configuration and one detailed table of dimensions and approximate masses across many diameter codes. The table supports design selection, drawing definition, and incoming inspection by linking the nominal shaft diameter to the ring dimensions.

The document also includes a designation example that shows how to write the product name and identity block. This is useful for procurement and part numbering. Clause 5 gives the marking method, Clause 6 points to the technical specification, and Clause 7 points to the mounting standard, so the document works as a complete identification and application reference for the ring family.