IS 12145:1987

In this competitive scenario, it isn't easy to survive in the market without a standard quality and certified product. BIS license may also be required to sell products in the Indian market.

To get BIS certification and produce a standard quality product, the manufacturer must ensure that their product must follow the specified Indian standard.

Let's take a closer look at IS 12145:1987 for quenched and tempered alloy steel forgings for pressure vessels.

This standard specifies the requirements for quenched and tempered alloy steel forgings for pressure vessels, such as those used in the reactor system. Forgings for vessel closures, flanges, shells, tube sheets, heads, rings, and similar parts are specifically covered in this standard.

According to IS 12145: 1987, forgings are classified into 3 grades: I, II and III based upon chemical composition (C, Mn and Alloy Content (Ni, Cr, Mo)) and Mechanical Properties (YS, TS, Elongation, Impact).

Grades I and II have been subdivided into I A, I B, and II A, II B, with higher YS for B grades. Grade III has the lowest carbon content, the highest alloy content, and the highest YS among the 3 grades.

The general requirements for material supply shall be as specified in the standard. The forgings must be made from killed steel produced by any of the primary processes, such as open hearth, basic oxygen, or electric furnace, and may be followed by secondary steel production processes.

To ensure adequate deformation throughout the sections, forgings must be mechanically hot worked using a suitable process. After hot working, the forgings must be cooled to achieve complete austenite transformation without any detrimental effects such as cracking or distortion.

All forgings shall be heat-treated, which includes quenching and tempering. Following tempering, the forgings must be slowly cooled from the tempering temperature. The finished forgings must be subjected to product analysis. The mechanical properties of the forgings shall be as specified in the standard.


Tests shall be carried out in accordance with the method prescribed in the standard.

  • Chemical composition analysis
  • Mechanical tests
  • Appearance
  • Shapes, dimensions and tolerances
  • Ultrasonic testing


Each forging must be stamped with the grade of material, heat number or identification mark, and the manufacturer's trademark. The standard mark (ISI Mark) may also be applied to the forgings. The Manufacturer must obtain a BIS license from the Bureau of Indian Standards to use a standard mark (ISI Mark). The Bureau grants a license based on a successful assessment of manufacturing infrastructure, production process, and quality control and testing capabilities during a visit to its manufacturing premises.

ALSO READ: BIS QCO for the Steel and Steel Products (Specification for Quenched and Tempered Alloy Steel Forgings for Pressure Vessels)

isi mark


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If a product falls under the scope of the BIS Conformity Assessment Scheme, All the manufacturers, importers, and foreign entities must obtain BIS ISI Certification. The Bureau may cancel the License if the product fails to meet certification requirements.

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