Properties of Stainless Steel Rebar (grades, standards, properties, ...)

Standards

The main stainless steel rebar standards used today are BS 6744 (UK) [23] and ASTM A955 (USA) [24], although there are others such as  XP135014 (France). Other countries just use the carbon steel standard, sometimes with minor adjustments, such as SIA 262 (Switzerland) or DIN 488(Germany).

Grades

Stainless Steel Type

BS 6744
EN 
Grades

ASTM A955
UNS 
Grades

ASTM A955
Type

 Austenitic with Mn

 -

S24000

XM29

 

 -

S24100

XM28

 Standard Austenitic

1.4301

S30400

304

 

1.4436

 -

    -

 

 -

S31603

316

 

1.4429

S31653

316LN

Duplex 

1.4162

 -

 -

 

1.4362

 -

 -

 

1.4462

S31803

 -

 

1.4501

  -

 -

Super Austenitic 

1.4529

 -

 -

Important notice: Other grades can be sold under CARES approval, of which grade EN 1.4482 (X2CrMnNiMoN21-5-3).

BS 6744
Tensile properties
0.2% Proof Strength Rp0.2
Mpa Min
Stress Ratio Rm/Rp0.2
Min
Elongation at Fracture, %,
Min
Total Elongation at Maximum Force, %
Min
Grade 200 200 1.1 22 5
Grade 500 500 1.1 14 5
Grade 650 650 1.1 14 5

Tensile properties 

ASTM A955
Tensile properties

Grade 40 [280]

Grade 60 [420]

Grade 75 [520]

Yield Strength, Mpa [ksi] Min

280 [40]

420 [50]

520 [75]

Tensile Strength, Mpa [ksi] Min

500 [70]

620 [90]

690 [100]

Elongation, % Min

20

20

20

Stainless steel rebar is  usually selected for the critical parts of the structure. There is no  detrimental effect of  using stainless steel and carbon steel together [25] [26] [27]

Guidance

Standard BS6744 [23] provides advice on the grades of stainless steel suitable for various service conditions:

Table B.1 - Guidance on the use of stainless steel reinforcement for different service conditions

Grade in accordance with BS EN 10088-1

Service condition

 

For structures or components with either a long design life, or which are inaccessible for future maintenance

For structures or components exposed to chloride contamination with no relaxation in durability design (e.g. concrete cover, quality or water proofing treatment requirements)

Reinforcement bridging joints, or penetrating the concrete surface and also subject to chloride contamination (e.g. dowel bars or holding down bolts)

Structures subject to chloride contamination where reductions in normal durability requirements are proposed (e.g. reduced cover, concrete quality or omission of water proofing treatment)

1.4301

1

1

5

3

1.4162

1

1

5

3

1.4436

2

2

1

1

1.4429

2

2

1

1

1.4362

2

2

1

1

1.4462

2

2

1

1

1.4529

4

4

4

4

1.4501

4

4

4

4

Key

1 – Appropriate choice for corrosion resistance and cost

2 – Over-specification of corrosion resistance for the application

3 – May be suitable in some instances: specialist advice should be obtained

4 – Grades suitable for specialist applications which should only be specified after consultation with corrosion specialists.

5 – Unsuitable for the application

Lean Duplex stainless steel grades (4162, 4362) are now increasingly used:

  • They are now readily available
  • In many cases they are the preferred option because they give the best  performance for the capital cost. 

Further reading

Guide for the use of stainless steel reinforcement in concrete structures (published in 2006) [28]
Guidelines For Shipping, Handling, Fabricating & Placement Of Stainless Steel Rebar [29]