The Use of Stainless Steelin the Construction Industry

CI/SfB Xt6

June 2010

2

Ancon designs and manufactures high integrity steel products for

the construction industry. Through continuous programmes of

new product development, inward investment and employee

advancement, the company is committed to maintaining the

highest level of customer service within a dynamic and

challenging industry.

The majority of Ancon products aremanufactured from stainless steel. This materialoffers many advantages to the specifier and itsuse in the Construction Industry continues toincrease. Stainless steel building productsensure a high degree of corrosion resistancewithout requiring additional protection and are100% recyclable at the end of their longservice life.

What is Stainless Steel 4Why Use Stainless Steel 4Types of Stainless Steel 5Material Specification 6Properties and Working Stresses 7Effect of Cold Working 7Bi-Metallic Contact 8Surface Finish 9Relevant British Standards 9Ancon Products 10-11

3

ISO 9001: 2008FM 12226

ISO 14001: 2004EMS 505377

Masonry Support Systems

Windposts and Lintels

Masonry Reinforcement

Wall Ties and Restraint Fixings

Channel and Bolt Fixings

Tension and Compression Systems

Insulated Balcony Connectors

Shear Load Connectors

Punching Shear Reinforcement

Reinforcing Bar Couplers

Reinforcement Continuity Systems

Stainless Steel Fabrications

Flooring and Formed Sections

Refractory Fixings

The Use of Stainless Steel

4

WHAT IS STAINLESS STEEL?Stainless steel is not a single specific material;it is the name given to a group of corrosionresistant steel alloys which contain a minimumof 10.5% chromium.

The chromium in stainless steel reacts withoxygen in the air to produce a very thin, inert,chromium rich oxide film on the surface of thesteel. It is the presence of this film which providesthe corrosion resistance of stainless steel.

This passive film is unlike coatings such aspaint or galvanising in one very important way.If it is damaged by abrasion or mechanicalmeans such as cutting, it re-forms andcontinues to protect the steel.

Life-cycle costing is increasingly recognisedas the true way to establish the cost of buildingcomponents. The use of stainless steel meansno costly remedial or refurbishment measuresare required during the life of the structure.

As the trend to higher specification and longerservice life continues, stainless steel willprovide cost-effective long term solutions tospecifiers’ problems.

RecyclingStainless steel is 100% recyclable. When aproduct finally reaches the end of its longservice life, it remains a valuable source of itsmain alloying elements - chromium, nickel andmolybdenum. These can be easily recoveredand separated from the other materials andreturned to the production process.

Stainless steel recycling is an economicallyviable, self-sustaining process. There areconsiderable savings in energy, and reducedCO2 emissions, in production methods whichuse recycled materials. The amount ofrecycled material in any stainless steel productis typically 60%, and as scrap availability is thelimiting factor, this percentage will increase asthe use of stainless steel continues to grow.The raw material produced today will not berecycled for many years.

In addition to a product’s end-of-life recycling,any scrap material generated during itsmanufacture is recycled in the same way.Ancon recycles 100% of its stainless steelscrap.

WHY USE STAINLESS STEEL?Stainless steel has been used with success bythe construction industry throughout the UKand Europe for over seventy years. Its use hasincreased rapidly in recent times as thebenefits of stainless steel over traditionalmaterials have become more widelyrecognised.

Stainless steel offers many advantages to thespecifier:

• Excellent corrosion resistance

• High ductility and strength

• Non-magnetic (Austenitic only)

• Excellent high and low temperature properties

• Resistance to unsightly staining

• Life-cycle costing benefits

• Aesthetic surface finish

• 60% recycled content

• 100% recyclable

Tel: +44 (0) 114 275 5224 Web: www.ancon.co.uk

5

TYPES OF STAINLESS STEEL

Austenitic Stainless SteelsAustenitic stainless steels offer excellentresistance to corrosion. These high chromiumsteels are ductile and strong. They are non-magnetic and can be readily formed andwelded. Higher strengths can be obtained bycold working, although this makes the metalslightly magnetic and may reduce its corrosionresistance. Austenitic stainless steels are widelyused in the construction, pharmaceutical andchemical industries.

Martensitic Stainless SteelsThe high carbon content of martensitic steels means they can be hardened by heattreatment; ultimate tensile strengths in excessof 2000N/mm2 can be obtained. They aremagnetic and cannot easily be welded.Although they are cheaper than austeniticsteels, their low corrosion resistance limits therange of suitable applications to componentssuch as valves, dies and knife blades.

