IS 16644:2018 Standard for Stress-Relieved Low Relaxation Steel Wire for Pre-Stressed Concrete outlines specifications for the production, distribution, and examination of cold-drawn steel wires with low relaxation. These wires may be plain, indented, or crimped, serving critical roles in pre-stressed concrete applications.

Below are the classifications for stress-relieved, low relaxation steel wires:

1. Nominal Diameter: 3 mm, 4 mm, 5 mm, 6 mm, 7 mm and 8 mm.

2. Type of Surface configuration:

   • Plain wire

   • Indented wire

   • Crimped wire

3. "Tensile strength are available in megapascals (MPa) at the following levels: 1470, 1570, 1670, 1770, and 1860."

Each nominal diameter and surface configuration of wire must undergo comprehensive testing to ensure compliance with the specific diameter and surface type covered by the license scope. Additionally, if high tensile strength wire is tested, low tensile strength wires may also be encompassed within the license scope.

The company must specify the types of wires included under the License, which may be restricted based on the manufacturer's production and testing capacities. Additionally, steel wire must adhere to the standards' specified requirements

TESTS

The subsequent test must be conducted for Steel Wire.

• Chemical composition

• Dimension and surface configuration

• Tensile strength

• Bending ductility

• Relaxation

LABELLING AND MARKING

Labelling and marking procedures must adhere to the guidelines outlined in IS 16644:2018. Each product must bear the standard mark (ISI mark) if it meets all specifications. To utilize the standard mark (ISI Mark), manufacturers must acquire a BIS license from the Bureau of Indian Standards. This license is granted following a thorough evaluation of manufacturing infrastructure, quality control measures, testing capabilities, and production processes.

PROCESS FOR BIS ISI MARK CERTIFICATION