1. Anchor
Channel Systems
2. HAC
Portfolio
3. HAC
Applications
5.3.2.3 H
YDROGEN ASSISTED STRESS
CORROSION CRACKING
Mean corrosion rate
Industrial 5.6 μm/year
Urban non-industrial or marine 1.5 μm/year
Suburban 1.3 μm/year
Rural 0.8 μm/year
Indoors Considerably less than 0.5 μm/year
Source: ASTM B633 Appendix X1. Service life of zinc
9. Special Anchor
Channel Design
Component
Carbon steel
Carbon steel
Rivet
Anchort
Rebar
• Interior applications without any
particular influence of moisture
• If covered sufficiently by noncorrosive
concrete
Mechanically deposited
zinc coating 40 – 107 μm • Interior applications in damp
environments and near saltwater
(ASTM B695)
Hot-dip galvanizing (HDG)
>50 μm (ASTM A153)
Sherardizing process > 50 μm • E xterior applications in only slight to mild
corrosive atmospheres
Stainless steel
(AISI 303 / 304) • Interior applications where heavy
condensation is present
• E xterior applications in corrosive
environments
Stainless steel (AISI 316) • Near saltwater
• Exterior corrosive environments
The specifier should also consult:
a. Local and national building code requirements (e.g., IBC,
UBC)
b. Standard practice manuals for specific types of
construction (e.g., ACI, PCI, AISC, PCA, CRSI, AASHTO,
NDS/APA)
c. Manufacturers of structural components
d. Hilti Technical Support
Stainless steel
Hot dip galvanized (F) ≥ 55 µm
Hot dip galvanized (F) ≥ 70 µm 2 -
Hot dip galvanized (F) ≥ 45 µm -
Hot dip galvanized (F) ≥ 45 µm -
BSt500 B Hot dip galvanized (F) ≥ 45 µm -
S235 Hot dip galvanized (F) ≥ 45 µm -
Channel bolt Grade 4.6 and 8.8 according to
DIN EN ISO 898-1:2009-8 Hot dip galvanized (F) ≥ 45 µm,
or
electroplated (G) ≥ 8 µm Grade 50 according to DIN EN ISO 3506-1:2010-4,
passivation according ASTM A380
Plain washer 3
ISO 7089 and
ISO 7093-1 Hardness A, 200 HV Hot dip galvanized (F),
or
electroplated (G) Hardness A, 200 HV according to ISO 3506-1
Hexagonal nut
ISO 4032 or
DIN 934 4
Property class 8 according to ISO 898-2,
or
property class 5 according to DIN 267-4
Hot dip galvanized (F) ≥ 45 µm,
or
electroplated (G) ≥ 8 µm
Property class 70 according to DIN 267-11
5.3.5.1 GENERAL APPLICATION
These application charts are offered as general guidelines. Site specific conditions may influence the decision.
Application
1
2
3
4
Conditions
Fastener recommendations
Structural steel components to concrete
and masonry (interior connections within
the building envelope not subjected to free
weathering) 1,2 Interior applications without condensation Galvanic zinc electroplating
Interior applications with occasional
condensation HDG or Sherardized
Structural steel components to concrete and
masonry (exterior connections subjected to free
weathering) 1,2 Slightly corrosive environments HDG or Sherardized
Highly corrosive environments Stainless steel
Temporary formwork, erection bracing and
short-term scaffolding Interior applications Galvanic zinc electroplating
Exterior applications HDG or Sherardized
Parking garages / parking decks subject to
periodic application of de-icers including
chloride solutions 3 Non-safety critical HDG, Sherardized
Safety critical Stainless steel 1
Road / bridge decks subject to periodic
application of de-icers including chloride
solutions Non-safety critical HDG or Sherardized
Safety critical Stainless steel
Zinc electro-plated 5 – 10 μm
(ASTM B633, SC 1, Type III)
Organic coatings –
KWIK Cote≥17.8 μm
14. Design
Example
It is difficult to offer generalized solutions to corrosion problems.
A general guide can be used as a starting point for fastener
material selection based on the desired application.