Ferritic Stainless SteelsFerritic steels are weaker and less ductile thanaustenitic steels. They are magnetic and theirstrength can be increased to a certain extentby cold working. Generally, common ferriticsteels are comparatively cheap but theycannot be welded in thick sections. They havepoorer resistance to pitting, but superiorresistance to stress corrosion cracking thanaustenitics. If appearance is important, theiruse should be restricted to indoor applications.They are used for internal shop-fitting.

Duplex and Super Duplex Stainless SteelsThese steels have a mixed austenitic/ferriticmicrostructure. They are stronger thanaustenitic steels but are not as easily formed.They are magnetic and can be welded; theircorrosion resistance is better than that ofaustenitic steels, particularly their resistance tostress corrosion cracking. Duplex steels areused in the paper, chemical, oil andconstruction industries.

Shearing

Welding

Laser Cutting

Section Forming

Ancon has the capability to fabricate all Austenitic, Duplex and Super Duplex stainless steels.Building products are normally manufactured from Austenitic stainless steels. This material issuitable for the vast majority of applications.

The Use of Stainless Steel

6

MATERIAL SPECIFICATIONThere are many grades of stainless steelresulting in a proliferation of national andinternational specifications. The two maingrades of austenitic stainless steel used in themanufacture of Ancon products are 1.4301(304) and 1.4401 (316).

These grades of stainless steel are adequatefor almost all construction applications,however grades which have even greaterpitting or corrosion resistance can also besupplied. Some products are manufactured ingrade 1.4462 duplex stainless steel.

In recent years, lean duplex grades have beendeveloped to give similar pitting corrosionresistance to standard austenitic grades butwith higher strength and better resistance tostress corrosion cracking e.g. grade 1.4362.

All plate material meets the chemicalcomposition and mechanical propertyrequirements of the new European materialstandard for stainless steel, BS EN 10088.

Please contact Ancon’s Technical ServicesTeam on +44 (0) 114 275 5224 ortech@ancon.co.uk for further advice onselecting the most appropriate grade ofstainless steel for your application. For moregeneral advice, please contact the StainlessSteel Advisory Service, a service provided bythe British Stainless Steel Association, on+44 (0) 114 267 1265 or ssas@bssa.org.uk.

EN 10088 EN 10088Number Name BS 1449

1.4301 X5CrNi 18-10 304S15304S16304S31

1.4306 X2CrNi 19-11 304S111.4401 X5CrNiMo 17-12-2 316S31

316S331.4404 X2CrNiMo 17-12-2 316S111.4432 X2CrNiMo 17-12-3 316S13

1.4462 X2CrNiMoN 22-5-3 -

National and European Specifications for Equivalent Grades of Stainless Steel

Grade 1.4462This is a high strength duplex stainless steelwith a minimum chromium content of 22%, anickel content of 4.5-6.5% and a molybdenumcontent of 2.5-3.5%. It offers superiorcorrosion resistance especially against pittingand crevice corrosion.

Grade 1.4301 (304)This austenitic grade is the most commonlyused and is suitable for a broad range ofconstruction applications. It typically containsalloying elements of at least 18% chromiumand 8-10% nickel. Marginal differences incomposition have no significant effect on thematerial’s excellent all-round corrosion resistance.

Grade 1.4401 (316)This austenitic grade is recommended forhighly corrosive areas such as marine locationsor heavily polluted industrial environments. The addition of a small proportion ofmolybdenum (around 2%) and an increase inthe nickel content to 10-13% provide a morerobust passive film and hence higherresistance to corrosion

Tel: +44 (0) 114 275 5224 Web: www.ancon.co.uk

PROPERTIES AND WORKINGSTRESSESThe behaviour of constructional stainless steelsdiffers from mild steels in that these stainlesssteels do not exhibit a well defined yield pointwhen representative test pieces are submittedto tensile load.

A true yield point is obtained in mild steel whenplastic deformation starts to occur without anyincrease in loading. The stress in the test pieceat the yield point is known as the yield strengthof the material.

Constructional grades of stainless steel showearly plastic deformation in test, but continueto sustain increasing load with increasing strain.In order to characterise the useful design strengthof such materials, proof strengths are usedand are determined as the stress (Rp) at whichplastic extension equals a specified strain. Forstainless steels this is commonly at 0.2% strainand the proof strength for a particular grade ofsteel is based on the (Rp) 0.2% proof stress.

Grade Alloying Elements Applications Minimum Ultimate Elongation Working Stresses0.2% Tensile After Tension

Proof Stress Strength Fracture Compression ShearRp (N/mm2) Rm (N/mm2) (%) (N/mm2) (N/mm2)

1.4301 Chromium- Suitable for rural, urban and light 210 520 - 720 45 140 93(304) nickel steel industrial sites.

(Basic stainless steel) Regular washing down is recommended for exposed architectural features to maintain a good appearance.

