IS 4432:1988 pertains to Case Hardening Steels, outlining the technical delivery specifications for case-hardening wrought low carbon unalloyed and alloyed steel bars, billets, rods, and finished forgings. Typically, these steels are utilized for the fabrication of case-hardened machinery or automobile components.

Case hardening of components involves subjecting them to carburization or carbonitriding on their surface, followed by hardening to achieve a high level of surface hardness, while maintaining relative toughness in the core material.

Material supply must adhere to the guidelines outlined in IS 1387:1967. Unless specified otherwise in the order, manufacturers have the discretion to choose the processes for steel production and product manufacturing, with the condition that the steel is fully killed.

The material should be devoid of any surface or internal imperfections that might hinder the steel's forgeability or negatively impact the mechanical characteristics of the components. The standard outlines the suggested temperature ranges for hot working and heat treatments aimed at regulating hardness, machinability, shearability, and other pertinent properties.

TESTS

The subsequent test must be conducted for Case Hardening Steels.

• Chemical composition

• Hardness test

• Ultrasonic test

• Mechanical properties

• Grain size

• Dimensional tolerances

• Additional tests

MARKING

Each bar must be stamped with the material designation, heat number, and the manufacturer's name or trademark. Additionally, the standard mark (ISI Mark) can be affixed to the material. Manufacturers are required to obtain a BIS license from the Bureau of Indian Standards to use the standard mark. This license is granted after a thorough evaluation of manufacturing infrastructure, production processes, and quality control and testing capabilities during an inspection at the manufacturing premises.

PROCESS FOR BIS ISI MARK CERTIFICATION