1
Front Plate
• Interior applications without any
particular influence of moisture
13. Field Fixes
Surface
Channel Profile
Typical conditions of use
12. Instructions
for Use
5.3.5 APPLICATIONS
Most Hilti metal anchors are available in carbon steel with an
electrodeposited zinc coating of at least 5 μm with chromate
passivation. Chromate passivation reduces the rate of corrosion
for zinc coatings, maintains color, abrasion resistance and,
when damaged, exhibits a unique “self healing” property. This
means that the chromium contained within the film on the
anchor surface will repassivate any exposed areas and lower
the corrosion rate.
Use of AISI 316 stainless steel in environments where pitting or
stress corrosion is likely to occur should be avoided due to the
possibility of sudden failure without visual warning. Fastenings
used in these applications should be regularly inspected for
serviceability conditions. See chart below for more details.
Phosphate and oil coatings
(Black oxide)
11. Best
Practices
5.3.4.1 ANCHOR CHANNELS
5.3.3.1 SUGGESTED CORROSION
RESISTANCE
Corrosion resistance
10. Design
Software
5.3.4 HILTI FASTENING SYSTEMS
Zinc coatings can be applied to anchors and fasteners by
different methods. These include (in order of increasing coating
thickness and corrosion protection):
a. ASTM B633 – Standard Specification for Electrodeposited
Coatings of Zinc on Iron and Steel
b. ASTM B695 – Standard Specification for Coatings of Zinc
Mechanically Deposited on Iron and Steel
c. A
STM A153 – Standard Specification for Zinc Coating
(Hot-Dip) on Iron and Steel Hardware
d. Sherardizing Process – Proprietary Diffusion Controlled
Zinc Coating Process
138
8. Reinforcing
Bar Anchorage
An estimating table for the mean corrosion rate and service
life of zinc coatings in various atmospheres is provided to the
right. These values are for reference only, due to the large
variances in the research findings and specific project site
conditions, but they can provide the specifier with a better
understanding of the expected service life of zinc coatings. In
controlled environments where the relative humidity is low and
no corrosive elements are present, the rate of corrosion of zinc
coatings is approximately 0.15 microns per year.
Atmosphere
7. Anchor Channel
Design Code
The most common material used for corrosion protection of
carbon steel fasteners is zinc. Zinc coatings can be uniformly
applied by a variety of methods to achieve a wide range of
coating thickness depending on the application. All things
being equal, thicker coatings typically provide higher levels of
protection.
6. Loading
5.3.3 CORROSION PROTECTION
5. Base material
Often incorrectly referred to as hydrogen embrittlement,
hydrogen assisted stress corrosion cracking (HASCC) is an
environmentally induced failure mechanism that is sometimes
delayed and most times occurs without warning. HASCC occurs
when a hardened steel fastener is stressed (loaded) in a service
environment which chemically generates hydrogen (such as
when zinc and iron combine in the presence of moisture). The
potential for HASCC is directly related to steel hardness. The
higher the fastener hardness, the greater the susceptibility to
stress corrosion cracking failures. Eliminating or reducing any
one of these contributing factors (high steel hardness, corrosion
or stress) reduces the overall potential for this type of failure.
Hydrogen embrittlement, on the other hand, refers to a potential
damaging side effect of the steel fastener manufacturing
process, and is unrelated to project site corrosion. Hydrogen
embrittlement is neutralized by proper processing during
fastener pickling, cleaning and plating operations (specifically,
by “baking” the fasteners after the application of the galvanic
coating).
4. Design
Introduction
Refer to ACI 318-14 Chapter 19 – Durability
Refer to ACI 530.1 Section 2.4F – Coatings for Corrosion Protection
Refer to PCI Parking Structures: Recommended Practice for Design and Construction – Chapters 3, 5 and Appendix
G eneral guidelines address environmental corrosion (direct chemical attack). Additional considerations should be taken into account when using hardened steel fasteners susceptible to
HASCC.
Cast-In Anchor Channel Product Guide, Edition 1 • 02/2019
139