1.4306 Low carbon Not suitable for exposure 200 500 - 650 45 133 89(304L) chromium- in heavily polluted

nickel steel industrial or coastal sites.(Lower carbon content Low carbon grade need only beimproves resistance to considered for welded fabricationsintergranular corrosion involving plates thicker thanof thick sections 16-20mm depending on the following welding) welding procedure.

1.4401 Chromium- Suitable for industrial and 220 520 - 670 45 146 97(316) nickel-molybdenum steel coastal sites.

(Molybdenum greatly Tarnishing or staining may improves overall occur; regular washing corrosion resistance down is recommended for and especially exposed architectural features pitting resistance) to maintain a good appearance.

1.4404 Low carbon Low carbon grade need 220 520 - 670 45 146 971.4432 chromium-nickel- only be considered for (316L) molybdenum steel welded fabrications involving

(Lower carbon content plates thicker than 16-20mm improves resistance to depending on the welding intergranular corrosion procedures.of thick sections following welding)

1.4462 Low carbon, high Suitable for applications where 460 640 - 840 25 306 204chromium-nickel- high strength is required ormolybdenum steel, where pitting and crevicewith an austenitic- corrosion are likely to occur.ferritic microstructure

7

Commonly used Grades for Flat Products and their Applications, Properties and Design Stresses

The maximum design stresses are derived fromthe 0.2% proof stress which is factored toensure that the material stresses remain withinthe elastic region of the stress/strain curve.

Strain

Stre

ss

0.2% Plastic Strain

Typical Stress/Strain Curve for Stainless Steel

0.2% Proof Stress (Rp)

Plastic

Elastic

EFFECT OF COLD WORKINGThe working of austenitic stainless steelsignificantly increases the proof strength.Localised cold working arises during theforming of angle and channel sections. The benefits of this cold working are not takeninto account in Ancon’s designs, but provideadditional reserves of strength.

1200

1000

800

600

400

200

0

Stre

ngth

N/m

m2

60

40

20

00 20 40 60

Cold Work %

Effect of Cold Working in Grade 304Stainless Steel

Elon

gatio

n %

Elongation

0.2% ProofStrength

Ultimate TensileStrength

Notes: The properties and design stresses are for hot rolled plate to EN 10088. Ancon is able to use higher stresses in accordance with S.C.I. recommendations in the “StructuralDesign of Stainless Steel”, available from the Steel Construction Institute, Silwood Park, Ascot, Berkshire SL5 7QN (www.steel-sci.org).

Metals

Stainless Steel � � � � � � � �

Mild Steel � � � � � � � �

Aluminium Bronze � � � � � � � �

Phosphor Bronze � � � � � � � �

Copper � � � � � � � �

Cast Iron � � � � � � � �

Aluminium � � � � � � � �

Zinc � � � � � � � �

The Use of Stainless Steel

8

BI-METALLIC CONTACTWhen two dissimilar metals are in contact inthe presence of an electrolyte, bi-metalliccorrosion may occur. This may result in thecorrosion of the base metal while the noblemetal is protected. Where contact is unavoidableand moisture is likely to be present, the twometals should be separated.

The table of recommendations indicates whichmetals may, in certain circumstances, be usedtogether.

The degree of corrosion resulting frombi-metallic contact depends collectively upon:

• The metals in contact

• The environmental conditions

• The time that the contact remains wet or moist

• The relative surface areas of the anodic (carbon steel) and cathodic (stainless steel) metals

Prevention is possible by excluding water fromthe detail (painting or taping over theassembled joint) or by isolating the metals fromeach other (painting the contact surfaces ofthe dissimilar metals or using isolation patches).Isolation around bolted connections can beachieved by non-conductive waterproof gasketsand nylon or Teflon washers and bushes.

Stai

nles

s St

eel

Mild

Ste

el

Alum

iniu

m B

ronz

e

Phos

phor

Bro

nze

Cop

per

Cas

t Iro

n

Alum

iniu

m

Zinc

Key� Can be used in contact under all conditions.� Can be used in contact under dry conditions (i.e. cast-in, or within a cavity above d.p.c. level

except where the cavity is used for free drainage).� Should not be used in contact.

The general behaviour of metals in bi-metalliccontact in rural, urban, industrial and coastalenvironments is fully documented in PD 6484 :Commentary on corrosion at bi-metalliccontacts and its alleviation.

