Specification of Mechanical Properties for Reinforcing Steel for Use in RCC Structure - IS 16651:2017

IS 16651:2017 ‘High Strength Deformed Stainless Steel Bars and Wires for Concrete Reinforcement ― Specification’

The performance of a reinforced cement concrete (RCC) structure decreases substantially in a corrosive environment. India has a large coastline where chances of chloride induced corrosion in the reinforcing steel used in RCC structure made in the marine type environment of this area, are high. A need was therefore felt to provide options to users, to consider use, in appropriate cases, such material, which in addition to satisfying mechanical properties required for reinforcing steel for use in RCC structure, also provide better corrosion resistance properties than carbon steel. Stainless steel reinforcement bars/wires are one such material which offer these properties.

BIS has therefore formulated the Indian Standard, IS 16651:2017 which covers requirements and methods of test for high strength deformed stainless steel bars/wires of the following strength grades for use as concrete reinforcement:

(a) SS 500, (b) SS 550, (c) SS 600, and (d) SS 650.

This standard covers three categories of stainless steel alloy, namely, austenitic, austenitic-ferritic (duplex) and ferritic.

This standard applies to solid stainless steel bars/wires in which the deformations/ribs have been formed by cold working or hot rolling processes. This standard applies to hot rolled steel without subsequent heat treatment, or to hot rolled steel subsequently annealed and cold worked.

The parameters covered in the standard for the product includes,

a) chemical composition of the ladle and that of the product;

b) surface quality;

c) bond requirements including deformations and surface characteristics;

d) tolerances on dimensions and nominal mass; and

e) mechanical, physical and corrosion resistance properties.

The various tests to be performed for ascertaining mechanical, physical and corrosion resistance properties of stainless steel deformed bars/wires include,

1) tensile test for 0.2 percent proof strength, percentage elongation after fracture, tensile strength and percentage total elongation at maximum force of the steel;

2) bend and rebend test;

3) fatigue test;

4) Charpy impact test; and

5) resistance to inter-granular corrosion test.

The general requirements relating to the supply of material, inspection and testing, and requirements relating to identification and marking of the product are also covered in the standard.

An informative annexure providing guidance on selection and use of stainless steel reinforcement bars, as also their use with carbon steel reinforcement on selective use basis, is also covered in the standard.

The standard is available for purchase at various BIS sales outlet and may also be purchased online at the link www.standardsbis.in.