Active Standard ASTM A986 / A986M | Developed by Subcommittee: A01.06
Book of Standards Volume: 01.05
Historical (view previous versions of standard)
This test method covers the procedures for the standard practice of performing magnetic particle examination of continuous grain flow crankshaft forgings intended for medium speed diesel engines. Crankshafts shall be divided into four zones of decreasing operational stress, each of which have been designated its own set of acceptance criteria. Zone 1, which consists of the major critical areas, includes the crankpin journals, main bearing journals, and oil holes. Zone 2, which consists of the minor critical areas, includes the balance of the fillet radii of the crankpin and main bearing journals not included in Zone 1. Zone 3, which comprises the journal running surfaces, includes the remainder of the crankpin and main bearing journal surfaces not covered by Zones 1 and 2. Finally, Zone 4 comprises all other remaining areas, including the crankpin web surfaces, and flange faces and periphery. Dimpling technique may be used to remove unwanted visual or magnetic particle indications.
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1.1 This specification covers the magnetic particle examination of forged continuous grain flow (CGF) crankshafts intended for medium speed diesel engines.
1.2 For the purpose of magnetic particle indication assessment, the crankshaft is divided into four zones of decreasing operational stress. Acceptance criteria have been set for each zone.
1.3 The engines to which these crankshafts are fitted are commonly used for diesel electric locomotives, marine propulsion, and power generation. Engines fueled by natural gas also fall into this medium speed category.
1.4 Specification A983/A983M is a product specification that covers the manufacture of CGF crankshafts.
1.5 The values stated in either inch-pound units or SI units are to be regarded separately as standard. Within the text, the SI units are shown in brackets. The values stated in each system are not exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in nonconformance with the specification.
2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.
A788/A788M Specification for Steel Forgings, General Requirements
A966/A966M Practice for Magnetic Particle Examination of Steel Forgings Using Alternating Current
A983/A983M Specification for Continuous Grain Flow Forged Carbon and Alloy Steel Crankshafts for Medium Speed Diesel Engines
ICS Number Code 77.140.85 (Iron and steel forgings)