Prevention of Bi-metallic Corrosion

Stainless steel

Mild steelIsolation material

Tel: +44 (0) 114 275 5224 Web: www.ancon.co.uk

9

SURFACE FINISHThe surface finish of stainless steel can vary froma matt descaled finish used for constructionfixings to a bright highly polished finish.

Mill Finishes

• Hot rolled, softened and descaled (normallyused on thicknesses of 4mm, 5mm, 6mm, 8mm and 10mm)

• Cold rolled

• Cold rolled and lightly rolled on polishing rolls

• Bright annealed

Polished Finishes

• Electropolished

• Satin Finish

• Bead Blast

Products supplied by Ancon will usually be inthe hot rolled, softened and pickled mill finish1D to EN 10088 - 2. If a different finish isrequired, please contact Ancon’s TechnicalServices Team.

Where a surface finish is of primaryimportance, pre-production samples should beproduced and agreed.

STANDARDSThe British, European and InternationalStandards in the adjacent table are relevant tothe design of stainless steel constructionproducts.

For copies, please contact the BritishStandards Institution, 389 Chiswick HighRoad, London W4 4AL. Tel: 020 8996 9000.www.bsi-global.com

Standards for Stainless Steel Fixings and Ancillary Building Components

Standard TitleBS EN 845-1: 2003 Specification for ancillary components for masonry. Ties, tension straps, hangers

and brackets

BS EN 845-2: 2003 Specification for ancillary components for masonry. LintelsBS EN 845-3: 2003 Specification for ancillary components for masonry. Bed joint reinforcement of

steel meshworkBS EN 1996-1-1: 2005 Eurocode 6 Design of masonry structures. General rules for reinforced

and unreinforced masonry structuresBS EN 1996-2: 2006 Eurocode 6 Design of masonry structures. Design considerations,

selection of materials and execution of masonryBS EN 1996-3: 2006 Eurocode 6 Design of masonry structures. Simplified calculation methods

for unreinforced masonry structures

BS 5628-1: 2005 Code of practice for the use of masonry. Structural use of unreinforced masonryBS 5628-2: 2005 Code of practice for the use of masonry. Structural use of reinforced and

prestressed masonryBS 5628-3: 2005 Code of practice for the use of masonry. Materials and components, design

and workmanship

BS 8298: 1994 Code of practice for design and installation of natural stone cladding and lining

BS 5268-6.1: 1996 Structural use of timberBS EN ISO 3506-1: 2009 Mechanical properties of corrosion-resistant stainless steel fasteners. Bolts, screws

and studsBS EN ISO 3506-2: 2009 Mechanical properties of corrosion-resistant stainless steel fasteners. NutsBS EN ISO 3506-3: 2009 Mechanical properties of corrosion-resistant stainless steel fasteners. Set screws

and similar fasteners not under tensile stress

BS 6744: 2001 Stainless steel bars for the reinforcement of and use in concrete

The Use of Stainless Steel

10

ANCON BUILDING PRODUCTSAncon has a wealth of experience in workingwith a range of types and grades of stainlesssteel. Products are manufactured from wire,coil, plate and bar. Considerable materialstocks are maintained in order to meet urgentdelivery deadlines.

Technical AdviceThe use of stainless steel offers manyadvantages to the specifier. As a member ofthe British Stainless Steel Association, Anconwill advise on the most appropriate and cost-effective solution to suit individual applications.

Masonry Support and Restraint FixingsAncon fixings for masonry cladding are usuallymanufactured from grade 1.4301 (304)stainless steel which is suitable for mostbuilding applications. In particularly corrosiveenvironments, or where part of the fixing isexposed, grade 1.4401 (316) should beconsidered.

Structures with brick or stone cladding willusually necessitate the use of stainless steelsupport for the masonry. Ancon SupportSystems are fixed to the structural frame, spanthe cavity and form a horizontal shelf in the outerleaf. Ancon Windposts span vertically betweenfloors to provide lateral support for large panelsof brickwork or panels with openings.

The standard range of Ancon Lintels suits themajority of loading conditions found inresidential and commercial buildings. Speciallintels can be manufactured to suitarchitectural features and wall construction notcovered by the standard range.

Wall ties and other restraint fixings are anessential element in the stability of masonrypanels. Prior to 1978 wall ties were usuallymanufactured from galvanised mild steel. Theywere expected to last the lifetime of thebuilding, but some corroded after only 15 yearsleading to a change in the British Standards.The confirmed integrity of stainless steel meanno costly remedial action will be required.

