Section 2 Materials
Clasification Society 2024 - Version 9.40
Clasifications Register Rules and Regulations - Rules and Regulations for the Classification of Ships, July 2022 - Part 5 Main and Auxiliary Machinery - Chapter 6 Main Propulsion Shafting - Section 2 Materials

Section 2 Materials

Parent topic: Chapter 6 Main Propulsion Shafting

2.1 Materials for shafts

2.1.1 The specified minimum tensile strength of forgings for shafts is to be selected within the following general limits:

  1. Carbon and carbon-manganese steel − 400 to 760 N/mm2 (41 to 77,5 kgf/mm2). See also Pt 5, Ch 6, 3.5 Screwshafts and tube shafts 3.5.1.

  2. Alloy steel − not exceeding 800 N/mm2 (82 kgf/mm2).

2.1.2 Where it is proposed to use alloy steel, details of the chemical composition, heat treatment and mechanical properties are to be submitted for approval.

2.1.3 Where shafts may experience vibratory stresses close to the permissible stresses for transient operation, the materials are to have a specified minimum tensile strength of 500 N/mm2 (51 kgf/mm2).

2.1.4 Where materials with greater specified or actual tensile strengths than the limitations given above are used, reduced shaft dimensions or higher permissible vibration stresses are not acceptable when derived from the formulae used in Pt 5, Ch 6, 3.1 Intermediate shafts, Pt 5, Ch 6, 3.5 Screwshafts and tube shafts, Pt 5, Ch 6, 3.6 Hollow shafts and Pt 5, Ch 8, 2.5 Limiting stress in propulsion shafting unless, for intermediate shafts only, it is verified that the materials exhibit a similar fatigue life to conventional steels through compliance with the requirements in Pt 5, Ch 6, 5 Approval of alloy steel used for intermediate shaft material.

2.1.5 Components are to be manufactured and tested in accordance with the requirements of the Rules for the Manufacture, Testing and Certification of Materials, July 2022.

2.2 Ultrasonic tests

2.2.1 Ultrasonic tests are required on shaft forgings where the diameter is 250 mm or greater.

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