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 is currently submitted to the CEN Enquiry.

This document will supersede EN 2948:1996.

This document includes the following significant technical changes with respect to EN 2948:1996:

— Clause 3 “Terms and definitions” added;

— Clause 8 “Quality assurance” updated;

— Annex A “Bending test and installation example” added.

1.0 Scope

This document specifies the characteristics of tab washers, in heat resisting steel, passivated, for maximum operating temperature 650 °C, for aerospace applications.

Their use under hexagon head bolts is conditional upon the user accepting the possibility of some interference.

2.0 Normative references

The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.

EN 2175,^[1] Aerospace series — Heat resisting alloy FE-PA2602 (X4NiCrTiMoV26-15) — Solution treated and precipitation treated — Sheet, strip and plate — 0,5 mm ≤ a ≤ 10 mm — R_m ≥ 850 MPa

EN 2424, Aerospace series - Marking of aerospace products

EN 2516, Aerospace series - Passivation of corrosion resisting steels and decontamination of nickel or cobalt base alloys

3.0 Terms and definitions

No terms and definitions are listed in this document.

ISO and IEC maintain terminology databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https://www.iso.org/obp/

— IEC Electropedia: available at https://www.electropedia.org/

4.0 Required characteristics

4.1 Configuration – Dimensions – Masses

Configuration, dimensions, and masses shall be in accordance with Figure 1 and Table 1. Dimensions and tolerances are expressed in millimetres and apply after surface treatment.

4.1.1 Material

Material shall be in accordance with EN 2175.

4.1.2 Surface treatment

Surface treatment shall be in accordance with EN 2516.

Values in micrometres apply prior to surface treatment.

Remove sharp edges 0,1 to 0,2.

^a Shape optional.

Figure 1 — Configuration

Table 1 — Dimensions and masses

Diameter code	A	B	C	E	F	G	H	J	K	L	R₁	R₂	T		Mass^a
Diameter code	H13	js13											nom.	Tol.	Mass^a
040	4,2	7	8	4	4,4	—	—	—	3,4	6	1	—	0,5	±0,05	0,2
050	5,2	8	10	5	5	—	—	—	4	7	1	—	0,5	±0,05	0,27
060	6,2	10	12	6	6	—	—	—	5	8	1,5	—	0,8	±0,1	0,68
070	7,2	11	12	9	6	4,4	2,3	5	5,5	9		1,7			0,70
080	8,3	14	16	10	8	4,4	2,8	8	6,5	10,5		1,7			1,15
100	10,5	17	18	12	10	5	3,5	9	8	13		2	1		1,88
120	12,5	20	20	13	11	5	4	10	9	16	3	2			2,47
140	14,5	22	24	15	12	6	4,5	12	10,5	17	3	2,5			3,07
160	16,5	24	26	15	13		4,5	13	11,5	19	4				3,52
180	18,5	27	30	16	15		5	15	12,5	21	5				4,36
200	21	30	32	18	16	7	5,5	16	14	23	6	3			5,17
^a Approximate values (kg/1 000 pieces), calculated on the basis of 7,85 kg/dm³, given for information purposes only.

5.0 Designation

EXAMPLE

TAB WASHER EN 2948‑080

In this designation, the elements have the following meaning:

080	Diameter code (see Table 1)

6.0 Marking

Marking shall be in accordance with EN 2424, style G.

7.0 Inspections and tests

7.1 Appearance

On visual examination, a number of tab washers, as given in Table 2, shall be free from burrs, scratches and cracks.

Table 2 — Visual Examination

Delivered quantity	Minimum quantity to be checked
< 1 000	1 % with three pieces min.
≥ 1 000	15
< 2 000	15
≥ 2 000	20
< 5 000	20
≥ 5 000	30

7.1.1 Bend test

This test shall be carried out on 0,1 % of tab washers to be inspected, with a minimum of three parts.

Assemble the tab washers under normal operating conditions.

After the locking tabs have been folded and straightened twice, they shall be free from cracks.

For detailed Information see Annex A.

8.0 Quality assurance

The manufacturer’s operations shall be an approved production organization for aerospace products and shall demonstrate that it has implemented and is able to maintain a quality management system (e.g. according to EN 9100 or an equivalent aerospace accepted and established quality management system).

The qualification procedure for aerospace standard products (e.g. according to EN 9133 or an equivalent aerospace accepted and established qualification procedure) shall be used and documented according to the specified tests if not otherwise agreed between customer and supplier.

(informative)

Bending test and installation example
1. Bending of a leg for anchoring in a hole

Table A.1 — Dimensions

Dimensions in millimetres

Nominal	M	N	O	P
4	—	—	—	—
5
6
7	9,5	2,5	10,5	3
8	12,5	3	13	4
10	14,5	3,5	15,5	4,5
12	16	4	17	5
14	20	4	21	5,5
16	22	4,5	22,5	5,5
18	26		27	6
20	28		29	6,5

Figure A.1 — Configuration

For this part, a bending test (see Figure A.1) is needed, the bending test shall be performed on finished part (with actual 180/90° angles) and acceptance conditions (no cracks allowed).

1. Installation examples

Common jobs occasional employment

Folding anchor anchoring on rib (from D = 7) anchoring in a hole (from D = 6) on right edge (see Figure A.2).

a) Washer tab

b) Folding anchor anchoring on rib

c) Anchoring in a hole

Folding the leg and drilling the hole according to Table A.1.

Figure A.2 — Configuration

During to the folding process and after installation there are no cracks allowed on curved edge (see Figure A.3).

a) Anchoring round base