RT2 Wall Tie

MDC Support System with Stirrups

Unilintel

WP3 Windposts

11

Tension SystemsTension Bar Systems are increasingly beingused in structures and buildings as anarchitectural as well as a structural element.A variety of assemblies can be created fromsimple tie bars to complex bracing systemsinvolving several bars joined at one point. TheAncon Tension System is available in carbonand stainless steel. The latter is recommendedfor applications demanding corrosionresistance, a maintenance-free life and wherea highly polished finish is required.

Shear Load ConnectorsAncon Shear Connectors are used to transferload across movement joints in concrete. Eachconnector is a two-part assembly comprising asleeve and a dowel component. The sleeve isnailed to the formwork ensuring subsequentalignment with the dowel. This alignment isessential for effective movement. The dowelsare manufactured from duplex stainless steelto ensure a high degree of corrosion resistancewith no requirement for additional protection.

Floorplate and Open Grid FlooringAncon's stainless steel floorplate and opengrid flooring are ideal for environments wherecorrosion resistance, hygiene, durability andslip resistance are essential. This flooring issuitable for a wide variety of industriesincluding chemical, marine engineering,catering and pharmaceutical. When required,floorplates can be supplied with a polishedsurface finish.

Insulated Balcony ConnectionsAncon Isolan connectors join external concretebalconies to internal floor slabs. Used tominimise cold bridging, these connectorsprovide continuity to the thermal insulation.Standard systems, comprising rigid CFC-freepolystyrene insulation and stainless steel shearreinforcement, suit most depths of cantileverand simply supported balconies.

Corner GuardsAncon Corner Guards protect exposed edges ofcolumns and walls in areas of high traffic, suchas car parks and warehouses. Where aestheticsare important, stainless steel corner guards canbe supplied with a satin-polished surface finish.

Reinforcing BarAncon supplies stainless steel plain and ribbedreinforcing bar direct from stock. Grade 1.4301(304), grade 1.4436 (316) and increasinglyduplex grades are readily available.

Floorplate andOpen Grid Flooring

Tension System

DSD Shear Load Connector

Special FabricationsAncon has the capability to fabricate allAustenitic, Duplex and Super Duplexstainless steels in a plate thickness of up to 30mm. Special fabrications are suppliedto industries such as civil and marineengineering, water treatment, petrochemicaland food handling.

Tel: +44 (0) 114 275 5224 Web: www.ancon.co.uk

Corner Guards

Insulated Balcony Connections

© Ancon Building Products 2010

The construction applications and details provided in this literatureare indicative only. In every case, project working details should beentrusted to appropriately qualified and experienced persons.

Whilst every care has been exercised in the preparation of thisdocument to ensure that any advice, recommendations orinformation is accurate, no liability or responsibility of any kind isaccepted in respect of Ancon Building Products.

With a policy of continuous product development Ancon BuildingProducts reserves the right to modify product design andspecification without due notice.

These products are available from:

Ancon Building ProductsPresident Way, President ParkSheffield S4 7URUnited KingdomTel: +44 (0) 114 275 5224Fax: +44 (0) 114 276 8543Email: info@ancon.co.ukVisit: www.ancon.co.uk

Ancon (Middle East) FZEPO Box 17225Jebel AliDubaiUnited Arab EmiratesTel: +971 (0) 4 883 4346Fax: +971 (0) 4 883 4347Email: info@ancon.aeVisit: www.ancon.ae

Ancon Building Products114 Kurrajong AvenueMount DruittSydneyNSW 2770AustraliaTel: +61 (0) 2 8808 1111Fax: +61 (0) 2 9675 3390Email: info@anconbp.com.auVisit: www.anconbp.com.au

Ancon (Schweiz) AGGewerbezone Widalmi 103216 Ried bei KerzersSwitzerlandTel: +41 (0) 31 750 3030Fax: +41 (0) 31 750 3033 Email: info@ancon.chVisit: www.ancon.ch

Ancon Building Products GesmbHGerspergasse 9/3 Top 1A-1210 ViennaAustriaTel: +43 (0) 1 259 58 62-0Fax: +43 (0) 1 259 58 62-40Email: info@ancon.atVisit: www.ancon.at

Ancon GmbHBartholomäusstrasse 2690489 NurembergGermanyTel: +49 (0) 911 955 1234 0Fax: +49 (0) 911 955 1234 9Email: info@anconbp.deVisit: www.anconbp.de

ISO 9001: 2008FM 12226

ISO 14001: 2004EMS 505377

This brochure is printed on paper produced from 80%recycled post-consumer fibre and 20% virgin pulp which issourced from responsibly managed and sustainable forests(FSC certified). The printing inks and sealant are vegetable-based making the document fully recyclable.