Corrosion handbook

ManualsBrandsHilti Manuals3D structuresMQV-4/3 D

06/21 37

5.1 Selecting the right corrosion protection for

anchors, power-driven fasteners and screws

For fasteners to be perfectly satisfactory and reliable for their entire service life

from a corrosion perspective, all the influencing factors must be identified before

a suitable fastener can be selected.

The following table provides a general guideline for the most common applications

for fastening elements. The appropriate corrosion protection for each fastening

material is shown based on the typical atmospheric environments (see notes).

Hilti anchor channels (HAC) are available in hot-dip galvanized steel according to

E ISO 1460:2009-10. HBC special bolts are available in electro-galvanized, hot-dip

galvanized and A4 versions. HAC may be used together with HBC in any material

combination in dry indoor environments according to ETA-11/0006 (28th February

2012). When HBC are hot-dip galvanized, they may also be used in indoor

environments with temporary condensation.

Anchors,

power-driven

fasteners and screws

product examples

Anchors

HSA,

HUS3,

HST, HIT-

V, HRD

HUS3-HF HS A-F,

HIT-V-F

HSA-R2,

HRD-R2

HUS-HR,

HSA-R

HST-R,

HIT-V-R

HIT-Z-R,

HRD-R

HST-HCR

Screws

S-DS01,

S-DD01

S-MD Z,

S-MP Z

S-CD C,

S-IT C

S-MD S,

S-CD S

S-MD SS,

S-CD SS

Power-driven

fasteners

X-ENP

X-U

X- G H P,

X-GN

X-FCM-M,

X-GR

X-BT,

X-BT-ER

X-CR,

X-FCM-R

On request

Coating/

material

Carbon

steel with

or without

phosphating

Electro-

galvanized

Duplex-

coated

carbon

steel

HDG/

sherardized

45-50 µm

AISI 304

AISI 316

HCR,

e.g. 1.4529

Environmental conditions Fastened part

Dry indoor

Steel (zinc-coated,

painted), aluminum,

stainless steel

Indoor with temporary

condensation

Steel (zinc-coated,

painted), aluminum

‒ –

Stainless steel – –

Outdoor with low

pollution

Steel (zinc-coated,

painted), aluminum

‒ ‒

Stainless steel – –

Outdoor with mode-

rate concentration of

pollutants

Steel (zinc-coated,

painted), aluminum

‒ ‒

Stainless steel – –

Coastal areas

Steel (zinc-coated,

painted), aluminum,

stainless steel

‒ ‒ – ‒ ‒

Outdoor, areas with

heavy industrial

pollution

Steel (zinc-coated,

painted), aluminum,

stainless steel

‒ ‒ – ‒ ‒

Close proximity to

roads

Steel (zinc-coated,

painted), aluminum,

stainless steel

‒ ‒ – ‒ ‒

Special

applications

Consult experts

= expected lifetime of anchors made from this material is typically satisfactory in the specified environment based on the typically expected lifetime of a building. The

assumed service life in European Technical Assessments is 50 years for concrete anchors, 25 years for power-driven fasteners, steel and sandwich panel screws,

and 10 years for flat roof insulation screws.

= a decrease in the expected lifetime of non-stainless fasteners in these atmospheres must be taken into account (≤ 25 years). Higher expected lifetime needs a

specific assessment.

‒ = fasteners made from this material are not suitable in the specified environment. Exceptions need a specific assessment.

Outdoor exposure for up to 6 months during construction is permissible for Hilti high-strength electro-galvanized siding and decking fasteners such as the X-ENP

(see instructions for use for details).

From a technical point of view, HDG/duplex coatings and A2/304 material are suitable for outdoor environments with certain application restrictions. This is based

on long-term experience with these materials as reflected e.g. in the corrosion rates for Zn given in the ISO 9224:2012 (corrosivity categories, C-classes), the

selection guidelines for stainless steel grades provided in Eurocode 3 EN 1993 (final draft 2014) or in the national technical approval issued by the DIBt Z.30.3-6

(April 2014) and the ICC-ES evaluation reports for our products for North America (e.g. ESR-1917, May 2013). The use of those materials in outdoor environments

however is currently not covered by the European Technical Assessments (ETA) of anchors, where it is stated that anchors made of galvanized carbon steel or

stainless steel grade A2 may only be used in structures subject to dry indoor conditions, based on an assumed working life of the anchor of 50 years.